Update to ruby/mspec@ca2bc42

author: Benoit Daloze <eregontp@gmail.com> 2019-06-27 21:02:33 +0200
committer: Benoit Daloze <eregontp@gmail.com> 2019-06-27 21:02:33 +0200
commit: c940397116c5aef76b1c0d05561c11d43ef596a7 (patch)
tree: df0094c1f2252c9c49b1284414e7e9b0a5a879e8 /spec/ruby/core/integer/to_int_spec.rb
parent: 310a42e89c431f9650c6727f934f35c5e6f9a6cc (diff)
0 files changed, 0 insertions, 0 deletions
diff --git a/.appveyor.yml b/.appveyor.yml
deleted file mode 100644
index c8bf89e0d6..0000000000
--- a/.appveyor.yml
+++ /dev/null
@@ -1,134 +0,0 @@
----
-version: '{build}'
-init:
-  - git config --global user.name git
-  - git config --global user.email svn-admin@ruby-lang.org
-  - git config --global core.autocrlf false
-  - git config --global core.eol lf
-  - git config --global advice.detachedHead 0
-shallow_clone: true
-clone_depth: 10
-platform:
-  - x64
-skip_commits:
-  message: /^\[DOC\]/
-  files:
-    - doc/*
-    - '**/*.md'
-    - '**/*.rdoc'
-environment:
-  ruby_version: "24-%Platform%"
-  zlib_version: "1.2.12"
-  matrix:
-    - build: vs
-      vs: 120
-      ssl: OpenSSL
-      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
-      GEMS_FOR_TEST: ""
-    - build: vs
-      vs: 140
-      ssl: OpenSSL-v111
-      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
-      GEMS_FOR_TEST: ""
-  RELINE_TEST_ENCODING: "UTF-8"
-cache:
-  - c:\Tools\vcpkg\installed\
-for:
--
-  matrix:
-    only:
-      - build: vs
-  install:
-    - ver
-    - chcp
-    - SET BITS=%Platform:x86=32%
-    - SET BITS=%BITS:x=%
-    - SET OPENSSL_DIR=C:\%ssl%-Win%BITS%
-    - cd C:\Tools\vcpkg
-    - git pull -q
-    - .\bootstrap-vcpkg.bat
-    - cd %APPVEYOR_BUILD_FOLDER%
-    - vcpkg --triplet %Platform%-windows install libffi libyaml readline zlib
-    - CALL SET vcvars=%%^VS%VS%COMNTOOLS^%%..\..\VC\vcvarsall.bat
-    - SET vcvars
-    - '"%vcvars%" %Platform:x64=amd64%'
-    - SET ruby_path=C:\Ruby%ruby_version:-x86=%
-    - SET PATH=\usr\local\bin;%ruby_path%\bin;%PATH%;C:\msys64\mingw64\bin;C:\msys64\usr\bin
-    - ruby --version
-    - 'cl'
-    - echo> Makefile srcdir=.
-    - echo>> Makefile MSC_VER=0
-    - echo>> Makefile RT=none
-    - echo>> Makefile RT_VER=0
-    - echo>> Makefile BUILTIN_ENCOBJS=nul
-    - type win32\Makefile.sub >> Makefile
-    - nmake %mflags% up VCSUP="echo Update OK"
-    - nmake %mflags% extract-extlibs
-    - del Makefile
-    - mkdir \usr\local\bin
-    - mkdir \usr\local\include
-    - mkdir \usr\local\lib
-    - SET ZLIB_ZIP=.downloaded-cache\zlib%zlib_version:.=%.zip
-    - if not exist %ZLIB_ZIP% curl -fsSL -o %ZLIB_ZIP% --retry 10 https://zlib.net/zlib%zlib_version:.=%.zip
-    - 7z x -aos -o%APPVEYOR_BUILD_FOLDER%\ext\zlib %ZLIB_ZIP%
-    - for %%I in (%OPENSSL_DIR%\*.dll) do mklink /h \usr\local\bin\%%~nxI %%I
-    - for %%I in (c:\Tools\vcpkg\installed\%Platform%-windows\bin\*.dll) do (
-        if not %%~nI == readline mklink \usr\local\bin\%%~nxI %%I
-      )
-    - attrib +r /s /d
-    - mkdir %Platform%-mswin_%vs%
-  build_script:
-    - cd %APPVEYOR_BUILD_FOLDER%
-    - cd %Platform%-mswin_%vs%
-    - >-
-      ..\win32\configure.bat
-      --with-opt-dir="/usr/local;c:/Tools/vcpkg/installed/%Platform%-windows"
-      --with-openssl-dir=%OPENSSL_DIR:\=/%
-    - nmake -l
-    - nmake install-nodoc
-    - \usr\bin\ruby -v -e "p :locale => Encoding.find('locale'), :filesystem => Encoding.find('filesystem')"
-    - if not "%GEMS_FOR_TEST%" == "" \usr\bin\gem install --no-document %GEMS_FOR_TEST%
-    - \usr\bin\ruby -ropenssl -e "puts 'Build    ' + OpenSSL::OPENSSL_VERSION, 'Runtime  ' + OpenSSL::OPENSSL_LIBRARY_VERSION"
-  test_script:
-    - set /a JOBS=%NUMBER_OF_PROCESSORS%
-    - nmake -l "TESTOPTS=-v -q" btest
-    - nmake -l "TESTOPTS=-v -q" test-basic
-    - >-
-      nmake -l "TESTOPTS=-v --timeout-scale=3.0
-      --excludes=../test/excludes/_appveyor -j%JOBS%
-      --exclude win32ole
-      --exclude test_bignum
-      --exclude test_syntax
-      --exclude test_open-uri
-      --exclude test_bundled_ca
-      " test-all
-    # separately execute tests without -j which may crash worker with -j.
-    - >-
-      nmake -l
-      "TESTOPTS=-v --timeout-scale=3.0 --excludes=../test/excludes/_appveyor"
-      TESTS="
-      ../test/win32ole
-      ../test/ruby/test_bignum.rb
-      ../test/ruby/test_syntax.rb
-      ../test/open-uri/test_open-uri.rb
-      ../test/rubygems/test_bundled_ca.rb
-      " test-all
-    - nmake -l test-spec MSPECOPT=-fs # not using `-j` because sometimes `mspec -j` silently dies on Windows
-notifications:
-  - provider: Webhook
-    method: POST
-    url:
-      secure: CcFlJNDJ/a6to7u3Z4Fnz6dScEPNx7hTha2GkSRlV+1U6dqmxY/7uBcLXYb9gR3jfQk6w+2o/HrjNAyXMNGU/JOka3s2WRI4VKitzM+lQ08owvJIh0R7LxrGH0J2e81U # ruby-lang slack: ruby/simpler-alerts-bot
-    body: >-
-      {{^isPullRequest}}
-        {
-          "ci": "AppVeyor CI",
-          "env": "Visual Studio 2013 / 2015",
-          "url": "{{buildUrl}}",
-          "commit": "{{commitId}}",
-          "branch": "{{branch}}"
-        }
-      {{/isPullRequest}}
-    on_build_success: false
-    on_build_failure: true
-    on_build_status_changed: false
diff --git a/.cirrus.yml b/.cirrus.yml
deleted file mode 100644
index 0cab0023c2..0000000000
--- a/.cirrus.yml
+++ /dev/null
@@ -1,64 +0,0 @@
-# This CI is used to test Arm cases. We can set the maximum 16 tasks.
-# The entire testing design is inspired from .github/workflows/compilers.yml.
-
-# By default, Cirrus mounts an empty volume to `/tmp`
-# which triggers all sorts of warnings like "system temporary path is world-writable: /tmp".
-# Lets workaround it by specifying a custom volume mount point.
-env:
-  CIRRUS_VOLUME: /cirrus-ci-volume
-  LANG: C.UTF-8
-
-task:
-  name: Arm64 Graviton2 / $CC
-  skip: "changesIncludeOnly('doc/**', '**.{md,rdoc}')"
-  arm_container:
-    # We use the arm64 images at https://github.com/ruby/ruby-ci-image/pkgs/container/ruby-ci-image .
-    image: ghcr.io/ruby/ruby-ci-image:$CC
-    # Define the used cpu core in each matrix task. We can use total 16 cpu
-    # cores in entire matrix. [cpu] = [total cpu: 16] / [number of tasks]
-    cpu: 8
-    # We can request maximum 4 GB per cpu.
-    # [memory per task] = [memory per cpu: 4 GB] * [cpu]
-    memory: 32G
-  env:
-    CIRRUS_CLONE_DEPTH: 50
-    optflags: '-O1'
-    debugflags: '-ggdb3'
-    RUBY_PREFIX: /tmp/ruby-prefix
-    RUBY_DEBUG: ci rgengc
-    RUBY_TESTOPTS: >-
-      -q
-      --color=always
-      --tty=no
-    matrix:
-      CC: clang-12
-      CC: gcc-11
-  id_script: id
-  set_env_script:
-    # Set `GNUMAKEFLAGS`, because the flags are GNU make specific. Note using
-    # the `make` environment variable used in compilers.yml causes some rubygems
-    # tests to fail.
-    # https://github.com/rubygems/rubygems/issues/4921
-    - echo "GNUMAKEFLAGS=-s -j$((1 + $CIRRUS_CPU))" >> $CIRRUS_ENV
-  print_env_script:
-    - echo "GNUMAKEFLAGS=$GNUMAKEFLAGS"
-  # Arm containers are executed in AWS's EKS, and it's not yet supporting IPv6
-  # See https://github.com/aws/containers-roadmap/issues/835
-  disable_ipv6_script: sudo ./tool/disable_ipv6.sh
-  autogen_script: ./autogen.sh
-  configure_script: >-
-    ./configure -C
-    --enable-debug-env
-    --disable-install-doc
-    --with-ext=-test-/cxxanyargs,+
-    --prefix="$RUBY_PREFIX"
-  make_extract-extlibs_script: make extract-extlibs
-  make_incs_script: make incs
-  make_script: make
-  make_leaked-globals_script: make leaked-globals
-  make_test_script: make test
-  make_install_script: make install
-  install_gems_for_test_script: $RUBY_PREFIX/bin/gem install --no-doc timezone tzinfo
-  make_test-tool_script: make test-tool
-  make_test-all_script: make test-all
-  make_test-spec_script: make test-spec
diff --git a/.document b/.document
index 6e08f42698..b6dfcdeee0 100644
--- a/.document
+++ b/.document
@@ -15,16 +15,25 @@ array.rb
 ast.rb
 dir.rb
 gc.rb
+hash.rb
 io.rb
 kernel.rb
 marshal.rb
+rjit.rb
 numeric.rb
 nilclass.rb
 pack.rb
 ractor.rb
+string.rb
+symbol.rb
 timev.rb
+thread_sync.rb
 trace_point.rb
 warning.rb
+yjit.rb
+
+# Errno::*
+known_errors.inc
 
 # the lib/ directory (which has its own .document file)
 lib
@@ -40,11 +49,7 @@ README.ja.md
 
 COPYING
 COPYING.ja
-CONTRIBUTING.md
 
 LEGAL
 
-# win32/README.win32 linked from README.md
-win32
-
 doc
diff --git a/.gdbinit b/.gdbinit
index 8979e8b47c..b778305c8d 100644
--- a/.gdbinit
+++ b/.gdbinit
@@ -1,23 +1,7 @@
-set startup-with-shell off
-
-define hook-run
-  set $color_type = 0
-  set $color_highlite = 0
-  set $color_end = 0
-end
-
 define ruby_gdb_init
-  if !$color_type
-    set $color_type = "\033[31m"
-  end
-  if !$color_highlite
-    set $color_highlite = "\033[36m"
-  end
-  if !$color_end
-    set $color_end = "\033[m"
-  end
-  if ruby_dummy_gdb_enums.special_consts
-  end
+  init-if-undefined $color_type = "\033[31m"
+  init-if-undefined $color_highlite = "\033[36m"
+  init-if-undefined $color_end = "\033[m"
 end
 
 # set prompt \033[36m(gdb)\033[m\040
@@ -67,7 +51,7 @@ define rp
     printf "%sT_OBJECT%s: ", $color_type, $color_end
     print ((struct RObject *)($arg0))->basic
     if ($flags & ROBJECT_EMBED)
-      print/x *((VALUE*)((struct RObject*)($arg0))->as.ary) @ (ROBJECT_EMBED_LEN_MAX+0)
+      print/x *((VALUE*)((struct RObject*)($arg0))->as.ary) @ (rb_shape_get_shape($arg0)->capacity)
     else
       print (((struct RObject *)($arg0))->as.heap)
       if (((struct RObject*)($arg0))->as.heap.numiv) > 0
@@ -99,13 +83,11 @@ define rp
     set $regsrc = ((struct RRegexp*)($arg0))->src
     set $rsflags = ((struct RBasic*)$regsrc)->flags
     printf "%sT_REGEXP%s: ", $color_type, $color_end
-    set $len = ($rsflags & RUBY_FL_USER1) ? \
-            ((struct RString*)$regsrc)->as.heap.len : \
-            (($rsflags & (RUBY_FL_USER2|RUBY_FL_USER3|RUBY_FL_USER4|RUBY_FL_USER5|RUBY_FL_USER6)) >> RUBY_FL_USHIFT+2)
+    set $len = ((struct RString*)($arg0))->len
     set print address off
     output *(char *)(($rsflags & RUBY_FL_USER1) ? \
-	    ((struct RString*)$regsrc)->as.heap.ptr : \
-	    ((struct RString*)$regsrc)->as.ary) @ $len
+            ((struct RString*)$regsrc)->as.heap.ptr : \
+            ((struct RString*)$regsrc)->as.embed.ary) @ $len
     set print address on
     printf " len:%ld ", $len
     if $flags & RUBY_FL_USER6
@@ -126,26 +108,26 @@ define rp
       printf "%sT_ARRAY%s: len=%ld ", $color_type, $color_end, $len
       printf "(embed) "
       if ($len == 0)
-	printf "{(empty)} "
+        printf "{(empty)} "
       else
-	print/x *((VALUE*)((struct RArray*)($arg0))->as.ary) @ $len
-	printf " "
+        print/x *((VALUE*)((struct RArray*)($arg0))->as.ary) @ $len
+        printf " "
       end
     else
       set $len = ((struct RArray*)($arg0))->as.heap.len
       printf "%sT_ARRAY%s: len=%ld ", $color_type, $color_end, $len
       if ($flags & RUBY_FL_USER2)
-	printf "(shared) shared="
-	output/x ((struct RArray*)($arg0))->as.heap.aux.shared_root
-	printf " "
+        printf "(shared) shared="
+        output/x ((struct RArray*)($arg0))->as.heap.aux.shared_root
+        printf " "
       else
-	printf "(ownership) capa=%ld ", ((struct RArray*)($arg0))->as.heap.aux.capa
+        printf "(ownership) capa=%ld ", ((struct RArray*)($arg0))->as.heap.aux.capa
       end
       if ($len == 0)
-	printf "{(empty)} "
+        printf "{(empty)} "
       else
-	print/x *((VALUE*)((struct RArray*)($arg0))->as.heap.ptr) @ $len
-	printf " "
+        print/x *((VALUE*)((struct RArray*)($arg0))->as.heap.ptr) @ $len
+        printf " "
       end
     end
     print (struct RArray *)($arg0)
@@ -440,13 +422,11 @@ end
 
 define output_string
   set $flags = ((struct RBasic*)($arg0))->flags
-  set $len = ($flags & RUBY_FL_USER1) ? \
-          ((struct RString*)($arg0))->as.heap.len : \
-          (($flags & (RUBY_FL_USER2|RUBY_FL_USER3|RUBY_FL_USER4|RUBY_FL_USER5|RUBY_FL_USER6)) >> RUBY_FL_USHIFT+2)
+  set $len = ((struct RString*)($arg0))->len
   if $len > 0
     output *(char *)(($flags & RUBY_FL_USER1) ? \
-	    ((struct RString*)($arg0))->as.heap.ptr : \
-	    ((struct RString*)($arg0))->as.ary) @ $len
+            ((struct RString*)($arg0))->as.heap.ptr : \
+            ((struct RString*)($arg0))->as.embed.ary) @ $len
   else
     output ""
   end
@@ -454,13 +434,11 @@ end
 
 define print_string
   set $flags = ((struct RBasic*)($arg0))->flags
-  set $len = ($flags & RUBY_FL_USER1) ? \
-          ((struct RString*)($arg0))->as.heap.len : \
-          (($flags & (RUBY_FL_USER2|RUBY_FL_USER3|RUBY_FL_USER4|RUBY_FL_USER5|RUBY_FL_USER6)) >> RUBY_FL_USHIFT+2)
+  set $len = ((struct RString*)($arg0))->len
   if $len > 0
     printf "%s", *(char *)(($flags & RUBY_FL_USER1) ? \
-	    ((struct RString*)($arg0))->as.heap.ptr : \
-	    ((struct RString*)($arg0))->as.ary) @ $len
+            ((struct RString*)($arg0))->as.heap.ptr : \
+            ((struct RString*)($arg0))->as.embed.ary) @ $len
   end
 end
 
@@ -544,13 +522,13 @@ end
 
 define rp_class
   printf "(struct RClass *) %p", (void*)$arg0
-  if ((struct RClass *)($arg0))->ptr.origin_ != $arg0
-    printf " -> %p", ((struct RClass *)($arg0))->ptr.origin_
+  if RCLASS_ORIGIN((struct RClass *)($arg0)) != $arg0
+    printf " -> %p", RCLASS_ORIGIN((struct RClass *)($arg0))
   end
   printf "\n"
   rb_classname $arg0
   print/x *(struct RClass *)($arg0)
-  print *((struct RClass *)($arg0))->ptr
+  print *RCLASS_EXT((struct RClass *)($arg0))
 end
 document rp_class
   Print the content of a Class/Module.
@@ -689,11 +667,6 @@ define nd_stts
 end
 
 
-define nd_entry
-  printf "%su3.entry%s: ", $color_highlite, $color_end
-  p ($arg0).u3.entry
-end
-
 define nd_vid
   printf "%su1.id%s: ", $color_highlite, $color_end
   p ($arg0).u1.id
@@ -868,22 +841,22 @@ define rb_numtable_entry
     set $rb_numtable_p = $rb_numtable_tbl->as.packed.bins
     while $rb_numtable_p && $rb_numtable_p < $rb_numtable_tbl->as.packed.bins+$rb_numtable_tbl->num_entries
       if $rb_numtable_p.k == $rb_numtable_id
-	set $rb_numtable_key = $rb_numtable_p.k
-	set $rb_numtable_rec = $rb_numtable_p.v
-	set $rb_numtable_p = 0
+        set $rb_numtable_key = $rb_numtable_p.k
+        set $rb_numtable_rec = $rb_numtable_p.v
+        set $rb_numtable_p = 0
       else
-	set $rb_numtable_p = $rb_numtable_p + 1
+        set $rb_numtable_p = $rb_numtable_p + 1
       end
     end
   else
     set $rb_numtable_p = $rb_numtable_tbl->as.big.bins[st_numhash($rb_numtable_id) % $rb_numtable_tbl->num_bins]
     while $rb_numtable_p
       if $rb_numtable_p->key == $rb_numtable_id
-	set $rb_numtable_key = $rb_numtable_p->key
-	set $rb_numtable_rec = $rb_numtable_p->record
-	set $rb_numtable_p = 0
+        set $rb_numtable_key = $rb_numtable_p->key
+        set $rb_numtable_rec = $rb_numtable_p->record
+        set $rb_numtable_p = 0
       else
-	set $rb_numtable_p = $rb_numtable_p->next
+        set $rb_numtable_p = $rb_numtable_p->next
       end
     end
   end
@@ -961,7 +934,7 @@ define iseq
       set $operand_size = ((INSN*)($arg0))->operand_size
       set $operands = ((INSN*)($arg0))->operands
       while $i < $operand_size
-	rp $operands[$i++]
+        rp $operands[$i++]
       end
     end
   end
@@ -979,8 +952,8 @@ end
 
 define rb_ps_vm
   print $ps_vm = (rb_vm_t*)$arg0
-  set $ps_thread_ln = $ps_vm->living_threads.n.next
-  set $ps_thread_ln_last = $ps_vm->living_threads.n.prev
+  set $ps_thread_ln      = $ps_vm->ractor.main_ractor.threads.set.n.next
+  set $ps_thread_ln_last = $ps_vm->ractor.main_ractor.threads.set.n.prev
   while 1
     set $ps_thread_th = (rb_thread_t *)$ps_thread_ln
     set $ps_thread = (VALUE)($ps_thread_th->self)
@@ -1131,7 +1104,7 @@ define rb_ps_thread
   set $ps_thread = (struct RTypedData*)$arg0
   set $ps_thread_th = (rb_thread_t*)$ps_thread->data
   printf "* #<Thread:%p rb_thread_t:%p native_thread:%p>\n", \
-    $ps_thread, $ps_thread_th, $ps_thread_th->thread_id
+    $ps_thread, $ps_thread_th, $ps_thread_th->nt
   set $cfp = $ps_thread_th->ec->cfp
   set $cfpend = (rb_control_frame_t *)($ps_thread_th->ec->vm_stack + $ps_thread_th->ec->vm_stack_size)-1
   while $cfp < $cfpend
@@ -1279,9 +1252,9 @@ document rb_count_objects
   Counts all objects grouped by type.
 end
 
-# Details: https://bugs.ruby-lang.org/projects/ruby-master/wiki/MachineInstructionsTraceWithGDB
+# Details: https://github.com/ruby/ruby/wiki/Machine-Instructions-Trace-with-GDB
 define trace_machine_instructions
-  set logging on
+  set logging enabled
   set height 0
   set width 0
   display/i $pc
@@ -1316,7 +1289,7 @@ define dump_node
   set $flags = ((struct RBasic*)($str))->flags
   printf "%s", (char *)(($flags & RUBY_FL_USER1) ? \
                         ((struct RString*)$str)->as.heap.ptr : \
-                        ((struct RString*)$str)->as.ary)
+                        ((struct RString*)$str)->as.embed.ary)
 end
 
 define print_flags
@@ -1348,3 +1321,8 @@ define print_flags
   printf "RUBY_FL_USER17      : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_USER17 ? "1" : "0"
   printf "RUBY_FL_USER18      : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_USER18 ? "1" : "0"
 end
+
+source -s misc/gdb.py
+
+# Moved from beginning, since it fails on older gdbs
+set startup-with-shell off
diff --git a/.git-blame-ignore-revs b/.git-blame-ignore-revs
new file mode 100644
index 0000000000..de62eb432a
--- /dev/null
+++ b/.git-blame-ignore-revs
@@ -0,0 +1,36 @@
+# This is a file used by GitHub to ignore the following commits on `git blame`.
+#
+# You can also do the same thing in your local repository with:
+# $ git config --local blame.ignoreRevsFile .git-blame-ignore-revs
+
+# Expand tabs
+5b21e94bebed90180d8ff63dad03b8b948361089
+c5e9af9c9d890578182a21e7b71b50334cd5579e
+e63a2115f64433b21cb5dd67c5bf8b30f87ef293
+712ac99e4d0384a941c80a9f48f62943ba7d97c0
+d1474affa8e105bece209cc9d594bb0a989859e1
+2da92388b948821269b18d6b178a680f17e41750
+
+# Enable Style/StringLiterals cop for RubyGems/Bundler
+d7ffd3fea402239b16833cc434404a7af82d44f3
+
+# [ruby/digest] Revert tab-expansion in external files
+48b09aae7ec5632209229dcc294dd0d75a93a17f
+8a65cf3b61c60e4cb886f59a73ff6db44364bfa9
+39dc9f9093901d40d2998653948d5da38b18ee2c
+
+# [ruby/io-nonblock] Revert tab expansion
+f28287d34c03f472ffe90ea262bdde9affd4b965
+0d842fecb4f75ab3b1d4097ebdb8e88f51558041
+4ba2c66761d6a293abdfba409241d31063cefd62
+
+# Make benchmark indentation consistent
+fc4acf8cae82e5196186d3278d831f2438479d91
+
+# Make prism_compile.c indentation consistent
+40b2c8e5e7e6e5f83cee9276dc9c1922a69292d6
+d2c5867357ed88eccc28c2b3bd4a46e206e7ff85
+
+# Miss-and-revived commits
+a0f7de814ae5c299d6ce99bed5fb308a05d50ba0
+d4e24021d39e1f80f0055b55d91f8d5f22e15084
diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
deleted file mode 100644
index 15abc79af6..0000000000
--- a/.github/CODEOWNERS
+++ /dev/null
@@ -1,10 +0,0 @@
-# Lines starting with '#' are comments.
-# Each line is a file pattern followed by one or more owners.
-# Code owners will be automatically tagged as reviewers when a pull request is opened
-
-# YJIT sources and tests
-yjit* @maximecb @xrxr @tenderlove
-doc/yjit/* @maximecb @xrxr @tenderlove
-bootstraptest/test_yjit* @maximecb @xrxr @tenderlove
-test/ruby/test_yjit* @maximecb @xrxr @tenderlove
-.github/workflows/yjit* @maximecb @xrxr @tenderlove
diff --git a/.github/actions/compilers/action.yml b/.github/actions/compilers/action.yml
new file mode 100644
index 0000000000..ff060ce2e0
--- /dev/null
+++ b/.github/actions/compilers/action.yml
@@ -0,0 +1,125 @@
+name: Compiles ruby in a container
+description: >-
+  Makes ruby using a dedicated container
+
+inputs:
+  tag:
+    required: false
+    default: clang-18
+    description: >-
+      container image tag to use in this run.
+
+  with_gcc:
+    required: false
+    description: >-
+      override compiler path & flags.
+
+  CFLAGS:
+    required: false
+    description: >-
+      C compiler flags to override.
+
+  CXXFLAGS:
+    required: false
+    description: >-
+      C++ compiler flags to override.
+
+  optflags:
+    required: false
+    # -O1 is faster than -O3 in our tests... Majority of time are consumed trying
+    # to optimize binaries.  Also GitHub Actions run on relatively modern CPUs
+    # compared to, say, GCC 4 or Clang 3.  We don't specify `-march=native`
+    # because compilers tend not understand what the CPU is.
+    default: '-O1'
+    description: >-
+      Compiler flags for optimisations.
+
+  cppflags:
+    required: false
+    description: >-
+      Additional preprocessor flags.
+
+  append_configure:
+    required: false
+    default: >-
+      --without-valgrind
+      --without-jemalloc
+      --without-gmp
+    description: >-
+      flags to append to configure.
+
+  enable_shared:
+    required: false
+    default: true
+    description: >-
+      Whether to build libruby.so.
+
+  check:
+    required: false
+    default: ''
+    description: >-
+      Whether to run `make check`
+
+  mspecopt:
+    required: false
+    default: ''
+    description: >-
+      Additional options for mspec.
+
+  static_exts:
+    required: false
+    description: >-
+      whitespace separated list of extensions that need be linked statically.
+
+runs:
+  using: composite
+  steps:
+    - shell: bash
+      run: docker pull --quiet 'ghcr.io/ruby/ruby-ci-image:${{ inputs.tag }}'
+
+    - name: Enable Launchable conditionally
+      id: enable-launchable
+      run: echo "enable-launchable=true" >> $GITHUB_OUTPUT
+      shell: bash
+      if: >-
+        ${{
+        github.repository == 'ruby/ruby' ||
+        (github.repository != 'ruby/ruby' && env.LAUNCHABLE_TOKEN)
+        }}
+
+    - name: compile
+      shell: bash
+      run: >-
+        docker run
+        --rm
+        --user=root
+        --volume '${{ github.workspace }}:/github/workspace:ro'
+        --workdir=/github/workspace
+        --entrypoint=/github/workspace/.github/actions/compilers/entrypoint.sh
+        --env CI
+        --env GITHUB_ACTION
+        --env INPUT_WITH_GCC='${{ inputs.with_gcc || inputs.tag }}'
+        --env INPUT_CFLAGS='${{ inputs.CFLAGS }}'
+        --env INPUT_CXXFLAGS='${{ inputs.CXXFLAGS }}'
+        --env INPUT_OPTFLAGS='${{ inputs.OPTFLAGS }}'
+        --env INPUT_CPPFLAGS='${{ inputs.cppflags }}'
+        --env INPUT_APPEND_CONFIGURE='${{ inputs.append_configure }}'
+        --env INPUT_CHECK='${{ inputs.check }}'
+        --env INPUT_MSPECOPT='${{ inputs.mspecopt }}'
+        --env INPUT_ENABLE_SHARED='${{ inputs.enable_shared }}'
+        --env INPUT_STATIC_EXTS='${{ inputs.static_exts }}'
+        --env LAUNCHABLE_ORGANIZATION='${{ github.repository_owner }}'
+        --env LAUNCHABLE_WORKSPACE='${{ github.event.repository.name }}'
+        --env LAUNCHABLE_ENABLED='${{ steps.enable-launchable.outputs.enable-launchable || false }}'
+        --env GITHUB_PR_HEAD_SHA='${{ github.event.pull_request.head.sha || github.sha }}'
+        --env GITHUB_PULL_REQUEST_URL='${{ github.event.pull_request.html_url }}'
+        --env GITHUB_REF='${{ github.ref }}'
+        --env GITHUB_ACTIONS
+        --env GITHUB_RUN_ID
+        --env GITHUB_REPOSITORY
+        --env GITHUB_WORKFLOW
+        --env GITHUB_RUN_NUMBER
+        --env GITHUB_EVENT_NAME
+        --env GITHUB_SHA
+        --env GITHUB_HEAD_REF
+        'ghcr.io/ruby/ruby-ci-image:${{ inputs.tag }}'
diff --git a/.github/actions/compilers/entrypoint.sh b/.github/actions/compilers/entrypoint.sh
new file mode 100755
index 0000000000..cc8e6e4b23
--- /dev/null
+++ b/.github/actions/compilers/entrypoint.sh
@@ -0,0 +1,164 @@
+#! /bin/bash
+
+# Copyright (c) 2024 Ruby developers.  All rights reserved.
+#
+# This file is  a part of the programming language  Ruby.  Permission is hereby
+# granted, to  either redistribute and/or  modify this file, provided  that the
+# conditions  mentioned in  the file  COPYING are  met.  Consult  the file  for
+# details.
+
+grouped()
+{
+    echo "::group::${@}"
+    "${@}"
+    echo "::endgroup::"
+}
+
+set -e
+set -u
+set -o pipefail
+
+srcdir="/github/workspace/src"
+builddir="$(mktemp -dt)"
+
+export GITHUB_WORKFLOW='Compilations'
+export CONFIGURE_TTY='never'
+export RUBY_DEBUG='ci rgengc'
+export RUBY_TESTOPTS='-q --color=always --tty=no'
+export RUBY_DEBUG_COUNTER_DISABLE='1'
+export GNUMAKEFLAGS="-j$((1 + $(nproc --all)))"
+
+case "x${INPUT_ENABLE_SHARED}" in
+x | xno | xfalse )
+    enable_shared='--disable-shared'
+    ;;
+*)
+    enable_shared='--enable-shared'
+    ;;
+esac
+
+pushd ${builddir}
+
+grouped git config --global --add safe.directory ${srcdir}
+
+grouped ${srcdir}/configure        \
+    -C                             \
+    --with-gcc="${INPUT_WITH_GCC}" \
+    --enable-debug-env             \
+    --disable-install-doc          \
+    --with-ext=-test-/cxxanyargs,+ \
+    ${enable_shared}               \
+    ${INPUT_APPEND_CONFIGURE}      \
+    CFLAGS="${INPUT_CFLAGS}"       \
+    CXXFLAGS="${INPUT_CXXFLAGS}"   \
+    optflags="${INPUT_OPTFLAGS}"   \
+    cppflags="${INPUT_CPPFLAGS}"   \
+    debugflags='-ggdb3' # -g0 disables backtraces when SEGV.  Do not set that.
+
+popd
+
+if [[ -n "${INPUT_STATIC_EXTS}" ]]; then
+    echo "::group::ext/Setup"
+    set -x
+    mkdir ${builddir}/ext
+    (
+        for ext in ${INPUT_STATIC_EXTS}; do
+            echo "${ext}"
+        done
+    ) >> ${builddir}/ext/Setup
+    set +x
+    echo "::endgroup::"
+fi
+
+btests=''
+tests=''
+spec_opts=''
+
+# Launchable
+setup_launchable() {
+    pushd ${srcdir}
+    # Launchable creates .launchable file in the current directory, but cannot a file to ${srcdir} directory.
+    # As a workaround, we set LAUNCHABLE_SESSION_DIR to ${builddir}.
+    export LAUNCHABLE_SESSION_DIR=${builddir}
+    local github_ref="${GITHUB_REF//\//_}"
+    local build_name="${github_ref}"_"${GITHUB_PR_HEAD_SHA}"
+    btest_report_path='launchable_bootstraptest.json'
+    test_report_path='launchable_test_all.json'
+    test_spec_report_path='launchable_test_spec_report'
+    test_all_session_file='launchable_test_all_session.txt'
+    btest_session_file='launchable_btest_session.txt'
+    test_spec_session_file='launchable_test_spec_session.txt'
+    btests+=--launchable-test-reports="${btest_report_path}"
+    echo "::group::Setup Launchable"
+    launchable record build --name "${build_name}" || true
+    launchable record session \
+        --build "${build_name}" \
+        --flavor test_task=test \
+        --flavor workflow=Compilations \
+        --flavor with-gcc="${INPUT_WITH_GCC}" \
+        --flavor CFLAGS="${INPUT_CFLAGS}" \
+        --flavor CXXFLAGS="${INPUT_CXXFLAGS}" \
+        --flavor optflags="${INPUT_OPTFLAGS}" \
+        --flavor cppflags="${INPUT_CPPFLAGS}" \
+        --test-suite btest \
+        > "${builddir}"/${btest_session_file}
+    if [ "$INPUT_CHECK" = "true" ]; then
+        tests+=--launchable-test-reports="${test_report_path}"
+        launchable record session \
+            --build "${build_name}" \
+            --flavor test_task=test-all \
+            --flavor workflow=Compilations \
+            --flavor with-gcc="${INPUT_WITH_GCC}" \
+            --flavor CFLAGS="${INPUT_CFLAGS}" \
+            --flavor CXXFLAGS="${INPUT_CXXFLAGS}" \
+            --flavor optflags="${INPUT_OPTFLAGS}" \
+            --flavor cppflags="${INPUT_CPPFLAGS}" \
+            --test-suite test-all \
+            > "${builddir}"/${test_all_session_file}
+        mkdir "${builddir}"/"${test_spec_report_path}"
+        spec_opts+=--launchable-test-reports="${test_spec_report_path}"
+        launchable record session \
+            --build "${build_name}" \
+            --flavor test_task=test-spec \
+            --flavor workflow=Compilations \
+            --flavor with-gcc="${INPUT_WITH_GCC}" \
+            --flavor CFLAGS="${INPUT_CFLAGS}" \
+            --flavor CXXFLAGS="${INPUT_CXXFLAGS}" \
+            --flavor optflags="${INPUT_OPTFLAGS}" \
+            --flavor cppflags="${INPUT_CPPFLAGS}" \
+            --test-suite test-spec \
+            > "${builddir}"/${test_spec_session_file}
+    fi
+    echo "::endgroup::"
+    trap launchable_record_test EXIT
+}
+launchable_record_test() {
+    pushd "${builddir}"
+    grouped launchable record tests --session "$(cat "${btest_session_file}")" raw "${btest_report_path}" || true
+    if [ "$INPUT_CHECK" = "true" ]; then
+        grouped launchable record tests --session "$(cat "${test_all_session_file}")" raw "${test_report_path}" || true
+        grouped launchable record tests --session "$(cat "${test_spec_session_file}")" raw "${test_spec_report_path}"/* || true
+    fi
+}
+if [ "$LAUNCHABLE_ENABLED" = "true" ]; then
+    setup_launchable
+fi
+
+pushd ${builddir}
+
+grouped make showflags
+grouped make all
+grouped make test BTESTS="${btests}"
+
+[[ -z "${INPUT_CHECK}" ]] && exit 0
+
+if [ "$INPUT_CHECK" = "true" ]; then
+  tests+=" -- ruby -ext-"
+else
+  tests+=" -- $INPUT_CHECK"
+fi
+
+# grouped make install
+grouped make test-tool
+grouped make test-all TESTS="$tests"
+grouped env CHECK_LEAKS=true make test-spec MSPECOPT="$INPUT_MSPECOPT" SPECOPTS="${spec_opts}"
diff --git a/.github/actions/launchable/setup/action.yml b/.github/actions/launchable/setup/action.yml
new file mode 100644
index 0000000000..164eb1db5d
--- /dev/null
+++ b/.github/actions/launchable/setup/action.yml
@@ -0,0 +1,274 @@
+name: Set up Launchable
+description: >-
+  Install the required dependencies and execute the necessary Launchable commands for test recording
+
+inputs:
+  os:
+    required: true
+    description: The operating system that CI runs on. This value is used in Launchable flavor.
+
+  test-opts:
+    default: none
+    required: false
+    description: >-
+      Test options that determine how tests are run.
+      This value is used in the Launchable flavor.
+
+  launchable-token:
+    required: false
+    description: >-
+      Launchable token is needed if you want to run Launchable on your forked repository.
+      See https://github.com/ruby/ruby/wiki/CI-Servers#launchable-ci for details.
+
+  builddir:
+    required: false
+    default: ${{ github.workspace }}
+    description: >-
+      Directory to create Launchable report file.
+
+  srcdir:
+    required: false
+    default: ${{ github.workspace }}
+    description: >-
+      Directory to (re-)checkout source codes. Launchable retrieves the commit information
+      from the directory.
+
+  test-task:
+    required: false
+    default: ${{ matrix.test_task }}
+    description: >-
+      Specifies a single test task to be executed.
+      This value is used in the Launchable flavor.
+      Either 'test-task' or 'multi-test-tasks' must be configured.
+
+  test-tasks:
+    required: false
+    default: '[]'
+    description: >-
+      Specifies an array of multiple test tasks to be executed.
+      For example: '["test", "test-all"]'.
+      If you want to run a single test task, use the 'test-task' input instead.
+
+  is-yjit:
+    required: false
+    default: 'false'
+    description: >-
+      Whether this workflow is executed on YJIT.
+
+runs:
+  using: composite
+
+  steps:
+    - name: Enable Launchable conditionally
+      id: enable-launchable
+      run: echo "enable-launchable=true" >> $GITHUB_OUTPUT
+      shell: bash
+      if: >-
+        ${{
+        (github.repository == 'ruby/ruby'
+          || (github.repository != 'ruby/ruby'
+          && env.LAUNCHABLE_TOKEN))
+        && (inputs.test-task == 'check'
+          || inputs.test-task == 'test-all'
+          || inputs.test-task == 'test'
+          || contains(fromJSON(inputs.test-tasks), 'test-all')
+          || contains(fromJSON(inputs.test-tasks), 'test'))
+        }}
+
+    # Launchable CLI requires Python and Java.
+    # https://www.launchableinc.com/docs/resources/cli-reference/
+    - name: Set up Python
+      uses: actions/setup-python@871daa956ca9ea99f3c3e30acb424b7960676734 # v5.0.0
+      with:
+        python-version: "3.x"
+      if: steps.enable-launchable.outputs.enable-launchable
+
+    - name: Set up Java
+      uses: actions/setup-java@7a445ee88d4e23b52c33fdc7601e40278616c7f8 # v4.0.0
+      with:
+        distribution: 'temurin'
+        java-version: '17'
+      if: steps.enable-launchable.outputs.enable-launchable
+
+    - name: Set global vars
+      id: global
+      shell: bash
+      run: |
+        test_all_enabled="${{ inputs.test-task == 'check' ||  inputs.test-task == 'test-all' || contains(fromJSON(inputs.test-tasks), 'test-all') }}"
+        btest_enabled="${{ inputs.test-task == 'check' ||  inputs.test-task == 'test' || contains(fromJSON(inputs.test-tasks), 'test') }}"
+        test_spec_enabled="${{ inputs.test-task == 'check' ||  inputs.test-task == 'test-spec' || contains(fromJSON(inputs.test-tasks), 'test-spec') }}"
+        echo test_all_enabled="${test_all_enabled}" >> $GITHUB_OUTPUT
+        echo btest_enabled="${btest_enabled}" >> $GITHUB_OUTPUT
+        echo test_spec_enabled="${test_spec_enabled}" >> $GITHUB_OUTPUT
+        echo test_all_session_file='launchable_test_all_session.txt' >> $GITHUB_OUTPUT
+        echo btest_session_file='launchable_btest_session.txt' >> $GITHUB_OUTPUT
+        echo test_spec_session_file='launchable_test_spec_session.txt' >> $GITHUB_OUTPUT
+        echo test_all_report_file='launchable_test_all_report.json' >> $GITHUB_OUTPUT
+        echo btest_report_file='launchable_btest_report.json' >> $GITHUB_OUTPUT
+        echo test_spec_report_dir='launchable_test_spec_report' >> $GITHUB_OUTPUT
+      if: steps.enable-launchable.outputs.enable-launchable
+
+    - name: Set environment variables for Launchable
+      shell: bash
+      run: |
+        : # GITHUB_PULL_REQUEST_URL are used for commenting test reports in Launchable Github App.
+        : # https://github.com/launchableinc/cli/blob/v1.80.1/launchable/utils/link.py#L42
+        echo "GITHUB_PULL_REQUEST_URL=${{ github.event.pull_request.html_url }}" >> $GITHUB_ENV
+        : # The following envs are necessary in Launchable tokenless authentication.
+        : # https://github.com/launchableinc/cli/blob/v1.80.1/launchable/utils/authentication.py#L20
+        echo "LAUNCHABLE_ORGANIZATION=${{ github.repository_owner }}" >> $GITHUB_ENV
+        echo "LAUNCHABLE_WORKSPACE=${{ github.event.repository.name }}" >> $GITHUB_ENV
+        : # https://github.com/launchableinc/cli/blob/v1.80.1/launchable/utils/authentication.py#L71
+        echo "GITHUB_PR_HEAD_SHA=${{ github.event.pull_request.head.sha || github.sha }}" >> $GITHUB_ENV
+        echo "LAUNCHABLE_TOKEN=${{ inputs.launchable-token }}" >> $GITHUB_ENV
+      if: steps.enable-launchable.outputs.enable-launchable
+
+    - name: Set up path
+      shell: bash
+      working-directory: ${{ inputs.srcdir }}
+      # Since updated PATH variable will be available in only subsequent actions, we need to add the path beforehand.
+      # https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#adding-a-system-path
+      run: echo "$(python -msite --user-base)/bin" >> $GITHUB_PATH
+      if: steps.enable-launchable.outputs.enable-launchable && startsWith(inputs.os, 'macos')
+
+    - name: Set up Launchable
+      shell: bash
+      working-directory: ${{ inputs.srcdir }}
+      run: |
+        set -x
+        pip install --user launchable
+        : # The build name cannot include a slash, so we replace the string here.
+        github_ref="${{ github.ref }}"
+        github_ref="${github_ref//\//_}"
+        : # With the --name option, we need to configure a unique identifier for this build.
+        : # To avoid setting the same build name as the CI which runs on other branches, we use the branch name here.
+        build_name="${github_ref}_${GITHUB_PR_HEAD_SHA}"
+        test_opts="${{ inputs.test-opts }}"
+        test_opts="${test_opts// /}"
+        test_opts="${test_opts//=/:}"
+        test_all_test_suite='test-all'
+        btest_test_suite='btest'
+        test_spec_test_suite='test-spec'
+        if [ "${{ inputs.is-yjit }}" = "true" ]; then
+          test_all_test_suite="yjit-${test_all_test_suite}"
+          btest_test_suite="yjit-${btest_test_suite}"
+          test_spec_test_suite="yjit-${test_spec_test_suite}"
+        fi
+        launchable record build --name "${build_name}"
+        if [ "${test_all_enabled}" = "true" ]; then
+          launchable record session \
+            --build "${build_name}" \
+            --flavor os=${{ inputs.os }} \
+            --flavor test_task=${{ inputs.test-task }} \
+            --flavor test_opts=${test_opts} \
+            --test-suite ${test_all_test_suite} \
+            > "${test_all_session_file}"
+          echo "TESTS=${TESTS} --launchable-test-reports=${test_all_report_file}" >> $GITHUB_ENV
+        fi
+        if [ "${btest_enabled}" = "true" ]; then
+          launchable record session \
+            --build "${build_name}" \
+            --flavor os=${{ inputs.os }} \
+            --flavor test_task=${{ inputs.test-task }} \
+            --flavor test_opts=${test_opts} \
+            --test-suite ${btest_test_suite} \
+            > "${btest_session_file}"
+          echo "BTESTS=${BTESTS} --launchable-test-reports=${btest_report_file}" >> $GITHUB_ENV
+        fi
+        if [ "${test_spec_enabled}" = "true" ]; then
+          launchable record session \
+            --build "${build_name}" \
+            --flavor os=${{ inputs.os }} \
+            --flavor test_task=${{ inputs.test-task }} \
+            --flavor test_opts=${test_opts} \
+            --test-suite ${test_spec_test_suite} \
+            > "${test_spec_session_file}"
+          echo "SPECOPTS=${SPECOPTS} --launchable-test-reports=${test_spec_report_dir}" >> $GITHUB_ENV
+        fi
+      if: steps.enable-launchable.outputs.enable-launchable
+      env:
+        test_all_enabled: ${{ steps.global.outputs.test_all_enabled }}
+        btest_enabled: ${{ steps.global.outputs.btest_enabled }}
+        test_spec_enabled: ${{ steps.global.outputs.test_spec_enabled }}
+        test_all_session_file: ${{ steps.global.outputs.test_all_session_file }}
+        btest_session_file: ${{ steps.global.outputs.btest_session_file }}
+        test_spec_session_file: ${{ steps.global.outputs.test_spec_session_file }}
+        test_all_report_file: ${{ steps.global.outputs.test_all_report_file }}
+        btest_report_file: ${{ steps.global.outputs.btest_report_file }}
+        test_spec_report_dir: ${{ steps.global.outputs.test_spec_report_dir }}
+
+    - name: Variables to report Launchable
+      id: variables
+      shell: bash
+      working-directory: ${{ inputs.srcdir }}
+      run: |
+        set -x
+        : # report-path from srcdir
+        if [ "${srcdir}" = "${{ github.workspace }}" ]; then
+          dir=
+        else
+          # srcdir must be equal to or under workspace
+          dir=$(echo ${srcdir:+${srcdir}/} | sed 's:[^/][^/]*/:../:g')
+        fi
+        if [ "${test_all_enabled}" = "true" ]; then
+          test_report_path="${dir}${builddir:+${builddir}/}${test_all_report_file}"
+          echo test_report_path="${test_report_path}" >> $GITHUB_OUTPUT
+        fi
+        if [ "${btest_enabled}" = "true" ]; then
+          btest_report_path="${dir}${builddir:+${builddir}/}${btest_report_file}"
+          echo btest_report_path="${btest_report_path}" >> $GITHUB_OUTPUT
+        fi
+        if [ "${test_spec_enabled}" = "true" ]; then
+          test_spec_report_path="${dir}${builddir:+${builddir}/}${test_spec_report_dir}"
+          mkdir "${test_spec_report_path}"
+          echo test_spec_report_path="${test_spec_report_path}" >> $GITHUB_OUTPUT
+        fi
+      if: steps.enable-launchable.outputs.enable-launchable
+      env:
+        srcdir: ${{ inputs.srcdir }}
+        builddir: ${{ inputs.builddir }}
+        test_all_enabled: ${{ steps.global.outputs.test_all_enabled }}
+        btest_enabled: ${{ steps.global.outputs.btest_enabled }}
+        test_spec_enabled: ${{ steps.global.outputs.test_spec_enabled }}
+        test_all_report_file: ${{ steps.global.outputs.test_all_report_file }}
+        btest_report_file: ${{ steps.global.outputs.btest_report_file }}
+        test_spec_report_dir: ${{ steps.global.outputs.test_spec_report_dir }}
+
+    - name: Record test results in Launchable
+      uses: gacts/run-and-post-run@674528335da98a7afc80915ff2b4b860a0b3553a # v1.4.0
+      with:
+        shell: bash
+        working-directory: ${{ inputs.srcdir }}
+        post: |
+          [[ "${test_all_enabled}" = "true" ]] && \
+            launchable record tests \
+              --session "$(cat "${test_all_session_file}")" \
+              raw "${test_report_path}" || true
+
+          [[ "${btest_enabled}" = "true" ]] && \
+            launchable record tests \
+              --session "$(cat "${btest_session_file}")" \
+              raw "${btest_report_path}" || true
+
+          [[ "${test_spec_enabled}" = "true" ]] && \
+            launchable record tests \
+              --session "$(cat "${test_spec_session_file}")" \
+              raw ${test_spec_report_path}/* || true
+
+          rm -f "${test_all_session_file}"
+          rm -f "${btest_session_file}"
+          rm -f "${test_spec_session_file}"
+          rm -f "${test_report_path}"
+          rm -f "${btest_report_path}"
+          rm -fr "${test_spec_report_path}"
+      if: ${{ always() && steps.enable-launchable.outputs.enable-launchable }}
+      env:
+        test_report_path: ${{ steps.variables.outputs.test_report_path }}
+        btest_report_path: ${{ steps.variables.outputs.btest_report_path }}
+        test_spec_report_path: ${{ steps.variables.outputs.test_spec_report_path }}
+        test_all_enabled: ${{ steps.global.outputs.test_all_enabled }}
+        btest_enabled: ${{ steps.global.outputs.btest_enabled }}
+        test_spec_enabled: ${{ steps.global.outputs.test_spec_enabled }}
+        test_all_session_file: ${{ steps.global.outputs.test_all_session_file }}
+        btest_session_file: ${{ steps.global.outputs.btest_session_file }}
+        test_spec_session_file: ${{ steps.global.outputs.test_spec_session_file }}
diff --git a/.github/actions/setup/directories/action.yml b/.github/actions/setup/directories/action.yml
new file mode 100644
index 0000000000..6cc66407a3
--- /dev/null
+++ b/.github/actions/setup/directories/action.yml
@@ -0,0 +1,178 @@
+name: Setup directories etc.
+description: >-
+  Set up the source code and build directories (plus some
+  environmental tweaks)
+
+inputs:
+  srcdir:
+    required: false
+    default: ${{ github.workspace }}
+    description: >-
+      Directory to (re-)checkout source codes.  This will be created
+      if absent.  If there is no `configure` file that is also
+      generated inside.
+
+  builddir:
+    required: false
+    default: ${{ github.workspace }}
+    description: >-
+      Where binaries and other generated contents go.  This will be
+      created if absent.
+
+  makeup:
+    required: false
+    type: boolean
+    # Note that `default: false` evaluates to a string constant
+    # `'false'`, which is a truthy value :sigh:
+    # https://github.com/actions/runner/issues/2238
+    default: ''
+    description: >-
+      If set to true, additionally runs `make up`.
+
+  checkout:
+    required: false
+    type: boolean
+    default: true
+    description: >-
+      If set to '' (false), skip running actions/checkout. This is useful when
+      you don't want to overwrite a GitHub token that is already set up.
+
+  dummy-files:
+    required: false
+    type: boolean
+    default: ''
+    description: >-
+      If set to true, creates dummy files in build dir.
+
+  fetch-depth:
+    required: false
+    default: '1'
+    description: The depth of commit history fetched from the remote repository
+
+  clean:
+    required: false
+    type: boolean
+    default: ''
+    description: >-
+      If set to true, clean build directory.
+
+outputs: {} # nothing?
+
+runs:
+  using: composite
+
+  steps:
+    # Note that `shell: bash` works on both Windows and Linux, but not
+    # `shell: sh`.  This is because GitHub hosted Windows runners have
+    # their bash manually installed.
+    - shell: bash
+      run: |
+        mkdir -p ${{ inputs.srcdir }}
+        mkdir -p ${{ inputs.builddir }}
+
+    # Did you know that actions/checkout works without git(1)?  We are
+    # checking that here.
+    - id: which
+      shell: bash
+      run: |
+        echo "git=`command -v git`" >> "$GITHUB_OUTPUT"
+        echo "sudo=`command -v sudo`" >> "$GITHUB_OUTPUT"
+        echo "autoreconf=`command -v autoreconf`" >> "$GITHUB_OUTPUT"
+
+    - if: steps.which.outputs.git
+      shell: bash
+      run: |
+        git config --global core.autocrlf false
+        git config --global core.eol lf
+        git config --global advice.detachedHead 0
+        git config --global init.defaultBranch garbage
+
+    - if: inputs.checkout
+      uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      with:
+        path: ${{ inputs.srcdir }}
+        fetch-depth: ${{ inputs.fetch-depth }}
+
+    - uses: actions/cache@1bd1e32a3bdc45362d1e726936510720a7c30a57 # v4.2.0
+      with:
+        path: ${{ inputs.srcdir }}/.downloaded-cache
+        key: downloaded-cache
+
+    - if: steps.which.outputs.autoreconf
+      shell: bash
+      working-directory: ${{ inputs.srcdir }}
+      run: ./autogen.sh --install
+
+    # This is for MinGW.
+    - if: runner.os == 'Windows'
+      shell: bash
+      run: echo "GNUMAKEFLAGS=-j$((2 * NUMBER_OF_PROCESSORS))" >> $GITHUB_ENV
+
+    - if: runner.os == 'Linux'
+      shell: bash
+      run: echo "GNUMAKEFLAGS=-sj$((1 + $(nproc --all)))" >> "$GITHUB_ENV"
+
+    # macOS' GNU make is so old that they doesn't understand `GNUMAKEFLAGS`.
+    - if: runner.os == 'macOS'
+      shell: bash
+      run: echo "MAKEFLAGS=-j$((1 + $(sysctl -n hw.activecpu)))" >> "$GITHUB_ENV"
+
+    - if: inputs.makeup
+      shell: bash
+      working-directory: ${{ inputs.srcdir }}
+      run: |
+        touch config.status .rbconfig.time
+        for mk in Makefile GNUmakefile; do
+          sed -f tool/prereq.status template/$mk.in > $mk
+        done
+        make up
+
+    # Cleanup, runs even on failure
+    - if: always() && inputs.makeup
+      shell: bash
+      working-directory: ${{ inputs.srcdir }}
+      run: |
+        rm -f config.status .rbconfig.time \
+          Makefile GNUmakefile uncommon.mk enc.mk noarch-fake.rb
+
+    - if: steps.which.outputs.sudo
+      shell: bash
+      run: |
+        sudo chmod -R go-w /usr/share
+        chmod -v go-w $HOME $HOME/.config || :
+        SAVE_IFS="$IFS" IFS=:; set $PATH; dirs=() IFS="$SAVE_IFS"
+        for d do [ ! -d "$d" ] || dirs+=("$d"); done
+        sudo chmod -v go-w "${dirs[@]}" || :
+
+    - if: inputs.dummy-files == 'true'
+      shell: bash
+      id: dummy-files
+      working-directory: ${{ inputs.builddir }}
+      run: |
+        : Create dummy files in build dir
+        set {{a..z},{A..Z},{0..9},foo,bar,test,zzz}.rb
+        for file; do \
+          echo > $file "raise 'do not load $file'"; \
+        done
+        # drop {a..z}.rb if case-insensitive filesystem
+        grep -F A.rb a.rb > /dev/null && set "${@:27}"
+        echo clean="cd ${{ inputs.builddir }} && rm $*" >> $GITHUB_OUTPUT
+
+    - if: inputs.clean == 'true'
+      shell: bash
+      id: clean
+      run: |
+        echo distclean='make -C ${{ inputs.builddir }} distclean' >> $GITHUB_OUTPUT
+        echo remained-files='find ${{ inputs.builddir }} -ls' >> $GITHUB_OUTPUT
+        [ "${{ inputs.builddir }}" = "${{ inputs.srcdir }}" ] ||
+        echo final='rmdir ${{ inputs.builddir }}' >> $GITHUB_OUTPUT
+
+    - name: clean
+      uses: gacts/run-and-post-run@4683764dd706df847f57b9bed39d08164bcd2690 # v1.4.1
+      with:
+        working-directory:
+        post: |
+          ${{ steps.dummy-files.outputs.clean }}
+          ${{ steps.clean.outputs.distclean }}
+          ${{ steps.clean.outputs.remained-files }}
+          ${{ steps.clean.outputs.final }}
diff --git a/.github/actions/setup/macos/action.yml b/.github/actions/setup/macos/action.yml
new file mode 100644
index 0000000000..5da7c6d44c
--- /dev/null
+++ b/.github/actions/setup/macos/action.yml
@@ -0,0 +1,29 @@
+name: Setup macOS environment
+description: >-
+  Installs necessary packages via Homebrew.
+
+inputs: {} # nothing?
+
+outputs: {} # nothing?
+
+runs:
+  using: composite
+
+  steps:
+    - name: brew
+      shell: bash
+      run: |
+        brew install --quiet jemalloc gmp libffi openssl@3 zlib autoconf automake libtool
+
+    - name: Set ENV
+      shell: bash
+      run: |
+        dir_config() {
+          local args=() lib var="$1"; shift
+          for lib in "$@"; do
+            args+="--with-${lib%@*}-dir=$(brew --prefix $lib)"
+          done
+          echo "$var=${args[*]}" >> $GITHUB_ENV
+        }
+        dir_config ruby_configure_args gmp
+        dir_config CONFIGURE_ARGS openssl@3
diff --git a/.github/actions/setup/ubuntu/action.yml b/.github/actions/setup/ubuntu/action.yml
new file mode 100644
index 0000000000..a9e5b41951
--- /dev/null
+++ b/.github/actions/setup/ubuntu/action.yml
@@ -0,0 +1,53 @@
+name: Setup ubuntu environment
+description: >-
+  At the beginning there was no way but to copy & paste `apt-get`
+  everywhere.  But now that we have composite actions, it seems better
+  merge them into one.
+
+inputs:
+  arch:
+    required: false
+    default: ''
+    description: >-
+      Architecture.  Because we run this on a GitHub-hosted runner
+      acceptable value for this input is very limited.
+
+outputs:
+  arch:
+    value: ${{ steps.uname.outputs.uname }}
+    description: >-
+      Actual architecture.  This could be different from the one
+      passed to the `inputs.arch`.  For instance giving `i386` to this
+      action yields `i686`.
+
+runs:
+  using: composite
+
+  steps:
+    - name: set SETARCH
+      shell: bash
+      run: echo "SETARCH=${setarch}" >> "$GITHUB_ENV"
+      env:
+        setarch: ${{ inputs.arch && format('setarch {0} --', inputs.arch) }}
+
+    - id: uname
+      name: uname
+      shell: bash
+      run: |
+        echo uname=`${SETARCH} uname -m` >> "$GITHUB_OUTPUT"
+        echo dpkg=`${SETARCH} uname -m | sed s/686/386/` >> "$GITHUB_OUTPUT"
+
+    - name: apt-get
+      shell: bash
+      env:
+        arch: ${{ inputs.arch && format(':{0}', steps.uname.outputs.dpkg) || '' }}
+      run: |
+        set -x
+        ${arch:+sudo dpkg --add-architecture ${arch#:}}
+        sudo apt-get update -qq || :
+        sudo apt-get install --no-install-recommends -qq -y -o=Dpkg::Use-Pty=0 \
+        ${arch:+cross}build-essential${arch/:/-} \
+        libssl-dev${arch} libyaml-dev${arch} libreadline6-dev${arch} \
+        zlib1g-dev${arch} libncurses5-dev${arch} libffi-dev${arch} \
+        autoconf ruby
+        sudo apt-get install -qq -y pkg-config${arch} || :
diff --git a/.github/actions/slack/action.yml b/.github/actions/slack/action.yml
new file mode 100644
index 0000000000..98171efc5e
--- /dev/null
+++ b/.github/actions/slack/action.yml
@@ -0,0 +1,39 @@
+name: Post a message to slack
+description: >-
+  We have our ruby/action-slack webhook.  However its arguments are
+  bit verbose to be listed in every workflow files.  Better merge them
+  into one.
+
+inputs:
+  SLACK_WEBHOOK_URL:
+    required: true
+    description: >-
+      The URL to post the payload.  This is an input because it tends
+      to be stored in a secrets vault and a composite action cannot
+      look into one.
+
+  label:
+    required: false
+    description: >-
+      Human-readable description of the run, something like "DEBUG=1".
+      This need not be unique among runs.
+
+outputs: {} # Nothing?
+
+runs:
+  using: composite
+
+  steps:
+    - uses: ruby/action-slack@54175162371f1f7c8eb94d7c8644ee2479fcd375 # v3.2.2
+      with:
+        payload: |
+          {
+            "ci": "GitHub Actions",
+            "env": "${{ github.workflow }}${{ inputs.label && format(' / {0}', inputs.label) }}",
+            "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
+            "commit": "${{ github.sha }}",
+            "branch": "${{ github.ref_name }}"
+          }
+      env:
+        SLACK_WEBHOOK_URL: ${{ inputs.SLACK_WEBHOOK_URL }}
+      if: ${{github.event_name == 'push' && startsWith(github.repository, 'ruby/')}}
diff --git a/.github/auto_request_review.yml b/.github/auto_request_review.yml
new file mode 100644
index 0000000000..8726df577d
--- /dev/null
+++ b/.github/auto_request_review.yml
@@ -0,0 +1,13 @@
+files:
+  'yjit*': [team:yjit]
+  'yjit/**/*': [team:yjit]
+  'yjit/src/cruby_bindings.inc.rs': []
+  'doc/yjit/*': [team:yjit]
+  'bootstraptest/test_yjit*': [team:yjit]
+  'test/ruby/test_yjit*': [team:yjit]
+options:
+  ignore_draft: true
+  # This currently doesn't work as intended. We want to skip reviews when only
+  # cruby_bingings.inc.rs is modified, but this skips reviews even when other
+  # yjit files are modified as well. To be enabled after fixing the behavior.
+  #last_files_match_only: true
diff --git a/.github/codeql/codeql-config.yml b/.github/codeql/codeql-config.yml
deleted file mode 100644
index 91f82b842b..0000000000
--- a/.github/codeql/codeql-config.yml
+++ /dev/null
@@ -1,3 +0,0 @@
-name: "CodeQL config for the Ruby language"
-
-languages: cpp
diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index b18fd29357..426893be2a 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -3,4 +3,16 @@ updates:
   - package-ecosystem: 'github-actions'
     directory: '/'
     schedule:
-      interval: 'weekly'
+      interval: 'daily'
+  - package-ecosystem: 'github-actions'
+    directory: '/.github/actions/slack'
+    schedule:
+      interval: 'daily'
+  - package-ecosystem: 'github-actions'
+    directory: '/.github/actions/setup/directories'
+    schedule:
+      interval: 'daily'
+  - package-ecosystem: 'cargo'
+    directory: '/yjit'
+    schedule:
+      interval: 'daily'
diff --git a/.github/workflows/annocheck.yml b/.github/workflows/annocheck.yml
new file mode 100644
index 0000000000..8cc482c428
--- /dev/null
+++ b/.github/workflows/annocheck.yml
@@ -0,0 +1,112 @@
+name: Annocheck
+
+on:
+  push:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man/*'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
+  pull_request:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man/*'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
+  merge_group:
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:
+  contents: read
+
+jobs:
+  compile:
+    name: test-annocheck
+
+    runs-on: ubuntu-latest
+
+    container:
+      image: ghcr.io/ruby/ruby-ci-image:gcc-11
+      options: --user root
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.head_commit.message, 'Document')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.title, 'Document')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
+    env:
+      CONFIGURE_TTY: never
+      GITPULLOPTIONS: --no-tags origin ${{ github.ref }}
+      RUBY_DEBUG: ci rgengc
+      RUBY_TESTOPTS: >-
+        -q
+        --color=always
+        --tty=no
+      # FIXME: Drop skipping options
+      # https://bugs.ruby-lang.org/issues/18061
+      # https://sourceware.org/annobin/annobin.html/Test-pie.html
+      TEST_ANNOCHECK_OPTS: '--skip-pie --skip-gaps'
+
+    steps:
+      - run: id
+        working-directory:
+
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with:
+          sparse-checkout-cone-mode: false
+          sparse-checkout: /.github
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          srcdir: src
+          builddir: build
+          makeup: true
+
+      - uses: ruby/setup-ruby@a6e6f86333f0a2523ece813039b8b4be04560854 # v1.190.0
+        with:
+          ruby-version: '3.0'
+          bundler: none
+
+      # Minimal flags to pass the check.
+      # -g0 disables backtraces when SEGV.  Do not set that.
+      - name: Run configure
+        run: >
+          ../src/configure -C
+          --enable-debug-env
+          --disable-install-doc
+          --with-ext=-test-/cxxanyargs,+
+          --without-valgrind
+          --without-jemalloc
+          --without-gmp
+          --with-gcc="gcc-11 -fcf-protection -Wa,--generate-missing-build-notes=yes"
+          --enable-shared
+          debugflags=-ggdb3
+          optflags=-O2
+          LDFLAGS=-Wl,-z,now
+
+      - run: make showflags
+
+      - run: make
+
+      - run: make test-annocheck
+
+      - uses: ./.github/actions/slack
+        with:
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() }}
+
+defaults:
+  run:
+    working-directory: build
diff --git a/.github/workflows/auto_request_review.yml b/.github/workflows/auto_request_review.yml
new file mode 100644
index 0000000000..ca27244b46
--- /dev/null
+++ b/.github/workflows/auto_request_review.yml
@@ -0,0 +1,19 @@
+name: Auto Request Review
+on:
+  pull_request_target:
+    types: [opened, ready_for_review, reopened]
+
+permissions:
+  contents: read
+
+jobs:
+  auto-request-review:
+    name: Auto Request Review
+    runs-on: ubuntu-latest
+    if: ${{ github.repository == 'ruby/ruby' && github.base_ref == 'master' }}
+    steps:
+      - name: Request review based on files changes and/or groups the author belongs to
+        uses: necojackarc/auto-request-review@e89da1a8cd7c8c16d9de9c6e763290b6b0e3d424 # v0.13.0
+        with:
+          # scope: public_repo
+          token: ${{ secrets.MATZBOT_GITHUB_TOKEN }}
diff --git a/.github/workflows/baseruby.yml b/.github/workflows/baseruby.yml
index 7385fc4d9e..3dbf135736 100644
--- a/.github/workflows/baseruby.yml
+++ b/.github/workflows/baseruby.yml
@@ -4,63 +4,74 @@ on:
   push:
     paths-ignore:
       - 'doc/**'
+      - '**/man/*'
       - '**.md'
       - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
   pull_request:
     paths-ignore:
       - 'doc/**'
+      - '**/man/*'
       - '**.md'
       - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
+  merge_group:
 
 concurrency:
   group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
   cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
 
+permissions:
+  contents: read
+
 jobs:
   baseruby:
     name: BASERUBY
+
     runs-on: ubuntu-20.04
-    if: ${{ !startsWith(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.head_commit.message, 'Document')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.title, 'Document')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
     strategy:
       matrix:
         ruby:
-          - ruby-2.2
-#         - ruby-2.3
-#         - ruby-2.4
-#         - ruby-2.5
-#         - ruby-2.6
-#         - ruby-2.7
           - ruby-3.0
           - ruby-3.1
+          - ruby-3.2
+          - ruby-3.3
 
     steps:
-      - uses: actions/checkout@v3
-      - uses: actions/cache@v3
-        with:
-          path: .downloaded-cache
-          key: downloaded-cache
-      - uses: ruby/setup-ruby@v1
+      - uses: ruby/setup-ruby@a6e6f86333f0a2523ece813039b8b4be04560854 # v1.190.0
         with:
           ruby-version: ${{ matrix.ruby }}
           bundler: none
-      - run: echo "GNUMAKEFLAGS=-j$((1 + $(nproc --all)))" >> $GITHUB_ENV
-      - run: sudo apt-get install build-essential autoconf bison libyaml-dev
-      - run: ./autogen.sh
+
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+
+      - uses: ./.github/actions/setup/ubuntu
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          makeup: true
+
       - run: ./configure --disable-install-doc
-      - run: make common-srcs
-      - run: make incs
+
       - run: make all
+
       - run: make test
-      - uses: k0kubun/action-slack@v2.0.0
+
+      - uses: ./.github/actions/slack
         with:
-          payload: |
-            {
-              "ci": "GitHub Actions",
-              "env": "${{ github.workflow }} / BASERUBY @ ${{ matrix.ruby }}",
-              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
-              "commit": "${{ github.sha }}",
-              "branch": "${{ github.ref }}".split('/').reverse()[0]
-            }
-        env:
+          label: ${{ matrix.ruby }}
           SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
-        if: ${{ failure() && github.event_name == 'push' }}
+        if: ${{ failure() }}
diff --git a/.github/workflows/bundled_gems.yml b/.github/workflows/bundled_gems.yml
index 83f01d5868..da2c7028c2 100644
--- a/.github/workflows/bundled_gems.yml
+++ b/.github/workflows/bundled_gems.yml
@@ -2,132 +2,135 @@ name: bundled_gems
 
 on:
   push:
+    branches: ['master']
     paths:
       - '.github/workflows/bundled_gems.yml'
       - 'gems/bundled_gems'
   pull_request:
+    branches: ['master']
     paths:
       - '.github/workflows/bundled_gems.yml'
       - 'gems/bundled_gems'
+  merge_group:
   schedule:
     - cron: '45 6 * * *'
+  workflow_dispatch:
+
+permissions: # added using https://github.com/step-security/secure-workflows
+  contents: read
 
 jobs:
   update:
+    permissions:
+      contents: write # for Git to git push
+
     if: ${{ github.event_name != 'schedule' || github.repository == 'ruby/ruby' }}
+
     name: update ${{ github.workflow }}
+
     runs-on: ubuntu-latest
+
     steps:
-      - name: git config
-        run: |
-          git config --global advice.detachedHead 0
-          git config --global init.defaultBranch garbage
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with:
+          token: ${{ (github.repository == 'ruby/ruby' && !startsWith(github.event_name, 'pull')) && secrets.MATZBOT_GITHUB_TOKEN || secrets.GITHUB_TOKEN }}
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          # Skip overwriting MATZBOT_GITHUB_TOKEN
+          checkout: '' # false (ref: https://github.com/actions/runner/issues/2238)
 
       - name: Set ENV
         run: |
-          echo "GNUMAKEFLAGS=-j$((1 + $(nproc --all)))" >> $GITHUB_ENV
           echo "TODAY=$(date +%F)" >> $GITHUB_ENV
 
-      - uses: actions/checkout@v3
-
-      - uses: actions/cache@v3
-        with:
-          path: .downloaded-cache
-          key: downloaded-cache-${{ github.sha }}
-          restore-keys: |
-            downloaded-cache
-
       - name: Download previous gems list
         run: |
-          data=bundled_gems.json
           mkdir -p .downloaded-cache
-          ln -s .downloaded-cache/$data .
-          curl -O -R -z ./$data https://stdgems.org/$data
+          for data in bundled_gems.json default_gems.json; do
+            ln -s .downloaded-cache/$data .
+            curl -O -R -z ./$data https://stdgems.org/$data
+          done
 
       - name: Update bundled gems list
+        id: bundled_gems
+        run: |
+          ruby -i~ tool/update-bundled_gems.rb gems/bundled_gems >> $GITHUB_OUTPUT
+
+      - name: Update spec/bundler/support/builders.rb
         run: |
-          ruby -i~ tool/update-bundled_gems.rb gems/bundled_gems
+          #!ruby
+          rake_version = File.read("gems/bundled_gems")[/^rake\s+(\S+)/, 1]
+          print ARGF.read.sub(/^ *def rake_version\s*\K".*?"/) {rake_version.dump}
+        shell: ruby -i~ {0} spec/bundler/support/builders.rb
 
       - name: Maintain updated gems list in NEWS
         run: |
-          require 'json'
-          news = File.read("NEWS.md")
-          prev = news[/since the \*+(\d+\.\d+\.\d+)\*+/, 1]
-          prevs = [prev, prev.sub(/\.\d+\z/, '')]
-          %W[bundled].each do |type|
-            last = JSON.parse(File.read("#{type}_gems.json"))['gems'].filter_map do |g|
-              v = g['versions'].values_at(*prevs).compact.first
-              g = g['gem']
-              g = 'RubyGems' if g == 'rubygems'
-              [g, v] if v
-            end.to_h
-            changed = File.foreach("gems/#{type}_gems").filter_map do |l|
-              next if l.start_with?("#")
-              g, v = l.split(" ", 3)
-              [g, v] unless last[g] == v
-            end
-            changed, added = changed.partition {|g, _| last[g]}
-            news.sub!(/^\*( +)The following #{type} gems? are updated\.\n\K(?: \1\* .*\n)*/) do
-              mark = "#{$1} * "
-              changed.map {|g, v|"#{mark}#{g} #{v}\n"}.join("")
-            end or next
-            news.sub!(/^\*( +)The following default gems are now bundled gems\.\n\K(?: \1\* .*\n)*/) do
-              mark = "#{$1} * "
-              added.map {|g, v|"#{mark}#{g} #{v}\n"}.join("")
-            end or next if added
-            File.write("NEWS.md", news)
-          end
-        shell: ruby {0}
+          ruby tool/update-NEWS-gemlist.rb bundled
 
       - name: Check diffs
         id: diff
         run: |
-          git add -- NEWS.md
-          git diff --no-ext-diff --ignore-submodules --quiet -- gems/bundled_gems
-        continue-on-error: true
+          news= gems=
+          git diff --color --no-ext-diff --ignore-submodules --exit-code -- NEWS.md ||
+          news=true
+          git diff --color --no-ext-diff --ignore-submodules --exit-code -- gems/bundled_gems ||
+          gems=true
+          git add -- NEWS.md gems/bundled_gems
+          git add -- spec/bundler/support/builders.rb
+          echo news=$news >> $GITHUB_OUTPUT
+          echo gems=$gems >> $GITHUB_OUTPUT
+          echo update=${news:-$gems} >> $GITHUB_OUTPUT
 
       - name: Install libraries
-        run: |
-          set -x
-          sudo apt-get update -q || :
-          sudo apt-get install --no-install-recommends -q -y build-essential libssl-dev libyaml-dev libreadline6-dev zlib1g-dev libncurses5-dev libffi-dev bison autoconf ruby
-        if: ${{ steps.diff.outcome == 'failure' }}
+        uses: ./.github/actions/setup/ubuntu
+        if: ${{ steps.diff.outputs.gems }}
 
       - name: Build
         run: |
           ./autogen.sh
           ./configure -C --disable-install-doc
           make
-        if: ${{ steps.diff.outcome == 'failure' }}
+        if: ${{ steps.diff.outputs.gems }}
+
+      - name: Prepare bundled gems
+        run: |
+          make -s prepare-gems
+        if: ${{ steps.diff.outputs.gems }}
 
       - name: Test bundled gems
         run: |
           make -s test-bundled-gems
-          git add -- gems/bundled_gems
         timeout-minutes: 30
         env:
-          RUBY_TESTOPTS: "-q --tty=no"
-          TEST_BUNDLED_GEMS_ALLOW_FAILURES: ""
-        if: ${{ steps.diff.outcome == 'failure' }}
-
-      - name: Show diffs
-        id: show
-        run: |
-          git diff --cached --color --no-ext-diff --ignore-submodules --exit-code --
-        continue-on-error: true
+          RUBY_TESTOPTS: '-q --tty=no'
+          TEST_BUNDLED_GEMS_ALLOW_FAILURES: 'typeprof'
+        if: ${{ steps.diff.outputs.gems }}
 
       - name: Commit
         run: |
           git pull --ff-only origin ${GITHUB_REF#refs/heads/}
-          message="Update bundled gems list at "
-          if [ ${{ steps.diff.outcome }} = success ]; then
-            git commit --message="${message}${GITHUB_SHA:0:30} [ci skip]"
+          message="Update bundled gems list"
+          if [ -z "${gems}" ]; then
+            git commit --message="${message} at ${GITHUB_SHA:0:30} [ci skip]"
           else
-            git commit --message="${message}${TODAY}"
+            git commit --message="${message} as of ${TODAY}"
           fi
           git push origin ${GITHUB_REF#refs/heads/}
         env:
+          TODAY: ${{ steps.bundled_gems.outputs.latest_date || env.TODAY }}
           EMAIL: svn-admin@ruby-lang.org
           GIT_AUTHOR_NAME: git
           GIT_COMMITTER_NAME: git
-        if: ${{ github.repository == 'ruby/ruby' && !startsWith(github.event_name, 'pull') && steps.show.outcome == 'failure' }}
+          gems: ${{ steps.diff.outputs.gems }}
+        if: >-
+          ${{
+          github.repository == 'ruby/ruby' &&
+          !startsWith(github.event_name, 'pull') &&
+          steps.diff.outputs.update
+          }}
+
+      - uses: ./.github/actions/slack
+        with:
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() }}
diff --git a/.github/workflows/check_dependencies.yml b/.github/workflows/check_dependencies.yml
index f606a86b66..d871ef02c0 100644
--- a/.github/workflows/check_dependencies.yml
+++ b/.github/workflows/check_dependencies.yml
@@ -3,63 +3,61 @@ on:
   push:
     paths-ignore:
       - 'doc/**'
+      - '**/man/*'
       - '**.md'
       - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
   pull_request:
-    paths-ignore:
-      - 'doc/**'
-      - '**.md'
-      - '**.rdoc'
+  merge_group:
 
 concurrency:
   group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
   cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
 
+permissions:
+  contents: read
+
 jobs:
   update-deps:
+    name: Dependency checks
+
     strategy:
       matrix:
-        os: [ubuntu-20.04]
+        os: [ubuntu-latest]
       fail-fast: true
+
     runs-on: ${{ matrix.os }}
-    if: ${{ !startsWith(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
+
     steps:
-      - name: Install libraries
-        run: |
-          set -x
-          sudo apt-get update -q || :
-          sudo apt-get install --no-install-recommends -q -y build-essential libssl-dev libyaml-dev libreadline6-dev zlib1g-dev libncurses5-dev libffi-dev bison autoconf ruby
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+
+      - uses: ./.github/actions/setup/ubuntu
         if: ${{ contains(matrix.os, 'ubuntu') }}
-      - name: Install libraries
-        run: |
-          brew upgrade
-          brew install gmp libffi openssl@1.1 zlib autoconf automake libtool readline
+
+      - uses: ./.github/actions/setup/macos
         if: ${{ contains(matrix.os, 'macos') }}
-      - name: git config
-        run: |
-          git config --global advice.detachedHead 0
-          git config --global init.defaultBranch garbage
-      - uses: actions/checkout@v3
-      - uses: actions/cache@v3
+
+      - uses: ./.github/actions/setup/directories
+
+      - uses: ruby/setup-ruby@a6e6f86333f0a2523ece813039b8b4be04560854 # v1.190.0
         with:
-          path: .downloaded-cache
-          key: downloaded-cache
-      - run: ./autogen.sh
+          ruby-version: '3.0'
+          bundler: none
+
       - name: Run configure
         run: ./configure -C --disable-install-doc --disable-rubygems --with-gcc 'optflags=-O0' 'debugflags=-save-temps=obj -g'
+
       - run: make all golf
+
+      - run: ./goruby -veh
+
       - run: ruby tool/update-deps --fix
+
       - run: git diff --no-ext-diff --ignore-submodules --exit-code
-      - uses: k0kubun/action-slack@v2.0.0
+
+      - uses: ./.github/actions/slack
         with:
-          payload: |
-            {
-              "ci": "GitHub Actions",
-              "env": "${{ matrix.os }} / Dependencies need to update",
-              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
-              "commit": "${{ github.sha }}",
-              "branch": "${{ github.ref }}".split('/').reverse()[0]
-            }
-        env:
+          label: ${{ matrix.os }} / Dependencies need to update
           SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
-        if: ${{ failure() && github.event_name == 'push' }}
+        if: ${{ failure() }}
diff --git a/.github/workflows/check_misc.yml b/.github/workflows/check_misc.yml
index 9e35d7f432..42ad551430 100644
--- a/.github/workflows/check_misc.yml
+++ b/.github/workflows/check_misc.yml
@@ -1,97 +1,81 @@
-name: Miscellaneous checks
-on: [push, pull_request]
+name: Misc
+on: [push, pull_request, merge_group]
 
 concurrency:
   group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
   cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
 
+permissions:
+  contents: read
+
 jobs:
   checks:
+    name: Miscellaneous checks
+
+    permissions:
+      contents: write # for Git to git push
+
     runs-on: ubuntu-latest
+
     steps:
-      - uses: actions/checkout@v3
-      - name: Check if C-sources are US-ASCII
-        run: |
-          ! grep -r -n '[^	 -~]' *.[chy] include internal win32/*.[ch]
-      - name: Check for trailing spaces
-        run: |
-          ! git grep -n '[	 ]$' '*.rb' '*.[chy]'
-      - name: Check for header macros
-        run: |
-          ! for header in ruby/*.h; do \
-            git grep -l -F -e $header -e HAVE_`echo $header | tr a-z./ A-Z__` -- . > /dev/null || echo $header
-          done | grep -F .
-        working-directory: include
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with:
+          token: ${{ (github.repository == 'ruby/ruby' && !startsWith(github.event_name, 'pull')) && secrets.MATZBOT_GITHUB_TOKEN || secrets.GITHUB_TOKEN }}
 
-      - uses: actions/cache@v3
+      - uses: ./.github/actions/setup/directories
         with:
-          path: .downloaded-cache
-          key: downloaded-cache-${{ github.sha }}
-          restore-keys: |
-            downloaded-cache
+          makeup: true
+          # Skip overwriting MATZBOT_GITHUB_TOKEN
+          checkout: '' # false (ref: https://github.com/actions/runner/issues/2238)
 
-      - name: Download previous gems list
+      - name: Check if C-sources are US-ASCII
         run: |
-          data=default_gems.json
-          mkdir -p .downloaded-cache
-          ln -s .downloaded-cache/$data .
-          curl -O -R -z ./$data https://stdgems.org/$data
+          grep -r -n --include='*.[chyS]' --include='*.asm' $'[^\t-~]' -- . && exit 1 || :
 
-      - name: Make default gems list
+      - name: Check for trailing spaces
         run: |
-          require 'rubygems'
-          $:.unshift "lib"
-          rgver = File.foreach("lib/rubygems.rb") do |line|
-            break $1 if /^\s*VERSION\s*=\s*"([^"]+)"/ =~ line
-          end
-          gems = Dir.glob("{ext,lib}/**/*.gemspec").map do |f|
-            spec = Gem::Specification.load(f)
-            "#{spec.name} #{spec.version}"
-          end.sort
-          File.open("gems/default_gems", "w") do |f|
-            f.puts "RubyGems #{rgver}"
-            f.puts gems
-          end
-        shell: ruby --disable=gems {0}
+          git grep -I -n $'[\t ]$' -- '*.rb' '*.[chy]' '*.rs' '*.yml' && exit 1 || :
+          git grep -n $'^[\t ][\t ]*$' -- '*.md' && exit 1 || :
 
-      - name: Maintain updated gems list in NEWS
+      - name: Check for bash specific substitution in configure.ac
         run: |
-          require 'json'
-          news = File.read("NEWS.md")
-          prev = news[/since the \*+(\d+\.\d+\.\d+)\*+/, 1]
-          prevs = [prev, prev.sub(/\.\d+\z/, '')]
-          %W[default].each do |type|
-            last = JSON.parse(File.read("#{type}_gems.json"))['gems'].filter_map do |g|
-              v = g['versions'].values_at(*prevs).compact.first
-              g = g['gem']
-              g = 'RubyGems' if g == 'rubygems'
-              [g, v] if v
-            end.to_h
-            changed = File.foreach("gems/#{type}_gems").filter_map do |l|
-              next if l.start_with?("#")
-              g, v = l.split(" ", 3)
-              [g, v] unless last[g] == v
-            end
-            news.sub!(/^\*( +)The following #{type} gems? are updated\.\n\K(?: \1\* .*\n)*/) do
-              mark = "#{$1} * "
-              changed.map {|g, v|"#{mark}#{g} #{v}\n"}.join("")
-            end or next
-            File.write("NEWS.md", news)
-          end
-        shell: ruby {0}
+          git grep -n '\${[A-Za-z_0-9]*/' -- configure.ac && exit 1 || :
 
-      - name: Check diffs
-        id: diff
+      - name: Check for header macros
         run: |
-          git diff --color --no-ext-diff --ignore-submodules --exit-code NEWS.md
-        continue-on-error: true
-      - name: Commit
+          fail=
+          for header in ruby/*.h; do
+            git grep -l -F -e $header -e HAVE_`echo $header | tr a-z./ A-Z__` -- . > /dev/null && continue
+            fail=1
+            echo $header
+          done
+          exit $fail
+        working-directory: include
+
+      - name: Generate docs
+        id: docs
         run: |
-          git pull --ff-only origin ${GITHUB_REF#refs/heads/}
-          git commit --message="Update default gems list at ${GITHUB_SHA:0:30} [ci skip]" NEWS.md
-          git push origin ${GITHUB_REF#refs/heads/}
-        env:
-          EMAIL: svn-admin@ruby-lang.org
-          GIT_AUTHOR_NAME: git
-          GIT_COMMITTER_NAME: git
-        if: ${{ github.repository == 'ruby/ruby' && !startsWith(github.event_name, 'pull') && steps.diff.outcome == 'failure' }}
+          ruby -W0 --disable-gems -I./lib tool/rdoc-srcdir -q --op html .
+          echo htmlout=ruby-html-${GITHUB_SHA:0:10} >> $GITHUB_OUTPUT
+        # Generate only when document commit/PR
+        if: >-
+          ${{false
+          || contains(github.event.head_commit.message, '[ruby/rdoc]')
+          || contains(github.event.head_commit.message, '[DOC]')
+          || contains(github.event.head_commit.message, 'Document')
+          || contains(github.event.pull_request.title, '[DOC]')
+          || contains(github.event.pull_request.title, 'Document')
+          || contains(github.event.pull_request.labels.*.name, 'Documentation')
+          }}
+
+      - name: Upload docs
+        uses: actions/upload-artifact@v4
+        with:
+          path: html
+          name: ${{ steps.docs.outputs.htmlout }}
+        if: ${{ steps.docs.outcome == 'success' }}
+
+      - uses: ./.github/actions/slack
+        with:
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() }}
diff --git a/.github/workflows/codeql-analysis.yml b/.github/workflows/codeql-analysis.yml
index 70fd22a7a0..5310d0875f 100644
--- a/.github/workflows/codeql-analysis.yml
+++ b/.github/workflows/codeql-analysis.yml
@@ -1,61 +1,121 @@
-name: "Code scanning - action"
+name: 'CodeQL'
 
 on:
   push:
+    branches: ['master']
     paths-ignore:
       - 'doc/**'
+      - '**/man/*'
       - '**.md'
       - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
   pull_request:
     paths-ignore:
       - 'doc/**'
+      - '**/man/*'
       - '**.md'
       - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
   schedule:
-    - cron: '0 12 * * 4'
+    - cron: '0 12 * * *'
+  workflow_dispatch:
 
 concurrency:
   group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
   cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
 
-jobs:
-  CodeQL-Build:
+permissions: # added using https://github.com/step-security/secure-workflows
+  contents: read
 
-    # CodeQL runs on ubuntu-latest and windows-latest
+jobs:
+  analyze:
+    name: Analyze
     runs-on: ubuntu-latest
-    if: ${{ !startsWith(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
+    permissions:
+      actions: read # for github/codeql-action/init to get workflow details
+      contents: read # for actions/checkout to fetch code
+      security-events: write # for github/codeql-action/autobuild to send a status report
+    # CodeQL fails to run pull requests from dependabot due to missing write access to upload results.
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.head_commit.message, 'Document')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.title, 'Document')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
 
     env:
       enable_install_doc: no
 
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - language: cpp
+          - language: ruby
+
     steps:
-    - name: Install libraries
-      run: |
-        set -x
-        sudo apt-get update -q || :
-        sudo apt-get install --no-install-recommends -q -y build-essential libssl-dev libyaml-dev libreadline6-dev zlib1g-dev libncurses5-dev libffi-dev bison autoconf ruby
+      - name: Checkout repository
+        uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+
+      - name: Install libraries
+        if: ${{ contains(matrix.os, 'macos') }}
+        uses: ./.github/actions/setup/macos
+
+      - name: Install libraries
+        if : ${{ matrix.os == 'ubuntu-latest' }}
+        uses: ./.github/actions/setup/ubuntu
 
-    - name: Checkout repository
-      uses: actions/checkout@v3
+      - uses: ./.github/actions/setup/directories
 
-    - uses: actions/cache@v3
-      with:
-        path: .downloaded-cache
-        key: downloaded-cache
+      - name: Remove an obsolete rubygems vendored file
+        if: ${{ matrix.os == 'ubuntu-latest' }}
+        run: sudo rm /usr/lib/ruby/vendor_ruby/rubygems/defaults/operating_system.rb
 
-    - name: Remove an obsolete rubygems vendored file
-      run: sudo rm /usr/lib/ruby/vendor_ruby/rubygems/defaults/operating_system.rb
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@df409f7d9260372bd5f19e5b04e83cb3c43714ae # v3.27.9
+        with:
+          languages: ${{ matrix.language }}
 
-    - name: Initialize CodeQL
-      uses: github/codeql-action/init@v1
-      with:
-        config-file: ./.github/codeql/codeql-config.yml
+      - name: Autobuild
+        uses: github/codeql-action/autobuild@df409f7d9260372bd5f19e5b04e83cb3c43714ae # v3.27.9
 
-    - name: Set ENV
-      run: echo "GNUMAKEFLAGS=-j$((1 + $(nproc --all)))" >> $GITHUB_ENV
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@df409f7d9260372bd5f19e5b04e83cb3c43714ae # v3.27.9
+        with:
+          category: '/language:${{ matrix.language }}'
+          upload: False
+          output: sarif-results
 
-    - name: Autobuild
-      uses: github/codeql-action/autobuild@v1
+      - name: filter-sarif
+        uses: advanced-security/filter-sarif@f3b8118a9349d88f7b1c0c488476411145b6270d # v1.0.1
+        with:
+          patterns: |
+            +**/*.rb
+            -lib/uri/mailto.rb:rb/overly-large-range
+            -lib/uri/rfc3986_parser.rb:rb/overly-large-range
+            -lib/bundler/vendor/uri/lib/uri/mailto.rb:rb/overly-large-range
+            -lib/bundler/vendor/uri/lib/uri/rfc3986_parser.rb:rb/overly-large-range
+            -test/ruby/test_io.rb:rb/non-constant-kernel-open
+            -test/open-uri/test_open-uri.rb:rb/non-constant-kernel-open
+            -test/open-uri/test_ssl.rb:rb/non-constant-kernel-open
+            -spec/ruby/core/io/binread_spec.rb:rb/non-constant-kernel-open
+            -spec/ruby/core/io/readlines_spec.rb:rb/non-constant-kernel-open
+            -spec/ruby/core/io/foreach_spec.rb:rb/non-constant-kernel-open
+            -spec/ruby/core/io/write_spec.rb:rb/non-constant-kernel-open
+            -spec/ruby/core/io/read_spec.rb:rb/non-constant-kernel-open
+            -spec/ruby/core/kernel/open_spec.rb:rb/non-constant-kernel-open
+          input: sarif-results/${{ matrix.language }}.sarif
+          output: sarif-results/${{ matrix.language }}.sarif
+        if: ${{ matrix.language == 'ruby' }}
+        continue-on-error: true
 
-    - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@v1
+      - name: Upload SARIF
+        uses: github/codeql-action/upload-sarif@df409f7d9260372bd5f19e5b04e83cb3c43714ae # v3.27.9
+        with:
+          sarif_file: sarif-results/${{ matrix.language }}.sarif
+        continue-on-error: true
diff --git a/.github/workflows/compilers.yml b/.github/workflows/compilers.yml
index 3bd299640d..d8fcfc2638 100644
--- a/.github/workflows/compilers.yml
+++ b/.github/workflows/compilers.yml
@@ -1,249 +1,319 @@
+# Some tests depending on this name 'Compilations' via $GITHUB_WORKFLOW. Make sure to update such tests when renaming this workflow.
 name: Compilations
 
 on:
   push:
     paths-ignore:
       - 'doc/**'
+      - '**/man/*'
       - '**.md'
       - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
   pull_request:
     paths-ignore:
       - 'doc/**'
+      - '**/man/*'
       - '**.md'
       - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
+  merge_group:
 
 concurrency:
   group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
   cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
 
-# Github actions does not support YAML anchors.  This creative use of
-# environment variables (plus the "echo $GITHUB_ENV" hack) is to reroute that
-# restriction.
-env:
-  default_cc: clang-15
-  append_cc: ''
-  crosshost: ''
-
-  # -O1 is faster than -O3 in our tests... Majority of time are consumed trying
-  # to optimize binaries.  Also Github Actions run on relatively modern CPUs
-  # compared to, say, GCC 4 or Clang 3.  We don't specify `-march=native`
-  # because compilers tend not understand what the CPU is.
-  optflags: '-O1'
-
-  # -g0 disables backtraces when SEGV.  Do not set that.
-  debugflags: '-ggdb3'
-
-  default_configure: >-
-    --enable-debug-env
-    --disable-install-doc
-    --with-ext=-test-/cxxanyargs,+
-  append_configure: >-
-    --without-valgrind
-    --without-jemalloc
-    --without-gmp
-
-  UPDATE_UNICODE: >-
-    UNICODE_FILES=.
-    UNICODE_PROPERTY_FILES=.
-    UNICODE_AUXILIARY_FILES=.
-    UNICODE_EMOJI_FILES=.
-  CONFIGURE_TTY: never
-  GITPULLOPTIONS: --no-tags origin ${{github.ref}}
-  RUBY_DEBUG: ci rgengc
-  RUBY_TESTOPTS: >-
-    -q
-    --color=always
-    --tty=no
+permissions:
+  contents: read
 
+# Each job is split so that they roughly take 30min to run through.
 jobs:
-  compile:
-    strategy:
-      fail-fast: false
-      matrix:
-        entry:
-          - { key: default_cc, name: gcc-11,    value: gcc-11,    container: gcc-11 }
-          - { key: default_cc, name: gcc-10,    value: gcc-10,    container: gcc-10 }
-          - { key: default_cc, name: gcc-9,     value: gcc-9,     container: gcc-9 }
-          - { key: default_cc, name: gcc-8,     value: gcc-8,     container: gcc-8 }
-          - { key: default_cc, name: gcc-7,     value: gcc-7,     container: gcc-7 }
-          - { key: default_cc, name: gcc-6,     value: gcc-6,     container: gcc-6 }
-          - { key: default_cc, name: gcc-5,     value: gcc-5,     container: gcc-5 }
-          - { key: default_cc, name: gcc-4.8,   value: gcc-4.8,   container: gcc-4.8 }
-          - key: default_cc
-            name: 'gcc-11 LTO'
-            value: 'gcc-11 -O2 -flto=auto -ffat-lto-objects'
-            container: gcc-11
-            shared: '--disable-shared'
-            # check: true
-          - { key: default_cc, name: clang-15,  value: clang-15,  container: clang-15 }
-          - { key: default_cc, name: clang-14,  value: clang-14,  container: clang-14 }
-          - { key: default_cc, name: clang-13,  value: clang-13,  container: clang-13 }
-          - { key: default_cc, name: clang-12,  value: clang-12,  container: clang-12 }
-          - { key: default_cc, name: clang-11,  value: clang-11,  container: clang-11 }
-          - { key: default_cc, name: clang-10,  value: clang-10,  container: clang-10 }
-          - { key: default_cc, name: clang-9,   value: clang-9,   container: clang-9 }
-          - { key: default_cc, name: clang-8,   value: clang-8,   container: clang-8 }
-          - { key: default_cc, name: clang-7,   value: clang-7,   container: clang-7 }
-          - { key: default_cc, name: clang-6.0, value: clang-6.0, container: clang-6.0 }
-          - { key: default_cc, name: clang-5.0, value: clang-5.0, container: clang-5.0 }
-          - { key: default_cc, name: clang-4.0, value: clang-4.0, container: clang-4.0 }
-          - { key: default_cc, name: clang-3.9, value: clang-3.9, container: clang-3.9 }
-          - key: default_cc
-            name: 'clang-14 LTO'
-            value: 'clang-14 -O2 -flto=auto'
-            container: clang-14
-            shared: '--disable-shared'
-            # check: true
-
-#         - { key: crosshost, name: aarch64-linux-gnu,     value: aarch64-linux-gnu, container: crossbuild-essential-arm64 }
-#         - { key: crosshost, name: arm-linux-gnueabi,     value: arm-linux-gnueabi }
-#         - { key: crosshost, name: arm-linux-gnueabihf,   value: arm-linux-gnueabihf }
-#         - { key: crosshost, name: i686-w64-mingw32,      value: i686-w64-mingw32 }
-#         - { key: crosshost, name: powerpc-linux-gnu,     value: powerpc-linux-gnu }
-#         - { key: crosshost, name: powerpc64le-linux-gnu, value: powerpc64le-linux-gnu, container: crossbuild-essential-ppc64el }
-#         - { key: crosshost, name: s390x-linux-gnu,       value: s390x-linux-gnu, container: crossbuild-essential-s390x }
-#         - { key: crosshost, name: x86_64-w64-mingw32,    value: x86_64-w64-mingw32, container: mingw-w64 }
-
-          - { key: append_cc, name: c99,   value: '-std=c99   -Werror=pedantic -pedantic-errors' }
-#         - { key: append_cc, name: c11,   value: '-std=c11   -Werror=pedantic -pedantic-errors' }
-#         - { key: append_cc, name: c17,   value: '-std=c17   -Werror=pedantic -pedantic-errors' }
-          - { key: append_cc, name: c2x,   value: '-std=c2x   -Werror=pedantic -pedantic-errors' }
-          - { key: CXXFLAGS,  name: c++98, value: '-std=c++98 -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' }
-#         - { key: CXXFLAGS,  name: c++11, value: '-std=c++11 -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' }
-#         - { key: CXXFLAGS,  name: c++14, value: '-std=c++14 -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' }
-#         - { key: CXXFLAGS,  name: c++17, value: '-std=c++17 -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' }
-          - { key: CXXFLAGS,  name: c++2a, value: '-std=c++2a -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' }
-
-          - { key: optflags, name: '-O0', value: '-O0 -march=x86-64 -mtune=generic' }
-#         - { key: optflags, name: '-O3', value: '-O3 -march=x86-64 -mtune=generic', check: true }
-
-          - { key: append_configure, name: gmp,                  value: '--with-gmp' }
-          - { key: append_configure, name: jemalloc,             value: '--with-jemalloc' }
-          - { key: append_configure, name: valgrind,             value: '--with-valgrind' }
-          - { key: append_configure, name: 'coroutine=ucontext', value: '--with-coroutine=ucontext' }
-          - { key: append_configure, name: 'coroutine=pthread',  value: '--with-coroutine=pthread' }
-          - { key: append_configure, name: disable-jit-support,  value: '--disable-jit-support' }
-          - { key: append_configure, name: disable-dln,          value: '--disable-dln' }
-          - { key: append_configure, name: disable-rubygems,     value: '--disable-rubygems' }
-
-          - { key: cppflags, name: OPT_THREADED_CODE=1,            value: '-DOPT_THREADED_CODE=1' }
-          - { key: cppflags, name: OPT_THREADED_CODE=2,            value: '-DOPT_THREADED_CODE=2' }
-          - { key: cppflags, name: OPT_THREADED_CODE=3,            value: '-DOPT_THREADED_CODE=3' }
-
-          - { key: cppflags, name: NDEBUG,                         value: '-DNDEBUG' }
-          - { key: cppflags, name: RUBY_DEBUG,                     value: '-DRUBY_DEBUG' }
-#         - { key: cppflags, name: ARRAY_DEBUG,                    value: '-DARRAY_DEBUG' }
-#         - { key: cppflags, name: BIGNUM_DEBUG,                   value: '-DBIGNUM_DEBUG' }
-#         - { key: cppflags, name: CCAN_LIST_DEBUG,                value: '-DCCAN_LIST_DEBUG' }
-#         - { key: cppflags, name: CPDEBUG=-1,                     value: '-DCPDEBUG=-1' }
-#         - { key: cppflags, name: ENC_DEBUG,                      value: '-DENC_DEBUG' }
-#         - { key: cppflags, name: GC_DEBUG,                       value: '-DGC_DEBUG' }
-#         - { key: cppflags, name: HASH_DEBUG,                     value: '-DHASH_DEBUG' }
-#         - { key: cppflags, name: ID_TABLE_DEBUG,                 value: '-DID_TABLE_DEBUG' }
-#         - { key: cppflags, name: RGENGC_DEBUG=-1,                value: '-DRGENGC_DEBUG=-1' }
-#         - { key: cppflags, name: SYMBOL_DEBUG,                   value: '-DSYMBOL_DEBUG' }
-#         - { key: cppflags, name: THREAD_DEBUG=-1,                value: '-DTHREAD_DEBUG=-1' }
-
-#         - { key: cppflags, name: RGENGC_CHECK_MODE,              value: '-DRGENGC_CHECK_MODE' }
-#         - { key: cppflags, name: TRANSIENT_HEAP_CHECK_MODE,      value: '-DTRANSIENT_HEAP_CHECK_MODE' }
-#         - { key: cppflags, name: VM_CHECK_MODE,                  value: '-DVM_CHECK_MODE' }
-
-          - { key: cppflags, name: USE_EMBED_CI=0,                 value: '-DUSE_EMBED_CI=0' }
-          - { key: cppflags, name: USE_FLONUM=0,                   value: '-DUSE_FLONUM=0' }
-#         - { key: cppflags, name: USE_GC_MALLOC_OBJ_INFO_DETAILS, value: '-DUSE_GC_MALLOC_OBJ_INFO_DETAILS' }
-          - { key: cppflags, name: USE_LAZY_LOAD,                  value: '-DUSE_LAZY_LOAD' }
-#         - { key: cppflags, name: USE_RINCGC=0,                   value: '-DUSE_RINCGC=0' }
-#         - { key: cppflags, name: USE_SYMBOL_GC=0,                value: '-DUSE_SYMBOL_GC=0' }
-#         - { key: cppflags, name: USE_THREAD_CACHE=0,             value: '-DUSE_THREAD_CACHE=0' }
-#         - { key: cppflags, name: USE_TRANSIENT_HEAP=0,           value: '-DUSE_TRANSIENT_HEAP=0' }
-#         - { key: cppflags, name: USE_RUBY_DEBUG_LOG=1,           value: '-DUSE_RUBY_DEBUG_LOG=1' }
-          - { key: cppflags, name: USE_RVARGC=0,                   value: '-DUSE_RVARGC=0' }
-#         - { key: cppflags, name: USE_RVARGC=1,                   value: '-DUSE_RVARGC=1' }
-
-          - { key: cppflags, name: DEBUG_FIND_TIME_NUMGUESS,       value: '-DDEBUG_FIND_TIME_NUMGUESS' }
-          - { key: cppflags, name: DEBUG_INTEGER_PACK,             value: '-DDEBUG_INTEGER_PACK' }
-#         - { key: cppflags, name: ENABLE_PATH_CHECK,              value: '-DENABLE_PATH_CHECK' }
-
-          - { key: cppflags, name: GC_DEBUG_STRESS_TO_CLASS,       value: '-DGC_DEBUG_STRESS_TO_CLASS' }
-#         - { key: cppflags, name: GC_ENABLE_LAZY_SWEEP=0,         value: '-DGC_ENABLE_LAZY_SWEEP=0' }
-#         - { key: cppflags, name: GC_PROFILE_DETAIL_MEMOTY,       value: '-DGC_PROFILE_DETAIL_MEMOTY' }
-#         - { key: cppflags, name: GC_PROFILE_MORE_DETAIL,         value: '-DGC_PROFILE_MORE_DETAIL' }
-
-#         - { key: cppflags, name: CALC_EXACT_MALLOC_SIZE,         value: '-DCALC_EXACT_MALLOC_SIZE' }
-#         - { key: cppflags, name: MALLOC_ALLOCATED_SIZE_CHECK,    value: '-DMALLOC_ALLOCATED_SIZE_CHECK' }
-
-#         - { key: cppflags, name: IBF_ISEQ_ENABLE_LOCAL_BUFFER,   value: '-DIBF_ISEQ_ENABLE_LOCAL_BUFFER' }
-
-#         - { key: cppflags, name: RGENGC_ESTIMATE_OLDMALLOC,      value: '-DRGENGC_ESTIMATE_OLDMALLOC' }
-#         - { key: cppflags, name: RGENGC_FORCE_MAJOR_GC,          value: '-DRGENGC_FORCE_MAJOR_GC' }
-#         - { key: cppflags, name: RGENGC_OBJ_INFO,                value: '-DRGENGC_OBJ_INFO' }
-#         - { key: cppflags, name: RGENGC_OLD_NEWOBJ_CHECK,        value: '-DRGENGC_OLD_NEWOBJ_CHECK' }
-#         - { key: cppflags, name: RGENGC_PROFILE,                 value: '-DRGENGC_PROFILE' }
-
-#         - { key: cppflags, name: VM_DEBUG_BP_CHECK,              value: '-DVM_DEBUG_BP_CHECK' }
-#         - { key: cppflags, name: VM_DEBUG_VERIFY_METHOD_CACHE,   value: '-DVM_DEBUG_VERIFY_METHOD_CACHE' }
-
-          - { key: cppflags, name: MJIT_FORCE_ENABLE,              value: '-DMJIT_FORCE_ENABLE' }
-          - { key: cppflags, name: YJIT_FORCE_ENABLE,              value: '-DYJIT_FORCE_ENABLE' }
-
-    name: ${{ matrix.entry.name }}
+  compile-if:
+    name: 'omnibus compilations, trigger'
     runs-on: ubuntu-latest
-    container:
-      image: ghcr.io/ruby/ruby-ci-image:${{ matrix.entry.container || 'clang-15' }}
-      options: --user root
-    if: ${{ !startsWith(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.head_commit.message, 'Document')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.title, 'Document')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
     steps:
-      - run: id
+      - run: true
         working-directory:
-      - run: mkdir build
-        working-directory:
-      - name: setenv
-        run: |
-          echo "${{ matrix.entry.key }}=${{ matrix.entry.value }}" >> $GITHUB_ENV
-          echo "GNUMAKEFLAGS=-sj$((1 + $(nproc --all)))" >> $GITHUB_ENV
-      - uses: actions/checkout@v3
+
+  compile1:
+    name: 'omnibus compilations, #1'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with: { sparse-checkout-cone-mode: false, sparse-checkout: /.github }
+      # Set fetch-depth: 10 so that Launchable can receive commits information.
+      - { uses: './.github/actions/setup/directories', with: { srcdir: 'src', builddir: 'build', makeup: true, fetch-depth: 10 } }
+      - name: 'clang 18 LTO'
+        uses: './.github/actions/compilers'
         with:
-          path: src
-      - uses: actions/cache@v3
+          tag: clang-18
+          with_gcc: 'clang-18 -flto=auto'
+          optflags: '-O2'
+          enable_shared: false
+      - { uses: './.github/actions/compilers', name: '-O0', with: { optflags: '-O0 -march=x86-64 -mtune=generic' } }
+      # - { uses: './.github/actions/compilers', name: '-O3', with: { optflags: '-O3 -march=x86-64 -mtune=generic', check: true } }
+
+  compile2:
+    name: 'omnibus compilations, #2'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with: { sparse-checkout-cone-mode: false, sparse-checkout: /.github }
+      - { uses: './.github/actions/setup/directories', with: { srcdir: 'src', builddir: 'build', makeup: true, fetch-depth: 10 } }
+      - name: 'GCC 13 LTO'
+        uses: './.github/actions/compilers'
         with:
-          path: src/.downloaded-cache
-          key: downloaded-cache
-      - run: ./autogen.sh
-        working-directory: src
-      - name: Run configure
-        run: >
-          ../src/configure -C ${default_configure} ${append_configure}
-          ${{ matrix.entry.key == 'crosshost' && '--host="${crosshost}"' || '--with-gcc="${default_cc} ${append_cc}"' }}
-          ${{ matrix.entry.shared || '--enable-shared' }}
-      - run: make extract-extlibs
-      - run: make incs
-      - run: make
-      - run: make leaked-globals
-      - run: make test
-      - run: make install
-        if: ${{ matrix.entry.check }}
-      - run: make prepare-gems
-        if: ${{ matrix.entry.check }}
-      - run: make test-tool
-        if: ${{ matrix.entry.check }}
-      - run: make test-all TESTS='-- ruby -ext-'
-        if: ${{ matrix.entry.check }}
-      - run: make test-spec
-        if: ${{ matrix.entry.check }}
-
-      - uses: k0kubun/action-slack@v2.0.0
+          tag: gcc-13
+          with_gcc: 'gcc-13 -flto=auto -ffat-lto-objects -Werror=lto-type-mismatch'
+          optflags: '-O2'
+          enable_shared: false
+      - { uses: './.github/actions/compilers', name: 'ext/Setup', with: { static_exts: 'etc json/* */escape' } }
+      - { uses: './.github/actions/compilers', name: 'GCC 14', with: { tag: 'gcc-14' } }
+      - { uses: './.github/actions/compilers', name: 'GCC 13', with: { tag: 'gcc-13' } }
+      - { uses: './.github/actions/compilers', name: 'GCC 12', with: { tag: 'gcc-12' } }
+      - { uses: './.github/actions/compilers', name: 'GCC 11', with: { tag: 'gcc-11' } }
+      - { uses: './.github/actions/compilers', name: 'GCC 10', with: { tag: 'gcc-10' } }
+      - { uses: './.github/actions/compilers', name: 'GCC 9',  with: { tag: 'gcc-9'  } }
+      - { uses: './.github/actions/compilers', name: 'GCC 8',  with: { tag: 'gcc-8'  } }
+      - { uses: './.github/actions/compilers', name: 'GCC 7',  with: { tag: 'gcc-7'  } }
+
+  compile3:
+    name: 'omnibus compilations, #3'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with: { sparse-checkout-cone-mode: false, sparse-checkout: /.github }
+      - { uses: './.github/actions/setup/directories', with: { srcdir: 'src', builddir: 'build', makeup: true, fetch-depth: 10 } }
+      - { uses: './.github/actions/compilers', name: 'clang 20', with: { tag: 'clang-20' } }
+      - { uses: './.github/actions/compilers', name: 'clang 19', with: { tag: 'clang-19' } }
+      - { uses: './.github/actions/compilers', name: 'clang 18', with: { tag: 'clang-18' } }
+      - { uses: './.github/actions/compilers', name: 'clang 17', with: { tag: 'clang-17' } }
+      - { uses: './.github/actions/compilers', name: 'clang 16', with: { tag: 'clang-16' } }
+      - { uses: './.github/actions/compilers', name: 'clang 15', with: { tag: 'clang-15' } }
+      - { uses: './.github/actions/compilers', name: 'clang 14', with: { tag: 'clang-14' } }
+
+  compile4:
+    name: 'omnibus compilations, #4'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with: { sparse-checkout-cone-mode: false, sparse-checkout: /.github }
+      - { uses: './.github/actions/setup/directories', with: { srcdir: 'src', builddir: 'build', makeup: true, fetch-depth: 10 } }
+      - { uses: './.github/actions/compilers', name: 'clang 13', with: { tag: 'clang-13' } }
+      - { uses: './.github/actions/compilers', name: 'clang 12', with: { tag: 'clang-12' } }
+      - { uses: './.github/actions/compilers', name: 'clang 11', with: { tag: 'clang-11' } }
+      - { uses: './.github/actions/compilers', name: 'clang 10', with: { tag: 'clang-10' } }
+        # llvm-objcopy<=9 doesn't have --wildcard. It compiles, but leaves Rust symbols in libyjit.o.
+      - { uses: './.github/actions/compilers', name: 'clang 9',  with: { tag: 'clang-9',   append_configure: '--disable-yjit' } }
+      - { uses: './.github/actions/compilers', name: 'clang 8',  with: { tag: 'clang-8',   append_configure: '--disable-yjit' } }
+      - { uses: './.github/actions/compilers', name: 'clang 7',  with: { tag: 'clang-7',   append_configure: '--disable-yjit' } }
+      - { uses: './.github/actions/compilers', name: 'clang 6',  with: { tag: 'clang-6.0', append_configure: '--disable-yjit' } }
+
+  compile5:
+    name: 'omnibus compilations, #5'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with: { sparse-checkout-cone-mode: false, sparse-checkout: /.github }
+      - { uses: './.github/actions/setup/directories', with: { srcdir: 'src', builddir: 'build', makeup: true, fetch-depth: 10 } }
+      # -Wno-strict-prototypes is necessary with current clang-15 since
+      # older autoconf generate functions without prototype and -pedantic
+      # now implies strict-prototypes. Disabling the error but leaving the
+      # warning generates a lot of noise from use of ANYARGS in
+      # rb_define_method() and friends.
+      # See: https://github.com/llvm/llvm-project/commit/11da1b53d8cd3507959022cd790d5a7ad4573d94
+      - { uses: './.github/actions/compilers', name: 'C99',      with: { CFLAGS: '-std=c99 -Werror=pedantic -pedantic-errors -Wno-strict-prototypes' } }
+      - { uses: './.github/actions/compilers', name: 'C11',   with: { CFLAGS:   '-std=c11   -Werror=pedantic -pedantic-errors -Wno-strict-prototypes' } }
+      - { uses: './.github/actions/compilers', name: 'C17',   with: { CFLAGS:   '-std=c17   -Werror=pedantic -pedantic-errors -Wno-strict-prototypes' } }
+      - { uses: './.github/actions/compilers', name: 'C23',   with: { CFLAGS:   '-std=c2x   -Werror=pedantic -pedantic-errors -Wno-strict-prototypes' } }
+      - { uses: './.github/actions/compilers', name: 'C++98', with: { CXXFLAGS: '-std=c++98 -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' } }
+      - { uses: './.github/actions/compilers', name: 'C++11', with: { CXXFLAGS: '-std=c++11 -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' } }
+      - { uses: './.github/actions/compilers', name: 'C++14', with: { CXXFLAGS: '-std=c++14 -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' } }
+      - { uses: './.github/actions/compilers', name: 'C++17', with: { CXXFLAGS: '-std=c++17 -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' } }
+
+  compile6:
+    name: 'omnibus compilations, #6'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with: { sparse-checkout-cone-mode: false, sparse-checkout: /.github }
+      - { uses: './.github/actions/setup/directories', with: { srcdir: 'src', builddir: 'build', makeup: true, fetch-depth: 10 } }
+      - { uses: './.github/actions/compilers', name: 'C++20', with: { CXXFLAGS: '-std=c++20 -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' } }
+      - { uses: './.github/actions/compilers', name: 'C++23', with: { CXXFLAGS: '-std=c++23 -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' } }
+      - { uses: './.github/actions/compilers', name: 'C++26', with: { CXXFLAGS: '-std=c++26 -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' } }
+      - { uses: './.github/actions/compilers', name: 'gmp',                 with: { append_configure: '--with-gmp', check: 'ruby/test_bignum.rb', mspecopt: "/github/workspace/src/spec/ruby/core/integer" } }
+      - { uses: './.github/actions/compilers', name: 'jemalloc',            with: { append_configure: '--with-jemalloc' } }
+      - { uses: './.github/actions/compilers', name: 'valgrind',            with: { append_configure: '--with-valgrind' } }
+      - { uses: './.github/actions/compilers', name: 'coroutine=ucontext',  with: { append_configure: '--with-coroutine=ucontext' } }
+      - { uses: './.github/actions/compilers', name: 'coroutine=pthread',   with: { append_configure: '--with-coroutine=pthread' } }
+
+  compile7:
+    name: 'omnibus compilations, #7'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with: { sparse-checkout-cone-mode: false, sparse-checkout: /.github }
+      - { uses: './.github/actions/setup/directories', with: { srcdir: 'src', builddir: 'build', makeup: true, fetch-depth: 10 } }
+      - { uses: './.github/actions/compilers', name: 'disable-jit',         with: { append_configure: '--disable-yjit --disable-rjit' } }
+      - { uses: './.github/actions/compilers', name: 'disable-dln',         with: { append_configure: '--disable-dln' } }
+      - { uses: './.github/actions/compilers', name: 'enable-mkmf-verbose', with: { append_configure: '--enable-mkmf-verbose' } }
+      - { uses: './.github/actions/compilers', name: 'disable-rubygems',    with: { append_configure: '--disable-rubygems' } }
+      - { uses: './.github/actions/compilers', name: 'RUBY_DEVEL',          with: { append_configure: '--enable-devel' } }
+      - { uses: './.github/actions/compilers', name: 'OPT_THREADED_CODE=0',            with: { cppflags: '-DOPT_THREADED_CODE=0' } }
+      - { uses: './.github/actions/compilers', name: 'OPT_THREADED_CODE=1',            with: { cppflags: '-DOPT_THREADED_CODE=1' } }
+      - { uses: './.github/actions/compilers', name: 'OPT_THREADED_CODE=2',            with: { cppflags: '-DOPT_THREADED_CODE=2' } }
+
+  compile8:
+    name: 'omnibus compilations, #8'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with: { sparse-checkout-cone-mode: false, sparse-checkout: /.github }
+      - { uses: './.github/actions/setup/directories', with: { srcdir: 'src', builddir: 'build', makeup: true, fetch-depth: 10 } }
+      - { uses: './.github/actions/compilers', name: 'NDEBUG',                         with: { cppflags: '-DNDEBUG' } }
+      - { uses: './.github/actions/compilers', name: 'RUBY_DEBUG',                     with: { cppflags: '-DRUBY_DEBUG' } }
+      - { uses: './.github/actions/compilers', name: 'ARRAY_DEBUG',                    with: { cppflags: '-DARRAY_DEBUG' } }
+      - { uses: './.github/actions/compilers', name: 'BIGNUM_DEBUG',                   with: { cppflags: '-DBIGNUM_DEBUG' } }
+      - { uses: './.github/actions/compilers', name: 'CCAN_LIST_DEBUG',                with: { cppflags: '-DCCAN_LIST_DEBUG' } }
+      - { uses: './.github/actions/compilers', name: 'CPDEBUG=-1',                     with: { cppflags: '-DCPDEBUG=-1' } }
+      - { uses: './.github/actions/compilers', name: 'ENC_DEBUG',                      with: { cppflags: '-DENC_DEBUG' } }
+      - { uses: './.github/actions/compilers', name: 'GC_DEBUG',                       with: { cppflags: '-DGC_DEBUG' } }
+
+  compile9:
+    name: 'omnibus compilations, #9'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with: { sparse-checkout-cone-mode: false, sparse-checkout: /.github }
+      - { uses: './.github/actions/setup/directories', with: { srcdir: 'src', builddir: 'build', makeup: true, fetch-depth: 10 } }
+      - { uses: './.github/actions/compilers', name: 'HASH_DEBUG',                     with: { cppflags: '-DHASH_DEBUG' } }
+      - { uses: './.github/actions/compilers', name: 'ID_TABLE_DEBUG',                 with: { cppflags: '-DID_TABLE_DEBUG' } }
+      - { uses: './.github/actions/compilers', name: 'RGENGC_DEBUG=-1',                with: { cppflags: '-DRGENGC_DEBUG=-1' } }
+      - { uses: './.github/actions/compilers', name: 'SYMBOL_DEBUG',                   with: { cppflags: '-DSYMBOL_DEBUG' } }
+      - { uses: './.github/actions/compilers', name: 'RGENGC_CHECK_MODE',              with: { cppflags: '-DRGENGC_CHECK_MODE' } }
+      - { uses: './.github/actions/compilers', name: 'VM_CHECK_MODE',                  with: { cppflags: '-DVM_CHECK_MODE' } }
+      - { uses: './.github/actions/compilers', name: 'USE_EMBED_CI=0',                 with: { cppflags: '-DUSE_EMBED_CI=0' } }
+      - { uses: './.github/actions/compilers', name: 'USE_FLONUM=0',                   with: { cppflags: '-DUSE_FLONUM=0', append_configure: '--disable-yjit' } }
+
+  compileX:
+    name: 'omnibus compilations, #10'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with: { sparse-checkout-cone-mode: false, sparse-checkout: /.github }
+      - { uses: './.github/actions/setup/directories', with: { srcdir: 'src', builddir: 'build', makeup: true, fetch-depth: 10 } }
+      - { uses: './.github/actions/compilers', name: 'USE_LAZY_LOAD',                  with: { cppflags: '-DUSE_LAZY_LOAD' } }
+      - { uses: './.github/actions/compilers', name: 'USE_SYMBOL_GC=0',                with: { cppflags: '-DUSE_SYMBOL_GC=0' } }
+      - { uses: './.github/actions/compilers', name: 'USE_THREAD_CACHE=0',             with: { cppflags: '-DUSE_THREAD_CACHE=0' } }
+      - { uses: './.github/actions/compilers', name: 'USE_RUBY_DEBUG_LOG=1',           with: { cppflags: '-DUSE_RUBY_DEBUG_LOG=1' } }
+      - { uses: './.github/actions/compilers', name: 'USE_DEBUG_COUNTER',              with: { cppflags: '-DUSE_DEBUG_COUNTER=1' } }
+      - { uses: './.github/actions/compilers', name: 'SHARABLE_MIDDLE_SUBSTRING',      with: { cppflags: '-DSHARABLE_MIDDLE_SUBSTRING=1' } }
+      - { uses: './.github/actions/compilers', name: 'DEBUG_FIND_TIME_NUMGUESS',       with: { cppflags: '-DDEBUG_FIND_TIME_NUMGUESS' } }
+      - { uses: './.github/actions/compilers', name: 'DEBUG_INTEGER_PACK',             with: { cppflags: '-DDEBUG_INTEGER_PACK' } }
+
+  compileB:
+    name: 'omnibus compilations, #11'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with: { sparse-checkout-cone-mode: false, sparse-checkout: /.github }
+      - { uses: './.github/actions/setup/directories', with: { srcdir: 'src', builddir: 'build', makeup: true, fetch-depth: 10 } }
+      - { uses: './.github/actions/compilers', name: 'GC_DEBUG_STRESS_TO_CLASS',       with: { cppflags: '-DGC_DEBUG_STRESS_TO_CLASS' } }
+      - { uses: './.github/actions/compilers', name: 'GC_ENABLE_LAZY_SWEEP=0',         with: { cppflags: '-DGC_ENABLE_LAZY_SWEEP=0' } }
+      - { uses: './.github/actions/compilers', name: 'GC_PROFILE_DETAIL_MEMORY',       with: { cppflags: '-DGC_PROFILE_DETAIL_MEMORY' } }
+      - { uses: './.github/actions/compilers', name: 'GC_PROFILE_MORE_DETAIL',         with: { cppflags: '-DGC_PROFILE_MORE_DETAIL' } }
+      - { uses: './.github/actions/compilers', name: 'MALLOC_ALLOCATED_SIZE_CHECK',    with: { cppflags: '-DMALLOC_ALLOCATED_SIZE_CHECK' } }
+      - { uses: './.github/actions/compilers', name: 'RGENGC_ESTIMATE_OLDMALLOC',      with: { cppflags: '-DRGENGC_ESTIMATE_OLDMALLOC' } }
+      - { uses: './.github/actions/compilers', name: 'RGENGC_OBJ_INFO',                with: { cppflags: '-DRGENGC_OBJ_INFO' } }
+      - { uses: './.github/actions/compilers', name: 'RGENGC_PROFILE',                 with: { cppflags: '-DRGENGC_PROFILE' } }
+
+  compileC:
+    name: 'omnibus compilations, #12'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with: { sparse-checkout-cone-mode: false, sparse-checkout: /.github }
+      - { uses: './.github/actions/setup/directories', with: { srcdir: 'src', builddir: 'build', makeup: true, fetch-depth: 10 } }
+      - { uses: './.github/actions/compilers', name: 'VM_DEBUG_BP_CHECK',              with: { cppflags: '-DVM_DEBUG_BP_CHECK' } }
+      - { uses: './.github/actions/compilers', name: 'VM_DEBUG_VERIFY_METHOD_CACHE',   with: { cppflags: '-DVM_DEBUG_VERIFY_METHOD_CACHE' } }
+      - { uses: './.github/actions/compilers', name: 'enable-yjit',                    with: { append_configure: '--enable-yjit --disable-rjit' } }
+      - { uses: './.github/actions/compilers', name: 'enable-rjit',                    with: { append_configure: '--enable-rjit --disable-yjit' } }
+      - { uses: './.github/actions/compilers', name: 'YJIT_FORCE_ENABLE',              with: { cppflags: '-DYJIT_FORCE_ENABLE' } }
+      - { uses: './.github/actions/compilers', name: 'RJIT_FORCE_ENABLE',              with: { cppflags: '-DRJIT_FORCE_ENABLE' } }
+      - { uses: './.github/actions/compilers', name: 'UNIVERSAL_PARSER',               with: { cppflags: '-DUNIVERSAL_PARSER' } }
+
+  compilemax:
+    name: 'omnibus compilations, result'
+    runs-on: ubuntu-latest
+    if: ${{ always() }}
+    needs:
+      - 'compile1'
+      - 'compile2'
+      - 'compile3'
+      - 'compile4'
+      - 'compile5'
+      - 'compile6'
+      - 'compile7'
+      - 'compile8'
+      - 'compile9'
+      - 'compileX'
+      - 'compileB'
+      - 'compileC'
+    steps:
+      - uses: ./.github/actions/slack
         with:
-          payload: |
-            {
-              "ci": "GitHub Actions",
-              "env": "${{ github.workflow }} / ${{ matrix.entry.name }}",
-              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
-              "commit": "${{ github.sha }}",
-              "branch": "${{ github.ref }}".split('/').reverse()[0]
-            }
-        env:
+          label: 'omnibus'
           SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
-        if: ${{ failure() && github.event_name == 'push' }}
+        if: ${{ contains(needs.*.result, 'failure') || contains(needs.*.result, 'cancelled') }}
+      - run: false
+        working-directory:
+        if: ${{ contains(needs.*.result, 'failure') || contains(needs.*.result, 'cancelled') }}
 
 defaults:
   run:
diff --git a/.github/workflows/cygwin.yml b/.github/workflows/cygwin.yml
new file mode 100644
index 0000000000..3467fc0b70
--- /dev/null
+++ b/.github/workflows/cygwin.yml
@@ -0,0 +1,61 @@
+name: Cygwin
+on:
+  push:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man/*'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
+  pull_request:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man/*'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
+  merge_group:
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:
+  contents: read
+
+jobs:
+  make:
+    runs-on: windows-2022
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.head_commit.message, 'Document')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.title, 'Document')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
+    steps:
+      - run: git config --global core.autocrlf input
+
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+
+      - name: Setup Cygwin
+        uses: cygwin/cygwin-install-action@master
+        with:
+          packages: ruby gcc-core make autoconf libtool libssl-devel libyaml-devel libffi-devel zlib-devel
+
+      - name: configure
+        run: |
+          ./autogen.sh
+          ./configure --disable-install-doc
+        shell: C:\cygwin\bin\bash.EXE --noprofile --norc -e -o igncr -o pipefail {0}
+
+      - name: make all
+        timeout-minutes: 30
+        run: make -j2 V=1
+        shell: C:\cygwin\bin\bash.EXE --noprofile --norc -e -o igncr -o pipefail {0}
diff --git a/.github/workflows/default_gems.yml b/.github/workflows/default_gems.yml
new file mode 100644
index 0000000000..ea2e287066
--- /dev/null
+++ b/.github/workflows/default_gems.yml
@@ -0,0 +1,95 @@
+name: Update default gems list
+on: [push, pull_request, merge_group]
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:
+  contents: read
+
+jobs:
+  update_default_gems:
+    name: Update default gems list
+
+    permissions:
+      contents: write # for Git to git push
+
+    runs-on: ubuntu-latest
+
+    if: ${{ github.repository == 'ruby/ruby' }}
+
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with:
+          token: ${{ (github.repository == 'ruby/ruby' && !startsWith(github.event_name, 'pull')) && secrets.MATZBOT_GITHUB_TOKEN || secrets.GITHUB_TOKEN }}
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          makeup: true
+          # Skip overwriting MATZBOT_GITHUB_TOKEN
+          checkout: '' # false (ref: https://github.com/actions/runner/issues/2238)
+
+      - id: gems
+        run: true
+        if: ${{ github.ref == 'refs/heads/master' }}
+
+      - name: Download previous gems list
+        run: |
+          data=default_gems.json
+          mkdir -p .downloaded-cache
+          ln -s .downloaded-cache/$data .
+          curl -O -R -z ./$data https://stdgems.org/$data
+        if: ${{ steps.gems.outcome == 'success' }}
+
+      - name: Make default gems list
+        run: |
+          #!ruby
+          require 'rubygems'
+          $:.unshift "lib"
+          rgver = File.foreach("lib/rubygems.rb") do |line|
+            break $1 if /^\s*VERSION\s*=\s*"([^"]+)"/ =~ line
+          end
+          gems = Dir.glob("{ext,lib}/**/*.gemspec").map do |f|
+            spec = Gem::Specification.load(f)
+            "#{spec.name} #{spec.version}"
+          end.sort
+          File.open("gems/default_gems", "w") do |f|
+            f.puts "RubyGems #{rgver}"
+            f.puts gems
+          end
+        shell: ruby --disable=gems {0}
+        if: ${{ steps.gems.outcome == 'success' }}
+
+      - name: Maintain updated gems list in NEWS
+        run: |
+          ruby tool/update-NEWS-gemlist.rb default
+        if: ${{ steps.gems.outcome == 'success' }}
+
+      - name: Check diffs
+        id: diff
+        run: |
+          git diff --color --no-ext-diff --ignore-submodules --exit-code NEWS.md ||
+          echo update=true >> $GITHUB_OUTPUT
+        if: ${{ steps.gems.outcome == 'success' }}
+
+      - name: Commit
+        run: |
+          git pull --ff-only origin ${GITHUB_REF#refs/heads/}
+          git commit --message="Update default gems list at ${GITHUB_SHA:0:30} [ci skip]" NEWS.md
+          git push origin ${GITHUB_REF#refs/heads/}
+        env:
+          EMAIL: svn-admin@ruby-lang.org
+          GIT_AUTHOR_NAME: git
+          GIT_COMMITTER_NAME: git
+        if: >-
+          ${{
+          github.repository == 'ruby/ruby' &&
+          !startsWith(github.event_name, 'pull') &&
+          steps.diff.outputs.update
+          }}
+
+      - uses: ./.github/actions/slack
+        with:
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() }}
diff --git a/.github/workflows/dependabot_automerge.yml b/.github/workflows/dependabot_automerge.yml
new file mode 100644
index 0000000000..69ab5d9131
--- /dev/null
+++ b/.github/workflows/dependabot_automerge.yml
@@ -0,0 +1,30 @@
+# from https://github.com/gofiber/swagger/blob/main/.github/workflows/dependabot_automerge.yml
+name: Dependabot auto-merge
+on:
+  pull_request_target:
+
+jobs:
+  automerge:
+    runs-on: ubuntu-latest
+
+    if: ${{ github.event.pull_request.user.login == 'dependabot[bot]' }}
+
+    steps:
+      - name: Dependabot metadata
+        uses: dependabot/fetch-metadata@dbb049abf0d677abbd7f7eee0375145b417fdd34 # v2.2.0
+        id: metadata
+
+      - name: Wait for status checks
+        uses: lewagon/wait-on-check-action@ccfb013c15c8afb7bf2b7c028fb74dc5a068cccc # v1.3.4
+        with:
+          repo-token: ${{ secrets.MATZBOT_GITHUB_TOKEN }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
+          check-regexp: 'make \(check, .*\)'
+          wait-interval: 30
+
+      - name: Auto-merge for Dependabot PRs
+        if: ${{ steps.metadata.outputs.update-type == 'version-update:semver-minor' || steps.metadata.outputs.update-type == 'version-update:semver-patch' }}
+        run: gh pr merge --auto --rebase "$PR_URL"
+        env:
+          PR_URL: ${{ github.event.pull_request.html_url }}
+          GITHUB_TOKEN: ${{ secrets.MATZBOT_GITHUB_TOKEN }}
diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
new file mode 100644
index 0000000000..d0cdfc69af
--- /dev/null
+++ b/.github/workflows/macos.yml
@@ -0,0 +1,187 @@
+name: macOS
+on:
+  push:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man/*'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
+  pull_request:
+    # Do not use paths-ignore for required status checks
+    # https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/collaborating-on-repositories-with-code-quality-features/troubleshooting-required-status-checks#handling-skipped-but-required-checks
+  merge_group:
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:
+  contents: read
+
+jobs:
+  make:
+    strategy:
+      matrix:
+        include:
+          - test_task: check
+            os: macos-14
+          - test_task: check
+            os: macos-14
+            configure_args: '--with-gcc=gcc-14'
+          - test_task: check
+            os: macos-14
+            configure_args: '--with-jemalloc --with-opt-dir=$(brew --prefix jemalloc)'
+          - test_task: check
+            os: macos-14
+            configure_args: '--with-gmp'
+          - test_task: test-all
+            test_opts: --repeat-count=2
+            os: macos-14
+          - test_task: test-bundler-parallel
+            os: macos-14
+          - test_task: test-bundled-gems
+            os: macos-14
+          - test_task: check
+            os: macos-15
+          - test_task: check
+            os: macos-13
+      fail-fast: false
+
+    env:
+      GITPULLOPTIONS: --no-tags origin ${{ github.ref }}
+
+    runs-on: ${{ matrix.os }}
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.head_commit.message, 'Document')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.title, 'Document')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with:
+          sparse-checkout-cone-mode: false
+          sparse-checkout: /.github
+
+      - name: Install libraries
+        uses: ./.github/actions/setup/macos
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          srcdir: src
+          builddir: build
+          makeup: true
+          clean: true
+          dummy-files: ${{ matrix.test_task == 'check' }}
+          # Set fetch-depth: 0 so that Launchable can receive commits information.
+          fetch-depth: 10
+
+      - name: make sure that kern.coredump=1
+        run: |
+          sysctl -n kern.coredump
+          sudo sysctl -w kern.coredump=1
+          sudo chmod -R +rwx /cores/
+
+      - name: Delete unused SDKs
+        # To free up disk space to not run out during the run
+        run: |
+          sudo rm -rf ~/.dotnet
+          sudo rm -rf /Library/Android
+          sudo rm -rf /Library/Developer/CoreSimulator
+        continue-on-error: true
+
+      - name: Run configure
+        run: ../src/configure -C --disable-install-doc ${ruby_configure_args} ${{ matrix.configure_args }}
+
+      - run: make prepare-gems
+        if: ${{ matrix.test_task == 'test-bundled-gems' }}
+
+      - run: make
+
+      - run: make hello
+
+      - name: Set test options for skipped tests
+        run: |
+          set -x
+          TESTS="$(echo "${{ matrix.skipped_tests }}" | sed 's| |$$/ -n!/|g;s|^|-n!/|;s|$|$$/|')"
+          echo "TESTS=${TESTS}" >> $GITHUB_ENV
+        if: ${{ matrix.test_task == 'check' && matrix.skipped_tests }}
+
+      - name: Set up Launchable
+        uses: ./.github/actions/launchable/setup
+        with:
+          os: ${{ matrix.os }}
+          test-opts: ${{ matrix.test_opts }}
+          launchable-token: ${{ secrets.LAUNCHABLE_TOKEN }}
+          builddir: build
+          srcdir: src
+        continue-on-error: true
+
+      - name: Set extra test options
+        run: |
+          echo "TESTS=$TESTS ${{ matrix.test_opts }}" >> $GITHUB_ENV
+          echo "RUBY_TEST_TIMEOUT_SCALE=10" >> $GITHUB_ENV # With --repeat-count=2, flaky test by timeout occurs frequently for some reason
+        if: matrix.test_opts
+
+      - name: make ${{ matrix.test_task }}
+        run: |
+          ulimit -c unlimited
+          make -s ${{ matrix.test_task }} ${TESTS:+TESTS="$TESTS"}
+        timeout-minutes: 60
+        env:
+          RUBY_TESTOPTS: '-q --tty=no'
+          TEST_BUNDLED_GEMS_ALLOW_FAILURES: 'typeprof'
+          PRECHECK_BUNDLED_GEMS: 'no'
+
+      - name: make skipped tests
+        run: |
+          make -s test-all TESTS="${TESTS//-n!\//-n/}"
+        env:
+          GNUMAKEFLAGS: ''
+          RUBY_TESTOPTS: '-v --tty=no'
+          PRECHECK_BUNDLED_GEMS: 'no'
+        if: ${{ matrix.test_task == 'check' && matrix.skipped_tests }}
+        continue-on-error: ${{ matrix.continue-on-skipped_tests || false }}
+
+      - uses: ./.github/actions/slack
+        with:
+          label: ${{ matrix.os }} / ${{ matrix.test_task }}
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() }}
+
+      - name: Resolve job ID
+        id: job_id
+        uses: actions/github-script@main
+        env:
+          matrix: ${{ toJson(matrix) }}
+        with:
+          script: |
+            const { data: workflow_run } = await github.rest.actions.listJobsForWorkflowRun({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              run_id: context.runId
+            });
+            const matrix = JSON.parse(process.env.matrix);
+            const job_name = `${context.job}${matrix ? ` (${Object.values(matrix).join(", ")})` : ""}`;
+            return workflow_run.jobs.find((job) => job.name === job_name).id;
+
+  result:
+    if: ${{ always() }}
+    name: ${{ github.workflow }} result
+    runs-on: macos-latest
+    needs: [make]
+    steps:
+      - run: exit 1
+        working-directory:
+        if: ${{ contains(needs.*.result, 'failure') || contains(needs.*.result, 'cancelled') }}
+
+defaults:
+  run:
+    working-directory: build
diff --git a/.github/workflows/mingw.yml b/.github/workflows/mingw.yml
index 8e3aec6e6f..898a51b63f 100644
--- a/.github/workflows/mingw.yml
+++ b/.github/workflows/mingw.yml
@@ -3,158 +3,166 @@ on:
   push:
     paths-ignore:
       - 'doc/**'
+      - '**/man/*'
       - '**.md'
       - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
   pull_request:
     paths-ignore:
       - 'doc/**'
+      - '**/man/*'
       - '**.md'
       - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
+  merge_group:
 
 concurrency:
   group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
   cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
 
+permissions:
+  contents: read
+
 # Notes:
 # Actions console encoding causes issues, see test-all & test-spec steps
 #
 jobs:
   make:
     runs-on: windows-2022
+
     name: ${{ github.workflow }} (${{ matrix.msystem }})
+
     env:
       MSYSTEM: ${{ matrix.msystem }}
       MSYS2_ARCH: x86_64
-      CHOST: "x86_64-w64-mingw32"
-      CFLAGS:   "-march=x86-64 -mtune=generic -O3 -pipe -fstack-protector-strong"
-      CXXFLAGS: "-march=x86-64 -mtune=generic -O3 -pipe"
-      CPPFLAGS: "-D_FORTIFY_SOURCE=2 -D__USE_MINGW_ANSI_STDIO=1 -DFD_SETSIZE=2048"
-      LDFLAGS:  "-pipe -fstack-protector-strong"
-      UPDATE_UNICODE: "UNICODE_FILES=. UNICODE_PROPERTY_FILES=. UNICODE_AUXILIARY_FILES=. UNICODE_EMOJI_FILES=."
-      GITPULLOPTIONS: --no-tags origin ${{github.ref}}
+      CHOST: 'x86_64-w64-mingw32'
+      CFLAGS: '-march=x86-64 -mtune=generic -O3 -pipe'
+      CXXFLAGS: '-march=x86-64 -mtune=generic -O3 -pipe'
+      CPPFLAGS: '-D_FORTIFY_SOURCE=2 -D__USE_MINGW_ANSI_STDIO=1 -DFD_SETSIZE=2048'
+      LDFLAGS: '-pipe'
+      GITPULLOPTIONS: --no-tags origin ${{ github.ref }}
+
     strategy:
       matrix:
         include:
-          - msystem: "MINGW64"
-            base_ruby: 2.6
-            test_task: "check" # to make job names consistent
-          - msystem: "UCRT64"
-            base_ruby: head
-            test_task: "check" # to make job names consistent
+          # To mitigate flakiness of MinGW CI, we test only one runtime that newer MSYS2 uses.
+          # Ruby 3.2 is the first Windows Ruby to use OpenSSL 3.x
+          - msystem: 'UCRT64'
+            baseruby: '3.2'
+            test_task: 'check'
+            test-all-opts: '--name=!/TestObjSpace#test_reachable_objects_during_iteration/'
       fail-fast: false
-    if: ${{ !startsWith(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.head_commit.message, 'Document')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.title, 'Document')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
     steps:
-      - run: mkdir build
-        working-directory:
-      - name: git config
-        run: |
-          git config --global core.autocrlf false
-          git config --global core.eol lf
-          git config --global advice.detachedHead 0
-          git config --global init.defaultBranch garbage
-      - uses: actions/checkout@v3
-        with:
-          path: src
-      - uses: actions/cache@v3
-        with:
-          path: src/.downloaded-cache
-          key: downloaded-cache
       - name: Set up Ruby & MSYS2
-        uses: ruby/setup-ruby@v1
+        uses: ruby/setup-ruby@a6e6f86333f0a2523ece813039b8b4be04560854 # v1.190.0
         with:
-          ruby-version: ${{ matrix.base_ruby }}
-      - name: set env
-        run: |
-          echo "GNUMAKEFLAGS=-j$((2 * NUMBER_OF_PROCESSORS))" >> $GITHUB_ENV
-          echo "TEST_JOBS=$((15 * NUMBER_OF_PROCESSORS / 10))" >> $GITHUB_ENV
+          ruby-version: ${{ matrix.baseruby }}
 
-      - name: where check
+      - name: Misc system & package info
+        working-directory:
         run: |
           # show where
-          mv /c/Windows/System32/libcrypto-1_1-x64.dll /c/Windows/System32/libcrypto-1_1-x64.dll_
-          mv /c/Windows/System32/libssl-1_1-x64.dll    /c/Windows/System32/libssl-1_1-x64.dll_
           result=true
-          for e in gcc.exe ragel.exe make.exe bison.exe libcrypto-1_1-x64.dll libssl-1_1-x64.dll; do
-            echo '##['group']'$'\033[93m'$e$'\033[m'
+          for e in gcc.exe ragel.exe make.exe libcrypto-3-x64.dll libssl-3-x64.dll; do
+            echo ::group::$'\033[93m'$e$'\033[m'
             where $e || result=false
-            echo '##['endgroup']'
+            echo ::endgroup::
           done
-          $result
-
-      - name: version check
-        run: |
           # show version
-          result=true
-          for e in gcc ragel make bison "openssl version"; do
+          for e in gcc ragel make "openssl version"; do
             case "$e" in *" "*) ;; *) e="$e --version";; esac
-            echo '##['group']'$'\033[93m'$e$'\033[m'
+            echo ::group::$'\033[93m'$e$'\033[m'
             $e || result=false
-            echo '##['endgroup']'
+            echo ::endgroup::
           done
+          # show packages
+          echo ::group::$'\033[93m'Packages$'\033[m'
+          pacman -Qs mingw-w64-ucrt-x86_64-* | sed -n "s,local/mingw-w64-ucrt-x86_64-,,p"
+          echo ::endgroup::
           $result
 
-      - name: autogen
-        run: |
-          ./autogen.sh
-        working-directory: src
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with:
+          sparse-checkout-cone-mode: false
+          sparse-checkout: /.github
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          srcdir: src
+          builddir: build
+          makeup: true
+          # Set fetch-depth: 10 so that Launchable can receive commits information.
+          fetch-depth: 10
 
       - name: configure
         run: >
           ../src/configure --disable-install-doc --prefix=/.
           --build=$CHOST --host=$CHOST --target=$CHOST
 
-      - name: update
-        run: |
-          make incs
-
-      - name: download gems
-        run: |
-          make update-gems
-
       - name: make all
-        timeout-minutes: 20
-        run: |
-          make
-
-      - run: make leaked-globals
+        timeout-minutes: 30
+        run: make
 
       - name: make install
-        run: |
-          make DESTDIR=../install install-nodoc
+        run: make DESTDIR=../install install-nodoc
+
+      - name: Set up Launchable
+        uses: ./.github/actions/launchable/setup
+        with:
+          os: windows-2022
+          launchable-token: ${{ secrets.LAUNCHABLE_TOKEN }}
+          builddir: build
+          srcdir: src
+          test-tasks: '["test", "test-all", "test-spec"]'
+        continue-on-error: true
 
       - name: test
-        timeout-minutes: 5
-        run: |
-          make test
+        timeout-minutes: 30
+        run: make test
+        shell: cmd
+        env:
+          GNUMAKEFLAGS: ''
+          RUBY_TESTOPTS: '-v --tty=no'
+        if: ${{ matrix.test_task == 'check' || matrix.test_task == 'test' }}
 
       - name: test-all
         timeout-minutes: 45
+        shell: cmd
         run: |
-          # Actions uses UTF8, causes test failures, similar to normal OS setup
-          chcp.com 437
-          make test-all
+          make ${{ StartsWith(matrix.test_task, 'test/') && matrix.test_task || 'test-all' }}
         env:
-          RUBY_TESTOPTS: -j${{env.TEST_JOBS}} --retry --job-status=normal --show-skip --timeout-scale=1.5
+          RUBY_TESTOPTS: >-
+            --retry --job-status=normal --show-skip --timeout-scale=1.5
+            ${{ matrix.test-all-opts }}
+            ${{ env.TESTS }}
           BUNDLER_VERSION:
+        if: ${{ matrix.test_task == 'check' || matrix.test_task == 'test-all' || StartsWith(matrix.test_task, 'test/') }}
 
       - name: test-spec
         timeout-minutes: 10
         run: |
-          make test-spec
+          make ${{ StartsWith(matrix.test_task, 'spec/') && matrix.test_task || 'test-spec' }}
+        shell: cmd
+        if: ${{ matrix.test_task == 'check' || matrix.test_task == 'test-spec' || StartsWith(matrix.test_task, 'spec/') }}
 
-      - uses: k0kubun/action-slack@v2.0.0
+      - uses: ./src/.github/actions/slack
         with:
-          payload: |
-            {
-              "ci": "GitHub Actions",
-              "env": "${{ github.workflow }} ${{ matrix.msystem }} / ${{ matrix.test_task }}",
-              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
-              "commit": "${{ github.sha }}",
-              "branch": "${{ github.ref }}".split('/').reverse()[0]
-            }
-        env:
+          label: ${{ matrix.msystem }} / ${{ matrix.test_task }}
           SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
-        if: ${{ failure() && github.event_name == 'push' }}
+        if: ${{ failure() }}
 
 defaults:
   run:
diff --git a/.github/workflows/mjit.yml b/.github/workflows/mjit.yml
deleted file mode 100644
index d5d9cecc56..0000000000
--- a/.github/workflows/mjit.yml
+++ /dev/null
@@ -1,97 +0,0 @@
-name: MJIT
-on:
-  push:
-    paths-ignore:
-      - 'doc/**'
-      - '**.md'
-      - '**.rdoc'
-  pull_request:
-    paths-ignore:
-      - 'doc/**'
-      - '**.md'
-      - '**.rdoc'
-
-concurrency:
-  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
-  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
-
-jobs:
-  make:
-    strategy:
-      matrix:
-        test_task: [ "check" ] # to make job names consistent
-        jit_opts: [ "--mjit", "--mjit-wait" ]
-      fail-fast: false
-    runs-on: ubuntu-latest
-    if: ${{ !startsWith(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
-    env:
-      TESTOPTS: '-q --tty=no'
-      RUN_OPTS: '--disable-gems ${{ matrix.jit_opts }} --mjit-debug=-ggdb3'
-      GITPULLOPTIONS: --no-tags origin ${{github.ref}}
-    steps:
-      - run: mkdir build
-        working-directory:
-      - name: Install libraries
-        run: |
-          set -x
-          sudo apt-get update -q || :
-          sudo apt-get install --no-install-recommends -q -y build-essential libssl-dev libyaml-dev libreadline6-dev zlib1g-dev libncurses5-dev libffi-dev bison autoconf ruby
-      - name: git config
-        run: |
-          git config --global advice.detachedHead 0
-          git config --global init.defaultBranch garbage
-      - uses: actions/checkout@v3
-        with:
-          path: src
-      - uses: actions/cache@v3
-        with:
-          path: src/.downloaded-cache
-          key: downloaded-cache
-      - name: Fixed world writable dirs
-        run: |
-          chmod -v go-w $HOME $HOME/.config
-          sudo chmod -R go-w /usr/share
-          sudo bash -c 'IFS=:; for d in '"$PATH"'; do chmod -v go-w $d; done' || :
-      - name: Set ENV
-        run: |
-          echo "GNUMAKEFLAGS=-j$((1 + $(nproc --all)))" >> $GITHUB_ENV
-      - run: ./autogen.sh
-        working-directory: src
-      - name: Run configure
-        run: ../src/configure -C --disable-install-doc cppflags=-DVM_CHECK_MODE
-      - run: make incs
-      - run: make
-      - run: sudo make -s install
-      - run: sudo apt-get install gdb # used by test / test-all failure
-      - name: Run test
-        run: |
-          ulimit -c unlimited
-          make -s test RUN_OPTS="$RUN_OPTS"
-        timeout-minutes: 60
-      - name: Run test-all
-        run: |
-          ulimit -c unlimited
-          make -s test-all RUN_OPTS="$RUN_OPTS"
-        timeout-minutes: 60
-      - name: Run test-spec
-        run: |
-          ulimit -c unlimited
-          make -s test-spec RUN_OPTS="$RUN_OPTS"
-        timeout-minutes: 60
-      - uses: k0kubun/action-slack@v2.0.0
-        with:
-          payload: |
-            {
-              "ci": "GitHub Actions",
-              "env": "${{ github.workflow }} / ${{ matrix.test_task }} ${{ matrix.jit_opts }}",
-              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
-              "commit": "${{ github.sha }}",
-              "branch": "${{ github.ref }}".split('/').reverse()[0]
-            }
-        env:
-          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
-        if: ${{ failure() && github.event_name == 'push' }}
-
-defaults:
-  run:
-    working-directory: build
diff --git a/.github/workflows/modgc.yml b/.github/workflows/modgc.yml
new file mode 100644
index 0000000000..266f7e0593
--- /dev/null
+++ b/.github/workflows/modgc.yml
@@ -0,0 +1,191 @@
+name: ModGC
+on:
+  push:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man/*'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
+  pull_request:
+    # Do not use paths-ignore for required status checks
+    # https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/collaborating-on-repositories-with-code-quality-features/troubleshooting-required-status-checks#handling-skipped-but-required-checks
+  merge_group:
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:
+  contents: read
+
+jobs:
+  check:
+    strategy:
+      matrix:
+        gc:
+          - name: default
+          - name: mmtk
+            mmtk_plan: MarkSweep
+            mmtk_build: release
+        os: [macos-latest, ubuntu-latest]
+        include:
+          - test_task: check
+      fail-fast: false
+
+    env:
+      GITPULLOPTIONS: --no-tags origin ${{ github.ref }}
+      RUBY_DEBUG: ci
+
+    runs-on: ${{ matrix.os }}
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.head_commit.message, 'Document')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.title, 'Document')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with:
+          sparse-checkout-cone-mode: false
+          sparse-checkout: /.github
+
+      - name: Install libraries (macOS)
+        uses: ./.github/actions/setup/macos
+        if: ${{ contains(matrix.os, 'macos') }}
+
+      - name: Install libraries (Ubuntu)
+        uses: ./.github/actions/setup/ubuntu
+        if: ${{ contains(matrix.os, 'ubuntu') }}
+
+      - uses: ruby/setup-ruby@a6e6f86333f0a2523ece813039b8b4be04560854 # v1.190.0
+        with:
+          ruby-version: '3.0'
+          bundler: none
+        if: ${{ contains(matrix.os, 'ubuntu') }}
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          srcdir: src
+          builddir: build
+          makeup: true
+          clean: true
+          dummy-files: false
+          # Set fetch-depth: 10 so that Launchable can receive commits information.
+          fetch-depth: 10
+
+      - name: make sure that kern.coredump=1
+        run: |
+          sysctl -n kern.coredump
+          sudo sysctl -w kern.coredump=1
+          sudo chmod -R +rwx /cores/
+        if: ${{ contains(matrix.os, 'macos') }}
+
+      - name: Delete unused SDKs
+        # To free up disk space to not run out during the run
+        run: |
+          sudo rm -rf ~/.dotnet
+          sudo rm -rf /Library/Android
+          sudo rm -rf /Library/Developer/CoreSimulator
+        continue-on-error: true
+        if: ${{ contains(matrix.os, 'macos') }}
+
+      - name: Setup Ruby GC Directory
+        run: |
+          echo "MODULAR_GC_DIR=$HOME/ruby_gc" >> $GITHUB_ENV
+
+      - name: Run configure
+        env:
+          arch: ${{ matrix.arch }}
+        run: >-
+          $SETARCH ../src/configure -C --disable-install-doc --with-modular-gc=${{ env.MODULAR_GC_DIR }}
+          ${arch:+--target=$arch-$OSTYPE --host=$arch-$OSTYPE}
+
+      - uses: actions-rust-lang/setup-rust-toolchain@v1
+      - name: Set MMTk environment variables
+        run: |
+          if [[ ${{ matrix.gc.mmtk_build }} == debug ]]; then
+            echo 'RUST_LOG=' >> $GITHUB_ENV
+            # Debug builds run much slower so we should increase the timeout
+            echo 'RUBY_TEST_TIMEOUT_SCALE=10' >> $GITHUB_ENV
+            # SYNTAX_SUGGEST_TIMEOUT defaults to 1 second
+            echo 'SYNTAX_SUGGEST_TIMEOUT=60' >> $GITHUB_ENV
+          fi
+          echo 'MMTK_PLAN=${{ matrix.gc.mmtk_plan }}' >> $GITHUB_ENV
+          echo 'EXCLUDES=../src/test/.excludes-mmtk' >> $GITHUB_ENV
+          echo 'MSPECOPT=-B../src/spec/mmtk.mspec' >> $GITHUB_ENV
+          echo 'GITHUB_WORKFLOW=ModGC' >> $GITHUB_ENV
+        if: ${{ matrix.gc.name == 'mmtk' }}
+
+      - run: $SETARCH make
+
+      - name: Build Modular  GC
+        run: |
+          echo "RUBY_GC_LIBRARY=${{ matrix.gc.name }}" >> $GITHUB_ENV
+          make install-modular-gc MODULAR_GC=${{ matrix.gc.name }} MMTK_BUILD=${{ matrix.gc.mmtk_build }}
+          make distclean-modular-gc MODULAR_GC=${{ matrix.gc.name }}
+
+      - run: $SETARCH make hello
+
+      - name: Set test options for skipped tests
+        run: |
+          set -x
+          TESTS="$(echo "${{ matrix.skipped_tests }}" | sed 's| |$$/ -n!/|g;s|^|-n!/|;s|$|$$/|')"
+          echo "TESTS=${TESTS}" >> $GITHUB_ENV
+        if: ${{ matrix.test_task == 'check' && matrix.skipped_tests }}
+
+      - name: Set up Launchable
+        uses: ./.github/actions/launchable/setup
+        with:
+          os: ${{ matrix.os || 'ubuntu-22.04' }}
+          test-opts: ${{ matrix.configure }}
+          launchable-token: ${{ secrets.LAUNCHABLE_TOKEN }}
+          builddir: build
+          srcdir: src
+        continue-on-error: true
+
+      - name: make ${{ matrix.test_task }}
+        run: >-
+          $SETARCH make -s ${{ matrix.test_task }}
+          ${TESTS:+TESTS="$TESTS"}
+          ${{ !contains(matrix.test_task, 'bundle') && 'RUBYOPT=-w' || '' }}
+        timeout-minutes: ${{ matrix.gc.timeout || 40 }}
+        env:
+          RUBY_TESTOPTS: '-q --tty=no'
+          TEST_BUNDLED_GEMS_ALLOW_FAILURES: 'typeprof'
+          PRECHECK_BUNDLED_GEMS: 'no'
+
+      - name: make skipped tests
+        run: |
+          $SETARCH make -s test-all TESTS="${TESTS//-n!\//-n/}"
+        env:
+          GNUMAKEFLAGS: ''
+          RUBY_TESTOPTS: '-v --tty=no'
+        if: ${{ matrix.test_task == 'check' && matrix.skipped_tests }}
+        continue-on-error: ${{ matrix.continue-on-skipped_tests || false }}
+
+      - uses: ./.github/actions/slack
+        with:
+          label: ${{ matrix.test_task }} ${{ matrix.configure }}${{ matrix.arch }}
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() }}
+
+  result:
+    if: ${{ always() }}
+    name: ${{ github.workflow }} result
+    runs-on: ubuntu-latest
+    needs: [check]
+    steps:
+      - run: exit 1
+        working-directory:
+        if: ${{ contains(needs.*.result, 'failure') || contains(needs.*.result, 'cancelled') }}
+
+defaults:
+  run:
+    working-directory: build
diff --git a/.github/workflows/parsey.yml b/.github/workflows/parsey.yml
new file mode 100644
index 0000000000..a7416952b6
--- /dev/null
+++ b/.github/workflows/parsey.yml
@@ -0,0 +1,93 @@
+name: parse.y
+on:
+  push:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man/*'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
+  pull_request:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man/*'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
+  merge_group:
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:
+  contents: read
+
+jobs:
+  make:
+    strategy:
+      matrix:
+        include:
+          - test_task: check
+          - test_task: test-bundler-parallel
+          - test_task: test-bundled-gems
+      fail-fast: false
+
+    env:
+      GITPULLOPTIONS: --no-tags origin ${{ github.ref }}
+      RUBY_DEBUG: ci
+      SETARCH: ${{ matrix.arch && format('setarch {0}', matrix.arch) }}
+
+    runs-on: ubuntu-22.04
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.head_commit.message, 'Document')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.title, 'Document')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with:
+          sparse-checkout-cone-mode: false
+          sparse-checkout: /.github
+
+      - uses: ./.github/actions/setup/ubuntu
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          srcdir: src
+          builddir: build
+          makeup: true
+          clean: true
+          dummy-files: ${{ matrix.test_task == 'check' }}
+
+      - name: Run configure
+        run: ../src/configure -C --disable-install-doc cppflags=-DRUBY_DEBUG --with-parser=parse.y
+
+      - run: make
+
+      - name: make ${{ matrix.test_task }}
+        run: make -s ${{ matrix.test_task }} RUN_OPTS="$RUN_OPTS" SPECOPTS="$SPECOPTS"
+        env:
+          RUBY_TESTOPTS: ${{ matrix.testopts }}
+          EXCLUDES: '../src/test/.excludes-parsey'
+          RUN_OPTS: ${{ matrix.run_opts || '--parser=parse.y' }}
+          SPECOPTS: ${{ matrix.specopts || '-T --parser=parse.y' }}
+          TEST_BUNDLED_GEMS_ALLOW_FAILURES: 'typeprof'
+
+      - uses: ./.github/actions/slack
+        with:
+          label: ${{ matrix.run_opts }}
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() }}
+
+defaults:
+  run:
+    working-directory: build
diff --git a/.github/workflows/pr-playground.yml b/.github/workflows/pr-playground.yml
new file mode 100644
index 0000000000..cc06006142
--- /dev/null
+++ b/.github/workflows/pr-playground.yml
@@ -0,0 +1,127 @@
+name: Post Playground link to PR
+on:
+  pull_request_target:
+    types: [labeled]
+  workflow_run:
+    workflows: ["WebAssembly"]
+    types: [completed]
+
+jobs:
+  post-summary:
+    name: Post Playground link
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
+    # Post a comment only if the PR status check is passed and the PR is labeled with `Playground`.
+    # Triggered twice: when the PR is labeled and when PR build is passed.
+    if: >-
+      ${{ false
+      || (true
+        && github.event_name == 'pull_request_target'
+        && contains(github.event.pull_request.labels.*.name, 'Playground'))
+      || (true
+        && github.event_name == 'workflow_run'
+        && github.event.workflow_run.conclusion == 'success'
+        && github.event.workflow_run.event == 'pull_request')
+      }}
+    steps:
+      - uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          script: |
+            const fs = require('fs/promises');
+
+            const buildWorkflowPath = '.github/workflows/wasm.yml';
+            const findSuccessfuBuildRun = async (pr) => {
+              const opts = github.rest.actions.listWorkflowRunsForRepo.endpoint.merge({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                status: 'success',
+                branch: pr.head.ref,
+              });
+              const runs = await github.paginate(opts);
+              const buildRun = runs.find(run => run.path == buildWorkflowPath);
+              return buildRun;
+            }
+
+            const postComment = async (body, pr) => {
+              const { data: comments } = await github.rest.issues.listComments({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                issue_number: pr.number,
+              });
+
+              const commentOpts = { owner: context.repo.owner, repo: context.repo.repo, body: comment };
+
+              const existingComment = comments.find(comment => comment.body.startsWith(magicComment));
+              if (existingComment) {
+                core.info(`Updating existing comment: ${existingComment.html_url}`);
+                await github.rest.issues.updateComment({
+                  ...commentOpts, comment_id: existingComment.id
+                });
+              } else {
+                await github.rest.issues.createComment({
+                  ...commentOpts, issue_number: pr.number
+                });
+              }
+            }
+
+            const derivePRNumber = async () => {
+              if (context.payload.pull_request) {
+                return context.payload.pull_request.number;
+              }
+              // Workaround for https://github.com/orgs/community/discussions/25220
+
+              const { data: { artifacts } } = await github.rest.actions.listWorkflowRunArtifacts({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                run_id: context.payload.workflow_run.id,
+              });
+              const artifact = artifacts.find(artifact => artifact.name == 'github-pr-info');
+              if (!artifact) {
+                throw new Error('Cannot find github-pr-info.txt artifact');
+              }
+
+              const { data } = await github.rest.actions.downloadArtifact({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                artifact_id: artifact.id,
+                archive_format: 'zip',
+              });
+
+              await fs.writeFile('pr-info.zip', Buffer.from(data));
+              await exec.exec('unzip', ['pr-info.zip']);
+              return await fs.readFile('github-pr-info.txt', 'utf8');
+            }
+
+            const prNumber = await derivePRNumber();
+
+            const { data: pr } = await github.rest.pulls.get({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              pull_number: prNumber,
+            });
+
+            core.info(`Checking if the PR ${prNumber} is labeled with Playground...`);
+            if (!pr.labels.some(label => label.name == 'Playground')) {
+              core.info(`The PR is not labeled with Playground.`);
+              return;
+            }
+
+            core.info(`Checking if the build is successful for ${pr.head.ref} in ${pr.head.repo.owner.login}/${pr.head.repo.name}...`);
+            const buildRun = await findSuccessfuBuildRun(pr);
+            if (!buildRun) {
+              core.info(`No successful build run found for ${buildWorkflowPath} on ${pr.head.ref} yet.`);
+              return;
+            }
+            core.info(`Found a successful build run: ${buildRun.html_url}`);
+
+            const runLink = `${process.env.GITHUB_SERVER_URL}/${process.env.GITHUB_REPOSITORY}/actions/runs/${process.env.GITHUB_RUN_ID}`;
+            const magicComment = `<!-- AUTO-GENERATED-COMMENT-PR-PLAYGROUND -->`;
+            const comment = `${magicComment}
+            **Try on Playground**: https://ruby.github.io/play-ruby?run=${buildRun.id}
+            This is an automated comment by [\`pr-playground.yml\`](${runLink}) workflow.
+            `;
+            core.info(`Comment: ${comment}`);
+            await postComment(comment, pr);
+
diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
new file mode 100644
index 0000000000..5d4474d978
--- /dev/null
+++ b/.github/workflows/publish.yml
@@ -0,0 +1,18 @@
+name: Start release workflow
+on:
+  push:
+    tags:
+      - '*'
+
+jobs:
+  notify:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Build release package
+        run: |
+          curl -L -X POST \
+            -H "Authorization: Bearer ${{ secrets.MATZBOT_GITHUB_WORKFLOW_TOKEN }}" \
+            -H "Accept: application/vnd.github+json" \
+            -H "X-GitHub-Api-Version: 2022-11-28" \
+            https://api.github.com/repos/ruby/actions/dispatches \
+            -d '{"event_type": "${{ github.ref }}"}'
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
new file mode 100644
index 0000000000..5534e3defe
--- /dev/null
+++ b/.github/workflows/release.yml
@@ -0,0 +1,108 @@
+name: Publish Ruby packages
+
+on:
+  repository_dispatch:
+    types:
+      - release
+  workflow_dispatch:
+    inputs:
+      version:
+        description: 'Version of the Ruby package to release'
+        required: true
+        default: '3.3.4'
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: 3.3.4
+
+      - name: Store Ruby version
+        run: |
+          echo "RUBY_VERSION=${{ github.event.client_payload.version || github.event.inputs.version }}" >> $GITHUB_ENV
+
+      - name: Store ABI version
+        run: echo "ABI_VERSION=$(echo ${{ env.RUBY_VERSION }} | cut -d '.' -f 1-2)" >> $GITHUB_ENV
+
+      - name: Copy draft package `/tmp` to `/pub` directory
+        run: tool/release.sh ${{ env.RUBY_VERSION }}
+        env:
+          AWS_ACCESS_KEY_ID: ${{ secrets.FTP_R_L_O_AWS_ACCESS_KEY_ID }}
+          AWS_SECRET_ACCESS_KEY: ${{ secrets.FTP_R_L_O_AWS_SECRET_ACCESS_KEY }}
+          AWS_DEFAULT_REGION: us-west-2
+
+      - name: Purge URLs of release package
+        run: |
+          curl -X POST \
+            -H "Fastly-Key: ${{ secrets.FASTLY_PURGE_TOKEN }}" \
+            https://api.fastly.com/purge/cache.ruby-lang.org/pub/ruby/${{ env.ABI_VERSION }}/ruby-${{ env.RUBY_VERSION }}.tar.gz
+          curl -X POST \
+            -H "Fastly-Key: ${{ secrets.FASTLY_PURGE_TOKEN }}" \
+            https://api.fastly.com/purge/cache.ruby-lang.org/pub/ruby/${{ env.ABI_VERSION }}/ruby-${{ env.RUBY_VERSION }}.tar.xz
+          curl -X POST \
+            -H "Fastly-Key: ${{ secrets.FASTLY_PURGE_TOKEN }}" \
+            https://api.fastly.com/purge/cache.ruby-lang.org/pub/ruby/${{ env.ABI_VERSION }}/ruby-${{ env.RUBY_VERSION }}.zip
+
+      - name: Create a release on GitHub
+        run: |
+          RELEASE_TAG=$(echo v${{ env.RUBY_VERSION }} | sed 's/\./_/g')
+          echo $RELEASE_TAG
+          PREVIOUS_RELEASE_TAG=$(echo $RELEASE_TAG | awk 'BEGIN {FS="_"; OFS="_"}{ $NF=$NF-1; print }')
+          echo $PREVIOUS_RELEASE_TAG
+          tool/gen-github-release.rb $PREVIOUS_RELEASE_TAG $RELEASE_TAG --no-dry-run
+        env:
+          GITHUB_TOKEN: ${{ secrets.MATZBOT_GITHUB_WORKFLOW_TOKEN }}
+
+      - name: Update versions index
+        run: |
+          curl -L -X POST \
+            -H "Authorization: Bearer ${{ secrets.MATZBOT_GITHUB_WORKFLOW_TOKEN }}" \
+            -H "Accept: application/vnd.github+json" \
+            -H "X-GitHub-Api-Version: 2022-11-28" \
+            https://api.github.com/repos/ruby/actions/dispatches \
+            -d '{"event_type": "update_index"}'
+
+      - name: Set latest flag for Ruby 3.3
+        if: contains(${{ env.RUBY_VERSION }}, '3.3.')
+        run: |
+          echo "LATEST=true" >> $GITHUB_ENV
+
+      - name: Build and push Docker images
+        run: |
+          curl -L -X POST \
+            -H "Authorization: Bearer ${{ secrets.MATZBOT_GITHUB_WORKFLOW_TOKEN }}" \
+            -H "Accept: application/vnd.github+json" \
+            -H "X-GitHub-Api-Version: 2022-11-28" \
+            https://api.github.com/repos/ruby/docker-images/dispatches \
+            -d '{"event_type": "build", "client_payload": {"ruby_version": "${{ env.RUBY_VERSION }}", "arch": "amd64", "latest": "${{ env.LATEST }}"}}'
+
+      - name: Build snapcraft packages
+        run: |
+          curl -L -X POST \
+            -H "Authorization: Bearer ${{ secrets.MATZBOT_GITHUB_WORKFLOW_TOKEN }}" \
+            -H "Accept: application/vnd.github+json" \
+            -H "X-GitHub-Api-Version: 2022-11-28" \
+            https://api.github.com/repos/ruby/snap.ruby/dispatches \
+            -d '{"event_type": "build", "client_payload": {"ruby_version": "${{ env.RUBY_VERSION }}"}}'
+
+      - name: Update ruby-build definition
+        run: |
+          curl -L -X POST \
+            -H "Authorization: Bearer ${{ secrets.RUBY_BUILD_WORKFLOW_TOKEN }}" \
+            -H "Accept: application/vnd.github+json" \
+            -H "X-GitHub-Api-Version: 2022-11-28" \
+            https://api.github.com/repos/rbenv/ruby-build/dispatches \
+            -d '{"event_type": "update-ruby", "client_payload": {"ruby_version": "${{ env.RUBY_VERSION }}", "openssl_version": "3.0.15"}}'
+
+      - name: Update all-ruby definition
+        run: |
+          curl -L -X POST \
+            -H "Authorization: Bearer ${{ secrets.MATZBOT_GITHUB_WORKFLOW_TOKEN }}" \
+            -H "Accept: application/vnd.github+json" \
+            -H "X-GitHub-Api-Version: 2022-11-28" \
+            https://api.github.com/repos/ruby/all-ruby/dispatches \
+            -d '{"event_type": "update"}'
diff --git a/.github/workflows/rjit-bindgen.yml b/.github/workflows/rjit-bindgen.yml
new file mode 100644
index 0000000000..c2ec4a6a68
--- /dev/null
+++ b/.github/workflows/rjit-bindgen.yml
@@ -0,0 +1,86 @@
+name: RJIT bindgen
+on:
+  push:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man/*'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
+  pull_request:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man/*'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
+  merge_group:
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:
+  contents: read
+
+jobs:
+  make:
+    strategy:
+      matrix:
+        include:
+          - task: rjit-bindgen
+      fail-fast: false
+
+    runs-on: ubuntu-20.04
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.head_commit.message, 'Document')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.title, 'Document')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
+    steps:
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@a6e6f86333f0a2523ece813039b8b4be04560854 # v1.190.0
+        with:
+          ruby-version: '3.1'
+
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with:
+          sparse-checkout-cone-mode: false
+          sparse-checkout: /.github
+
+      - uses: ./.github/actions/setup/ubuntu
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          srcdir: src
+          builddir: build
+          makeup: true
+
+      - name: Run configure
+        run: ../src/configure -C --disable-install-doc --prefix=$(pwd)/install --enable-yjit=dev_nodebug
+
+      - run: make
+
+      - run: make install
+
+      - run: make ${{ matrix.task }}
+
+      - run: git diff --exit-code
+        working-directory: src
+
+      - uses: ./.github/actions/slack
+        with:
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() }}
+
+defaults:
+  run:
+    working-directory: build
diff --git a/.github/workflows/rjit.yml b/.github/workflows/rjit.yml
new file mode 100644
index 0000000000..a2358668f0
--- /dev/null
+++ b/.github/workflows/rjit.yml
@@ -0,0 +1,131 @@
+name: RJIT
+on:
+  push:
+    paths-ignore:
+      - 'doc/**'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+      - '**.[1-8]'
+      - '**.ronn'
+      - '.*.yml'
+  pull_request:
+    paths-ignore:
+      - 'doc/**'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+      - '**.[1-8]'
+      - '**.ronn'
+      - '.*.yml'
+  merge_group:
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:
+  contents: read
+
+jobs:
+  make:
+    strategy:
+      matrix:
+        # main variables included in the job name
+        test_task: [check]
+        run_opts: ['--rjit-call-threshold=1']
+        arch: ['']
+      fail-fast: false
+
+    env:
+      GITPULLOPTIONS: --no-tags origin ${{ github.ref }}
+      RUBY_DEBUG: ci
+      SETARCH: ${{ matrix.arch && format('setarch {0}', matrix.arch) }}
+
+    runs-on: ubuntu-22.04
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.head_commit.message, 'Document')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.title, 'Document')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with:
+          sparse-checkout-cone-mode: false
+          sparse-checkout: /.github
+
+      - uses: ./.github/actions/setup/ubuntu
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          srcdir: src
+          builddir: build
+          makeup: true
+          # Set fetch-depth: 10 so that Launchable can receive commits information.
+          fetch-depth: 10
+
+      - name: Run configure
+        env:
+          arch: ${{ matrix.arch }}
+        run: >-
+          $SETARCH ../src/configure -C --disable-install-doc cppflags=-DRUBY_DEBUG
+          ${arch:+--target=$arch-$OSTYPE --host=$arch-$OSTYPE}
+
+      - run: $SETARCH make
+
+      - name: Set up Launchable
+        uses: ./.github/actions/launchable/setup
+        with:
+          os: ubuntu-22.04
+          launchable-token: ${{ secrets.LAUNCHABLE_TOKEN }}
+          builddir: build
+          srcdir: src
+          test-opts: ${{ matrix.run_opts }}
+          test-tasks: '["test", "test-all", "test-spec"]'
+        continue-on-error: true
+
+      - name: make test
+        run: |
+          $SETARCH make -s test RUN_OPTS="$RUN_OPTS"
+        timeout-minutes: 30
+        env:
+          GNUMAKEFLAGS: ''
+          RUBY_TESTOPTS: >-
+            ${{ env.TESTS }}
+            --tty=no
+          RUN_OPTS: ${{ matrix.run_opts }}
+
+      - name: make test-all
+        run: >-
+          $SETARCH make -s test-all
+          RUN_OPTS="$RUN_OPTS"
+          ${TESTS:+TESTS="$TESTS"}
+        timeout-minutes: 60
+        env:
+          GNUMAKEFLAGS: ''
+          RUBY_TESTOPTS: '-q --tty=no'
+          RUN_OPTS: ${{ matrix.run_opts }}
+
+      - name: make test-spec
+        run: |
+          $SETARCH make -s test-spec RUN_OPTS="$RUN_OPTS"
+        timeout-minutes: 10
+        env:
+          GNUMAKEFLAGS: ''
+          RUN_OPTS: ${{ matrix.run_opts }}
+
+      - uses: ./.github/actions/slack
+        with:
+          label: ${{ matrix.run_opts }}
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() }}
+
+defaults:
+  run:
+    working-directory: build
diff --git a/.github/workflows/scorecards.yml b/.github/workflows/scorecards.yml
new file mode 100644
index 0000000000..afc41298ba
--- /dev/null
+++ b/.github/workflows/scorecards.yml
@@ -0,0 +1,72 @@
+# This workflow uses actions that are not certified by GitHub. They are provided
+# by a third-party and are governed by separate terms of service, privacy
+# policy, and support documentation.
+
+name: Scorecards supply-chain security
+on:
+  # For Branch-Protection check. Only the default branch is supported. See
+  # https://github.com/ossf/scorecard/blob/main/docs/checks.md#branch-protection
+  branch_protection_rule:
+  # To guarantee Maintained check is occasionally updated. See
+  # https://github.com/ossf/scorecard/blob/main/docs/checks.md#maintained
+  schedule:
+    - cron: '22 4 * * 2'
+  # push:
+  #   branches: [ "master" ]
+
+# Declare default permissions as read only.
+permissions: read-all
+
+jobs:
+  analysis:
+    name: Scorecards analysis
+    runs-on: ubuntu-latest
+    permissions:
+      # Needed to upload the results to code-scanning dashboard.
+      security-events: write
+      # Needed to publish results and get a badge (see publish_results below).
+      id-token: write
+      # Uncomment the permissions below if installing in a private repository.
+      # contents: read
+      # actions: read
+
+    steps:
+      - name: 'Checkout code'
+        uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with:
+          persist-credentials: false
+
+      - name: 'Run analysis'
+        uses: ossf/scorecard-action@62b2cac7ed8198b15735ed49ab1e5cf35480ba46 # v2.4.0
+        with:
+          results_file: results.sarif
+          results_format: sarif
+          # (Optional) Read-only PAT token. Uncomment the `repo_token` line below if:
+          # - you want to enable the Branch-Protection check on a *public* repository, or
+          # - you are installing Scorecards on a *private* repository
+          # To create the PAT, follow the steps in https://github.com/ossf/scorecard-action#authentication-with-pat.
+          repo_token: ${{ secrets.SCORECARD_READ_TOKEN }}
+
+          # Public repositories:
+          #   - Publish results to OpenSSF REST API for easy access by consumers
+          #   - Allows the repository to include the Scorecard badge.
+          #   - See https://github.com/ossf/scorecard-action#publishing-results.
+          # For private repositories:
+          #   - `publish_results` will always be set to `false`, regardless
+          #     of the value entered here.
+          publish_results: true
+
+      # Upload the results as artifacts (optional). Commenting out will disable uploads of run results in SARIF
+      # format to the repository Actions tab.
+      # - name: "Upload artifact"
+      #   uses: actions/upload-artifact@0b7f8abb1508181956e8e162db84b466c27e18ce # v3.1.2
+      #   with:
+      #     name: SARIF file
+      #     path: results.sarif
+      #     retention-days: 5
+
+      # Upload the results to GitHub's code scanning dashboard.
+      - name: 'Upload to code-scanning'
+        uses: github/codeql-action/upload-sarif@df409f7d9260372bd5f19e5b04e83cb3c43714ae # v3.27.9
+        with:
+          sarif_file: results.sarif
diff --git a/.github/workflows/spec_guards.yml b/.github/workflows/spec_guards.yml
index 18e2d3c1a8..321099f024 100644
--- a/.github/workflows/spec_guards.yml
+++ b/.github/workflows/spec_guards.yml
@@ -2,52 +2,65 @@ name: Rubyspec Version Guards Check
 
 on:
   push:
-    paths-ignore:
-      - 'doc/**'
-      - '**.md'
-      - '**.rdoc'
+    paths:
+      - 'spec/**'
+      - '!spec/*.md'
   pull_request:
-    paths-ignore:
-      - 'doc/**'
-      - '**.md'
-      - '**.rdoc'
+    paths:
+      - 'spec/**'
+      - '!spec/*.md'
+  merge_group:
 
 concurrency:
   group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
   cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
 
+permissions:
+  contents: read
+
 jobs:
   rubyspec:
     name: Rubyspec
+
     runs-on: ubuntu-20.04
-    if: ${{ !startsWith(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.head_commit.message, 'Document')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.title, 'Document')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
     strategy:
       matrix:
         # Specs from ruby/spec should still run on all supported Ruby versions.
         # This also ensures the needed ruby_version_is guards are there, see spec/README.md.
         ruby:
-          - ruby-2.7
+          - ruby-3.0
           - ruby-3.1
+          - ruby-3.2
+          - ruby-3.3
 
     steps:
-      - uses: actions/checkout@v3
-      - uses: ruby/setup-ruby@v1
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+
+      - uses: ruby/setup-ruby@a6e6f86333f0a2523ece813039b8b4be04560854 # v1.190.0
         with:
           ruby-version: ${{ matrix.ruby }}
           bundler: none
+
       - run: gem install webrick
+
       - run: ruby ../mspec/bin/mspec
         working-directory: spec/ruby
-      - uses: k0kubun/action-slack@v2.0.0
-        with:
-          payload: |
-            {
-              "ci": "GitHub Actions",
-              "env": "${{ github.workflow }} / rubyspec @ ${{ matrix.ruby }}",
-              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
-              "commit": "${{ github.sha }}",
-              "branch": "${{ github.ref }}".split('/').reverse()[0]
-            }
         env:
+          CHECK_LEAKS: true
+
+      - uses: ./.github/actions/slack
+        with:
+          label: ${{ matrix.ruby }}
           SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
-        if: ${{ failure() && github.event_name == 'push' }}
+        if: ${{ failure() }}
diff --git a/.github/workflows/ubuntu.yml b/.github/workflows/ubuntu.yml
index b7097cca53..2a77d03878 100644
--- a/.github/workflows/ubuntu.yml
+++ b/.github/workflows/ubuntu.yml
@@ -3,129 +3,153 @@ on:
   push:
     paths-ignore:
       - 'doc/**'
+      - '**/man/*'
       - '**.md'
       - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
   pull_request:
-    paths-ignore:
-      - 'doc/**'
-      - '**.md'
-      - '**.rdoc'
+    # Do not use paths-ignore for required status checks
+    # https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/collaborating-on-repositories-with-code-quality-features/troubleshooting-required-status-checks#handling-skipped-but-required-checks
+  merge_group:
 
 concurrency:
   group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
   cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
 
+permissions:
+  contents: read
+
 jobs:
   make:
     strategy:
       matrix:
-        test_task: ["check", "test-bundler-parallel", "test-bundled-gems"]
-        os:
-          - ubuntu-20.04
-#         - ubuntu-18.04
-        configure: ["", "cppflags=-DRUBY_DEBUG"]
         include:
-          - test_task: "check"
-            configure: "--host=i686-$OSTYPE"
-          - test_task: "check"
-            configure: "--enable-shared --enable-load-relative"
-            skipped_tests: "TestGem#test_.*_from_binstubs.*"
-            continue-on-skipped_tests: true
-          - test_task: "test-all TESTS=--repeat-count=2"
+          - test_task: check
+            configure: 'cppflags=-DVM_CHECK_MODE'
+          - test_task: check
+            arch: i686
+          - test_task: check
+            configure: '--disable-yjit'
+          - test_task: check
+            configure: '--enable-shared --enable-load-relative'
+          - test_task: test-bundler-parallel
+            timeout: 50
+          - test_task: test-bundled-gems
+          - test_task: check
+            os: ubuntu-20.04
+          - test_task: check
+            os: ubuntu-24.04
       fail-fast: false
+
     env:
-      GITPULLOPTIONS: --no-tags origin ${{github.ref}}
+      GITPULLOPTIONS: --no-tags origin ${{ github.ref }}
       RUBY_DEBUG: ci
-    runs-on: ${{ matrix.os || 'ubuntu-20.04' }}
-    if: ${{ !startsWith(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
+
+    runs-on: ${{ matrix.os || 'ubuntu-22.04' }}
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.head_commit.message, 'Document')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.title, 'Document')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
     steps:
-      - run: mkdir build
-        working-directory:
-      - name: Set ENV
-        env:
-          configure: ${{matrix.configure}}
-        run: |
-          echo "GNUMAKEFLAGS=-j$((1 + $(nproc --all)))" >> $GITHUB_ENV
-          arch=`echo " $configure" | sed '/.* --host=/!d;s///;s/[- ].*//'`
-          echo "SETARCH=${arch:+setarch $arch}" >> $GITHUB_ENV
-      - name: Install libraries
-        run: |
-          set -x
-          arch="${SETARCH##* }"
-          arch=${arch:+:${arch/i[3-6]86/i386}}
-          ${arch:+sudo dpkg --add-architecture ${arch#:}}
-          sudo apt-get update -q || :
-          sudo apt-get install --no-install-recommends -q -y \
-          ${arch:+cross}build-essential${arch/:/-} \
-          libssl-dev${arch} libyaml-dev${arch} libreadline6-dev${arch} \
-          zlib1g-dev${arch} libncurses5-dev${arch} libffi-dev${arch} \
-          bison autoconf ruby
-          sudo apt-get install -q -y pkg-config${arch} || :
-      - name: git config
-        run: |
-          git config --global advice.detachedHead 0
-          git config --global init.defaultBranch garbage
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
         with:
-          path: src
-      - uses: actions/cache@v3
+          sparse-checkout-cone-mode: false
+          sparse-checkout: /.github
+
+      - uses: ./.github/actions/setup/ubuntu
         with:
-          path: src/.downloaded-cache
-          key: downloaded-cache
-      - name: Fixed world writable dirs
-        run: |
-          chmod -v go-w $HOME $HOME/.config
-          sudo chmod -R go-w /usr/share
-          sudo bash -c 'IFS=:; for d in '"$PATH"'; do chmod -v go-w $d; done' || :
-      - run: ./autogen.sh
-        working-directory: src
+          arch: ${{ matrix.arch }}
+
+      - uses: ruby/setup-ruby@a6e6f86333f0a2523ece813039b8b4be04560854 # v1.190.0
+        with:
+          ruby-version: '3.0'
+          bundler: none
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          srcdir: src
+          builddir: build
+          makeup: true
+          clean: true
+          dummy-files: ${{ matrix.test_task == 'check' }}
+          # Set fetch-depth: 10 so that Launchable can receive commits information.
+          fetch-depth: 10
+
       - name: Run configure
         env:
-          arch: ${{matrix.arch}}
+          arch: ${{ matrix.arch }}
+          configure: ${{ matrix.configure }}
         run: >-
-          $SETARCH ../src/configure -C --disable-install-doc ${{ matrix.configure }}
-          ${arch:+--target=$arch-$OSTYPE}
-      - run: $SETARCH make incs
-      - run: $SETARCH make
-      - run: $SETARCH make leaked-globals
-        if: ${{ matrix.test_task == 'check' }}
+          $SETARCH ../src/configure -C --disable-install-doc ${configure:-cppflags=-DRUBY_DEBUG}
+          ${arch:+--target=$arch-$OSTYPE --host=$arch-$OSTYPE}
+
       - run: $SETARCH make prepare-gems
-        if: ${{ matrix.test_task == 'check' }}
-      - name: Create dummy files in build dir
+        if: ${{ matrix.test_task == 'test-bundled-gems' }}
+
+      - run: $SETARCH make
+
+      - run: $SETARCH make hello
+
+      - name: Set test options for skipped tests
         run: |
-          $SETARCH ./miniruby -e '(("a".."z").to_a+("A".."Z").to_a+("0".."9").to_a+%w[foo bar test zzz]).each{|basename|File.write("#{basename}.rb", "raise %(do not load #{basename}.rb)")}'
-        if: ${{ matrix.test_task == 'check' }}
+          set -x
+          TESTS="$(echo "${{ matrix.skipped_tests }}" | sed 's| |$$/ -n!/|g;s|^|-n!/|;s|$|$$/|')"
+          echo "TESTS=${TESTS}" >> $GITHUB_ENV
+        if: ${{ matrix.test_task == 'check' && matrix.skipped_tests }}
+
+      - name: Set up Launchable
+        uses: ./.github/actions/launchable/setup
+        with:
+          os: ${{ matrix.os || 'ubuntu-22.04' }}
+          test-opts: ${{ matrix.configure }}
+          launchable-token: ${{ secrets.LAUNCHABLE_TOKEN }}
+          builddir: build
+          srcdir: src
+        continue-on-error: true
+
       - name: make ${{ matrix.test_task }}
-        run: |
-          $SETARCH make -s ${{ matrix.test_task }} ${TESTS:+TESTS=`echo "$TESTS" | sed 's| |$$/ -n!/|g;s|^|-n!/|;s|$|$$/|'`}
-        timeout-minutes: 40
+        run: >-
+          $SETARCH make -s ${{ matrix.test_task }}
+          ${TESTS:+TESTS="$TESTS"}
+          ${{ !contains(matrix.test_task, 'bundle') && 'RUBYOPT=-w' || '' }}
+        timeout-minutes: ${{ matrix.timeout || 40 }}
         env:
-          RUBY_TESTOPTS: "-q --tty=no"
-          TESTS: ${{ matrix.test_task == 'check' && matrix.skipped_tests || '' }}
-          TEST_BUNDLED_GEMS_ALLOW_FAILURES: ""
-          PRECHECK_BUNDLED_GEMS: "no"
+          RUBY_TESTOPTS: '-q --tty=no'
+          TEST_BUNDLED_GEMS_ALLOW_FAILURES: 'typeprof'
+          PRECHECK_BUNDLED_GEMS: 'no'
+
       - name: make skipped tests
         run: |
-          $SETARCH make -s test-all TESTS=`echo "$TESTS" | sed 's| |$$/ -n/|g;s|^|-n/|;s|$|$$/|'`
+          $SETARCH make -s test-all TESTS="${TESTS//-n!\//-n/}"
         env:
-          GNUMAKEFLAGS: ""
-          RUBY_TESTOPTS: "-v --tty=no"
-          TESTS: ${{ matrix.skipped_tests }}
-        if: ${{ matrix.test_task == 'check' && matrix.skipped_tests != '' }}
+          GNUMAKEFLAGS: ''
+          RUBY_TESTOPTS: '-v --tty=no'
+        if: ${{ matrix.test_task == 'check' && matrix.skipped_tests }}
         continue-on-error: ${{ matrix.continue-on-skipped_tests || false }}
-      - uses: k0kubun/action-slack@v2.0.0
+
+      - uses: ./.github/actions/slack
         with:
-          payload: |
-            {
-              "ci": "GitHub Actions",
-              "env": "${{ matrix.os }} / ${{ matrix.test_task }}${{ matrix.configure }}",
-              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
-              "commit": "${{ github.sha }}",
-              "branch": "${{ github.ref }}".split('/').reverse()[0]
-            }
-        env:
+          label: ${{ matrix.test_task }} ${{ matrix.configure }}${{ matrix.arch }}
           SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
-        if: ${{ failure() && github.event_name == 'push' }}
+        if: ${{ failure() }}
+
+  result:
+    if: ${{ always() }}
+    name: ${{ github.workflow }} result
+    runs-on: ubuntu-latest
+    needs: [make]
+    steps:
+      - run: exit 1
+        working-directory:
+        if: ${{ contains(needs.*.result, 'failure') || contains(needs.*.result, 'cancelled') }}
 
 defaults:
   run:
diff --git a/.github/workflows/wasm.yml b/.github/workflows/wasm.yml
index db00db9009..3924aaeb99 100644
--- a/.github/workflows/wasm.yml
+++ b/.github/workflows/wasm.yml
@@ -3,57 +3,80 @@ on:
   push:
     paths-ignore:
       - 'doc/**'
+      - '**/man/*'
       - '**.md'
       - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
   pull_request:
     paths-ignore:
       - 'doc/**'
+      - '**/man/*'
       - '**.md'
       - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
+  merge_group:
 
 concurrency:
   group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
   cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
 
+permissions: # added using https://github.com/step-security/secure-workflows
+  contents: read
+
 jobs:
   make:
     strategy:
       matrix:
         entry:
 #         # wasmtime can't compile non-optimized Asyncified binary due to locals explosion
-#         - { name: O0-debuginfo, optflags: "-O0", debugflags: "-g", wasmoptflags: "-O1" }
-#         - { name: O1,           optflags: "-O1", debugflags: ""  , wasmoptflags: "-O1" }
-          - { name: O2,           optflags: "-O2", debugflags: ""  , wasmoptflags: "-O2" }
-#         - { name: O3,           optflags: "-O3", debugflags: ""  , wasmoptflags: "-O3" }
+#         - { name: O0-debuginfo, optflags: '-O0', debugflags: '-g', wasmoptflags: '-O1' }
+#         - { name: O1,           optflags: '-O1', debugflags: ''  , wasmoptflags: '-O1' }
+          - { name: O2, optflags: '-O2', debugflags: '', wasmoptflags: '-O2' }
+#         - { name: O3,           optflags: '-O3', debugflags: ''  , wasmoptflags: '-O3' }
 #         # -O4 is equivalent to -O3 in clang, but it's different in wasm-opt
-#         - { name: O4,           optflags: "-O3", debugflags: ""  , wasmoptflags: "-O4" }
-#         - { name: Oz,           optflags: "-Oz", debugflags: ""  , wasmoptflags: "-Oz" }
+#         - { name: O4,           optflags: '-O3', debugflags: ''  , wasmoptflags: '-O4' }
+#         - { name: Oz,           optflags: '-Oz', debugflags: ''  , wasmoptflags: '-Oz' }
       fail-fast: false
+
     env:
       RUBY_TESTOPTS: '-q --tty=no'
-      GITPULLOPTIONS: --no-tags origin ${{github.ref}}
-      WASI_SDK_VERSION_MAJOR: 14
+      GITPULLOPTIONS: --no-tags origin ${{ github.ref }}
+      WASI_SDK_VERSION_MAJOR: 20
       WASI_SDK_VERSION_MINOR: 0
-      # Use older version, which uses glibc instead of musl, to avoid https://github.com/WebAssembly/binaryen/issues/4401
-      BINARYEN_VERSION: 91
-      WASMTIME_VERSION: v0.33.0
+      BINARYEN_VERSION: 113
+      WASMTIME_VERSION: v15.0.0
+
     runs-on: ubuntu-20.04
-    if: ${{ !startsWith(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.head_commit.message, 'Document')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.title, 'Document')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
     steps:
-      - run: mkdir build
-        working-directory:
-      - name: git config
-        run: |
-          git config --global advice.detachedHead 0
-          git config --global init.defaultBranch garbage
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with:
+          sparse-checkout-cone-mode: false
+          sparse-checkout: /.github
+
+      - uses: ./.github/actions/setup/directories
         with:
-          path: src
+          srcdir: src
+          builddir: build
+          makeup: true
+
       - name: Install libraries
         run: |
           set -ex
           sudo apt-get update -q || :
-          sudo apt-get install --no-install-recommends -q -y ruby bison make autoconf git wget
+          sudo apt-get install --no-install-recommends -q -y ruby make autoconf git wget
 
           wasi_sdk_deb="wasi-sdk_${WASI_SDK_VERSION_MAJOR}.${WASI_SDK_VERSION_MINOR}_amd64.deb"
           wget "https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-${WASI_SDK_VERSION_MAJOR}/${wasi_sdk_deb}"
@@ -67,22 +90,37 @@ jobs:
           wget -O - "$wasmtime_url" | tar xJf -
           sudo ln -fs "$PWD/wasmtime-${WASMTIME_VERSION}-x86_64-linux/wasmtime" /usr/local/bin/wasmtime
 
-          binaryen_tarball="binaryen-version_${BINARYEN_VERSION}-x86-linux.tar.gz"
+          binaryen_tarball="binaryen-version_${BINARYEN_VERSION}-x86_64-linux.tar.gz"
           binaryen_url="https://github.com/WebAssembly/binaryen/releases/download/version_${BINARYEN_VERSION}/${binaryen_tarball}"
           wget -O - "$binaryen_url" | tar xfz -
-          sudo ln -fs "$PWD/binaryen-version_${BINARYEN_VERSION}/wasm-opt" /usr/local/bin/wasm-opt
+          sudo ln -fs "$PWD/binaryen-version_${BINARYEN_VERSION}/bin/wasm-opt" /usr/local/bin/wasm-opt
         working-directory: src
+
       - name: Set ENV
         run: |
-          echo "MAKEFLAGS=-j$((1 + $(sysctl -n hw.activecpu)))" >> $GITHUB_ENV
           echo "WASI_SDK_PATH=/opt/wasi-sdk" >> $GITHUB_ENV
-      - run: ./autogen.sh
-        working-directory: src
+
+      - uses: ruby/setup-ruby@a6e6f86333f0a2523ece813039b8b4be04560854 # v1.190.0
+        with:
+          ruby-version: '3.0'
+          bundler: none
+
+      - name: Build baseruby
+        run: |
+          set -ex
+          mkdir ../baseruby
+          pushd ../baseruby
+          ../src/configure --prefix=$PWD/install
+          make
+          make install
+
       - name: Run configure
         run: |
           ../src/configure \
             --host wasm32-unknown-wasi \
+            --with-baseruby=$PWD/../baseruby/install/bin/ruby \
             --with-static-linked-ext \
+            --with-ext=cgi/escape,continuation,coverage,date,digest/bubblebabble,digest,digest/md5,digest/rmd160,digest/sha1,digest/sha2,etc,fcntl,json,json/generator,json/parser,objspace,pathname,rbconfig/sizeof,ripper,stringio,strscan,monitor \
             LDFLAGS=" \
               -Xlinker --stack-first \
               -Xlinker -z -Xlinker stack-size=16777216 \
@@ -91,16 +129,47 @@ jobs:
             debugflags="${{ matrix.entry.debugflags }}" \
             wasmoptflags="${{ matrix.entry.wasmoptflags }} ${{ matrix.entry.debugflags }}"
 
-      - run: make ruby
+      # miniruby may not be built when cross-compling
+      - run: make mini ruby
+
+      - run: make install DESTDIR=$PWD/../install
+      - run: tar cfz ../install.tar.gz -C ../install .
+
+      - name: Upload artifacts
+        uses: actions/upload-artifact@604373da6381bf24206979c74d06a550515601b9 # v4.4.1
+        with:
+          name: ruby-wasm-install
+          path: ${{ github.workspace }}/install.tar.gz
+      - name: Show Playground URL to try the build
+        run: |
+          echo "Try on Playground: https://ruby.github.io/play-ruby?run=$GITHUB_RUN_ID" >> $GITHUB_STEP_SUMMARY
+
       - name: Run basictest
         run: wasmtime run ./../build/miniruby --mapdir /::./ -- basictest/test.rb
         working-directory: src
+
       - name: Run bootstraptest (no thread)
         run: |
           NO_THREAD_TESTS="$(grep -L Thread -R ./bootstraptest | awk -F/ '{ print $NF }' | uniq | sed -n 's/test_\(.*\).rb/\1/p' | paste -s -d, -)"
           ruby ./bootstraptest/runner.rb --ruby="$(which wasmtime) run $PWD/../build/ruby --mapdir /::./ -- " --verbose "--sets=$NO_THREAD_TESTS"
         working-directory: src
 
+      - uses: ./.github/actions/slack
+        with:
+          label: ${{ matrix.entry.name }}
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() }}
+
+      # Workaround for https://github.com/orgs/community/discussions/25220
+      - name: Save Pull Request number
+        if: ${{ github.event_name == 'pull_request' }}
+        run: echo "${{ github.event.pull_request.number }}" >> ${{ github.workspace }}/github-pr-info.txt
+      - uses: actions/upload-artifact@604373da6381bf24206979c74d06a550515601b9 # v4.4.1
+        if: ${{ github.event_name == 'pull_request' }}
+        with:
+          name: github-pr-info
+          path: ${{ github.workspace }}/github-pr-info.txt
+
 defaults:
   run:
     working-directory: build
diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
index 9c9d7b9da0..90c8af82d6 100644
--- a/.github/workflows/windows.yml
+++ b/.github/workflows/windows.yml
@@ -3,148 +3,208 @@ on:
   push:
     paths-ignore:
       - 'doc/**'
+      - '**/man/*'
       - '**.md'
       - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
   pull_request:
-    paths-ignore:
-      - 'doc/**'
-      - '**.md'
-      - '**.rdoc'
+    # Do not use paths-ignore for required status checks
+    # https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/collaborating-on-repositories-with-code-quality-features/troubleshooting-required-status-checks#handling-skipped-but-required-checks
+  merge_group:
 
 concurrency:
   group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
   cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
 
+permissions:
+  contents: read
+
 jobs:
   make:
     strategy:
       matrix:
         include:
+          - vc: 2015
+            vs: 2019
+            vcvars: '10.0.14393.0 -vcvars_ver=14.0' # The oldest Windows 10 SDK w/ VC++ 2015 toolset (v140)
+            test_task: check
           - vs: 2019
+            test_task: check
+          - vs: 2022
+            test_task: check
           - vs: 2022
+            test_task: test-bundled-gems
       fail-fast: false
+
     runs-on: windows-${{ matrix.vs < 2022 && '2019' || matrix.vs }}
-    if: ${{ !startsWith(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
-    name: VisualStudio ${{ matrix.vs }}
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.head_commit.message, 'Document')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.title, 'Document')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
+    name: VisualStudio ${{ matrix.vc || matrix.vs }} (${{ matrix.test_task }})
+
     env:
-      GITPULLOPTIONS: --no-tags origin ${{github.ref}}
-      PATCH: C:\msys64\usr\bin\patch.exe
+      GITPULLOPTIONS: --no-tags origin ${{ github.ref }}
       OS_VER: windows-${{ matrix.vs < 2022 && '2019' || matrix.vs }}
+      VCPKG_DEFAULT_TRIPLET: ${{ matrix.target || 'x64' }}-windows
+
     steps:
       - run: md build
         working-directory:
-      - uses: msys2/setup-msys2@v2
+
+      - name: find tools
+        id: find-tools
+        run: |
+          ::- find needed tools
+          set NEEDS=
+          for %%I in (%NEEDED_TOOLS%) do if "%%~$PATH:I" == "" (
+            call set NEEDS=%%NEEDS%% %%~nI
+          ) else (
+            echo %%I: %%~$PATH:I
+          )
+          echo.needs=%NEEDS%>>%GITHUB_OUTPUT%
+          if "%NEEDS%" == "" (
+            echo [debug] All needed tools found
+          ) else (
+            echo [warning^]Needs%NEEDS%
+          )
+        env:
+          NEEDED_TOOLS: >-
+            patch.exe
+
+      - uses: msys2/setup-msys2@d40200dc2db4c351366b048a9565ad82919e1c24 # v2
         id: setup-msys2
         with:
           update: true
           install: >-
-            patch
-        if: ${{ env.OS_VER != 'windows-2019' }}
-      - name: patch path
-        shell: msys2 {0}
-        run: echo PATCH=$(cygpath -wa $(command -v patch)) >> $GITHUB_ENV
-        if: ${{ steps.setup-msys2.outcome == 'success' }}
-      - uses: actions/cache@v3
-        with:
-          path: C:\vcpkg\downloads
-          key: ${{ runner.os }}-vcpkg-download-${{ env.OS_VER }}-${{ github.sha }}
-          restore-keys: |
-            ${{ runner.os }}-vcpkg-download-${{ env.OS_VER }}-
-            ${{ runner.os }}-vcpkg-download-
-      - uses: actions/cache@v3
+            ${{ steps.find-tools.outputs.needs }}
+        if: ${{ steps.find-tools.outputs.needs != '' }}
+
+      - uses: ruby/setup-ruby@a6e6f86333f0a2523ece813039b8b4be04560854 # v1.190.0
         with:
-          path: C:\vcpkg\installed
-          key: ${{ runner.os }}-vcpkg-installed-${{ matrix.os }}-${{ github.sha }}
-          restore-keys: |
-            ${{ runner.os }}-vcpkg-installed-${{ matrix.os }}-
-            ${{ runner.os }}-vcpkg-installed-
-      - name: Install libraries with vcpkg
-        run: |
-          vcpkg --triplet x64-windows install libffi libyaml openssl readline zlib
-      - uses: actions/cache@v3
+          ruby-version: '3.0'
+          bundler: none
+          windows-toolchain: none
+
+      - name: Export GitHub Actions cache environment variables
+        uses: actions/github-script@v7
         with:
-          path: C:\Users\runneradmin\AppData\Local\Temp\chocolatey
-          key: ${{ runner.os }}-chocolatey-${{ env.OS_VER }}-${{ github.sha }}
-          restore-keys: |
-            ${{ runner.os }}-chocolatey-${{ env.OS_VER }}-
-            ${{ runner.os }}-chocolatey-
-      - name: Install libraries with chocolatey
+          script: |
+            core.exportVariable('ACTIONS_CACHE_URL', process.env.ACTIONS_CACHE_URL || '');
+            core.exportVariable('ACTIONS_RUNTIME_TOKEN', process.env.ACTIONS_RUNTIME_TOKEN || '');
+
+      - name: Install libraries with scoop
         run: |
-          # Using Choco-Install for retries, but it doesn't detect failures properly
-          # if you pass multiple package names in a single command.
-          Choco-Install -PackageName winflexbison3
+          iex "& {$(irm get.scoop.sh)} -RunAsAdmin"
+          Join-Path (Resolve-Path ~).Path "scoop\shims" >> $Env:GITHUB_PATH
         shell: pwsh
-      - name: git config
-        run: |
-          git config --global core.autocrlf false
-          git config --global core.eol lf
-          git config --global advice.detachedHead 0
-          git config --global init.defaultBranch garbage
-      - uses: actions/checkout@v3
+
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
         with:
-          path: src
-      - uses: actions/cache@v3
+          sparse-checkout-cone-mode: false
+          sparse-checkout: /.github
+
+      - uses: ./.github/actions/setup/directories
         with:
-          path: src/.downloaded-cache
-          key: downloaded-cache
+          srcdir: src
+          builddir: build
+
       - name: setup env
+        # Available Ruby versions: https://github.com/actions/runner-images/blob/main/images/windows/Windows2019-Readme.md#ruby
         # %TEMP% is inconsistent with %TMP% and test-all expects they are consistent.
         # https://github.com/actions/virtual-environments/issues/712#issuecomment-613004302
         run: |
-          set VS=${{ matrix.vs }}
-          set VCVARS=${{ matrix.vcvars }}
-          if not "%VCVARS%" == "" goto :vcset
-            set VCVARS="C:\Program Files (x86)\Microsoft Visual Studio\%VS%\Enterprise\VC\Auxiliary\Build\vcvars64.bat"
-            if not exist %VCVARS% set VCVARS="C:\Program Files\Microsoft Visual Studio\%VS%\Enterprise\VC\Auxiliary\Build\vcvars64.bat"
-          :vcset
+          ::- Set up VC ${{ matrix.vc || matrix.vs }}
+          set vswhere="%ProgramFiles(x86)%\Microsoft Visual Studio\Installer\vswhere.exe"
+          for /f "delims=;" %%I in ('%vswhere% -latest -property installationPath') do (
+            set VCVARS="%%I\VC\Auxiliary\Build\vcvars64.bat"
+          )
+          set VCVARS
           set | C:\msys64\usr\bin\sort > old.env
-          call %VCVARS%
+          call %VCVARS% ${{ matrix.vcvars || '' }}
+          nmake -f nul
           set TMP=%USERPROFILE%\AppData\Local\Temp
           set TEMP=%USERPROFILE%\AppData\Local\Temp
+          set MAKEFLAGS=l
           set /a TEST_JOBS=(15 * %NUMBER_OF_PROCESSORS% / 10) > nul
           set | C:\msys64\usr\bin\sort > new.env
           C:\msys64\usr\bin\comm -13 old.env new.env >> %GITHUB_ENV%
           del *.env
-      - name: link libraries
+
+      - name: baseruby version
+        run: ruby -v
+
+      - name: compiler version
+        run: cl
+
+      - name: volume info
+        run: Get-Volume
+        shell: pwsh
+
+      - name: Install libraries with vcpkg
         run: |
-          for %%I in (C:\vcpkg\installed\x64-windows\bin\*.dll) do (
-            if not %%~nI == readline mklink %%~nxI %%I
-          )
-          for %%I in (libcrypto-1_1-x64 libssl-1_1-x64) do (
-            ren c:\Windows\System32\%%I.dll %%I.dll_
-          )
+          vcpkg install
+        working-directory: src
+        env:
+          VCPKG_BINARY_SOURCES: "clear;x-gha,readwrite"
+
+      # TODO: We should use `../src` instead of `D:/a/ruby/ruby/src`
       - name: Configure
         run: >-
           ../src/win32/configure.bat --disable-install-doc
-          --with-opt-dir=C:/vcpkg/installed/x64-windows
+          --with-opt-dir=D:/a/ruby/ruby/src/vcpkg_installed/%VCPKG_DEFAULT_TRIPLET%
+
+      - run: nmake prepare-vcpkg
+
       - run: nmake incs
+
       - run: nmake extract-extlibs
+
+      # On all other platforms, test-spec depending on extract-gems (in common.mk) is enough.
+      # But not for this Visual Studio workflow. So here we extract gems before building.
+      - run: nmake extract-gems
+
       - run: nmake
-        env:
-          YACC: win_bison
-      - run: nmake test
-        timeout-minutes: 5
-      - run: nmake test-all
-        env:
-          RUBY_TESTOPTS: -j${{env.TEST_JOBS}} --job-status=normal
-        timeout-minutes: 60
-        continue-on-error: ${{ matrix.continue-on-error || false }}
-      - run: nmake test-spec
-        timeout-minutes: 10
-        continue-on-error: ${{ matrix.continue-on-error || false }}
-      - uses: k0kubun/action-slack@v2.0.0
+
+      - name: Set up Launchable
+        uses: ./.github/actions/launchable/setup
         with:
-          payload: |
-            {
-              "ci": "GitHub Actions",
-              "env": "VS${{ matrix.vs }} / ${{ matrix.test_task || 'check' }}",
-              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
-              "commit": "${{ github.sha }}",
-              "branch": "${{ github.ref }}".split('/').reverse()[0]
-            }
+          os: windows-${{ matrix.vs < 2022 && '2019' || matrix.vs }}
+          launchable-token: ${{ secrets.LAUNCHABLE_TOKEN }}
+          builddir: build
+          srcdir: src
+          test-task: ${{ matrix.test_task || 'check' }}
+        continue-on-error: true
+        if: ${{ matrix.test_task != 'test-bundled-gems' }}
+
+      - run: nmake ${{ matrix.test_task || 'check' }}
         env:
+          RUBY_TESTOPTS: -j${{ env.TEST_JOBS || 4 }}
+        timeout-minutes: 70
+
+      - uses: ./.github/actions/slack
+        with:
+          label: VS${{ matrix.vc || matrix.vs }} / ${{ matrix.test_task || 'check' }}
           SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
-        if: ${{ failure() && github.event_name == 'push' }}
+        if: ${{ failure() }}
+
+  result:
+    if: ${{ always() }}
+    name: ${{ github.workflow }} result
+    runs-on: windows-latest
+    needs: [make]
+    steps:
+      - run: exit 1
+        working-directory:
+        if: ${{ contains(needs.*.result, 'failure') || contains(needs.*.result, 'cancelled') }}
 
 defaults:
   run:
diff --git a/.github/workflows/yjit-macos.yml b/.github/workflows/yjit-macos.yml
new file mode 100644
index 0000000000..b322abbfa1
--- /dev/null
+++ b/.github/workflows/yjit-macos.yml
@@ -0,0 +1,171 @@
+name: YJIT macOS Arm64
+on:
+  push:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man/*'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
+  pull_request:
+    # Do not use paths-ignore for required status checks
+    # https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/collaborating-on-repositories-with-code-quality-features/troubleshooting-required-status-checks#handling-skipped-but-required-checks
+  merge_group:
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:
+  contents: read
+
+jobs:
+  cargo:
+    name: cargo test
+
+    runs-on: macos-14
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.head_commit.message, 'Document')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.title, 'Document')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+
+      - run: RUST_BACKTRACE=1 cargo test
+        working-directory: yjit
+
+      # Also compile and test with all features enabled
+      - run: RUST_BACKTRACE=1 cargo test --all-features
+        working-directory: yjit
+
+      # Check that we can build in release mode too
+      - run: cargo build --release
+        working-directory: yjit
+
+  make:
+    strategy:
+      matrix:
+        include:
+          - test_task: 'check'
+            configure: '--enable-yjit'
+            yjit_opts: '--yjit'
+          - test_task: 'check'
+            configure: '--enable-yjit=dev'
+            yjit_opts: '--yjit-call-threshold=1 --yjit-verify-ctx --yjit-code-gc'
+            specopts: '-T --yjit-call-threshold=1 -T --yjit-verify-ctx -T --yjit-code-gc'
+      fail-fast: false
+
+    env:
+      GITPULLOPTIONS: --no-tags origin ${{ github.ref }}
+      RUN_OPTS: ${{ matrix.yjit_opts }}
+      SPECOPTS: ${{ matrix.specopts }}
+
+    runs-on: macos-14
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.head_commit.message, 'Document')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.title, 'Document')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with:
+          sparse-checkout-cone-mode: false
+          sparse-checkout: /.github
+
+      - name: Install libraries
+        uses: ./.github/actions/setup/macos
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          srcdir: src
+          builddir: build
+          makeup: true
+          dummy-files: ${{ matrix.test_task == 'check' }}
+          # Set fetch-depth: 10 so that Launchable can receive commits information.
+          fetch-depth: 10
+
+      - name: Run configure
+        run: ../src/configure -C --disable-install-doc ${{ matrix.configure }}
+
+      - run: make prepare-gems
+        if: ${{ matrix.test_task == 'test-bundled-gems' }}
+
+      - run: make
+
+      - name: Enable YJIT through ENV
+        run: echo "RUBY_YJIT_ENABLE=1" >> $GITHUB_ENV
+
+      - name: Set test options for skipped tests
+        run: |
+          set -x
+          TESTS="$(echo "${{ matrix.skipped_tests }}" | sed 's| |$$/ -n!/|g;s|^|-n!/|;s|$|$$/|')"
+          echo "TESTS=${TESTS}" >> $GITHUB_ENV
+        if: ${{ matrix.test_task == 'check' && matrix.skipped_tests }}
+
+      - name: Set up Launchable
+        uses: ./.github/actions/launchable/setup
+        with:
+          os: macos-14
+          test-opts: ${{ matrix.configure }}
+          launchable-token: ${{ secrets.LAUNCHABLE_TOKEN }}
+          builddir: build
+          srcdir: src
+          is-yjit: true
+        continue-on-error: true
+
+      - name: make ${{ matrix.test_task }}
+        run: >-
+          make -s ${{ matrix.test_task }} ${TESTS:+TESTS="$TESTS"}
+          RUN_OPTS="$RUN_OPTS"
+          SPECOPTS="$SPECOPTS"
+        timeout-minutes: 60
+        env:
+          RUBY_TESTOPTS: '-q --tty=no'
+          TEST_BUNDLED_GEMS_ALLOW_FAILURES: 'typeprof'
+          SYNTAX_SUGGEST_TIMEOUT: '5'
+          PRECHECK_BUNDLED_GEMS: 'no'
+        continue-on-error: ${{ matrix.continue-on-test_task || false }}
+
+      - name: make skipped tests
+        run: |
+          make -s test-all TESTS="${TESTS//-n!\//-n/}"
+        env:
+          GNUMAKEFLAGS: ''
+          RUBY_TESTOPTS: '-v --tty=no'
+          PRECHECK_BUNDLED_GEMS: 'no'
+        if: ${{ matrix.test_task == 'check' && matrix.skipped_tests }}
+        continue-on-error: ${{ matrix.continue-on-skipped_tests || false }}
+
+      - uses: ./.github/actions/slack
+        with:
+          label: ${{ matrix.test_task }} ${{ matrix.configure }} ${{ matrix.yjit_opts }}
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() }}
+
+  result:
+    if: ${{ always() }}
+    name: ${{ github.workflow }} result
+    runs-on: macos-14
+    needs: [make]
+    steps:
+      - run: exit 1
+        working-directory:
+        if: ${{ contains(needs.*.result, 'failure') || contains(needs.*.result, 'cancelled') }}
+
+defaults:
+  run:
+    working-directory: build
diff --git a/.github/workflows/yjit-ubuntu.yml b/.github/workflows/yjit-ubuntu.yml
index beec059e0c..f1c62c6c77 100644
--- a/.github/workflows/yjit-ubuntu.yml
+++ b/.github/workflows/yjit-ubuntu.yml
@@ -3,110 +3,219 @@ on:
   push:
     paths-ignore:
       - 'doc/**'
+      - '**/man/*'
       - '**.md'
       - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
   pull_request:
-    paths-ignore:
-      - 'doc/**'
-      - '**.md'
-      - '**.rdoc'
+    # Do not use paths-ignore for required status checks
+    # https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/collaborating-on-repositories-with-code-quality-features/troubleshooting-required-status-checks#handling-skipped-but-required-checks
+  merge_group:
 
 concurrency:
   group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
   cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
 
+permissions:
+  contents: read
+
 jobs:
+  cargo:
+    name: cargo test
+
+    # GitHub Action's image seems to already contain a Rust 1.58.0.
+    runs-on: ubuntu-20.04
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+
+      # For now we can't run cargo test --offline because it complains about the
+      # capstone dependency, even though the dependency is optional
+      #- run: cargo test --offline
+
+      - run: RUST_BACKTRACE=1 cargo test
+        working-directory: yjit
+
+      # Also compile and test with all features enabled
+      - run: RUST_BACKTRACE=1 cargo test --all-features
+        working-directory: yjit
+
+      # Check that we can build in release mode too
+      - run: cargo build --release
+        working-directory: yjit
+
+  lint:
+    name: cargo clippy
+
+    # GitHub Action's image seems to already contain a Rust 1.58.0.
+    runs-on: ubuntu-20.04
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
+    steps:
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+
+      # Check that we don't have linting errors in release mode, too
+      - run: cargo clippy --all-targets --all-features
+        working-directory: yjit
+
   make:
     strategy:
+      fail-fast: false
       matrix:
-        test_task: ["check"] # "test-bundler-parallel",
-        os:
-          - ubuntu-20.04
-#         - ubuntu-18.04
-        yjit_opts: [
-          "--yjit",
-          "--yjit --yjit-call-threshold=1",
-        ]
-        configure: ["", "cppflags=-DRUBY_DEBUG"]
         include:
-          - test_task: "test-all TESTS=--repeat-count=2"
-            os: ubuntu-20.04
-            configure: ""
-            yjit_enable_env: RUBY_YJIT_ENABLE
-          - test_task: "test-bundled-gems"
-            os: ubuntu-20.04
-            configure: "cppflags=-DRUBY_DEBUG"
-            yjit_enable_env: RUBY_YJIT_ENABLE
-      fail-fast: false
+          - test_task: 'yjit-bindgen'
+            hint: 'To fix: use patch in logs'
+            configure: '--with-gcc=clang-12 --enable-yjit=dev'
+
+          - test_task: 'check'
+            # YJIT should be automatically built in release mode on x86-64 Linux with rustc present
+            #configure: "--enable-yjit RUSTC='rustc +1.58.0'"
+            configure: "RUSTC='rustc +1.58.0'"
+            rust_version: '1.58.0'
+
+          - test_task: 'check'
+            configure: '--enable-yjit=dev'
+
+          - test_task: 'check'
+            configure: '--enable-yjit=dev'
+            yjit_opts: '--yjit-call-threshold=1 --yjit-verify-ctx --yjit-code-gc'
+            specopts: '-T --yjit-call-threshold=1 -T --yjit-verify-ctx -T --yjit-code-gc'
+
+          - test_task: 'test-bundled-gems'
+            configure: '--enable-yjit=dev'
+
+          - test_task: 'yjit-bench'
+            configure: '--enable-yjit=dev'
+            yjit_bench_opts: '--yjit-stats'
+            continue-on-test_task: true
+
     env:
-      GITPULLOPTIONS: --no-tags origin ${{github.ref}}
+      GITPULLOPTIONS: --no-tags origin ${{ github.ref }}
       RUN_OPTS: ${{ matrix.yjit_opts }}
+      YJIT_BENCH_OPTS: ${{ matrix.yjit_bench_opts }}
+      SPECOPTS: ${{ matrix.specopts }}
       RUBY_DEBUG: ci
-    runs-on: ${{ matrix.os }}
-    if: ${{ !startsWith(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
+      BUNDLE_JOBS: 8 # for yjit-bench
+      RUST_BACKTRACE: 1
+
+    runs-on: ubuntu-20.04
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.head_commit.message, 'Document')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.title, 'Document')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
     steps:
-      - run: mkdir build
-        working-directory:
-      - name: Install libraries
-        run: |
-          set -x
-          sudo apt-get update -q || :
-          sudo apt-get install --no-install-recommends -q -y build-essential libssl-dev libyaml-dev libreadline6-dev zlib1g-dev libncurses5-dev libffi-dev bison autoconf ruby
-      - name: git config
-        run: |
-          git config --global advice.detachedHead 0
-          git config --global init.defaultBranch garbage
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@d632683dd7b4114ad314bca15554477dd762a938 # v4.2.0
+        with:
+          sparse-checkout-cone-mode: false
+          sparse-checkout: /.github
+
+      - uses: ./.github/actions/setup/ubuntu
+
+      - uses: ruby/setup-ruby@a6e6f86333f0a2523ece813039b8b4be04560854 # v1.190.0
         with:
-          path: src
-      - uses: actions/cache@v3
+          ruby-version: '3.0'
+          bundler: none
+
+      - uses: ./.github/actions/setup/directories
         with:
-          path: src/.downloaded-cache
-          key: downloaded-cache
-      - name: Fixed world writable dirs
-        run: |
-          chmod -v go-w $HOME $HOME/.config
-          sudo chmod -R go-w /usr/share
-          sudo bash -c 'IFS=:; for d in '"$PATH"'; do chmod -v go-w $d; done' || :
-      - name: Set ENV
-        run: |
-          echo "GNUMAKEFLAGS=-j$((1 + $(nproc --all)))" >> $GITHUB_ENV
-      - run: ./autogen.sh
-        working-directory: src
+          srcdir: src
+          builddir: build
+          makeup: true
+          dummy-files: ${{ matrix.test_task == 'check' }}
+          # Set fetch-depth: 10 so that Launchable can receive commits information.
+          fetch-depth: 10
+
+      - name: Install Rust
+        if: ${{ matrix.rust_version }}
+        run: rustup install ${{ matrix.rust_version }} --profile minimal
+
       - name: Run configure
-        run: ../src/configure -C --disable-install-doc ${{ matrix.configure }}
+        run: ../src/configure -C --disable-install-doc --prefix=$(pwd)/install ${{ matrix.configure }}
+
       - run: make incs
-      - run: make
-      - run: make leaked-globals
-        if: ${{ matrix.test_task == 'check' }}
+
       - run: make prepare-gems
-        if: ${{ matrix.test_task == 'check' }}
-      - name: Create dummy files in build dir
-        run: |
-          ./miniruby -e '(("a".."z").to_a+("A".."Z").to_a+("0".."9").to_a+%w[foo bar test zzz]).each{|basename|File.write("#{basename}.rb", "raise %(do not load #{basename}.rb)")}'
-        if: ${{ matrix.test_task == 'check' }}
+        if: ${{ matrix.test_task == 'test-bundled-gems' }}
+
+      - run: make
+
       - name: Enable YJIT through ENV
         run: echo "RUBY_YJIT_ENABLE=1" >> $GITHUB_ENV
-        if: ${{ matrix.yjit_enable_env }}
-      - run: make -s ${{ matrix.test_task }} RUN_OPTS="$RUN_OPTS"
-        timeout-minutes: 60
-        env:
-          RUBY_TESTOPTS: "-q --tty=no"
-          TEST_BUNDLED_GEMS_ALLOW_FAILURES: ""
-          PRECHECK_BUNDLED_GEMS: "no"
-      - uses: k0kubun/action-slack@v2.0.0
+
+      # Check that the binary was built with YJIT
+      - name: Check YJIT enabled
+        run: ./miniruby --yjit -v | grep "+YJIT"
+
+      - name: Set up Launchable
+        uses: ./.github/actions/launchable/setup
         with:
-          payload: |
-            {
-              "ci": "GitHub Actions",
-              "env": "${{ matrix.os }} / ${{ matrix.test_task }}${{ matrix.configure }}",
-              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
-              "commit": "${{ github.sha }}",
-              "branch": "${{ github.ref }}".split('/').reverse()[0]
-            }
+          os: ubuntu-20.04
+          test-opts: ${{ matrix.configure }}
+          launchable-token: ${{ secrets.LAUNCHABLE_TOKEN }}
+          builddir: build
+          srcdir: src
+          is-yjit: true
+        continue-on-error: true
+
+      - name: make ${{ matrix.test_task }}
+        run: >-
+          make -s ${{ matrix.test_task }} ${TESTS:+TESTS="$TESTS"}
+          RUN_OPTS="$RUN_OPTS" MSPECOPT=--debug SPECOPTS="$SPECOPTS"
+          YJIT_BENCH_OPTS="$YJIT_BENCH_OPTS" YJIT_BINDGEN_DIFF_OPTS="$YJIT_BINDGEN_DIFF_OPTS"
+        timeout-minutes: 90
         env:
+          RUBY_TESTOPTS: '-q --tty=no'
+          TEST_BUNDLED_GEMS_ALLOW_FAILURES: 'typeprof'
+          PRECHECK_BUNDLED_GEMS: 'no'
+          SYNTAX_SUGGEST_TIMEOUT: '5'
+          YJIT_BINDGEN_DIFF_OPTS: '--exit-code'
+        continue-on-error: ${{ matrix.continue-on-test_task || false }}
+
+      - name: Show ${{ github.event.pull_request.base.ref }} GitHub URL for yjit-bench comparison
+        run: echo "https://github.com/${BASE_REPO}/commit/${BASE_SHA}"
+        env:
+          BASE_REPO: ${{ github.event.pull_request.base.repo.full_name }}
+          BASE_SHA: ${{ github.event.pull_request.base.sha }}
+        if: ${{ matrix.test_task == 'yjit-bench' && startsWith(github.event_name, 'pull') }}
+
+      - uses: ./.github/actions/slack
+        with:
+          label: ${{ matrix.test_task }} ${{ matrix.configure }}
           SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
-        if: ${{ failure() && github.event_name == 'push' }}
+        if: ${{ failure() }}
+
+  result:
+    if: ${{ always() }}
+    name: ${{ github.workflow }} result
+    runs-on: ubuntu-latest
+    needs: [make]
+    steps:
+      - run: exit 1
+        working-directory:
+        if: ${{ contains(needs.*.result, 'failure') || contains(needs.*.result, 'cancelled') }}
 
 defaults:
   run:
diff --git a/.github/workflows/yjit_asm_tests.yml b/.github/workflows/yjit_asm_tests.yml
deleted file mode 100644
index a7e05066dd..0000000000
--- a/.github/workflows/yjit_asm_tests.yml
+++ /dev/null
@@ -1,38 +0,0 @@
-name: YJIT x86 assembler tests
-
-on:
-  push:
-    paths-ignore:
-      - 'doc/**'
-      - '**.md'
-      - '**.rdoc'
-  pull_request:
-    paths-ignore:
-      - 'doc/**'
-      - '**.md'
-      - '**.rdoc'
-
-concurrency:
-  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
-  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
-
-jobs:
-  test:
-    runs-on: ubuntu-latest
-    if: ${{ !startsWith(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
-    steps:
-      - name: Install dependencies
-        run: |
-          set -x
-          sudo apt-get update -q || :
-          sudo apt-get install --no-install-recommends -q -y build-essential
-      - name: git config
-        run: |
-          git config --global advice.detachedHead 0
-          git config --global init.defaultBranch garbage
-      - uses: actions/checkout@v3
-        with:
-          path: src
-      - name: Run ASM tests
-        run: ./misc/test_yjit_asm.sh
-        working-directory: src
diff --git a/.gitignore b/.gitignore
index 675020fa91..f61ce9f889 100644
--- a/.gitignore
+++ b/.gitignore
@@ -14,6 +14,7 @@
 *.inc
 *.log
 *.o
+*.o.tmp
 *.obj
 *.old
 *.orig
@@ -25,6 +26,7 @@
 *.sav
 *.sl
 *.so
+*.so.*
 *.swp
 *.yarb
 *~
@@ -48,6 +50,7 @@ y.tab.c
 *.gcno
 *.gcov
 *.vscode
+!misc/.vscode
 lcov*.info
 
 # /
@@ -121,29 +124,33 @@ lcov*.info
 /repack
 /revision.h
 /revision.tmp
+/ripper.tmp.y
 /riscos
 /rubicon
 /ruby
 /ruby-runner
 /ruby-runner.h
 /ruby-man.rd.gz
+/rubyspec_temp
 /run.gdb
 /sizes.c
 /static-ruby
 /test.rb
 /test-coverage.dat
 /tmp
+/vcpkg_installed
 /transdb.h
 /uncommon.mk
 /verconf.h
 /verconf.mk
 /web
-/yasmdata.rb
 
 # /bin/
 
 /bin/*.exe
 /bin/*.dll
+/bin/goruby
+/bin/ruby
 
 # /benchmark/
 /benchmark/bm_require.data
@@ -159,6 +166,7 @@ lcov*.info
 
 # /coroutine/
 !/coroutine/**/*.s
+!/coroutine/**/*.S
 
 # /enc/trans/
 /enc/trans/*.c
@@ -198,8 +206,10 @@ lcov*.info
 
 # /ext/ripper/
 /ext/ripper/eventids1.c
+/ext/ripper/eventids1.h
 /ext/ripper/.eventids2-check
 /ext/ripper/eventids2table.c
+/ext/ripper/ripper_init.c
 /ext/ripper/ripper.*
 /ext/ripper/ids1
 /ext/ripper/ids2
@@ -218,8 +228,12 @@ lcov*.info
 /lib/ruby/[1-9]*.*
 /lib/ruby/vendor_ruby
 
-# /spec/bundler
+# /misc/
+/misc/**/__pycache__
+
+# for `make test-bundler`
 /.rspec_status
+/tool/bundler/*.lock
 
 # /tool/
 /tool/config.guess
@@ -228,10 +242,41 @@ lcov*.info
 # /win32/
 /win32/*.ico
 
-# MJIT
-/rb_mjit_header.h
-/mjit_config.h
-/include/ruby-*/*/rb_mjit_min_header-*.h
+# RJIT
+/include/ruby-*/*/rb_rjit_min_header-*.h
+/lib/ruby_vm/rjit/instruction.rb
+/lib/ruby_vm/rjit/instruction.rb
+/rjit_config.h
+/rb_rjit_header.h*
+
+# YJIT
+/yjit-bench
+/yjit_exit_locations.dump
 
 # /wasm/
 /wasm/tests/*.wasm
+
+# prism
+/lib/prism/compiler.rb
+/lib/prism/dispatcher.rb
+/lib/prism/dot_visitor.rb
+/lib/prism/dsl.rb
+/lib/prism/inspect_visitor.rb
+/lib/prism/mutation_compiler.rb
+/lib/prism/node.rb
+/lib/prism/reflection.rb
+/lib/prism/serialize.rb
+/lib/prism/visitor.rb
+/prism/api_node.c
+/prism/ast.h
+/prism/diagnostic.c
+/prism/diagnostic.h
+/prism/node.c
+/prism/prettyprint.c
+/prism/serialize.c
+/prism/token_type.c
+
+# tool/update-NEWS-gemlist.rb
+/bundled_gems.json
+/default_gems.json
+/gems/default_gems
diff --git a/.indent.pro b/.indent.pro
new file mode 100644
index 0000000000..1d61cbcad1
--- /dev/null
+++ b/.indent.pro
@@ -0,0 +1,32 @@
+-bap
+-nbbb
+-nbc
+-br
+-brs
+-nbs
+-ncdb
+-nce
+-cdw
+-cli2
+-cbi2
+-ndj
+-ncs
+-nfc1
+-i4
+-l120
+-lp
+-npcs
+-psl
+-sc
+-sob
+-sbi4
+-nut
+-par
+
+-TID
+-TVALUE
+-Tst_data_t
+-Tst_index_t
+-Tst_table
+-Trb_data_type_t
+-TFILE
diff --git a/.mailmap b/.mailmap
new file mode 100644
index 0000000000..213a0f4916
--- /dev/null
+++ b/.mailmap
@@ -0,0 +1,431 @@
+git[bot]                                <svn-admin@ruby-lang.org>
+git[bot]                                <svn-admin@ruby-lang.org> git <svn@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+svn[bot]                                <svn-admin@ruby-lang.org> svn <svn@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# a_matsuda
+Akira Matsuda                           <ronnie@dio.jp>
+Akira Matsuda                           <ronnie@dio.jp> <a_matsuda@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# aamine
+Minero Aoki                             <aamine@loveruby.net>
+Minero Aoki                             <aamine@loveruby.net> <aamine@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# akira
+akira yamada                            <akira@ruby-lang.org>
+## akira yamada                         <akira@ruby-lang.org> <akira@rice.p.arika.org>
+akira yamada                            <akira@ruby-lang.org> <akira@arika.org>
+akira yamada                            <akira@ruby-lang.org> <akira@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# akiyoshi
+AKIYOSHI, Masamichi                     <masamichi.akiyoshi@hp.com>
+AKIYOSHI, Masamichi                     <masamichi.akiyoshi@hp.com> <akiyoshi@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# akr
+Tanaka Akira                            <akr@fsij.org>
+Tanaka Akira                            <akr@fsij.org> <akr@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# arai
+Koji Arai                               <jca02266@nifty.ne.jp>
+Koji Arai                               <jca02266@nifty.ne.jp> <arai@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# arton
+Akio Tajima                             <artonx@yahoo.co.jp>
+Akio Tajima                             <artonx@yahoo.co.jp> <arton@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# aycabta
+aycabta                                 <aycabta@gmail.com>
+aycabta                                 <aycabta@gmail.com> <aycabta@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# ayumin
+Ayumu AIZAWA                            <ayumu.aizawa@gmail.com>
+Ayumu AIZAWA                            <ayumu.aizawa@gmail.com> <ayumin@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# azav
+Alexander Zavorine                      <alexandre.zavorine@nokia.com>
+Alexander Zavorine                      <alexandre.zavorine@nokia.com> <azav@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# charliesome
+Charlie Somerville                      <charliesome@ruby-lang.org>
+Charlie Somerville                      <charliesome@ruby-lang.org> <charliesome@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# dave
+Dave Thomas                             <dave@pragprog.com>
+Dave Thomas                             <dave@pragprog.com> <dave@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# davidflanagan
+David Flanagan                          <davidflanagan@ruby-lang.org>
+David Flanagan                          <davidflanagan@ruby-lang.org> <david@think32>
+David Flanagan                          <davidflanagan@ruby-lang.org> <david@davidflanagan.com>
+David Flanagan                          <davidflanagan@ruby-lang.org> <davidflanagan@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# dblack
+David A. Black                          <dblack@rubypal.com>
+David A. Black                          <dblack@rubypal.com> <dblack@wobblini.net>
+David A. Black                          <dblack@rubypal.com> <dblack@superlink.net>
+David A. Black                          <dblack@rubypal.com> <dblack@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# drbrain
+Eric Hodel                              <drbrain@segment7.net>
+Eric Hodel                              <drbrain@segment7.net> <drbrain@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# duerst
+Martin Dürst                            <duerst@it.aoyama.ac.jp>
+Martin Dürst                            <duerst@it.aoyama.ac.jp> <duerst@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# eban
+WATANABE Hirofumi                       <eban@ruby-lang.org>
+WATANABE Hirofumi                       <eban@ruby-lang.org> <eban@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# emboss
+Martin Bosslet                          <Martin.Bosslet@gmail.com>
+Martin Bosslet                          <Martin.Bosslet@gmail.com> <Martin.Bosslet@googlemail.com>
+Martin Bosslet                          <Martin.Bosslet@gmail.com> <emboss@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# eregon
+Benoit Daloze                           <eregontp@gmail.com>
+Benoit Daloze                           <eregontp@gmail.com> <eregon@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# evan
+Evan Phoenix                            <evan@ruby-lang.org>
+Evan Phoenix                            <evan@ruby-lang.org> <evan@fallingsnow.net>
+Evan Phoenix                            <evan@ruby-lang.org> <evan@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# glass
+Masaki Matsushita                       <glass.saga@gmail.com>
+Masaki Matsushita                       <glass.saga@gmail.com> <glass@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# gogotanaka
+Kazuki Tanaka                           <gogotanaka@ruby-lang.org>
+Kazuki Tanaka                           <gogotanaka@ruby-lang.org> <gogotanaka@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# gotoken
+Kentaro Goto                            <gotoken@gmail.com>
+Kentaro Goto                            <gotoken@gmail.com> <gotoken@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# gotoyuzo
+GOTOU Yuuzou                            <gotoyuzo@notwork.org>
+GOTOU Yuuzou                            <gotoyuzo@notwork.org> <gotoyuzo@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# gsinclair
+Gavin Sinclair                          <gsinclair@soyabean.com.au>
+Gavin Sinclair                          <gsinclair@soyabean.com.au> <gsinclair@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# H_Konishi
+KONISHI Hiromasa                        <konishih@fd6.so-net.ne.jp>
+KONISHI Hiromasa                        <konishih@fd6.so-net.ne.jp> <H_Konishi@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# headius
+Charles Oliver Nutter                   <headius@headius.com>
+Charles Oliver Nutter                   <headius@headius.com> <headius@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# hone
+Terence Lee                             <hone@heroku.com>
+Terence Lee                             <hone@heroku.com> <hone@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# hsbt
+Hiroshi SHIBATA                         <hsbt@ruby-lang.org>
+Hiroshi SHIBATA                         <hsbt@ruby-lang.org> <hsbt@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# iwamatsu
+Nobuhiro Iwamatsu                       <iwamatsu@nigauri.org>
+Nobuhiro Iwamatsu                       <iwamatsu@nigauri.org> <iwamatsu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# jeg2
+James Edward Gray II                    <james@graysoftinc.com>
+James Edward Gray II                    <james@graysoftinc.com> <jeg2@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# jim
+Jim Weirich                             <jim@tardis.local>
+Jim Weirich                             <jim@tardis.local> <jim@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# k0kubun
+Takashi Kokubun                         <takashikkbn@gmail.com>
+Takashi Kokubun                         <takashikkbn@gmail.com> <k0kubun@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# kanemoto
+Yutaka Kanemoto                         <kanemoto@ruby-lang.org>
+Yutaka Kanemoto                         <kanemoto@ruby-lang.org> <kanemoto@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# katsu
+UENO Katsuhiro                          <katsu@blue.sky.or.jp>
+UENO Katsuhiro                          <katsu@blue.sky.or.jp> <katsu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# kazu
+Kazuhiro NISHIYAMA                      <zn@mbf.nifty.com>
+Kazuhiro NISHIYAMA                      <zn@mbf.nifty.com> <kazu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# keiju
+Keiju Ishitsuka                         <keiju@ishitsuka.com>
+Keiju Ishitsuka                         <keiju@ishitsuka.com> <keiju@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# knu
+Akinori MUSHA                           <knu@iDaemons.org>
+Akinori MUSHA                           <knu@iDaemons.org> <knu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# ko1
+Koichi Sasada                           <ko1@atdot.net>
+Koichi Sasada                           <ko1@atdot.net> <ko1@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# kosaki
+KOSAKI Motohiro                         <kosaki.motohiro@gmail.com>
+KOSAKI Motohiro                         <kosaki.motohiro@gmail.com> <kosaki@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# kosako
+K.Kosako                                <sndgk393@ybb.ne.jp>
+K.Kosako                                <sndgk393@ybb.ne.jp> <kosako@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# kou
+Sutou Kouhei                            <kou@clear-code.com>
+Sutou Kouhei                            <kou@clear-code.com> <kou@cozmixng.org>
+Sutou Kouhei                            <kou@clear-code.com> <kou@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# kouji
+Kouji Takao                             <kouji.takao@gmail.com>
+Kouji Takao                             <kouji.takao@gmail.com> <kouji@takao7.net>
+Kouji Takao                             <kouji.takao@gmail.com> <kouji@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# ksaito
+Kazuo Saito                             <ksaito@uranus.dti.ne.jp>
+Kazuo Saito                             <ksaito@uranus.dti.ne.jp> <ksaito@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# ktsj
+Kazuki Tsujimoto                        <kazuki@callcc.net>
+Kazuki Tsujimoto                        <kazuki@callcc.net> <ktsj@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# luislavena
+Luis Lavena                             <luislavena@gmail.com>
+Luis Lavena                             <luislavena@gmail.com> <luislavena@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# mame
+Yusuke Endoh                            <mame@ruby-lang.org>
+## Yusuke Endoh                         <mame@ruby-lang.org> <mame@tsg.ne.jp>
+Yusuke Endoh                            <mame@ruby-lang.org> <mame@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# marcandre
+Marc-Andre Lafortune                    <github@marc-andre.ca>
+Marc-Andre Lafortune                    <ruby-core@marc-andre.ca>
+Marc-Andre Lafortune                    <ruby-core@marc-andre.ca> <marcandre@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# matz
+Yukihiro "Matz" Matsumoto               <matz@ruby.or.jp>
+Yukihiro "Matz" Matsumoto               <matz@ruby.or.jp> <matz@ruby-lang.org>
+Yukihiro "Matz" Matsumoto               <matz@ruby.or.jp> <matz@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# michal
+Michal Rokos                            <michal@ruby-lang.org>
+Michal Rokos                            <michal@ruby-lang.org> <michal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# mneumann
+Michael Neumann                         <mneumann@ruby-lang.org>
+Michael Neumann                         <mneumann@ruby-lang.org> <mneumann@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# mrkn
+Kenta Murata                            <mrkn@mrkn.jp>
+Kenta Murata                            <mrkn@mrkn.jp> <muraken@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+Kenta Murata                            <mrkn@mrkn.jp> <3959+mrkn@users.noreply.github.com>
+Kenta Murata                            <mrkn@mrkn.jp> <mrkn@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# nagachika
+nagachika                               <nagachika@ruby-lang.org>
+nagachika                               <nagachika@ruby-lang.org> <nagachika@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# nagai
+Hidetoshi NAGAI                         <nagai@ai.kyutech.ac.jp>
+Hidetoshi NAGAI                         <nagai@ai.kyutech.ac.jp> <nagai@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# nahi
+Hiroshi Nakamura                        <nahi@ruby-lang.org>
+Hiroshi Nakamura                        <nahi@ruby-lang.org> <nahi@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# nari
+Narihiro Nakamura                       <authornari@gmail.com>
+Narihiro Nakamura                       <authornari@gmail.com> <nari@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# naruse
+NARUSE, Yui                             <naruse@airemix.jp>
+NARUSE, Yui                             <naruse@airemix.jp> <naruse@ruby-lang.org>
+NARUSE, Yui                             <naruse@airemix.jp> <naruse@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# ngoto
+Naohisa Goto                            <ngotogenome@gmail.com>
+Naohisa Goto                            <ngotogenome@gmail.com> <ngoto@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# nobu
+Nobuyoshi Nakada                        <nobu@ruby-lang.org>
+Nobuyoshi Nakada                        <nobu@ruby-lang.org> <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# normal
+Eric Wong                               <normal@ruby-lang.org>
+Eric Wong                               <normal@ruby-lang.org> <e@80x24.org>
+Eric Wong                               <normal@ruby-lang.org> <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# ntalbott
+Nathaniel Talbott                       <ntalbott@ruby-lang.org>
+Nathaniel Talbott                       <ntalbott@ruby-lang.org> <ntalbott@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# ocean
+Hirokazu Yamamoto                       <ocean@m2.ccsnet.ne.jp>
+Hirokazu Yamamoto                       <ocean@m2.ccsnet.ne.jp> <ocean@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# odaira
+Rei Odaira                              <rodaira@us.ibm.com>
+Rei Odaira                              <rodaira@us.ibm.com> <Rei.Odaira@gmail.com>
+Rei Odaira                              <rodaira@us.ibm.com> <odaira@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# okkez
+okkez                                   <okkez000@gmail.com>
+okkez                                   <okkez000@gmail.com> <okkez@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# rhe
+Kazuki Yamaguchi                        <k@rhe.jp>
+Kazuki Yamaguchi                        <k@rhe.jp> <rhe@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# ryan
+Ryan Davis                              <ryand-github@zenspider.com>
+Ryan Davis                              <ryand-github@zenspider.com> <ryand-ruby@zenspider.com>
+Ryan Davis                              <ryand-github@zenspider.com> <ryan@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# samuel
+Samuel Williams                         <samuel.williams@oriontransfer.co.nz>
+Samuel Williams                         <samuel.williams@oriontransfer.co.nz> <samuel@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# seki
+Masatoshi SEKI                          <m_seki@mva.biglobe.ne.jp>
+Masatoshi SEKI                          <m_seki@mva.biglobe.ne.jp> <seki@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# ser
+Sean Russell                            <ser@germane-software.com>
+Sean Russell                            <ser@germane-software.com> <ser@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# shigek
+Shigeo Kobayashi                        <shigek@ruby-lang.org>
+Shigeo Kobayashi                        <shigek@ruby-lang.org> <shigek@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# shirosaki
+Hiroshi Shirosaki                       <h.shirosaki@gmail.com>
+Hiroshi Shirosaki                       <h.shirosaki@gmail.com> <shirosaki@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# sho-h
+Sho Hashimoto                           <sho-h@ruby-lang.org>
+Sho Hashimoto                           <sho-h@ruby-lang.org> <sho-h@netlab.jp>
+Sho Hashimoto                           <sho-h@ruby-lang.org> <sho.hsmt@gmail.com>
+Sho Hashimoto                           <sho-h@ruby-lang.org> <sho-h@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# shugo
+Shugo Maeda                             <shugo@ruby-lang.org>
+Shugo Maeda                             <shugo@ruby-lang.org> <shugo@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# shyouhei
+卜部昌平                                    <shyouhei@ruby-lang.org>
+卜部昌平                                    <shyouhei@ruby-lang.org> <shyouhei@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# siena
+Siena.                                  <siena@faculty.chiba-u.jp>
+Siena.                                  <siena@faculty.chiba-u.jp> <siena@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# sonots
+sonots                                  <sonots@gmail.com>
+sonots                                  <sonots@gmail.com> <sonots@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# sorah
+Sorah Fukumori                          <her@sorah.jp>
+Sorah Fukumori                          <her@sorah.jp> <sorah@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# stomar
+Marcus Stollsteimer                     <sto.mar@web.de>
+Marcus Stollsteimer                     <sto.mar@web.de> <stomar@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# suke
+Masaki Suketa                           <masaki.suketa@nifty.ne.jp>
+Masaki Suketa                           <masaki.suketa@nifty.ne.jp> <suke@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# tadd
+Tadashi Saito                           <tad.a.digger@gmail.com>
+Tadashi Saito                           <tad.a.digger@gmail.com> <tadd@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# tadf
+Tadayoshi Funaba                        <tadf@dotrb.org>
+Tadayoshi Funaba                        <tadf@dotrb.org> <tadf@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# takano32
+TAKANO Mitsuhiro                        <takano32@gmail.com>
+TAKANO Mitsuhiro                        <takano32@gmail.com> <takano32@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# tarui
+Masaya Tarui                            <tarui@ruby-lang.org>
+Masaya Tarui                            <tarui@ruby-lang.org> <tarui@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# technorama
+Technorama Ltd.                         <oss-ruby@technorama.net>
+Technorama Ltd.                         <oss-ruby@technorama.net> <technorama@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# tenderlove
+Aaron Patterson                         <tenderlove@ruby-lang.org>
+Aaron Patterson                         <tenderlove@ruby-lang.org> <tenderlove@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# tmm1
+Aman Gupta                              <ruby@tmm1.net>
+Aman Gupta                              <ruby@tmm1.net> <tmm1@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# ts
+Guy Decoux                              <ts@moulon.inra.fr>
+Guy Decoux                              <ts@moulon.inra.fr> <ts@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# ttate
+Takaaki Tateishi                        <ttate@ttsky.net>
+## Takaaki Tateishi                     <ttate@ttsky.net> <ttate@kt.jaist.ac.jp>
+Takaaki Tateishi                        <ttate@ttsky.net> <ttate@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# uema2
+Takaaki Uematsu                         <uema2x@jcom.home.ne.jp>
+Takaaki Uematsu                         <uema2x@jcom.home.ne.jp> <uema2@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# usa
+U.Nakamura                              <usa@ruby-lang.org>
+U.Nakamura                              <usa@ruby-lang.org> <usa@garbagecollect.jp>
+U.Nakamura                              <usa@ruby-lang.org> <usa@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# wakou
+Wakou Aoyama                            <wakou@ruby-lang.org>
+Wakou Aoyama                            <wakou@ruby-lang.org> <wakou@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# wanabe
+wanabe                                  <s.wanabe@gmail.com>
+wanabe                                  <s.wanabe@gmail.com> <wanabe@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# watson1978
+Watson                                  <watson1978@gmail.com>
+Watson                                  <watson1978@gmail.com> <watson1978@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# wew
+William Webber                          <william@williamwebber.com>
+William Webber                          <william@williamwebber.com> <wew@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# why
+why the lucky stiff                     <why@ruby-lang.org>
+why the lucky stiff                     <why@ruby-lang.org> <why@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# xibbar
+Takeyuki FUJIOKA                        <xibbar@ruby-lang.org>
+Takeyuki FUJIOKA                        <xibbar@ruby-lang.org> <xibbar@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# yugui
+Yuki Yugui Sonoda                       <yugui@yugui.jp>
+Yuki Yugui Sonoda                       <yugui@yugui.jp> <yugui@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# yui-knk
+yui-knk                                 <spiketeika@gmail.com>
+yui-knk                                 <spiketeika@gmail.com> <yui-knk@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# yuki
+Yuki Nishijima                          <yuki24@hey.com>
+Yuki Nishijima                          <yuki24@hey.com> <mail@yukinishijima.net>
+Yuki Nishijima                          <yuki24@hey.com> <yuki@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# zsombor
+Dee Zsombor                             <zsombor@ruby-lang.org>
+Dee Zsombor                             <zsombor@ruby-lang.org> <zsombor@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
+
+# zzak
+zzak                                    <zzakscott@gmail.com>
+zzak                                    <zzakscott@gmail.com> <zzak@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
diff --git a/.rdoc_options b/.rdoc_options
index 760507c7a2..f3d0ebfecd 100644
--- a/.rdoc_options
+++ b/.rdoc_options
@@ -1,4 +1,13 @@
 ---
 page_dir: doc
-main_page: README.md
+charset: UTF-8
+encoding: UTF-8
+main_page: index.md
 title: Documentation for Ruby development version
+visibility: :private
+rdoc_include:
+- doc
+
+exclude:
+- lib/irb
+- .gemspec
diff --git a/.travis.yml b/.travis.yml
index a34d3692af..236b87bced 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -6,63 +6,46 @@
 # conditions  mentioned in  the file  COPYING are  met.  Consult  the  file for
 # details.
 
-# We only manage non-amd64 free pipelines.
-# https://docs.travis-ci.com/user/billing-overview/
+# When you see Travis CI issues, or you are interested in understanding how to
+# manage, please check the link below.
+# https://github.com/ruby/ruby/wiki/CI-Servers#travis-ci
+
+# We enable Travis on the specific branches or forked repositories here.
+# https://docs.travis-ci.com/user/conditions-v1
+if: >-
+  (fork OR branch = master OR branch =~ /^ruby_\d_\d$/)
+  AND (commit_message !~ /(\[DOC\]|Document)/)
+  AND NOT (type = 'push' AND sender =~ /\[bot\]/)
 
 language: c
 
 os: linux
 
-if: commit_message !~ /^\[DOC\]/
-
-dist: focal
+dist: jammy
 
 git:
   quiet: true
 
-cache:
-  ccache: true
-  directories:
-    - $HOME/config_2nd
-    - $HOME/.downloaded-cache
-
 env:
   global:
-    # The tests skipped in `make test-all`.
-    - TEST_ALL_SKIPPED_TESTS=
-    # The tests executed separately by `make test-all`.
-    - TEST_ALL_SEPARATED_TESTS=
-    # Reset timestamps early
-    - _=$(touch NEWS && find . -type f -exec touch -r NEWS {} +)
-    - CONFIGURE_TTY=no
-    - CCACHE_COMPILERCHECK=none
-    - CCACHE_NOCOMPRESS=1
-    - CCACHE_MAXSIZE=512Mi
-    - NPROC="`nproc`"
-    # JOBS and SETARCH are overridden when necessary; see below.
-    - JOBS=-j$((1+${NPROC}))
-    - SETARCH=
-    - RUBY_PREFIX=/tmp/ruby-prefix
-    - GEMS_FOR_TEST='timezone tzinfo'
+    - NPROC="$(nproc)"
+    - JOBS="-j${NPROC}"
     # https://github.com/travis-ci/travis-build/blob/e411371dda21430a60f61b8f3f57943d2fe4d344/lib/travis/build/bash/travis_apt_get_options.bash#L7
     - travis_apt_get_options='--allow-downgrades --allow-remove-essential --allow-change-held-packages'
     - travis_apt_get_options="-yq --no-install-suggests --no-install-recommends $travis_apt_get_options"
-    # -O1 is faster than -O3 in our tests.
-    - optflags=-O1
-    # -g0 disables backtraces when SEGV.  Do not set that.
+    # -g0 disables backtraces when SEGV. Do not set that.
     - debugflags=-ggdb3
+    - RUBY_TESTOPTS="$JOBS -q --tty=no"
 
 .org.ruby-lang.ci.matrix-definitions:
-
-  - &gcc-10
-    compiler: gcc-10
+  - &gcc-11
+    compiler: gcc-11
     before_install:
       - tool/travis_retry.sh sudo bash -c "rm -rf '${TRAVIS_ROOT}/var/lib/apt/lists/'* && exec apt-get update -yq"
       - >-
         tool/travis_retry.sh sudo -E apt-get $travis_apt_get_options install
-        ccache
-        gcc-10
-        g++-10
+        gcc-11
+        g++-11
         libffi-dev
         libncurses-dev
         libncursesw5-dev
@@ -71,164 +54,65 @@ env:
         libyaml-dev
         openssl
         zlib1g-dev
-
-  # --------
-
+      - gcc-11 --version
   - &arm64-linux
     name: arm64-linux
     arch: arm64
-    <<: *gcc-10
-
+    <<: *gcc-11
   - &ppc64le-linux
     name: ppc64le-linux
     arch: ppc64le
-    <<: *gcc-10
-
+    <<: *gcc-11
   - &s390x-linux
     name: s390x-linux
     arch: s390x
-    <<: *gcc-10
-
-  - &arm32-linux
-    name: arm32-linux
-    arch: arm64
-    # https://packages.ubuntu.com/focal/crossbuild-essential-armhf
-    compiler: arm-linux-gnueabihf-gcc
+    <<: *gcc-11
     env:
-      - SETARCH='setarch linux32 --verbose --32bit'
-      # The "TestReadline#test_interrupt_in_other_thread" started failing on arm32
-      # from https://www.travis-ci.com/github/ruby/ruby/jobs/529005145
-      - TEST_ALL_SKIPPED_TESTS=test_interrupt_in_other_thread
-    before_install:
-      - sudo dpkg --add-architecture armhf
-      - tool/travis_retry.sh sudo bash -c "rm -rf '${TRAVIS_ROOT}/var/lib/apt/lists/'* && exec apt-get update -yq"
-      - >-
-        tool/travis_retry.sh sudo -E apt-get $travis_apt_get_options install
-        ccache
-        crossbuild-essential-armhf
-        libc6:armhf
-        libstdc++-10-dev:armhf
-        libffi-dev:armhf
-        libncurses-dev:armhf
-        libncursesw5-dev:armhf
-        libreadline-dev:armhf
-        libssl-dev:armhf
-        linux-libc-dev:armhf
-        zlib1g-dev:armhf
+      # Avoid possible test failures with the zlib applying the following patch
+      # on s390x CPU architecture.
+      # https://github.com/madler/zlib/pull/410
+      - DFLTCC=0
 
 matrix:
   include:
-    # Build every commit (Allowed Failures):
-    - <<: *arm32-linux
-    # Comment out as the 2nd arm64 pipeline is unstable.
-    # - <<: *arm64-linux
+    - <<: *arm64-linux
     - <<: *ppc64le-linux
     - <<: *s390x-linux
   allow_failures:
-    # We see multiple errors indicating errors on the Travis environment itself in a short while:
-    # https://app.travis-ci.com/github/ruby/ruby/jobs/544382885
-    # https://app.travis-ci.com/github/ruby/ruby/jobs/544361370
-    # It's not a fault of Ruby's arm32 support but just Travis arm32 seems unsable.
-    - name: arm32-linux
-    # - name: arm64-linux
-    # We see "Some worker was crashed." in about 40% of recent ppc64le-linux jobs
-    # e.g. https://app.travis-ci.com/github/ruby/ruby/jobs/530959548
+    # The arm64 is very slow to start the jobs.
+    - name: arm64-linux
     - name: ppc64le-linux
-    # Tentatively disable, because often hungs up **after** all tests
-    # have finished successfully and saving caches.
     - name: s390x-linux
   fast_finish: true
 
 before_script:
-  - . tool/ci_functions.sh
-  - |-
-    if [ -n "${TEST_ALL_SKIPPED_TESTS}" ]; then
-      TEST_ALL_OPTS="${TEST_ALL_OPTS} $(ci_to_excluded_test_opts "${TEST_ALL_SKIPPED_TESTS}")"
-      if [ -z "${TEST_ALL_SEPARATED_TESTS}" ]; then
-        TEST_ALL_SEPARATED_TESTS="${TEST_ALL_SKIPPED_TESTS}"
-      fi
-    fi
-  - |-
-    if [ -n "${TEST_ALL_SEPARATED_TESTS}" ]; then
-      TEST_ALL_OPTS_SEPARATED="$(ci_to_included_test_opts "${TEST_ALL_SEPARATED_TESTS}")"
-    fi
-  - echo TEST_ALL_OPTS="${TEST_ALL_OPTS}" TEST_ALL_OPTS_SEPARATED="${TEST_ALL_OPTS_SEPARATED}"
-  - rm -fr .ext autom4te.cache
-  - |-
-    [ -d ~/.downloaded-cache ] ||
-    mkdir ~/.downloaded-cache
-  - ln -s ~/.downloaded-cache
-  - "> config.status"
-  - "> .rbconfig.time"
-  - sed -f tool/prereq.status template/Makefile.in common.mk > Makefile
-  - make -s $JOBS up
-  - make -s $JOBS srcs
-  - rm -f config.status Makefile rbconfig.rb .rbconfig.time
-  - |-
-    if [ -d ~/config_2nd ]; then
-      cp -pr ~/config_2nd build
-    else
-      mkdir build
-    fi
-  - mkdir config_1st config_2nd
-  - chmod -R a-w .
-  - chmod -R u+w build config_1st config_2nd
+  - lscpu
+  - ./autogen.sh
+  - mkdir build
   - cd build
-  - |-
-    case "$CC" in
-    gcc*)   CC="ccache $CC${GCC_FLAGS:+ }$GCC_FLAGS -fno-diagnostics-color";;
-    clang*) CC="ccache $CC${GCC_FLAGS:+ }$GCC_FLAGS -fno-color-diagnostics";;
-    esac
-  - |-
-    [ ! -f config.cache ] ||
-    [ "$CC" = "`sed -n s/^ac_cv_prog_CC=//p config.cache`" ] ||
-    (set -x; exec rm config.cache)
-  - $SETARCH ../configure -C --disable-install-doc --prefix=$RUBY_PREFIX $CONFIG_FLAG
-  - cp -pr config.cache config.status .ext/include ../config_1st
-  - $SETARCH make reconfig
-  - cp -pr config.cache config.status .ext/include ../config_2nd
-  - (cd .. && exec diff -ru config_1st config_2nd)
-  - chmod u+w ..
-  - rm -rf ~/config_2nd
-  - mv ../config_2nd ~
-  - chmod u-w ..
-  - $SETARCH make -s $JOBS
-  - make -s install
-  - |-
-    [ -z "${GEMS_FOR_TEST}" ] ||
-    $RUBY_PREFIX/bin/gem install --no-document $GEMS_FOR_TEST
-  - echo "raise 'do not load ~/.irbrc in test'" > ~/.irbrc
+  - ../configure -C --disable-install-doc --prefix=$(pwd)/install
+  - make -s $JOBS
+  - make -s $JOBS install
+  # Useful info to report issues to the Ruby.
+  - $(pwd)/install/bin/ruby -v
+  # Useful info To report issues to the RubyGems.
+  - $(pwd)/install/bin/gem env
 
 script:
-  - $SETARCH make -s test -o showflags TESTOPTS="${TESTOPTS=$JOBS -q --tty=no}"
-  - ../tool/travis_wait.sh $SETARCH make -s test-all -o exts TESTOPTS="$JOBS -q --tty=no ${TEST_ALL_OPTS}" RUBYOPT="-w"
-  # Run the failing tests separately returning ok status to check if it works,
-  # visualize them.
-  - |
-    if [ -n "${TEST_ALL_OPTS_SEPARATED}" ]; then
-      $SETARCH make -s test-all -o exts TESTOPTS="$JOBS -v --tty=no ${TEST_ALL_OPTS_SEPARATED}" RUBYOPT="-w" || :
-    fi
-  - $SETARCH make -s test-spec MSPECOPT=-ff # not using `-j` because sometimes `mspec -j` silently dies
-  - $SETARCH make -s -o showflags leaked-globals
-
-# We enable Travis on the specific branches or forked repositories here.
-if: (repo = ruby/ruby AND (branch = master OR branch =~ /^ruby_\d_\d$/)) OR repo != ruby/ruby
+  - make -s test
+  - ../tool/travis_wait.sh make -s test-all RUBYOPT="-w"
+  - ../tool/travis_wait.sh make -s test-spec
 
 # We want to be notified when something happens.
 notifications:
-  irc:
-    channels:
-      - "chat.freenode.net#ruby-core"
-    on_success: change # [always|never|change] # default: always
-    on_failure: always # [always|never|change] # default: always
-    template:
-      - "%{message} by @%{author}: See %{build_url}"
-
   webhooks:
     urls:
-      - secure: mRsoS/UbqDkKkW5p3AEqM27d4SZnV6Gsylo3bm8T/deltQzTsGzZwrm7OIBXZv0UFZdE68XmPlyHfZFLSP2V9QZ7apXMf9/vw0GtcSe1gchtnjpAPF6lYBn7nMCbVPPx9cS0dwL927fjdRM1vj7IKZ2bk4F0lAJ25R25S6teqdk= # ruby-lang slack: ruby/simpler-alerts-bot (travis)
+      # ruby-lang slack: ruby/simpler-alerts-bot (travis)
+      - secure: mRsoS/UbqDkKkW5p3AEqM27d4SZnV6Gsylo3bm8T/deltQzTsGzZwrm7OIBXZv0UFZdE68XmPlyHfZFLSP2V9QZ7apXMf9/vw0GtcSe1gchtnjpAPF6lYBn7nMCbVPPx9cS0dwL927fjdRM1vj7IKZ2bk4F0lAJ25R25S6teqdk=
     on_success: never
     on_failure: always
-
   email:
-    - jaruga@ruby-lang.org
+    recipients:
+      - jun.aruga@gmail.com
+    on_success: never
+    on_failure: always
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 7363c106a2..13df6087ca 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -1,5 +1 @@
-Please see the [official issue tracker], [doc/contributing.rdoc] and wiki [HowToContribute].
-
-[official issue tracker]: https://bugs.ruby-lang.org
-[doc/contributing.rdoc]: contributing.rdoc
-[HowToContribute]: https://bugs.ruby-lang.org/projects/ruby/wiki/HowToContribute
+See ["Contributing to Ruby"](https://docs.ruby-lang.org/en/master/contributing_md.html), which includes setup and build instructions.
diff --git a/LEGAL b/LEGAL
index 9645728efe..55c7ffc291 100644
--- a/LEGAL
+++ b/LEGAL
@@ -58,12 +58,12 @@ mentioned below.
 
 [ccan/list/list.h]
 
-  This file is licensed under the {MIT License}[rdoc-label:label-MIT+License].
+  This file is licensed under the {MIT License}[rdoc-ref:@MIT+License].
 
 [coroutine]
 
   Unless otherwise specified, these files are licensed under the
-  {MIT License}[rdoc-label:label-MIT+License].
+  {MIT License}[rdoc-ref:@MIT+License].
 
 [include/ruby/onigmo.h]
 [include/ruby/oniguruma.h]
@@ -546,7 +546,7 @@ mentioned below.
 
 [vsnprintf.c]
 
-  This file is under the {old-style BSD license}[rdoc-label:label-Old-style+BSD+license].
+  This file is under the {old-style BSD license}[rdoc-ref:@Old-style+BSD+license].
 
   >>>
     Copyright (c) 1990, 1993::
@@ -577,7 +577,7 @@ mentioned below.
 
 [missing/crypt.c]
 
-  This file is under the {old-style BSD license}[rdoc-label:label-Old-style+BSD+license].
+  This file is under the {old-style BSD license}[rdoc-ref:@Old-style+BSD+license].
 
   >>>
     Copyright (c) 1989, 1993::
@@ -588,7 +588,7 @@ mentioned below.
 
 [missing/setproctitle.c]
 
-  This file is under the {old-style BSD license}[rdoc-label:label-Old-style+BSD+license].
+  This file is under the {old-style BSD license}[rdoc-ref:@Old-style+BSD+license].
 
   >>>
     Copyright 2003:: Damien Miller
@@ -702,54 +702,10 @@ mentioned below.
     OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     SUCH DAMAGE.
 
-[ext/json/generator/generator.c]
-
-  The file contains the following copyright notice.
-
-  >>>
-    Copyright 2001-2004:: Unicode, Inc.
-
-    Disclaimer::
-
-      This source code is provided as is by Unicode, Inc. No claims are
-      made as to fitness for any particular purpose. No warranties of any
-      kind are expressed or implied. The recipient agrees to determine
-      applicability of information provided. If this file has been
-      purchased on magnetic or optical media from Unicode, Inc., the
-      sole remedy for any claim will be exchange of defective media
-      within 90 days of receipt.
-
-    Limitations on Rights to Redistribute This Code::
-
-      Unicode, Inc. hereby grants the right to freely use the information
-      supplied in this file in the creation of products supporting the
-      Unicode Standard, and to make copies of this file in any form
-      for internal or external distribution as long as this notice
-      remains attached.
-
-[ext/nkf/nkf-utf8/config.h]
-[ext/nkf/nkf-utf8/nkf.c]
-[ext/nkf/nkf-utf8/utf8tbl.c]
-
-  These files are under the following license.  So to speak, it is
-  copyrighted semi-public-domain software.
-
-  >>>
-    Copyright (C) 1987:: Fujitsu LTD. (Itaru ICHIKAWA)
-
-    Everyone is permitted to do anything on this program
-    including copying, modifying, improving,
-    as long as you don't try to pretend that you wrote it.
-    i.e., the above copyright notice has to appear in all copies.
-    Binary distribution requires original version messages.
-    You don't have to ask before copying, redistribution or publishing.
-    THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE.
-
 [ext/psych]
 [test/psych]
 
-  The files under these directories are under the following license, except for
-  ext/psych/yaml.
+  The files under these directories are under the following license.
 
   >>>
     Copyright 2009:: Aaron Patterson, et al.
@@ -772,31 +728,6 @@ mentioned below.
     OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
     SOFTWARE.
 
-[ext/psych/yaml]
-
-  The files under this directory are under the following license.
-
-  >>>
-    Copyright (c) 2006:: Kirill Simonov
-
-    Permission is hereby granted, free of charge, to any person obtaining a copy of
-    this software and associated documentation files (the "Software"), to deal in
-    the Software without restriction, including without limitation the rights to
-    use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
-    of the Software, and to permit persons to whom the Software is furnished to do
-    so, subject to the following conditions:
-
-    The above copyright notice and this permission notice shall be included in all
-    copies or substantial portions of the Software.
-
-    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-    SOFTWARE.
-
 [ext/pty/pty.c]
 
   >>>
@@ -905,7 +836,7 @@ mentioned below.
   >>>
     RubyGems is copyrighted free software by Chad Fowler, Rich Kilmer, Jim
     Weirich and others.  You can redistribute it and/or modify it under
-    either the terms of the {MIT license}[rdoc-label:label-MIT+License], or the conditions
+    either the terms of the {MIT license}[rdoc-ref:@MIT+License], or the conditions
     below:
 
     1. You may make and give away verbatim copies of the source form of the
@@ -967,7 +898,7 @@ mentioned below.
     Portions copyright (c) 2010:: Andre Arko
     Portions copyright (c) 2009:: Engine Yard
 
-    {MIT License}[rdoc-label:label-MIT+License]
+    {MIT License}[rdoc-ref:@MIT+License]
 
 [lib/bundler/vendor/thor]
 
@@ -976,17 +907,25 @@ mentioned below.
   >>>
     Copyright (c) 2008 Yehuda Katz, Eric Hodel, et al.
 
-    {MIT License}[rdoc-label:label-MIT+License]
+    {MIT License}[rdoc-ref:@MIT+License]
 
-[lib/rubygems/resolver/molinillo]
-[lib/bundler/vendor/molinillo]
+[lib/rubygems/vendor/molinillo]
 
   molinillo is under the following license.
 
   >>>
     Copyright (c) 2014 Samuel E. Giddins segiddins@segiddins.me
 
-    {MIT License}[rdoc-label:label-MIT+License]
+    {MIT License}[rdoc-ref:@MIT+License]
+
+[lib/bundler/vendor/pub_grub]
+
+  pub_grub is under the following license.
+
+  >>>
+    Copyright (c) 2018 John Hawthorn
+
+    {MIT License}[rdoc-ref:@MIT+License]
 
 [lib/bundler/vendor/connection_pool]
 
@@ -995,7 +934,7 @@ mentioned below.
   >>>
     Copyright (c) 2011 Mike Perham
 
-    {MIT License}[rdoc-label:label-MIT+License]
+    {MIT License}[rdoc-ref:@MIT+License]
 
 [lib/bundler/vendor/net-http-persistent]
 
@@ -1004,7 +943,7 @@ mentioned below.
   >>>
     Copyright (c) Eric Hodel, Aaron Patterson
 
-    {MIT License}[rdoc-label:label-MIT+License]
+    {MIT License}[rdoc-ref:@MIT+License]
 
 [lib/did_you_mean]
 [lib/did_you_mean.rb]
@@ -1015,7 +954,7 @@ mentioned below.
   >>>
     Copyright (c) 2014-2016 Yuki Nishijima
 
-    {MIT License}[rdoc-label:label-MIT+License]
+    {MIT License}[rdoc-ref:@MIT+License]
 
 [lib/error_highlight]
 [lib/error_highlight.rb]
@@ -1026,7 +965,7 @@ mentioned below.
   >>>
     Copyright (c) 2021 Yusuke Endoh
 
-    {MIT License}[rdoc-label:label-MIT+License]
+    {MIT License}[rdoc-ref:@MIT+License]
 
 [benchmark/so_ackermann.rb]
 [benchmark/so_array.rb]
diff --git a/NEWS.md b/NEWS.md
index 00e9667603..699855566b 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,220 +1,913 @@
-# NEWS for Ruby 3.2.0
+# NEWS for Ruby 3.4.0
 
 This document is a list of user-visible feature changes
-since the **3.1.0** release, except for bug fixes.
+since the **3.3.0** release, except for bug fixes.
 
 Note that each entry is kept to a minimum, see links for details.
 
 ## Language changes
 
-* Anonymous rest and keyword rest arguments can now be passed as
-  arguments, instead of just used in method parameters.
-  [[Feature #18351]]
-
-    ```ruby
-    def foo(*)
-      bar(*)
-    end
-    def baz(**)
-      quux(**)
-    end
-    ```
+* `it` is added to reference a block parameter. [[Feature #18980]]
 
-* A proc that accepts a single positional argument and keywords will
-  no longer autosplat. [[Bug #18633]]
+* String literals in files without a `frozen_string_literal` comment now emit a deprecation warning
+  when they are mutated.
+  These warnings can be enabled with `-W:deprecated` or by setting `Warning[:deprecated] = true`.
+  To disable this change, you can run Ruby with the `--disable-frozen-string-literal`
+  command line argument. [[Feature #20205]]
 
-  ```ruby
-  proc{|a, **k| a}.call([1, 2])
-  # Ruby 3.1 and before
-  # => 1
-  # Ruby 3.2 and after
-  # => [1, 2]
-  ```
+    * `String#+@` now duplicates when mutating the string would emit
+      a deprecation warning, offered as a replacement for the
+      `str.dup if str.frozen?` pattern.
 
-* Constant assignment evaluation order for constants set on explicit
-  objects has been made consistent with single attribute assignment
-  evaluation order.  With this code:
+* Keyword splatting `nil` when calling methods is now supported.
+  `**nil` is treated similarly to `**{}`, passing no keywords,
+  and not calling any conversion methods.  [[Bug #20064]]
 
-    ```ruby
-    foo::BAR = baz
-    ```
+* Block passing is no longer allowed in index assignment
+  (e.g. `a[0, &b] = 1`).  [[Bug #19918]]
 
-  `foo` is now called before `baz`. Similarly, for multiple assignment
-  to constants,  left-to-right evaluation order is used.  With this
-  code:
+* Keyword arguments are no longer allowed in index assignment
+  (e.g. `a[0, kw: 1] = 2`).  [[Bug #20218]]
 
-    ```ruby
-      foo1::BAR1, foo2::BAR2 = baz1, baz2
-    ```
+* The toplevel name `::Ruby` is reserved now, and the definition will be warned
+  when `Warning[:deprecated]`.  [[Feature #20884]]
 
-  The following evaluation order is now used:
+## Core classes updates
 
-  1. `foo1`
-  2. `foo2`
-  3. `baz1`
-  4. `baz2`
+Note: We're only listing outstanding class updates.
 
-  [[Bug #15928]]
 
-* Find pattern is no longer experimental.
-  [[Feature #18585]]
+* Array
 
-## Command line options
+    * `Array#fetch_values` was added. [[Feature #20702]]
 
-## Core classes updates
+* Exception
 
-Note: We're only listing outstanding class updates.
+    * `Exception#set_backtrace` now accepts arrays of `Thread::Backtrace::Location`.
+      `Kernel#raise`, `Thread#raise` and `Fiber#raise` also accept this new format. [[Feature #13557]]
+
+* Fiber::Scheduler
+
+    * An optional `Fiber::Scheduler#blocking_operation_wait` hook allows blocking operations to be moved out of the
+      event loop in order to reduce latency and improve multi-core processor utilization. [[Feature #20876]]
+
+* GC
+
+    * `GC.config` added to allow setting configuration variables on the Garbage
+      Collector. [[Feature #20443]]
+
+    * GC configuration parameter `rgengc_allow_full_mark` introduced.  When `false`
+      GC will only mark young objects. Default is `true`.  [[Feature #20443]]
 
 * Hash
-    * Hash#shift now always returns nil if the hash is
-      empty, instead of returning the default value or
-      calling the default proc. [[Bug #16908]]
 
-* Kernel
-    * Kernel#binding raises RuntimeError if called from a non-Ruby frame
-      (such as a method defined in C). [[Bug #18487]]
+    * `Hash.new` now accepts an optional `capacity:` argument, to preallocate the hash with a given capacity.
+      This can improve performance when building large hashes incrementally by saving on reallocation and
+      rehashing of keys. [[Feature #19236]]
+
+* IO::Buffer
+
+    * `IO::Buffer#copy` can release the GVL, allowing other threads to run while copying data. [[Feature #20902]]
+
+* Integer
+
+    * `Integer#**` used to return `Float::INFINITY` when the return value is large, but now returns an `Integer`.
+      If the return value is extremely large, it raises an exception.
+      [[Feature #20811]]
 
 * MatchData
-    * MatchData#byteoffset has been added. [[Feature #13110]]
 
-* Module
-    * Module.used_refinements has been added. [[Feature #14332]]
-    * Module#refinements has been added. [[Feature #12737]]
-    * Module#const_added has been added. [[Feature #17881]]
+    * `MatchData#bytebegin` and `MatchData#byteend` have been added. [[Feature #20576]]
+
+* Object
+
+    * `Object#singleton_method` now returns methods in modules prepended to or included in the
+      receiver's singleton class. [[Bug #20620]]
+
+        ```rb
+        o = Object.new
+        o.extend(Module.new{def a = 1})
+        o.singleton_method(:a).call #=> 1
+        ```
+
+* Ractor
+
+    * `require` in Ractor is allowed. The requiring process will be run on
+      the main Ractor.
+      `Ractor._require(feature)` is added to run requiring process on the
+      main Ractor.
+      [[Feature #20627]]
+
+    * `Ractor.main?` is added. [[Feature #20627]]
+
+    * `Ractor.[]` and `Ractor.[]=` are added to access the ractor local storage
+      of the current Ractor. [[Feature #20715]]
+
+    * `Ractor.store_if_absent(key){ init }` is added to initialize ractor local
+      variables in thread-safety. [[Feature #20875]]
 
-* Proc
-    * Proc#dup returns an instance of subclass. [[Bug #17545]]
-    * Proc#parameters now accepts lambda keyword. [[Feature #15357]]
+* Range
 
-* Refinement
-    * Refinement#refined_class has been added. [[Feature #12737]]
+    * `Range#size` now raises `TypeError` if the range is not iterable. [[Misc #18984]]
+    * `Range#step` now consistently has a semantics of iterating by using `+` operator
+      for all types, not only numerics. [[Feature #18368]]
+
+        ```ruby
+        (Time.utc(2022, 2, 24)..).step(24*60*60).take(3)
+        #=> [2022-02-24 00:00:00 UTC, 2022-02-25 00:00:00 UTC, 2022-02-26 00:00:00 UTC]
+        ```
+
+* Rational
+
+    * `Rational#**` used to return `Float::INFINITY` or `Float::NAN`
+      when the numerator of the return value is large, but now returns an `Rational`.
+      If it is extremely large, it raises an exception. [[Feature #20811]]
+
+* RubyVM::AbstractSyntaxTree
+
+    * Add `RubyVM::AbstractSyntaxTree::Node#locations` method which returns location objects
+      associated with the AST node. [[Feature #20624]]
+    * Add `RubyVM::AbstractSyntaxTree::Location` class which holds location information. [[Feature #20624]]
 
-* Set
-    * Set is now available as a builtin class without the need for `require "set"`. [[Feature #16989]]
-      It is currently autoloaded via the `Set` constant or a call to `Enumerable#to_set`.
 
 * String
-    * String#byteindex and String#byterindex have been added. [[Feature #13110]]
-    * Update Unicode to Version 14.0.0 and Emoji Version 14.0. [[Feature #18037]]
-      (also applies to Regexp)
-    * String#bytesplice has been added.  [[Feature #18598]]
-
-* Struct
-    * A Struct class can also be initialized with keyword arguments
-      without `keyword_init: true` on `Struct.new` [[Feature #16806]]
-
-* TracePoint
-    * TracePoint#binding now returns `nil` for `c_call`/`c_return` TracePoints.
-      [[Bug #18487]]
-    * TracePoint#enable `target_thread` keyword argument now defaults to the
-      current thread if `target` and `target_line` keyword arguments are not
-      passed. [[Bug #16889]]
+
+    * `String#append_as_bytes` was added to more easily and efficiently work with binary buffers and protocols.
+      It directly concatenate the arguments into the string without any encoding validation or conversion.
+      [[Feature #20594]]
+
+* Symbol
+
+    * The string returned by `Symbol#to_s` now emits a deprecation warning when mutated, and will be
+      frozen in a future version of Ruby.
+      These warnings can be enabled with `-W:deprecated` or by setting `Warning[:deprecated] = true`.
+      [[Feature #20350]]
+
+* Time
+
+    * On Windows, now `Time#zone` encodes the system timezone name in UTF-8
+      instead of the active code page, if it contains non-ASCII characters.
+      [[Bug #20929]]
+
+    * `Time#xmlschema`, and its `Time#iso8601` alias have been moved into the core Time
+      class while previously it was an extension provided by the `time` gem. [[Feature #20707]]
+
+* Warning
+
+    * Add `Warning.categories` method which returns a list of possible warning categories.
+      [[Feature #20293]]
 
 ## Stdlib updates
 
-*   The following default gem are updated.
-    * RubyGems 3.4.0.dev
-    * bigdecimal 3.1.2
-    * bundler 2.4.0.dev
-    * cgi 0.3.2
-    * etc 1.4.0
-    * io-console 0.5.11
-    * io-wait 0.2.2.pre1
-    * ipaddr 1.2.4
-    * logger 1.5.1
-    * net-protocol 0.1.3
-    * ostruct 0.5.5
-    * reline 0.3.1
-    * securerandom 0.2.0
-*   The following bundled gems are updated.
-    * net-imap 0.2.3
-    * rbs 2.3.0
-    * typeprof 0.21.2
-    * debug 1.5.0
-*   The following default gems are now bundled gems.
+We only list stdlib changes that are notable feature changes.
+
+* RubyGems
+    * Add `--attestation` option to gem push. It enabled to store signature of build artifact to sigstore.dev.
+
+* Bundler
+    * Add a `lockfile_checksums` configuration to include checksums in fresh lockfiles.
+    * Add bundle lock `--add-checksums` to add checksums to an existing lockfile.
+
+* JSON
+
+    * Performance improvements `JSON.parse` about 1.5 times faster than json-2.7.x.
+
+* Tempfile
+
+    * The keyword argument `anonymous: true` is implemented for Tempfile.create.
+      `Tempfile.create(anonymous: true)` removes the created temporary file immediately.
+      So applications don't need to remove the file.
+      [[Feature #20497]]
+
+* win32/sspi.rb
+
+    * This library is now extracted from the Ruby repository to [ruby/net-http-sspi].
+      [[Feature #20775]]
+
+* Socket
+
+    * `Socket::ResolutionError` and `Socket::ResolutionError#error_code` was added.
+      [[Feature #20018]]
+
+* IRB
+
+    * Interactive method completion is now improved with type information by default.
+      [[Feature #20778]]
+
+Other changes are listed in the following sections. we also listed release history from the previous bundled version that is Ruby 3.3.0 if it has GitHub releases.
+
+The following default gem is added.
+
+* win32-registry 0.1.0
+
+The following default gems are updated.
+
+* [RubyGems][RubyGems] 3.6.2
+    * 3.5.3 to [v3.5.4][RubyGems-v3.5.4], [v3.5.5][RubyGems-v3.5.5], [v3.5.6][RubyGems-v3.5.6], [v3.5.7][RubyGems-v3.5.7], [v3.5.8][RubyGems-v3.5.8], [v3.5.9][RubyGems-v3.5.9], [v3.5.10][RubyGems-v3.5.10], [v3.5.11][RubyGems-v3.5.11], [v3.5.12][RubyGems-v3.5.12], [v3.5.13][RubyGems-v3.5.13], [v3.5.14][RubyGems-v3.5.14], [v3.5.15][RubyGems-v3.5.15], [v3.5.16][RubyGems-v3.5.16], [v3.5.17][RubyGems-v3.5.17], [v3.5.18][RubyGems-v3.5.18], [v3.5.19][RubyGems-v3.5.19], [v3.5.20][RubyGems-v3.5.20], [v3.5.21][RubyGems-v3.5.21], [v3.5.22][RubyGems-v3.5.22], [v3.5.23][RubyGems-v3.5.23], [v3.6.0][RubyGems-v3.6.0], [v3.6.1][RubyGems-v3.6.1], [v3.6.2][RubyGems-v3.6.2]
+* [benchmark][benchmark] 0.4.0
+    * 0.3.0 to [v0.4.0][benchmark-v0.4.0]
+* [bundler][bundler] 2.6.2
+    * 2.5.3 to [v2.5.4][bundler-v2.5.4], [v2.5.5][bundler-v2.5.5], [v2.5.6][bundler-v2.5.6], [v2.5.7][bundler-v2.5.7], [v2.5.8][bundler-v2.5.8], [v2.5.9][bundler-v2.5.9], [v2.5.10][bundler-v2.5.10], [v2.5.11][bundler-v2.5.11], [v2.5.12][bundler-v2.5.12], [v2.5.13][bundler-v2.5.13], [v2.5.14][bundler-v2.5.14], [v2.5.15][bundler-v2.5.15], [v2.5.16][bundler-v2.5.16], [v2.5.17][bundler-v2.5.17], [v2.5.18][bundler-v2.5.18], [v2.5.19][bundler-v2.5.19], [v2.5.20][bundler-v2.5.20], [v2.5.21][bundler-v2.5.21], [v2.5.22][bundler-v2.5.22], [v2.5.23][bundler-v2.5.23], [v2.6.0][bundler-v2.6.0], [v2.6.1][bundler-v2.6.1], [v2.6.2][bundler-v2.6.2]
+* [date][date] 3.4.1
+    * 3.3.4 to [v3.4.0][date-v3.4.0], [v3.4.1][date-v3.4.1]
+* [delegate][delegate] 0.4.0
+    * 0.3.1 to [v0.4.0][delegate-v0.4.0]
+* [did_you_mean][did_you_mean] 2.0.0
+    * 1.6.3 to [v2.0.0][did_you_mean-v2.0.0]
+* [digest][digest] 3.2.0
+    * 3.1.1 to [v3.2.0.pre0][digest-v3.2.0.pre0], [v3.2.0][digest-v3.2.0]
+* [erb][erb] 4.0.4
+    * 4.0.3 to [v4.0.4][erb-v4.0.4]
+* [error_highlight][error_highlight] 0.7.0
+    * 0.6.0 to [v0.7.0][error_highlight-v0.7.0]
+* [etc][etc] 1.4.5
+    * 1.4.3 to [v1.4.4][etc-v1.4.4], [v1.4.5][etc-v1.4.5]
+* [fcntl][fcntl] 1.2.0
+    * 1.1.0 to [v1.2.0][fcntl-v1.2.0]
+* [fiddle][fiddle] 1.1.6
+    * 1.1.2 to [v1.1.3][fiddle-v1.1.3], [v1.1.4][fiddle-v1.1.4], [v1.1.5][fiddle-v1.1.5], [v1.1.6][fiddle-v1.1.6]
+* [fileutils][fileutils] 1.7.3
+    * 1.7.2 to [v1.7.3][fileutils-v1.7.3]
+* [io-console][io-console] 0.8.0
+    * 0.7.1 to [v0.7.2][io-console-v0.7.2], [v0.8.0.beta1][io-console-v0.8.0.beta1], [v0.8.0][io-console-v0.8.0]
+* [io-nonblock][io-nonblock] 0.3.1
+    * 0.3.0 to [v0.3.1][io-nonblock-v0.3.1]
+* [ipaddr][ipaddr] 1.2.7
+    * 1.2.6 to [v1.2.7][ipaddr-v1.2.7]
+* [irb][irb] 1.14.3
+    * 1.11.0 to [v1.11.1][irb-v1.11.1], [v1.11.2][irb-v1.11.2], [v1.12.0][irb-v1.12.0], [v1.13.0][irb-v1.13.0], [v1.13.1][irb-v1.13.1], [v1.13.2][irb-v1.13.2], [v1.14.0][irb-v1.14.0], [v1.14.1][irb-v1.14.1], [v1.14.2][irb-v1.14.2], [v1.14.3][irb-v1.14.3]
+* [json][json] 2.9.1
+    * 2.7.1 to [v2.7.2][json-v2.7.2], [v2.7.3.rc1][json-v2.7.3.rc1], [v2.7.3][json-v2.7.3], [v2.7.4][json-v2.7.4], [v2.7.5][json-v2.7.5], [v2.7.6][json-v2.7.6], [v2.8.0][json-v2.8.0], [v2.8.1][json-v2.8.1], [v2.8.2][json-v2.8.2], [v2.9.0][json-v2.9.0], [v2.9.1][json-v2.9.1]
+* [logger][logger] 1.6.4
+    * 1.6.0 to [v1.6.1][logger-v1.6.1], [v1.6.2][logger-v1.6.2], [v1.6.3][logger-v1.6.3], [v1.6.4][logger-v1.6.4]
+* [net-http][net-http] 0.6.0
+    * 0.4.0 to [v0.4.1][net-http-v0.4.1], [v0.5.0][net-http-v0.5.0], [v0.6.0][net-http-v0.6.0]
+* [open-uri][open-uri] 0.5.0
+    * 0.4.1 to [v0.5.0][open-uri-v0.5.0]
+* [optparse][optparse] 0.6.0
+    * 0.4.0 to [v0.5.0][optparse-v0.5.0], [v0.6.0][optparse-v0.6.0]
+* [ostruct][ostruct] 0.6.1
+    * 0.6.0 to [v0.6.1][ostruct-v0.6.1]
+* [pathname][pathname] 0.4.0
+    * 0.3.0 to [v0.4.0][pathname-v0.4.0]
+* [pp][pp] 0.6.2
+    * 0.5.0 to [v0.6.0][pp-v0.6.0], [v0.6.1][pp-v0.6.1], [v0.6.2][pp-v0.6.2]
+* [prism][prism] 1.2.0
+    * 0.19.0 to [v0.20.0][prism-v0.20.0], [v0.21.0][prism-v0.21.0], [v0.22.0][prism-v0.22.0], [v0.23.0][prism-v0.23.0], [v0.24.0][prism-v0.24.0], [v0.25.0][prism-v0.25.0], [v0.26.0][prism-v0.26.0], [v0.27.0][prism-v0.27.0], [v0.28.0][prism-v0.28.0], [v0.29.0][prism-v0.29.0], [v0.30.0][prism-v0.30.0], [v1.0.0][prism-v1.0.0], [v1.1.0][prism-v1.1.0], [v1.2.0][prism-v1.2.0]
+* [pstore][pstore] 0.1.4
+    * 0.1.3 to [v0.1.4][pstore-v0.1.4]
+* [psych][psych] 5.2.2
+    * 5.1.2 to [v5.2.0.beta1][psych-v5.2.0.beta1], [v5.2.0.beta2][psych-v5.2.0.beta2], [v5.2.0.beta3][psych-v5.2.0.beta3], [v5.2.0.beta4][psych-v5.2.0.beta4], [v5.2.0.beta5][psych-v5.2.0.beta5], [v5.2.0.beta6][psych-v5.2.0.beta6], [v5.2.0.beta7][psych-v5.2.0.beta7], [v5.2.0][psych-v5.2.0], [v5.2.1][psych-v5.2.1], [v5.2.2][psych-v5.2.2]
+* [rdoc][rdoc] 6.10.0
+    * 6.6.2 to [v6.7.0][rdoc-v6.7.0], [v6.8.0][rdoc-v6.8.0], [v6.8.1][rdoc-v6.8.1], [v6.9.0][rdoc-v6.9.0], [v6.9.1][rdoc-v6.9.1], [v6.10.0][rdoc-v6.10.0]
+* [reline][reline] 0.6.0
+    * 0.4.1 to [v0.4.2][reline-v0.4.2], [v0.4.3][reline-v0.4.3], [v0.5.0.pre.1][reline-v0.5.0.pre.1], [v0.5.0][reline-v0.5.0], [v0.5.1][reline-v0.5.1], [v0.5.2][reline-v0.5.2], [v0.5.3][reline-v0.5.3], [v0.5.4][reline-v0.5.4], [v0.5.5][reline-v0.5.5], [v0.5.6][reline-v0.5.6], [v0.5.7][reline-v0.5.7], [v0.5.8][reline-v0.5.8], [v0.5.9][reline-v0.5.9], [v0.5.10][reline-v0.5.10], [v0.5.11][reline-v0.5.11], [v0.5.12][reline-v0.5.12], [v0.6.0][reline-v0.6.0]
+* [resolv][resolv] 0.6.0
+    * 0.3.0 to [v0.4.0][resolv-v0.4.0], [v0.5.0][resolv-v0.5.0], [v0.6.0][resolv-v0.6.0]
+* [securerandom][securerandom] 0.4.1
+    * 0.3.1 to [v0.3.2][securerandom-v0.3.2], [v0.4.0][securerandom-v0.4.0], [v0.4.1][securerandom-v0.4.1]
+* [set][set] 1.1.1
+    * 1.1.0 to [v1.1.1][set-v1.1.1]
+* [shellwords][shellwords] 0.2.2
+    * 0.2.0 to [v0.2.1][shellwords-v0.2.1], [v0.2.2][shellwords-v0.2.2]
+* [singleton][singleton] 0.3.0
+    * 0.2.0 to [v0.3.0][singleton-v0.3.0]
+* [stringio][stringio] 3.1.2
+    * 3.1.0 to [v3.1.1][stringio-v3.1.1], [v3.1.2][stringio-v3.1.2]
+* [strscan][strscan] 3.1.2
+    * 3.0.7 to [v3.0.8][strscan-v3.0.8], [v3.0.9][strscan-v3.0.9], [v3.1.0][strscan-v3.1.0], [v3.1.1][strscan-v3.1.1], [v3.1.2][strscan-v3.1.2]
+* [syntax_suggest][syntax_suggest] 2.0.2
+    * 2.0.0 to [v2.0.1][syntax_suggest-v2.0.1], [v2.0.2][syntax_suggest-v2.0.2]
+* [tempfile][tempfile] 0.3.1
+    * 0.2.1 to [v0.3.0][tempfile-v0.3.0], [v0.3.1][tempfile-v0.3.1]
+* [time][time] 0.4.1
+    * 0.3.0 to [v0.4.0][time-v0.4.0], [v0.4.1][time-v0.4.1]
+* [timeout][timeout] 0.4.3
+    * 0.4.1 to [v0.4.2][timeout-v0.4.2], [v0.4.3][timeout-v0.4.3]
+* [tmpdir][tmpdir] 0.3.1
+    * 0.2.0 to [v0.3.0][tmpdir-v0.3.0], [v0.3.1][tmpdir-v0.3.1]
+* [uri][uri] 1.0.2
+    * 0.13.0 to [v0.13.1][uri-v0.13.1], [v1.0.0][uri-v1.0.0], [v1.0.1][uri-v1.0.1], [v1.0.2][uri-v1.0.2]
+* [win32ole][win32ole] 1.9.1
+    * 1.8.10 to [v1.9.0][win32ole-v1.9.0], [v1.9.1][win32ole-v1.9.1]
+* [yaml][yaml] 0.4.0
+    * 0.3.0 to [v0.4.0][yaml-v0.4.0]
+* [zlib][zlib] 3.2.1
+    * 3.1.0 to [v3.1.1][zlib-v3.1.1], [v3.2.0][zlib-v3.2.0], [v3.2.1][zlib-v3.2.1]
+
+The following bundled gem is added.
+
+* [repl_type_completor][repl_type_completor] 0.1.9
+
+The following bundled gems are updated.
+
+* [minitest][minitest] 5.25.4
+    * 5.20.0 to [v5.25.4][minitest-v5.25.4]
+* [power_assert][power_assert] 2.0.5
+    * 2.0.3 to [v2.0.4][power_assert-v2.0.4], [v2.0.5][power_assert-v2.0.5]
+* [rake][rake] 13.2.1
+    * 13.1.0 to [v13.2.0][rake-v13.2.0], [v13.2.1][rake-v13.2.1]
+* [test-unit][test-unit] 3.6.7
+    * 3.6.1 to [3.6.2][test-unit-3.6.2], [3.6.3][test-unit-3.6.3], [3.6.4][test-unit-3.6.4], [3.6.5][test-unit-3.6.5], [3.6.6][test-unit-3.6.6], [3.6.7][test-unit-3.6.7]
+* [rexml][rexml] 3.4.0
+    * 3.2.6 to [v3.2.7][rexml-v3.2.7], [v3.2.8][rexml-v3.2.8], [v3.2.9][rexml-v3.2.9], [v3.3.0][rexml-v3.3.0], [v3.3.1][rexml-v3.3.1], [v3.3.2][rexml-v3.3.2], [v3.3.3][rexml-v3.3.3], [v3.3.4][rexml-v3.3.4], [v3.3.5][rexml-v3.3.5], [v3.3.6][rexml-v3.3.6], [v3.3.7][rexml-v3.3.7], [v3.3.8][rexml-v3.3.8], [v3.3.9][rexml-v3.3.9], [v3.4.0][rexml-v3.4.0]
+* [rss][rss] 0.3.1
+    * 0.3.0 to [0.3.1][rss-0.3.1]
+* [net-ftp][net-ftp] 0.3.8
+    * 0.3.3 to [v0.3.4][net-ftp-v0.3.4], [v0.3.5][net-ftp-v0.3.5], [v0.3.6][net-ftp-v0.3.6], [v0.3.7][net-ftp-v0.3.7], [v0.3.8][net-ftp-v0.3.8]
+* [net-imap][net-imap] 0.5.4
+    * 0.4.9 to [v0.4.9.1][net-imap-v0.4.9.1], [v0.4.10][net-imap-v0.4.10], [v0.4.11][net-imap-v0.4.11], [v0.4.12][net-imap-v0.4.12], [v0.4.13][net-imap-v0.4.13], [v0.4.14][net-imap-v0.4.14], [v0.4.15][net-imap-v0.4.15], [v0.4.16][net-imap-v0.4.16], [v0.4.17][net-imap-v0.4.17], [v0.5.0][net-imap-v0.5.0], [v0.4.18][net-imap-v0.4.18], [v0.5.1][net-imap-v0.5.1], [v0.5.2][net-imap-v0.5.2], [v0.5.3][net-imap-v0.5.3], [v0.5.4][net-imap-v0.5.4]
+* [net-smtp][net-smtp] 0.5.0
+    * 0.4.0 to [v0.4.0.1][net-smtp-v0.4.0.1], [v0.5.0][net-smtp-v0.5.0]
+* [prime][prime] 0.1.3
+    * 0.1.2 to [v0.1.3][prime-v0.1.3]
+* [rbs][rbs] 3.8.0
+    * 3.4.0 to [v3.4.1][rbs-v3.4.1], [v3.4.2][rbs-v3.4.2], [v3.4.3][rbs-v3.4.3], [v3.4.4][rbs-v3.4.4], [v3.5.0.pre.1][rbs-v3.5.0.pre.1], [v3.5.0.pre.2][rbs-v3.5.0.pre.2], [v3.5.0][rbs-v3.5.0], [v3.5.1][rbs-v3.5.1], [v3.5.2][rbs-v3.5.2], [v3.5.3][rbs-v3.5.3], [v3.6.0.dev.1][rbs-v3.6.0.dev.1], [v3.6.0.pre.1][rbs-v3.6.0.pre.1], [v3.6.0.pre.2][rbs-v3.6.0.pre.2], [v3.6.0.pre.3][rbs-v3.6.0.pre.3], [v3.6.0][rbs-v3.6.0], [v3.6.1][rbs-v3.6.1], [v3.7.0.dev.1][rbs-v3.7.0.dev.1], [v3.7.0.pre.1][rbs-v3.7.0.pre.1], [v3.7.0][rbs-v3.7.0], [v3.8.0.pre.1][rbs-v3.8.0.pre.1] [v3.8.0][rbs-v3.8.0]
+* [typeprof][typeprof] 0.30.1
+    * 0.21.9 to [v0.30.1][typeprof-v0.30.1]
+* [debug][debug] 1.10.0
+    * 1.9.1 to [v1.9.2][debug-v1.9.2], [v1.10.0][debug-v1.10.0]
+* [racc][racc] 1.8.1
+    * 1.7.3 to [v1.8.0][racc-v1.8.0], [v1.8.1][racc-v1.8.1]
+
+The following bundled gems are promoted from default gems.
+
+* [mutex_m][mutex_m] 0.3.0
+    * 0.2.0 to [v0.3.0][mutex_m-v0.3.0]
+* [getoptlong][getoptlong] 0.2.1
+* [base64][base64] 0.2.0
+* [bigdecimal][bigdecimal] 3.1.8
+    * 3.1.5 to [v3.1.6][bigdecimal-v3.1.6], [v3.1.7][bigdecimal-v3.1.7], [v3.1.8][bigdecimal-v3.1.8]
+* [observer][observer] 0.1.2
+* [abbrev][abbrev] 0.1.2
+* [resolv-replace][resolv-replace] 0.1.1
+* [rinda][rinda] 0.2.0
+* [drb][drb] 2.2.1
+    * 2.2.0 to [v2.2.1][drb-v2.2.1]
+* [nkf][nkf] 0.2.0
+    * 0.1.3 to [v0.2.0][nkf-v0.2.0]
+* [syslog][syslog] 0.2.0
+    * 0.1.2 to [v0.2.0][syslog-v0.2.0]
+* [csv][csv] 3.3.2
+    * 3.2.8 to [v3.2.9][csv-v3.2.9], [v3.3.0][csv-v3.3.0], [v3.3.1][csv-v3.3.1], [v3.3.2][csv-v3.3.2]
+
+## Supported platforms
 
 ## Compatibility issues
 
-Note: Excluding feature bug fixes.
+* Error messages and backtrace displays have been changed.
 
-### Removed constants
+    * Use a single quote instead of a backtick as an opening quote. [[Feature #16495]]
+    * Display a class name before a method name (only when the class has a permanent name). [[Feature #19117]]
+    * Extra `rescue`/`ensure` frames are no longer available on the backtrace. [[Feature #20275]]
+    * `Kernel#caller`, `Thread::Backtrace::Location`’s methods, etc. are also changed accordingly.
 
-The following deprecated constants are removed.
+        Old:
+        ```
+        test.rb:1:in `foo': undefined method `time' for an instance of Integer
+                from test.rb:2:in `<main>'
+        ```
 
-* `Fixnum` and `Bignum` [[Feature #12005]]
-* `Random::DEFAULT` [[Feature #17351]]
-* `Struct::Group`
-* `Struct::Passwd`
+        New:
+        ```
+        test.rb:1:in 'Object#foo': undefined method 'time' for an instance of Integer
+                from test.rb:2:in '<main>'
+        ```
 
-### Removed methods
+* `Hash#inspect` rendering have been changed. [[Bug #20433]]
 
-The following deprecated methods are removed.
+    * Symbol keys are displayed using the modern symbol key syntax: `"{user: 1}"`
+    * Other keys now have spaces around `=>`: `'{"user" => 1}'`, while previously they didn't: `'{"user"=>1}'`
 
-* `Dir.exists?` [[Feature #17391]]
-* `File.exists?` [[Feature #17391]]
-* `Kernel#=~` [[Feature #15231]]
-* `Kernel#taint`, `Kernel#untaint`, `Kernel#tainted?`
-  [[Feature #16131]]
-* `Kernel#trust`, `Kernel#untrust`, `Kernel#untrusted?`
-  [[Feature #16131]]
+* `Kernel#Float()` now accepts a decimal string with decimal part omitted. [[Feature #20705]]
 
-## Stdlib compatibility issues
+    ```rb
+    Float("1.")    #=> 1.0 (previously, an ArgumentError was raised)
+    Float("1.E-1") #=> 0.1 (previously, an ArgumentError was raised)
+    ```
 
-* `Psych` no longer bundles libyaml sources.
-  Users need to install the libyaml library themselves via the package
-  system.  [[Feature #18571]]
+* `String#to_f` now accepts a decimal string with decimal part omitted. [[Feature #20705]]
+  Note that the result changes when an exponent is specified.
 
-## C API updates
+    ```rb
+    "1.".to_f    #=> 1.0
+    "1.E-1".to_f #=> 0.1 (previously, 1.0 was returned)
+    ```
 
-### Removed C APIs
+* `Refinement#refined_class` has been removed. [[Feature #19714]]
 
-The following deprecated APIs are removed.
+## Stdlib compatibility issues
 
-* `rb_cData` variable.
-* "taintedness" and "trustedness" functions. [[Feature #16131]]
+* DidYouMean
 
-## Implementation improvements
+    * `DidYouMean::SPELL_CHECKERS[]=` and `DidYouMean::SPELL_CHECKERS.merge!` are removed.
+
+* Net::HTTP
 
-## JIT
+    * Removed the following deprecated constants:
+        * `Net::HTTP::ProxyMod`
+        * `Net::NetPrivate::HTTPRequest`
+        * `Net::HTTPInformationCode`
+        * `Net::HTTPSuccessCode`
+        * `Net::HTTPRedirectionCode`
+        * `Net::HTTPRetriableCode`
+        * `Net::HTTPClientErrorCode`
+        * `Net::HTTPFatalErrorCode`
+        * `Net::HTTPServerErrorCode`
+        * `Net::HTTPResponseReceiver`
+        * `Net::HTTPResponceReceiver`
 
-### MJIT
+      These constants were deprecated from 2012.
 
-### YJIT: New experimental in-process JIT compiler
+* Timeout
 
-## Static analysis
+    * Reject negative values for `Timeout.timeout`. [[Bug #20795]]
 
-### RBS
+* URI
 
-### TypeProf
+    * Switched default parser to RFC 3986 compliant from RFC 2396 compliant.
+      [[Bug #19266]]
 
-## Debugger
+## C API updates
 
-## error_highlight
+* `rb_newobj` and `rb_newobj_of` (and corresponding macros `RB_NEWOBJ`, `RB_NEWOBJ_OF`, `NEWOBJ`, `NEWOBJ_OF`) have been removed. [[Feature #20265]]
+* Removed deprecated function `rb_gc_force_recycle`. [[Feature #18290]]
+
+## Implementation improvements
 
-## IRB Autocomplete and Document Display
+* The default parser is now Prism.
+  To use the conventional parser, use the command-line argument `--parser=parse.y`.
+  [[Feature #20564]]
+
+* Happy Eyeballs version 2 (RFC8305), an algorithm that ensures faster and more reliable connections
+  by attempting IPv6 and IPv4 concurrently, is used in `Socket.tcp` and `TCPSocket.new`.
+  To disable it globally, set the environment variable `RUBY_TCP_NO_FAST_FALLBACK=1` or
+  call `Socket.tcp_fast_fallback=false`.
+  Or to disable it on a per-method basis, use the keyword argument `fast_fallback: false`.
+  [[Feature #20108]] [[Feature #20782]]
+
+* Alternative garbage collector (GC) implementations can be loaded dynamically
+  through the modular garbage collector feature. To enable this feature,
+  configure Ruby with `--with-modular-gc` at build time. GC libraries can be
+  loaded at runtime using the environment variable `RUBY_GC_LIBRARY`.
+  [[Feature #20351]]
+
+* Ruby's built-in garbage collector has been split into a separate file at
+  `gc/default/default.c` and interacts with Ruby using an API defined in
+  `gc/gc_impl.h`. The built-in garbage collector can now also be built as a
+  library using `make modular-gc MODULAR_GC=default` and enabled using the
+  environment variable `RUBY_GC_LIBRARY=default`. [[Feature #20470]]
+
+* An experimental GC library is provided based on [MMTk](https://www.mmtk.io/).
+  This GC library can be built using `make modular-gc MODULAR_GC=mmtk` and
+  enabled using the environment variable `RUBY_GC_LIBRARY=mmtk`. This requires
+  the Rust toolchain on the build machine. [[Feature #20860]]
+
+### YJIT
+
+#### New features
+
+* Command-line options
+    * `--yjit-mem-size` introduces a unified memory limit (default 128MiB) to track total YJIT memory usage,
+      providing a more intuitive alternative to the old `--yjit-exec-mem-size` option.
+    * `--yjit-trace-exits=COUNTER` allows tracing of counted exits and fallbacks.
+    * `--yjit-perf=codegen` allows profiling of JIT code based on YJIT's codegen functions.
+    * `--yjit-log` enables a compilation log to track what gets compiled.
+* Ruby API
+    * `RubyVM::YJIT.enable(log: true)` also enables a compilation log.
+    * `RubyVM::YJIT.log` provides access to the tail of the compilation log at run-time.
+* YJIT stats
+    * `RubyVM::YJIT.runtime_stats` now always provides additional statistics on
+      invalidation, inlining, and metadata encoding.
+    * `RubyVM::YJIT.runtime_stats[:iseq_calls]` is added to profile non-inlined Ruby method calls.
+    * `RubyVM::YJIT.runtime_stats[:cfunc_calls]` is truncated to the top 20 entries for better performance.
+
+#### New optimizations
+
+* Compressed context reduces memory needed to store YJIT metadata
+* Allocate registers for local variables and Ruby method arguments
+* When YJIT is enabled, use more Core primitives written in Ruby:
+    * `Array#each`, `Array#select`, `Array#map` rewritten in Ruby for better performance [[Feature #20182]].
+* Ability to inline small/trivial methods such as:
+    * Empty methods
+    * Methods returning a constant
+    * Methods returning `self`
+    * Methods directly returning an argument
+* Specialized codegen for many more runtime methods
+* Optimize `String#getbyte`, `String#setbyte` and other string methods
+* Optimize bitwise operations to speed up low-level bit/byte manipulation
+* Support shareable constants in multi-ractor mode
+* Various other incremental optimizations
 
 ## Miscellaneous changes
 
-[Feature #12005]: https://bugs.ruby-lang.org/issues/12005
-[Feature #12737]: https://bugs.ruby-lang.org/issues/12737
-[Feature #13110]: https://bugs.ruby-lang.org/issues/13110
-[Feature #14332]: https://bugs.ruby-lang.org/issues/14332
-[Feature #15231]: https://bugs.ruby-lang.org/issues/15231
-[Feature #15357]: https://bugs.ruby-lang.org/issues/15357
-[Bug #15928]:     https://bugs.ruby-lang.org/issues/15928
-[Feature #16131]: https://bugs.ruby-lang.org/issues/16131
-[Feature #16806]: https://bugs.ruby-lang.org/issues/16806
-[Bug #16889]:     https://bugs.ruby-lang.org/issues/16889
-[Bug #16908]:     https://bugs.ruby-lang.org/issues/16908
-[Feature #16989]: https://bugs.ruby-lang.org/issues/16989
-[Feature #17351]: https://bugs.ruby-lang.org/issues/17351
-[Feature #17391]: https://bugs.ruby-lang.org/issues/17391
-[Bug #17545]:     https://bugs.ruby-lang.org/issues/17545
-[Feature #17881]: https://bugs.ruby-lang.org/issues/17881
-[Feature #18037]: https://bugs.ruby-lang.org/issues/18037
-[Feature #18351]: https://bugs.ruby-lang.org/issues/18351
-[Bug #18487]:     https://bugs.ruby-lang.org/issues/18487
-[Feature #18571]: https://bugs.ruby-lang.org/issues/18571
-[Feature #18585]: https://bugs.ruby-lang.org/issues/18585
-[Feature #18598]: https://bugs.ruby-lang.org/issues/18598
-[Bug #18633]:     https://bugs.ruby-lang.org/issues/18633
+* Passing a block to a method which doesn't use the passed block will show
+  a warning on verbose mode (`-w`).
+  In connection with this, a new `strict_unused_block` warning category was introduced.
+  Turn them on with `-W:strict_unused_block` or `Warning[:strict_unused_block] = true`.
+  [[Feature #15554]]
+
+* Redefining some core methods that are specially optimized by the interpreter
+  and JIT like `String#freeze` or `Integer#+` now emits a performance class
+  warning (`-W:performance` or `Warning[:performance] = true`).
+  [[Feature #20429]]
+
+[Feature #13557]: https://bugs.ruby-lang.org/issues/13557
+[Feature #15554]: https://bugs.ruby-lang.org/issues/15554
+[Feature #16495]: https://bugs.ruby-lang.org/issues/16495
+[Feature #18290]: https://bugs.ruby-lang.org/issues/18290
+[Feature #18368]: https://bugs.ruby-lang.org/issues/18368
+[Feature #18980]: https://bugs.ruby-lang.org/issues/18980
+[Misc #18984]:    https://bugs.ruby-lang.org/issues/18984
+[Feature #19117]: https://bugs.ruby-lang.org/issues/19117
+[Feature #19236]: https://bugs.ruby-lang.org/issues/19236
+[Bug #19266]:     https://bugs.ruby-lang.org/issues/19266
+[Feature #19714]: https://bugs.ruby-lang.org/issues/19714
+[Bug #19918]:     https://bugs.ruby-lang.org/issues/19918
+[Feature #20018]: https://bugs.ruby-lang.org/issues/20018
+[Bug #20064]:     https://bugs.ruby-lang.org/issues/20064
+[Feature #20108]: https://bugs.ruby-lang.org/issues/20108
+[Feature #20182]: https://bugs.ruby-lang.org/issues/20182
+[Feature #20205]: https://bugs.ruby-lang.org/issues/20205
+[Bug #20218]:     https://bugs.ruby-lang.org/issues/20218
+[Feature #20265]: https://bugs.ruby-lang.org/issues/20265
+[Feature #20275]: https://bugs.ruby-lang.org/issues/20275
+[Feature #20293]: https://bugs.ruby-lang.org/issues/20293
+[Feature #20350]: https://bugs.ruby-lang.org/issues/20350
+[Feature #20351]: https://bugs.ruby-lang.org/issues/20351
+[Feature #20429]: https://bugs.ruby-lang.org/issues/20429
+[Bug #20433]:     https://bugs.ruby-lang.org/issues/20433
+[Feature #20443]: https://bugs.ruby-lang.org/issues/20443
+[Feature #20470]: https://bugs.ruby-lang.org/issues/20470
+[Feature #20497]: https://bugs.ruby-lang.org/issues/20497
+[Feature #20564]: https://bugs.ruby-lang.org/issues/20564
+[Feature #20576]: https://bugs.ruby-lang.org/issues/20576
+[Feature #20594]: https://bugs.ruby-lang.org/issues/20594
+[Bug #20620]:     https://bugs.ruby-lang.org/issues/20620
+[Feature #20624]: https://bugs.ruby-lang.org/issues/20624
+[Feature #20627]: https://bugs.ruby-lang.org/issues/20627
+[Feature #20702]: https://bugs.ruby-lang.org/issues/20702
+[Feature #20705]: https://bugs.ruby-lang.org/issues/20705
+[Feature #20707]: https://bugs.ruby-lang.org/issues/20707
+[Feature #20715]: https://bugs.ruby-lang.org/issues/20715
+[Feature #20775]: https://bugs.ruby-lang.org/issues/20775
+[Feature #20778]: https://bugs.ruby-lang.org/issues/20778
+[Feature #20782]: https://bugs.ruby-lang.org/issues/20782
+[Bug #20795]:     https://bugs.ruby-lang.org/issues/20795
+[Feature #20811]: https://bugs.ruby-lang.org/issues/20811
+[Feature #20860]: https://bugs.ruby-lang.org/issues/20860
+[Feature #20875]: https://bugs.ruby-lang.org/issues/20875
+[Feature #20876]: https://bugs.ruby-lang.org/issues/20876
+[Feature #20884]: https://bugs.ruby-lang.org/issues/20884
+[Feature #20902]: https://bugs.ruby-lang.org/issues/20902
+[Bug #20929]:     https://bugs.ruby-lang.org/issues/20929
+[RubyGems-v3.5.4]: https://github.com/rubygems/rubygems/releases/tag/v3.5.4
+[RubyGems-v3.5.5]: https://github.com/rubygems/rubygems/releases/tag/v3.5.5
+[RubyGems-v3.5.6]: https://github.com/rubygems/rubygems/releases/tag/v3.5.6
+[RubyGems-v3.5.7]: https://github.com/rubygems/rubygems/releases/tag/v3.5.7
+[RubyGems-v3.5.8]: https://github.com/rubygems/rubygems/releases/tag/v3.5.8
+[RubyGems-v3.5.9]: https://github.com/rubygems/rubygems/releases/tag/v3.5.9
+[RubyGems-v3.5.10]: https://github.com/rubygems/rubygems/releases/tag/v3.5.10
+[RubyGems-v3.5.11]: https://github.com/rubygems/rubygems/releases/tag/v3.5.11
+[RubyGems-v3.5.12]: https://github.com/rubygems/rubygems/releases/tag/v3.5.12
+[RubyGems-v3.5.13]: https://github.com/rubygems/rubygems/releases/tag/v3.5.13
+[RubyGems-v3.5.14]: https://github.com/rubygems/rubygems/releases/tag/v3.5.14
+[RubyGems-v3.5.15]: https://github.com/rubygems/rubygems/releases/tag/v3.5.15
+[RubyGems-v3.5.16]: https://github.com/rubygems/rubygems/releases/tag/v3.5.16
+[RubyGems-v3.5.17]: https://github.com/rubygems/rubygems/releases/tag/v3.5.17
+[RubyGems-v3.5.18]: https://github.com/rubygems/rubygems/releases/tag/v3.5.18
+[RubyGems-v3.5.19]: https://github.com/rubygems/rubygems/releases/tag/v3.5.19
+[RubyGems-v3.5.20]: https://github.com/rubygems/rubygems/releases/tag/v3.5.20
+[RubyGems-v3.5.21]: https://github.com/rubygems/rubygems/releases/tag/v3.5.21
+[RubyGems-v3.5.22]: https://github.com/rubygems/rubygems/releases/tag/v3.5.22
+[RubyGems-v3.5.23]: https://github.com/rubygems/rubygems/releases/tag/v3.5.23
+[RubyGems-v3.6.0]: https://github.com/rubygems/rubygems/releases/tag/v3.6.0
+[RubyGems-v3.6.1]: https://github.com/rubygems/rubygems/releases/tag/v3.6.1
+[RubyGems-v3.6.2]: https://github.com/rubygems/rubygems/releases/tag/v3.6.2
+[benchmark-v0.4.0]: https://github.com/ruby/benchmark/releases/tag/v0.4.0
+[bundler-v2.5.4]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.5.4
+[bundler-v2.5.5]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.5.5
+[bundler-v2.5.6]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.5.6
+[bundler-v2.5.7]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.5.7
+[bundler-v2.5.8]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.5.8
+[bundler-v2.5.9]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.5.9
+[bundler-v2.5.10]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.5.10
+[bundler-v2.5.11]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.5.11
+[bundler-v2.5.12]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.5.12
+[bundler-v2.5.13]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.5.13
+[bundler-v2.5.14]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.5.14
+[bundler-v2.5.15]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.5.15
+[bundler-v2.5.16]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.5.16
+[bundler-v2.5.17]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.5.17
+[bundler-v2.5.18]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.5.18
+[bundler-v2.5.19]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.5.19
+[bundler-v2.5.20]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.5.20
+[bundler-v2.5.21]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.5.21
+[bundler-v2.5.22]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.5.22
+[bundler-v2.5.23]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.5.23
+[bundler-v2.6.0]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.6.0
+[bundler-v2.6.1]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.6.1
+[bundler-v2.6.2]: https://github.com/rubygems/rubygems/releases/tag/bundler-v2.6.2
+[date-v3.4.0]: https://github.com/ruby/date/releases/tag/v3.4.0
+[date-v3.4.1]: https://github.com/ruby/date/releases/tag/v3.4.1
+[delegate-v0.4.0]: https://github.com/ruby/delegate/releases/tag/v0.4.0
+[did_you_mean-v2.0.0]: https://github.com/ruby/did_you_mean/releases/tag/v2.0.0
+[digest-v3.2.0.pre0]: https://github.com/ruby/digest/releases/tag/v3.2.0.pre0
+[digest-v3.2.0]: https://github.com/ruby/digest/releases/tag/v3.2.0
+[erb-v4.0.4]: https://github.com/ruby/erb/releases/tag/v4.0.4
+[etc-v1.4.4]: https://github.com/ruby/etc/releases/tag/v1.4.4
+[etc-v1.4.5]: https://github.com/ruby/etc/releases/tag/v1.4.5
+[fcntl-v1.2.0]: https://github.com/ruby/fcntl/releases/tag/v1.2.0
+[fiddle-v1.1.3]: https://github.com/ruby/fiddle/releases/tag/v1.1.3
+[fiddle-v1.1.4]: https://github.com/ruby/fiddle/releases/tag/v1.1.4
+[fiddle-v1.1.5]: https://github.com/ruby/fiddle/releases/tag/v1.1.5
+[fiddle-v1.1.6]: https://github.com/ruby/fiddle/releases/tag/v1.1.6
+[fileutils-v1.7.3]: https://github.com/ruby/fileutils/releases/tag/v1.7.3
+[io-console-v0.7.2]: https://github.com/ruby/io-console/releases/tag/v0.7.2
+[io-console-v0.8.0.beta1]: https://github.com/ruby/io-console/releases/tag/v0.8.0.beta1
+[io-console-v0.8.0]: https://github.com/ruby/io-console/releases/tag/v0.8.0
+[io-nonblock-v0.3.1]: https://github.com/ruby/io-nonblock/releases/tag/v0.3.1
+[ipaddr-v1.2.7]: https://github.com/ruby/ipaddr/releases/tag/v1.2.7
+[irb-v1.11.1]: https://github.com/ruby/irb/releases/tag/v1.11.1
+[irb-v1.11.2]: https://github.com/ruby/irb/releases/tag/v1.11.2
+[irb-v1.12.0]: https://github.com/ruby/irb/releases/tag/v1.12.0
+[irb-v1.13.0]: https://github.com/ruby/irb/releases/tag/v1.13.0
+[irb-v1.13.1]: https://github.com/ruby/irb/releases/tag/v1.13.1
+[irb-v1.13.2]: https://github.com/ruby/irb/releases/tag/v1.13.2
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+[power_assert]: https://github.com/ruby/power_assert
+[rake]: https://github.com/ruby/rake
+[test-unit]: https://github.com/test-unit/test-unit
+[rexml]: https://github.com/ruby/rexml
+[rss]: https://github.com/ruby/rss
+[net-ftp]: https://github.com/ruby/net-ftp
+[net-imap]: https://github.com/ruby/net-imap
+[net-smtp]: https://github.com/ruby/net-smtp
+[prime]: https://github.com/ruby/prime
+[rbs]: https://github.com/ruby/rbs
+[typeprof]: https://github.com/ruby/typeprof
+[debug]: https://github.com/ruby/debug
+[racc]: https://github.com/ruby/racc
+[mutex_m]: https://github.com/ruby/mutex_m
+[getoptlong]: https://github.com/ruby/getoptlong
+[base64]: https://github.com/ruby/base64
+[bigdecimal]: https://github.com/ruby/bigdecimal
+[observer]: https://github.com/ruby/observer
+[abbrev]: https://github.com/ruby/abbrev
+[resolv-replace]: https://github.com/ruby/resolv-replace
+[rinda]: https://github.com/ruby/rinda
+[drb]: https://github.com/ruby/drb
+[nkf]: https://github.com/ruby/nkf
+[syslog]: https://github.com/ruby/syslog
+[csv]: https://github.com/ruby/csv
diff --git a/README.ja.md b/README.ja.md
index bb69c09055..adacd57a4f 100644
--- a/README.ja.md
+++ b/README.ja.md
@@ -1,10 +1,9 @@
 [![Actions Status: MinGW](https://github.com/ruby/ruby/workflows/MinGW/badge.svg)](https://github.com/ruby/ruby/actions?query=workflow%3A"MinGW")
-[![Actions Status: MJIT](https://github.com/ruby/ruby/workflows/MJIT/badge.svg)](https://github.com/ruby/ruby/actions?query=workflow%3A"MJIT")
+[![Actions Status: RJIT](https://github.com/ruby/ruby/workflows/RJIT/badge.svg)](https://github.com/ruby/ruby/actions?query=workflow%3A"RJIT")
 [![Actions Status: Ubuntu](https://github.com/ruby/ruby/workflows/Ubuntu/badge.svg)](https://github.com/ruby/ruby/actions?query=workflow%3A"Ubuntu")
 [![Actions Status: Windows](https://github.com/ruby/ruby/workflows/Windows/badge.svg)](https://github.com/ruby/ruby/actions?query=workflow%3A"Windows")
 [![AppVeyor status](https://ci.appveyor.com/api/projects/status/0sy8rrxut4o0k960/branch/master?svg=true)](https://ci.appveyor.com/project/ruby/ruby/branch/master)
 [![Travis Status](https://app.travis-ci.com/ruby/ruby.svg?branch=master)](https://app.travis-ci.com/ruby/ruby)
-[![Cirrus Status](https://api.cirrus-ci.com/github/ruby/ruby.svg)](https://cirrus-ci.com/github/ruby/ruby/master)
 
 # Rubyとは
 
@@ -26,7 +25,7 @@ Rubyはテキスト処理関係の能力などに優れ，Perlと同じくらい
 *   ダイナミックローディング (アーキテクチャによる)
 *   移植性が高い．多くのUnix-like/POSIX互換プラットフォーム上で動くだけでなく，Windows， macOS，
     Haikuなどの上でも動く cf.
-    https://github.com/ruby/ruby/blob/master/doc/contributing.rdoc#platform-maintainers
+    https://docs.ruby-lang.org/en/master/maintainers_md.html#label-Platform+Maintainers
 
 
 ## 入手法
@@ -41,26 +40,19 @@ https://www.ruby-lang.org/ja/downloads/
 
 ミラーをGitHubに公開しています． 以下のコマンドでリポジトリを取得できます．
 
-    $ git clone https://github.com/ruby/ruby.git
+```console
+$ git clone https://github.com/ruby/ruby.git
+```
 
 他のブランチの一覧は次のコマンドで見られます．
 
-    $ git ls-remote https://github.com/ruby/ruby.git
+```console
+$ git ls-remote https://github.com/ruby/ruby.git
+```
 
 Rubyリポジトリの本来のmasterは https://git.ruby-lang.org/ruby.git にあります．
 コミッタはこちらを使います．
 
-### Subversion
-
-古いRubyのバージョンのソースコードは次のコマンドでも取得できます．
-
-    $ svn co https://svn.ruby-lang.org/repos/ruby/branches/ruby_2_6/ ruby
-
-他のブランチの一覧は次のコマンドで見られます．
-
-    $ svn ls https://svn.ruby-lang.org/repos/ruby/branches/
-
-
 ## ホームページ
 
 RubyのホームページのURLは
@@ -71,20 +63,20 @@ https://www.ruby-lang.org/
 
 ## メーリングリスト
 
-Rubyのメーリングリストがあります．参加希望の方は [ruby-list-request@ruby-lang.org] まで本文に
+Rubyのメーリングリストがあります．参加希望の方は [ruby-list-request@ml.ruby-lang.org] まで件名に
 
-    subscribe
+    join
 
 と書いて送って下さい．
 
 Ruby開発者向けメーリングリストもあります．こちらではrubyのバグ，将来の仕様拡張など実装上の問題について議論されています．
-参加希望の方は [ruby-dev-request@ruby-lang.org] までruby-listと同様の方法でメールしてください．
+参加希望の方は [ruby-dev-request@ml.ruby-lang.org] までruby-listと同様の方法でメールしてください．
 
 Ruby拡張モジュールについて話し合うruby-extメーリングリストと数学関係の話題について話し合うruby-mathメーリングリストと
 英語でrubyについて話し合うruby-talkメーリングリストもあります．参加方法はどれも同じです．
 
-[ruby-list-request@ruby-lang.org]: mailto:ruby-list-request@ruby-lang.org?subject=Join%20Ruby%20Mailing%20List&body=subscribe
-[ruby-dev-request@ruby-lang.org]: mailto:ruby-dev-request@ruby-lang.org?subject=Join%20Ruby%20Mailing%20List&body=subscribe
+[ruby-list-request@ml.ruby-lang.org]: mailto:ruby-list-request@ml.ruby-lang.org?subject=join
+[ruby-dev-request@ml.ruby-lang.org]: mailto:ruby-dev-request@ml.ruby-lang.org?subject=join
 
 ## コンパイル・インストール
 
@@ -163,7 +155,7 @@ UNIXであれば `configure` がほとんどの差異を吸収してくれるは
 
 ## 配布条件
 
-[COPYING.ja](COPYING.ja) ファイルを参照してください．
+[COPYING.ja](https://docs.ruby-lang.org/en/master/COPYING_ja.html) ファイルを参照してください．
 
 ## フィードバック
 
diff --git a/README.md b/README.md
index 9b5a553ffb..eb24a73ee3 100644
--- a/README.md
+++ b/README.md
@@ -1,12 +1,10 @@
 [![Actions Status: MinGW](https://github.com/ruby/ruby/workflows/MinGW/badge.svg)](https://github.com/ruby/ruby/actions?query=workflow%3A"MinGW")
-[![Actions Status: MJIT](https://github.com/ruby/ruby/workflows/MJIT/badge.svg)](https://github.com/ruby/ruby/actions?query=workflow%3A"MJIT")
+[![Actions Status: RJIT](https://github.com/ruby/ruby/workflows/RJIT/badge.svg)](https://github.com/ruby/ruby/actions?query=workflow%3A"RJIT")
 [![Actions Status: Ubuntu](https://github.com/ruby/ruby/workflows/Ubuntu/badge.svg)](https://github.com/ruby/ruby/actions?query=workflow%3A"Ubuntu")
 [![Actions Status: Windows](https://github.com/ruby/ruby/workflows/Windows/badge.svg)](https://github.com/ruby/ruby/actions?query=workflow%3A"Windows")
-[![AppVeyor status](https://ci.appveyor.com/api/projects/status/0sy8rrxut4o0k960/branch/master?svg=true)](https://ci.appveyor.com/project/ruby/ruby/branch/master)
 [![Travis Status](https://app.travis-ci.com/ruby/ruby.svg?branch=master)](https://app.travis-ci.com/ruby/ruby)
-[![Cirrus Status](https://api.cirrus-ci.com/github/ruby/ruby.svg)](https://cirrus-ci.com/github/ruby/ruby/master)
 
-# What's Ruby
+# What is Ruby?
 
 Ruby is an interpreted object-oriented programming language often
 used for web development. It also offers many scripting features
@@ -15,18 +13,17 @@ It is simple, straightforward, and extensible.
 
 ## Features of Ruby
 
-*   Simple Syntax
-*   **Normal** Object-oriented Features (e.g. class, method calls)
-*   **Advanced** Object-oriented Features (e.g. mix-in, singleton-method)
-*   Operator Overloading
-*   Exception Handling
-*   Iterators and Closures
-*   Garbage Collection
-*   Dynamic Loading of Object Files (on some architectures)
-*   Highly Portable (works on many Unix-like/POSIX compatible platforms as
-    well as Windows, macOS, etc.) cf.
-    https://github.com/ruby/ruby/blob/master/doc/maintainers.rdoc#label-Platform+Maintainers
-
+* Simple Syntax
+* **Normal** Object-oriented Features (e.g. class, method calls)
+* **Advanced** Object-oriented Features (e.g. mix-in, singleton-method)
+* Operator Overloading
+* Exception Handling
+* Iterators and Closures
+* Garbage Collection
+* Dynamic Loading of Object Files (on some architectures)
+* Highly Portable (works on many Unix-like/POSIX compatible platforms as
+  well as Windows, macOS, etc.) cf.
+    https://docs.ruby-lang.org/en/master/maintainers_md.html#label-Platform+Maintainers
 
 ## How to get Ruby
 
@@ -35,7 +32,10 @@ like rvm, see:
 
 https://www.ruby-lang.org/en/downloads/
 
-### Git
+You can download release packages and the snapshot of the repository. If you want to
+download whole versions of Ruby, please visit https://www.ruby-lang.org/en/downloads/releases/.
+
+### Download with Git
 
 The mirror of the Ruby source tree can be checked out with the following command:
 
@@ -49,117 +49,29 @@ to see the list of branches:
 You may also want to use https://git.ruby-lang.org/ruby.git (actual master of Ruby source)
 if you are a committer.
 
-### Subversion
-
-Stable branches for older Ruby versions can be checked out with also the
-following command:
-
-    $ svn co https://svn.ruby-lang.org/repos/ruby/branches/ruby_2_6/ ruby
-
-Try the following command to see the list of branches:
-
-    $ svn ls https://svn.ruby-lang.org/repos/ruby/branches/
+## How to build
 
+See [Building Ruby](https://docs.ruby-lang.org/en/master/contributing/building_ruby_md.html)
 
 ## Ruby home page
 
 https://www.ruby-lang.org/
 
+## Documentation
+
+- [English](https://docs.ruby-lang.org/en/master/index.html)
+- [Japanese](https://docs.ruby-lang.org/ja/master/index.html)
+
 ## Mailing list
 
 There is a mailing list to discuss Ruby. To subscribe to this list, please
 send the following phrase:
 
-    subscribe
-
-in the mail body (not subject) to the address [ruby-talk-request@ruby-lang.org].
-
-[ruby-talk-request@ruby-lang.org]: mailto:ruby-talk-request@ruby-lang.org?subject=Join%20Ruby%20Mailing%20List&body=subscribe
-
-## Requirements to build from repository
-
-1. GNU or BSD make
-2. C99 compiler
-3. autoconf 2.67 or higher
-4. automake 1.15 or higher
-5. bison 2.3 or higher
-6. Ruby 2.2 or higher
-
-When building from a released version, only a C99 compiler and GNU or BSD make
-is required.
-
-## How to compile and install
-
-1.  If you want to use Microsoft Visual C++ to compile Ruby, read
-    [win32/README.win32](rdoc-ref:win32/README.win32) instead of this document.
-
-2.  Run `./autogen.sh` to generate configure, when you build the source checked
-    out from the Git repository.
-
-3.  Run `./configure`, which will generate `config.h` and `Makefile`.
+    join
 
-    Some C compiler flags may be added by default depending on your
-    environment. Specify `optflags=..` and `warnflags=..` as necessary to
-    override them.
+in the mail subject (not body) to the address [ruby-talk-request@ml.ruby-lang.org].
 
-4.  Edit `include/ruby/defines.h` if you need. Usually this step will not be needed.
-
-5.  Optional: Remove comment mark(`#`) before the module names from `ext/Setup`.
-
-    This step is only necessary if you want to link modules statically.
-
-    If you don't want to compile dynamic extensions (probably on architectures
-    which do not allow dynamic loading), remove comment mark from the line
-    "`#option nodynamic`" in `ext/Setup`.
-
-    Usually this step will not be needed.
-
-6.  Run `make`.
-
-    * On Mac, set RUBY\_CODESIGN environment variable with a signing identity.
-      It uses the identity to sign `ruby` binary. See also codesign(1).
-
-7.  Optionally, run '`make check`' to check whether the compiled Ruby
-    interpreter works well. If you see the message "`check succeeded`", your
-    Ruby works as it should (hopefully).
-
-8.  Run '`make install`'.
-
-    This command will create the following directories and install files into
-    them.
-
-    *   `${DESTDIR}${prefix}/bin`
-    *   `${DESTDIR}${prefix}/include/ruby-${MAJOR}.${MINOR}.${TEENY}`
-    *   `${DESTDIR}${prefix}/include/ruby-${MAJOR}.${MINOR}.${TEENY}/${PLATFORM}`
-    *   `${DESTDIR}${prefix}/lib`
-    *   `${DESTDIR}${prefix}/lib/ruby`
-    *   `${DESTDIR}${prefix}/lib/ruby/${MAJOR}.${MINOR}.${TEENY}`
-    *   `${DESTDIR}${prefix}/lib/ruby/${MAJOR}.${MINOR}.${TEENY}/${PLATFORM}`
-    *   `${DESTDIR}${prefix}/lib/ruby/site_ruby`
-    *   `${DESTDIR}${prefix}/lib/ruby/site_ruby/${MAJOR}.${MINOR}.${TEENY}`
-    *   `${DESTDIR}${prefix}/lib/ruby/site_ruby/${MAJOR}.${MINOR}.${TEENY}/${PLATFORM}`
-    *   `${DESTDIR}${prefix}/lib/ruby/vendor_ruby`
-    *   `${DESTDIR}${prefix}/lib/ruby/vendor_ruby/${MAJOR}.${MINOR}.${TEENY}`
-    *   `${DESTDIR}${prefix}/lib/ruby/vendor_ruby/${MAJOR}.${MINOR}.${TEENY}/${PLATFORM}`
-    *   `${DESTDIR}${prefix}/lib/ruby/gems/${MAJOR}.${MINOR}.${TEENY}`
-    *   `${DESTDIR}${prefix}/share/man/man1`
-    *   `${DESTDIR}${prefix}/share/ri/${MAJOR}.${MINOR}.${TEENY}/system`
-
-
-    If Ruby's API version is '*x.y.z*', the `${MAJOR}` is '*x*', the
-    `${MINOR}` is '*y*', and the `${TEENY}` is '*z*'.
-
-    **NOTE**: teeny of the API version may be different from one of Ruby's
-    program version
-
-    You may have to be a super user to install Ruby.
-
-If you fail to compile Ruby, please send the detailed error report with the
-error log and machine/OS type, to help others.
-
-Some extension libraries may not get compiled because of lack of necessary
-external libraries and/or headers, then you will need to run '`make distclean-ext`'
-to remove old configuration after installing them in such case.
+[ruby-talk-request@ml.ruby-lang.org]: mailto:ruby-talk-request@ml.ruby-lang.org?subject=join
 
 ## Copying
 
@@ -167,17 +79,14 @@ See the file [COPYING](rdoc-ref:COPYING).
 
 ## Feedback
 
-Questions about the Ruby language can be asked on the [Ruby-Talk] mailing list
+Questions about the Ruby language can be asked on the [Ruby-Talk](https://www.ruby-lang.org/en/community/mailing-lists) mailing list
 or on websites like https://stackoverflow.com.
 
-Bugs should be reported at https://bugs.ruby-lang.org. Read [HowToReport] for more information.
-
-[Ruby-Talk]: https://www.ruby-lang.org/en/community/mailing-lists
-[HowToReport]: https://bugs.ruby-lang.org/projects/ruby/wiki/HowToReport
+Bugs should be reported at https://bugs.ruby-lang.org. Read ["Reporting Issues"](https://docs.ruby-lang.org/en/master/contributing/reporting_issues_md.html) for more information.
 
 ## Contributing
 
-See the file [CONTRIBUTING.md](rdoc-ref:CONTRIBUTING)
+See ["Contributing to Ruby"](https://docs.ruby-lang.org/en/master/contributing_md.html), which includes setup and build instructions.
 
 ## The Author
 
diff --git a/addr2line.c b/addr2line.c
index f660be9129..b783e8e470 100644
--- a/addr2line.c
+++ b/addr2line.c
@@ -8,10 +8,14 @@
 
 **********************************************************************/
 
-#if defined(__clang__)
+#if defined(__clang__) && defined(__has_warning)
+#if __has_warning("-Wgnu-empty-initializer")
 #pragma clang diagnostic ignored "-Wgnu-empty-initializer"
+#endif
+#if __has_warning("-Wgcc-compat")
 #pragma clang diagnostic ignored "-Wgcc-compat"
 #endif
+#endif
 
 #include "ruby/internal/config.h"
 #include "ruby/defines.h"
@@ -52,13 +56,26 @@
 #  ifdef _AIX
 #pragma alloca
 #  else
-#   ifndef alloca		/* predefined by HP cc +Olibcalls */
+#   ifndef alloca                /* predefined by HP cc +Olibcalls */
 void *alloca();
 #   endif
 #  endif /* AIX */
-# endif	/* HAVE_ALLOCA_H */
+# endif        /* HAVE_ALLOCA_H */
+# ifndef UNREACHABLE
+#  define UNREACHABLE __builtin_unreachable()
+# endif
+# ifndef UNREACHABLE_RETURN
+#  define UNREACHABLE_RETURN(_) __builtin_unreachable()
+# endif
 #endif /* __GNUC__ */
 
+#ifndef UNREACHABLE
+# define UNREACHABLE abort()
+#endif
+#ifndef UNREACHABLE_RETURN
+# define UNREACHABLE_RETURN(_) return (abort(), (_))
+#endif
+
 #ifdef HAVE_DLADDR
 # include <dlfcn.h>
 #endif
@@ -127,7 +144,7 @@ void *alloca();
 #define DW_LNE_define_file              0x03
 #define DW_LNE_set_discriminator        0x04  /* DWARF4 */
 
-PRINTF_ARGS(static int kprintf(const char *fmt, ...), 1, 2);
+#define kprintf(...) fprintf(errout, "" __VA_ARGS__)
 
 typedef struct line_info {
     const char *dirname;
@@ -159,12 +176,15 @@ typedef struct obj_info {
     struct dwarf_section debug_info;
     struct dwarf_section debug_line;
     struct dwarf_section debug_ranges;
+    struct dwarf_section debug_str_offsets;
+    struct dwarf_section debug_addr;
     struct dwarf_section debug_rnglists;
     struct dwarf_section debug_str;
+    struct dwarf_section debug_line_str;
     struct obj_info *next;
 } obj_info_t;
 
-#define DWARF_SECTION_COUNT 6
+#define DWARF_SECTION_COUNT 9
 
 static struct dwarf_section *
 obj_dwarf_section_at(obj_info_t *obj, int n)
@@ -174,11 +194,14 @@ obj_dwarf_section_at(obj_info_t *obj, int n)
         &obj->debug_info,
         &obj->debug_line,
         &obj->debug_ranges,
+        &obj->debug_str_offsets,
+        &obj->debug_addr,
         &obj->debug_rnglists,
-        &obj->debug_str
+        &obj->debug_str,
+        &obj->debug_line_str
     };
     if (n < 0 || DWARF_SECTION_COUNT <= n) {
-        abort();
+        UNREACHABLE_RETURN(0);
     }
     return ary[n];
 }
@@ -197,13 +220,13 @@ uleb128(const char **p)
     unsigned long r = 0;
     int s = 0;
     for (;;) {
-	unsigned char b = (unsigned char)*(*p)++;
-	if (b < 0x80) {
-	    r += (unsigned long)b << s;
-	    break;
-	}
-	r += (b & 0x7f) << s;
-	s += 7;
+        unsigned char b = (unsigned char)*(*p)++;
+        if (b < 0x80) {
+            r += (unsigned long)b << s;
+            break;
+        }
+        r += (b & 0x7f) << s;
+        s += 7;
     }
     return r;
 }
@@ -214,85 +237,101 @@ sleb128(const char **p)
     long r = 0;
     int s = 0;
     for (;;) {
-	unsigned char b = (unsigned char)*(*p)++;
-	if (b < 0x80) {
-	    if (b & 0x40) {
-		r -= (0x80 - b) << s;
-	    }
-	    else {
-		r += (b & 0x3f) << s;
-	    }
-	    break;
-	}
-	r += (b & 0x7f) << s;
-	s += 7;
+        unsigned char b = (unsigned char)*(*p)++;
+        if (b < 0x80) {
+            if (b & 0x40) {
+                r -= (0x80 - b) << s;
+            }
+            else {
+                r += (b & 0x3f) << s;
+            }
+            break;
+        }
+        r += (b & 0x7f) << s;
+        s += 7;
     }
     return r;
 }
 
 static const char *
-get_nth_dirname(unsigned long dir, const char *p)
+get_nth_dirname(unsigned long dir, const char *p, FILE *errout)
 {
     if (!dir--) {
-	return "";
+        return "";
     }
     while (dir--) {
-	while (*p) p++;
-	p++;
-	if (!*p) {
-	    kprintf("Unexpected directory number %lu in %s\n",
-		    dir, binary_filename);
-	    return "";
-	}
+        while (*p) p++;
+        p++;
+        if (!*p) {
+            kprintf("Unexpected directory number %lu in %s\n",
+                    dir, binary_filename);
+            return "";
+        }
     }
     return p;
 }
 
+static const char *parse_ver5_debug_line_header(
+    const char *p, int idx, uint8_t format,
+    obj_info_t *obj, const char **out_path,
+    uint64_t *out_directory_index, FILE *errout);
+
 static void
-fill_filename(int file, const char *include_directories, const char *filenames, line_info_t *line, obj_info_t *obj)
+fill_filename(int file, uint8_t format, uint16_t version, const char *include_directories,
+              const char *filenames, line_info_t *line, obj_info_t *obj, FILE *errout)
 {
     int i;
     const char *p = filenames;
     const char *filename;
     unsigned long dir;
-    for (i = 1; i <= file; i++) {
-	filename = p;
-	if (!*p) {
-	    /* Need to output binary file name? */
-	    kprintf("Unexpected file number %d in %s at %tx\n",
-		    file, binary_filename, filenames - obj->mapped);
-	    return;
-	}
-	while (*p) p++;
-	p++;
-	dir = uleb128(&p);
-	/* last modified. */
-	uleb128(&p);
-	/* size of the file. */
-	uleb128(&p);
-
-	if (i == file) {
-	    line->filename = filename;
-	    line->dirname = get_nth_dirname(dir, include_directories);
-	}
+    if (version >= 5) {
+        const char *path;
+        uint64_t directory_index = -1;
+        parse_ver5_debug_line_header(filenames, file, format, obj, &path, &directory_index, errout);
+        line->filename = path;
+        parse_ver5_debug_line_header(include_directories, (int)directory_index, format, obj, &path, NULL, errout);
+        line->dirname = path;
+    }
+    else {
+        for (i = 1; i <= file; i++) {
+            filename = p;
+            if (!*p) {
+                /* Need to output binary file name? */
+                kprintf("Unexpected file number %d in %s at %tx\n",
+                        file, binary_filename, filenames - obj->mapped);
+                return;
+            }
+            while (*p) p++;
+            p++;
+            dir = uleb128(&p);
+            /* last modified. */
+            uleb128(&p);
+            /* size of the file. */
+            uleb128(&p);
+
+            if (i == file) {
+                line->filename = filename;
+                line->dirname = get_nth_dirname(dir, include_directories, errout);
+            }
+        }
     }
 }
 
 static void
 fill_line(int num_traces, void **traces, uintptr_t addr, int file, int line,
-	  const char *include_directories, const char *filenames,
-	  obj_info_t *obj, line_info_t *lines, int offset)
+          uint8_t format, uint16_t version, const char *include_directories, const char *filenames,
+          obj_info_t *obj, line_info_t *lines, int offset, FILE *errout)
 {
     int i;
     addr += obj->base_addr - obj->vmaddr;
     for (i = offset; i < num_traces; i++) {
-	uintptr_t a = (uintptr_t)traces[i];
-	/* We assume one line code doesn't result >100 bytes of native code.
+        uintptr_t a = (uintptr_t)traces[i];
+        /* We assume one line code doesn't result >100 bytes of native code.
        We may want more reliable way eventually... */
-	if (addr < a && a < addr + 100) {
-	    fill_filename(file, include_directories, filenames, &lines[i], obj);
-	    lines[i].line = line;
-	}
+        if (addr < a && a < addr + 100) {
+            fill_filename(file, format, version, include_directories, filenames, &lines[i], obj, errout);
+            lines[i].line = line;
+        }
     }
 }
 
@@ -315,7 +354,7 @@ struct LineNumberProgramHeader {
 };
 
 static int
-parse_debug_line_header(const char **pp, struct LineNumberProgramHeader *header)
+parse_debug_line_header(obj_info_t *obj, const char **pp, struct LineNumberProgramHeader *header, FILE *errout)
 {
     const char *p = *pp;
     header->unit_length = *(uint32_t *)p;
@@ -323,8 +362,8 @@ parse_debug_line_header(const char **pp, struct LineNumberProgramHeader *header)
 
     header->format = 4;
     if (header->unit_length == 0xffffffff) {
-	header->unit_length = *(uint64_t *)p;
-	p += sizeof(uint64_t);
+        header->unit_length = *(uint64_t *)p;
+        p += sizeof(uint64_t);
         header->format = 8;
     }
 
@@ -332,7 +371,13 @@ parse_debug_line_header(const char **pp, struct LineNumberProgramHeader *header)
 
     header->version = *(uint16_t *)p;
     p += sizeof(uint16_t);
-    if (header->version > 4) return -1;
+    if (header->version > 5) return -1;
+
+    if (header->version >= 5) {
+        /* address_size = *(uint8_t *)p++; */
+        /* segment_selector_size = *(uint8_t *)p++; */
+        p += 2;
+    }
 
     header->header_length = header->format == 4 ? *(uint32_t *)p : *(uint64_t *)p;
     p += header->format;
@@ -353,20 +398,27 @@ parse_debug_line_header(const char **pp, struct LineNumberProgramHeader *header)
     /* header->standard_opcode_lengths = (uint8_t *)p - 1; */
     p += header->opcode_base - 1;
 
-    header->include_directories = p;
+    if (header->version >= 5) {
+        header->include_directories = p;
+        p = parse_ver5_debug_line_header(p, -1, header->format, obj, NULL, NULL, errout);
+        header->filenames = p;
+    }
+    else {
+        header->include_directories = p;
 
-    /* temporary measure for compress-debug-sections */
-    if (p >= header->cu_end) return -1;
+        /* temporary measure for compress-debug-sections */
+        if (p >= header->cu_end) return -1;
 
-    /* skip include directories */
-    while (*p) {
-	p = memchr(p, '\0', header->cu_end - p);
-	if (!p) return -1;
-	p++;
-    }
-    p++;
+        /* skip include directories */
+        while (*p) {
+            p = memchr(p, '\0', header->cu_end - p);
+            if (!p) return -1;
+            p++;
+        }
+        p++;
 
-    header->filenames = p;
+        header->filenames = p;
+    }
 
     *pp = header->cu_start;
 
@@ -375,7 +427,7 @@ parse_debug_line_header(const char **pp, struct LineNumberProgramHeader *header)
 
 static int
 parse_debug_line_cu(int num_traces, void **traces, const char **debug_line,
-		obj_info_t *obj, line_info_t *lines, int offset)
+                obj_info_t *obj, line_info_t *lines, int offset, FILE *errout)
 {
     const char *p = (const char *)*debug_line;
     struct LineNumberProgramHeader header;
@@ -392,107 +444,109 @@ parse_debug_line_cu(int num_traces, void **traces, const char **debug_line,
     /* int epilogue_begin = 0; */
     /* unsigned int isa = 0; */
 
-    if (parse_debug_line_header(&p, &header))
+    if (parse_debug_line_header(obj, &p, &header, errout))
         return -1;
     is_stmt = header.default_is_stmt;
 
-#define FILL_LINE()						    \
-    do {							    \
-	fill_line(num_traces, traces, addr, file, line,		    \
+#define FILL_LINE()                                                 \
+    do {                                                            \
+        fill_line(num_traces, traces, addr, file, line,             \
+                  header.format,                                    \
+                  header.version,                                   \
                   header.include_directories,                       \
                   header.filenames,                                 \
-		  obj, lines, offset);				    \
-	/*basic_block = prologue_end = epilogue_begin = 0;*/	    \
+                  obj, lines, offset, errout);                      \
+        /*basic_block = prologue_end = epilogue_begin = 0;*/        \
     } while (0)
 
     while (p < header.cu_end) {
-	unsigned long a;
-	unsigned char op = *p++;
-	switch (op) {
-	case DW_LNS_copy:
-	    FILL_LINE();
-	    break;
-	case DW_LNS_advance_pc:
-	    a = uleb128(&p) * header.minimum_instruction_length;
-	    addr += a;
-	    break;
-	case DW_LNS_advance_line: {
-	    long a = sleb128(&p);
-	    line += a;
-	    break;
-	}
-	case DW_LNS_set_file:
-	    file = (unsigned int)uleb128(&p);
-	    break;
-	case DW_LNS_set_column:
-	    /*column = (unsigned int)*/(void)uleb128(&p);
-	    break;
-	case DW_LNS_negate_stmt:
-	    is_stmt = !is_stmt;
-	    break;
-	case DW_LNS_set_basic_block:
-	    /*basic_block = 1; */
-	    break;
-	case DW_LNS_const_add_pc:
-	    a = ((255UL - header.opcode_base) / header.line_range) *
-		header.minimum_instruction_length;
-	    addr += a;
-	    break;
-	case DW_LNS_fixed_advance_pc:
-	    a = *(uint16_t *)p;
-	    p += sizeof(uint16_t);
-	    addr += a;
-	    break;
-	case DW_LNS_set_prologue_end:
-	    /* prologue_end = 1; */
-	    break;
-	case DW_LNS_set_epilogue_begin:
-	    /* epilogue_begin = 1; */
-	    break;
-	case DW_LNS_set_isa:
-	    /* isa = (unsigned int)*/(void)uleb128(&p);
-	    break;
-	case 0:
-	    a = uleb128(&p);
-	    op = *p++;
-	    switch (op) {
-	    case DW_LNE_end_sequence:
-		/* end_sequence = 1; */
-		FILL_LINE();
-		addr = 0;
-		file = 1;
-		line = 1;
-		/* column = 0; */
-		is_stmt = header.default_is_stmt;
-		/* end_sequence = 0; */
-		/* isa = 0; */
-		break;
-	    case DW_LNE_set_address:
-		addr = *(unsigned long *)p;
-		p += sizeof(unsigned long);
-		break;
-	    case DW_LNE_define_file:
-		kprintf("Unsupported operation in %s\n",
-			binary_filename);
-		break;
-	    case DW_LNE_set_discriminator:
-		/* TODO:currently ignore */
-		uleb128(&p);
-		break;
-	    default:
-		kprintf("Unknown extended opcode: %d in %s\n",
-			op, binary_filename);
-	    }
-	    break;
-	default: {
+        unsigned long a;
+        unsigned char op = *p++;
+        switch (op) {
+        case DW_LNS_copy:
+            FILL_LINE();
+            break;
+        case DW_LNS_advance_pc:
+            a = uleb128(&p) * header.minimum_instruction_length;
+            addr += a;
+            break;
+        case DW_LNS_advance_line: {
+            long a = sleb128(&p);
+            line += a;
+            break;
+        }
+        case DW_LNS_set_file:
+            file = (unsigned int)uleb128(&p);
+            break;
+        case DW_LNS_set_column:
+            /*column = (unsigned int)*/(void)uleb128(&p);
+            break;
+        case DW_LNS_negate_stmt:
+            is_stmt = !is_stmt;
+            break;
+        case DW_LNS_set_basic_block:
+            /*basic_block = 1; */
+            break;
+        case DW_LNS_const_add_pc:
+            a = ((255UL - header.opcode_base) / header.line_range) *
+                header.minimum_instruction_length;
+            addr += a;
+            break;
+        case DW_LNS_fixed_advance_pc:
+            a = *(uint16_t *)p;
+            p += sizeof(uint16_t);
+            addr += a;
+            break;
+        case DW_LNS_set_prologue_end:
+            /* prologue_end = 1; */
+            break;
+        case DW_LNS_set_epilogue_begin:
+            /* epilogue_begin = 1; */
+            break;
+        case DW_LNS_set_isa:
+            /* isa = (unsigned int)*/(void)uleb128(&p);
+            break;
+        case 0:
+            a = uleb128(&p);
+            op = *p++;
+            switch (op) {
+            case DW_LNE_end_sequence:
+                /* end_sequence = 1; */
+                FILL_LINE();
+                addr = 0;
+                file = 1;
+                line = 1;
+                /* column = 0; */
+                is_stmt = header.default_is_stmt;
+                /* end_sequence = 0; */
+                /* isa = 0; */
+                break;
+            case DW_LNE_set_address:
+                addr = *(unsigned long *)p;
+                p += sizeof(unsigned long);
+                break;
+            case DW_LNE_define_file:
+                kprintf("Unsupported operation in %s\n",
+                        binary_filename);
+                break;
+            case DW_LNE_set_discriminator:
+                /* TODO:currently ignore */
+                uleb128(&p);
+                break;
+            default:
+                kprintf("Unknown extended opcode: %d in %s\n",
+                        op, binary_filename);
+            }
+            break;
+        default: {
             uint8_t adjusted_opcode = op - header.opcode_base;
             uint8_t operation_advance = adjusted_opcode / header.line_range;
             /* NOTE: this code doesn't support VLIW */
             addr += operation_advance * header.minimum_instruction_length;
             line += header.line_base + (adjusted_opcode % header.line_range);
-	    FILL_LINE();
-	}
-	}
+            FILL_LINE();
+        }
+        }
     }
     *debug_line = (char *)p;
     return 0;
@@ -500,17 +554,17 @@ parse_debug_line_cu(int num_traces, void **traces, const char **debug_line,
 
 static int
 parse_debug_line(int num_traces, void **traces,
-		 const char *debug_line, unsigned long size,
-		 obj_info_t *obj, line_info_t *lines, int offset)
+                 const char *debug_line, unsigned long size,
+                 obj_info_t *obj, line_info_t *lines, int offset, FILE *errout)
 {
     const char *debug_line_end = debug_line + size;
     while (debug_line < debug_line_end) {
-	if (parse_debug_line_cu(num_traces, traces, &debug_line, obj, lines, offset))
-	    return -1;
+        if (parse_debug_line_cu(num_traces, traces, &debug_line, obj, lines, offset, errout))
+            return -1;
     }
     if (debug_line != debug_line_end) {
-	kprintf("Unexpected size of .debug_line in %s\n",
-		binary_filename);
+        kprintf("Unexpected size of .debug_line in %s\n",
+                binary_filename);
     }
     return 0;
 }
@@ -518,7 +572,7 @@ parse_debug_line(int num_traces, void **traces,
 /* read file and fill lines */
 static uintptr_t
 fill_lines(int num_traces, void **traces, int check_debuglink,
-	   obj_info_t **objp, line_info_t *lines, int offset);
+           obj_info_t **objp, line_info_t *lines, int offset, FILE *errout);
 
 static void
 append_obj(obj_info_t **objp)
@@ -546,7 +600,7 @@ append_obj(obj_info_t **objp)
 // check the path pattern of "/usr/lib/debug/usr/bin/ruby.debug"
 static void
 follow_debuglink(const char *debuglink, int num_traces, void **traces,
-		 obj_info_t **objp, line_info_t *lines, int offset)
+                 obj_info_t **objp, line_info_t *lines, int offset, FILE *errout)
 {
     static const char global_debug_dir[] = "/usr/lib/debug";
     const size_t global_debug_dir_len = sizeof(global_debug_dir) - 1;
@@ -556,13 +610,13 @@ follow_debuglink(const char *debuglink, int num_traces, void **traces,
 
     p = strrchr(binary_filename, '/');
     if (!p) {
-	return;
+        return;
     }
     p[1] = '\0';
 
     len = strlen(binary_filename);
     if (len >= PATH_MAX - global_debug_dir_len)
-	len = PATH_MAX - global_debug_dir_len - 1;
+        len = PATH_MAX - global_debug_dir_len - 1;
     memmove(binary_filename + global_debug_dir_len, binary_filename, len);
     memcpy(binary_filename, global_debug_dir, global_debug_dir_len);
     len += global_debug_dir_len;
@@ -572,13 +626,13 @@ follow_debuglink(const char *debuglink, int num_traces, void **traces,
     o2 = *objp;
     o2->base_addr = o1->base_addr;
     o2->path = o1->path;
-    fill_lines(num_traces, traces, 0, objp, lines, offset);
+    fill_lines(num_traces, traces, 0, objp, lines, offset, errout);
 }
 
 // check the path pattern of "/usr/lib/debug/.build-id/ab/cdef1234.debug"
 static void
 follow_debuglink_build_id(const char *build_id, size_t build_id_size, int num_traces, void **traces,
-                          obj_info_t **objp, line_info_t *lines, int offset)
+                          obj_info_t **objp, line_info_t *lines, int offset, FILE *errout)
 {
     static const char global_debug_dir[] = "/usr/lib/debug/.build-id/";
     const size_t global_debug_dir_len = sizeof(global_debug_dir) - 1;
@@ -603,7 +657,7 @@ follow_debuglink_build_id(const char *build_id, size_t build_id_size, int num_tr
     o2 = *objp;
     o2->base_addr = o1->base_addr;
     o2->path = o1->path;
-    fill_lines(num_traces, traces, 0, objp, lines, offset);
+    fill_lines(num_traces, traces, 0, objp, lines, offset, errout);
 }
 #endif
 
@@ -807,7 +861,11 @@ enum
     DW_FORM_addrx1 = 0x29,
     DW_FORM_addrx2 = 0x2a,
     DW_FORM_addrx3 = 0x2b,
-    DW_FORM_addrx4 = 0x2c
+    DW_FORM_addrx4 = 0x2c,
+
+    /* GNU extensions for referring to .gnu_debugaltlink dwz-compressed info */
+    DW_FORM_GNU_ref_alt = 0x1f20,
+    DW_FORM_GNU_strp_alt = 0x1f21
 };
 
 /* Range list entry encodings */
@@ -827,16 +885,23 @@ enum {
     VAL_cstr = 1,
     VAL_data = 2,
     VAL_uint = 3,
-    VAL_int = 4
+    VAL_int = 4,
+    VAL_addr = 5
 };
 
 # define ABBREV_TABLE_SIZE 256
 typedef struct {
     obj_info_t *obj;
     const char *file;
+    uint8_t current_version;
     const char *current_cu;
     uint64_t current_low_pc;
+    uint64_t current_str_offsets_base;
+    uint64_t current_addr_base;
+    uint64_t current_rnglists_base;
     const char *debug_line_cu_end;
+    uint8_t debug_line_format;
+    uint16_t debug_line_version;
     const char *debug_line_files;
     const char *debug_line_directories;
     const char *p;
@@ -861,6 +926,7 @@ typedef struct {
         const char *ptr;
         uint64_t uint64;
         int64_t int64;
+        uint64_t addr_idx;
     } as;
     uint64_t off;
     uint64_t at;
@@ -869,8 +935,11 @@ typedef struct {
     int type;
 } DebugInfoValue;
 
-/* TODO: Big Endian */
+#if defined(WORDS_BIGENDIAN)
+#define MERGE_2INTS(a,b,sz) (((uint64_t)(a)<<sz)|(b))
+#else
 #define MERGE_2INTS(a,b,sz) (((uint64_t)(b)<<sz)|(a))
+#endif
 
 static uint16_t
 get_uint16(const uint8_t *p)
@@ -973,6 +1042,9 @@ debug_info_reader_init(DebugInfoReader *reader, obj_info_t *obj)
     reader->pend = obj->debug_info.ptr + obj->debug_info.size;
     reader->debug_line_cu_end = obj->debug_line.ptr;
     reader->current_low_pc = 0;
+    reader->current_str_offsets_base = 0;
+    reader->current_addr_base = 0;
+    reader->current_rnglists_base = 0;
 }
 
 static void
@@ -1011,16 +1083,18 @@ di_read_debug_abbrev_cu(DebugInfoReader *reader)
 }
 
 static int
-di_read_debug_line_cu(DebugInfoReader *reader)
+di_read_debug_line_cu(DebugInfoReader *reader, FILE *errout)
 {
     const char *p;
     struct LineNumberProgramHeader header;
 
     p = (const char *)reader->debug_line_cu_end;
-    if (parse_debug_line_header(&p, &header))
+    if (parse_debug_line_header(reader->obj, &p, &header, errout))
         return -1;
 
     reader->debug_line_cu_end = (char *)header.cu_end;
+    reader->debug_line_format = header.format;
+    reader->debug_line_version = header.version;
     reader->debug_line_directories = (char *)header.include_directories;
     reader->debug_line_files = (char *)header.filenames;
 
@@ -1028,6 +1102,13 @@ di_read_debug_line_cu(DebugInfoReader *reader)
 }
 
 static void
+set_addr_idx_value(DebugInfoValue *v, uint64_t n)
+{
+    v->as.addr_idx = n;
+    v->type = VAL_addr;
+}
+
+static void
 set_uint_value(DebugInfoValue *v, uint64_t n)
 {
     v->as.uint64 = n;
@@ -1074,19 +1155,46 @@ get_cstr_value(DebugInfoValue *v)
     }
 }
 
-static void
-debug_info_reader_read_value(DebugInfoReader *reader, uint64_t form, DebugInfoValue *v)
+static const char *
+resolve_strx(DebugInfoReader *reader, uint64_t idx)
+{
+    const char *p = reader->obj->debug_str_offsets.ptr + reader->current_str_offsets_base;
+    uint64_t off;
+    if (reader->format == 4) {
+        off = ((uint32_t *)p)[idx];
+    }
+    else {
+        off = ((uint64_t *)p)[idx];
+    }
+    return reader->obj->debug_str.ptr + off;
+}
+
+static bool
+debug_info_reader_read_addr_value_member(DebugInfoReader *reader, DebugInfoValue *v, int size)
+{
+    if (size == 4) {
+        set_uint_value(v, read_uint32(&reader->p));
+    } else if (size == 8) {
+        set_uint_value(v, read_uint64(&reader->p));
+    } else {
+        return false;
+    }
+    return true;
+}
+
+#define debug_info_reader_read_addr_value(reader, v, mem) \
+    if (!debug_info_reader_read_addr_value_member((reader), (v), (reader)->mem)) { \
+        kprintf("unknown " #mem ":%d", (reader)->mem); \
+        return false; \
+    }
+
+
+static bool
+debug_info_reader_read_value(DebugInfoReader *reader, uint64_t form, DebugInfoValue *v, FILE *errout)
 {
     switch (form) {
       case DW_FORM_addr:
-        if (reader->address_size == 4) {
-            set_uint_value(v, read_uint32(&reader->p));
-        } else if (reader->address_size == 8) {
-            set_uint_value(v, read_uint64(&reader->p));
-        } else {
-            fprintf(stderr,"unknown address_size:%d", reader->address_size);
-            abort();
-        }
+        debug_info_reader_read_addr_value(reader, v, address_size);
         break;
       case DW_FORM_block2:
         v->size = read_uint16(&reader->p);
@@ -1138,13 +1246,12 @@ debug_info_reader_read_value(DebugInfoReader *reader, uint64_t form, DebugInfoVa
         set_uint_value(v, read_uleb128(reader));
         break;
       case DW_FORM_ref_addr:
-        if (reader->format == 4) {
-            set_uint_value(v, read_uint32(&reader->p));
-        } else if (reader->format == 8) {
-            set_uint_value(v, read_uint64(&reader->p));
+        if (reader->current_version <= 2) {
+            // DWARF Version 2 specifies that references have
+            // the same size as an address on the target system
+            debug_info_reader_read_addr_value(reader, v, address_size);
         } else {
-            fprintf(stderr,"unknown format:%d", reader->format);
-            abort();
+            debug_info_reader_read_addr_value(reader, v, format);
         }
         break;
       case DW_FORM_ref1:
@@ -1186,11 +1293,10 @@ debug_info_reader_read_value(DebugInfoReader *reader, uint64_t form, DebugInfoVa
         set_uint_value(v, 1);
         break;
       case DW_FORM_strx:
-        set_uint_value(v, uleb128(&reader->p));
+        set_cstr_value(v, resolve_strx(reader, uleb128(&reader->p)));
         break;
       case DW_FORM_addrx:
-        /* TODO: read .debug_addr */
-        set_uint_value(v, uleb128(&reader->p));
+        set_addr_idx_value(v, uleb128(&reader->p));
         break;
       case DW_FORM_ref_sup4:
         set_uint_value(v, read_uint32(&reader->p));
@@ -1205,8 +1311,7 @@ debug_info_reader_read_value(DebugInfoReader *reader, uint64_t form, DebugInfoVa
         reader->p += v->size;
         break;
       case DW_FORM_line_strp:
-        set_uint_value(v, read_uint(reader));
-        /* *p = reader->file + reader->line->sh_offset + ret; */
+        set_cstrp_value(v, reader->obj->debug_line_str.ptr, read_uint(reader));
         break;
       case DW_FORM_ref_sig8:
         set_uint_value(v, read_uint64(&reader->p));
@@ -1224,43 +1329,51 @@ debug_info_reader_read_value(DebugInfoReader *reader, uint64_t form, DebugInfoVa
         set_uint_value(v, read_uint64(&reader->p));
         break;
       case DW_FORM_strx1:
-        set_uint_value(v, read_uint8(&reader->p));
+        set_cstr_value(v, resolve_strx(reader, read_uint8(&reader->p)));
         break;
       case DW_FORM_strx2:
-        set_uint_value(v, read_uint16(&reader->p));
+        set_cstr_value(v, resolve_strx(reader, read_uint16(&reader->p)));
         break;
       case DW_FORM_strx3:
-        set_uint_value(v, read_uint24(&reader->p));
+        set_cstr_value(v, resolve_strx(reader, read_uint24(&reader->p)));
         break;
       case DW_FORM_strx4:
-        set_uint_value(v, read_uint32(&reader->p));
+        set_cstr_value(v, resolve_strx(reader, read_uint32(&reader->p)));
         break;
       case DW_FORM_addrx1:
-        set_uint_value(v, read_uint8(&reader->p));
+        set_addr_idx_value(v, read_uint8(&reader->p));
         break;
       case DW_FORM_addrx2:
-        set_uint_value(v, read_uint16(&reader->p));
+        set_addr_idx_value(v, read_uint16(&reader->p));
         break;
       case DW_FORM_addrx3:
-        set_uint_value(v, read_uint24(&reader->p));
+        set_addr_idx_value(v, read_uint24(&reader->p));
         break;
       case DW_FORM_addrx4:
-        set_uint_value(v, read_uint32(&reader->p));
+        set_addr_idx_value(v, read_uint32(&reader->p));
+        break;
+      /* we have no support for actually reading the real values of these refs out
+       * of the .gnu_debugaltlink dwz-compressed debuginfo at the moment, but "read"
+       * them anyway so that we advance the reader by the right amount. */
+      case DW_FORM_GNU_ref_alt:
+      case DW_FORM_GNU_strp_alt:
+        read_uint(reader);
+        set_uint_value(v, 0);
         break;
       case 0:
         goto fail;
         break;
     }
-    return;
+    return true;
 
   fail:
-    fprintf(stderr, "%d: unsupported form: %#"PRIx64"\n", __LINE__, form);
-    exit(1);
+    kprintf("%d: unsupported form: %#"PRIx64"\n", __LINE__, form);
+    return false;
 }
 
 /* find abbrev in current compilation unit */
 static const char *
-di_find_abbrev(DebugInfoReader *reader, uint64_t abbrev_number)
+di_find_abbrev(DebugInfoReader *reader, uint64_t abbrev_number, FILE *errout)
 {
     const char *p;
     if (abbrev_number < ABBREV_TABLE_SIZE) {
@@ -1273,8 +1386,8 @@ di_find_abbrev(DebugInfoReader *reader, uint64_t abbrev_number)
     di_skip_die_attributes(&p);
     for (uint64_t n = uleb128(&p); abbrev_number != n; n = uleb128(&p)) {
         if (n == 0) {
-            fprintf(stderr,"%d: Abbrev Number %"PRId64" not found\n",__LINE__, abbrev_number);
-            exit(1);
+            kprintf("%d: Abbrev Number %"PRId64" not found\n",__LINE__, abbrev_number);
+            return NULL;
         }
         uleb128(&p); /* tag */
         p++; /* has_children */
@@ -1285,52 +1398,52 @@ di_find_abbrev(DebugInfoReader *reader, uint64_t abbrev_number)
 
 #if 0
 static void
-hexdump0(const unsigned char *p, size_t n)
+hexdump0(const unsigned char *p, size_t n, FILE *errout)
 {
     size_t i;
-    fprintf(stderr, "     0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F\n");
+    kprintf("     0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F\n");
     for (i=0; i < n; i++){
         switch (i & 15) {
           case 0:
-            fprintf(stderr, "%02zd: %02X ", i/16, p[i]);
+            kprintf("%02" PRIdSIZE ": %02X ", i/16, p[i]);
             break;
           case 15:
-            fprintf(stderr, "%02X\n", p[i]);
+            kprintf("%02X\n", p[i]);
             break;
           default:
-            fprintf(stderr, "%02X ", p[i]);
+            kprintf("%02X ", p[i]);
             break;
         }
     }
     if ((i & 15) != 15) {
-        fprintf(stderr, "\n");
+        kprintf("\n");
     }
 }
-#define hexdump(p,n) hexdump0((const unsigned char *)p, n)
+#define hexdump(p,n,e) hexdump0((const unsigned char *)p, n, e)
 
 static void
-div_inspect(DebugInfoValue *v)
+div_inspect(DebugInfoValue *v, FILE *errout)
 {
     switch (v->type) {
       case VAL_uint:
-        fprintf(stderr,"%d: type:%d size:%zx v:%"PRIx64"\n",__LINE__,v->type,v->size,v->as.uint64);
+        kprintf("%d: type:%d size:%" PRIxSIZE " v:%"PRIx64"\n",__LINE__,v->type,v->size,v->as.uint64);
         break;
       case VAL_int:
-        fprintf(stderr,"%d: type:%d size:%zx v:%"PRId64"\n",__LINE__,v->type,v->size,(int64_t)v->as.uint64);
+        kprintf("%d: type:%d size:%" PRIxSIZE " v:%"PRId64"\n",__LINE__,v->type,v->size,(int64_t)v->as.uint64);
         break;
       case VAL_cstr:
-        fprintf(stderr,"%d: type:%d size:%zx v:'%s'\n",__LINE__,v->type,v->size,v->as.ptr);
+        kprintf("%d: type:%d size:%" PRIxSIZE " v:'%s'\n",__LINE__,v->type,v->size,v->as.ptr);
         break;
       case VAL_data:
-        fprintf(stderr,"%d: type:%d size:%zx v:\n",__LINE__,v->type,v->size);
-        hexdump(v->as.ptr, 16);
+        kprintf("%d: type:%d size:%" PRIxSIZE " v:\n",__LINE__,v->type,v->size);
+        hexdump(v->as.ptr, 16, errout);
         break;
     }
 }
 #endif
 
 static DIE *
-di_read_die(DebugInfoReader *reader, DIE *die)
+di_read_die(DebugInfoReader *reader, DIE *die, FILE *errout)
 {
     uint64_t abbrev_number = uleb128(&reader->p);
     if (abbrev_number == 0) {
@@ -1338,7 +1451,7 @@ di_read_die(DebugInfoReader *reader, DIE *die)
         return NULL;
     }
 
-    reader->q = di_find_abbrev(reader, abbrev_number);
+    if (!(reader->q = di_find_abbrev(reader, abbrev_number, errout))) return NULL;
 
     die->pos = reader->p - reader->obj->debug_info.ptr - 1;
     die->tag = (int)uleb128(&reader->q); /* tag */
@@ -1350,27 +1463,109 @@ di_read_die(DebugInfoReader *reader, DIE *die)
 }
 
 static DebugInfoValue *
-di_read_record(DebugInfoReader *reader, DebugInfoValue *vp)
+di_read_record(DebugInfoReader *reader, DebugInfoValue *vp, FILE *errout)
 {
     uint64_t at = uleb128(&reader->q);
     uint64_t form = uleb128(&reader->q);
     if (!at || !form) return NULL;
     vp->at = at;
     vp->form = form;
-    debug_info_reader_read_value(reader, form, vp);
+    if (!debug_info_reader_read_value(reader, form, vp, errout)) return NULL;
     return vp;
 }
 
-static void
-di_skip_records(DebugInfoReader *reader)
+static bool
+di_skip_records(DebugInfoReader *reader, FILE *errout)
 {
     for (;;) {
-        DebugInfoValue v = {{}};
+        DebugInfoValue v = {{0}};
         uint64_t at = uleb128(&reader->q);
         uint64_t form = uleb128(&reader->q);
-        if (!at || !form) return;
-        debug_info_reader_read_value(reader, form, &v);
+        if (!at || !form) return true;
+        if (!debug_info_reader_read_value(reader, form, &v, errout)) return false;
+    }
+}
+
+typedef struct addr_header {
+    const char *ptr;
+    uint64_t unit_length;
+    uint8_t format;
+    uint8_t address_size;
+    /* uint8_t segment_selector_size; */
+} addr_header_t;
+
+static bool
+addr_header_init(obj_info_t *obj, addr_header_t *header, FILE *errout)
+{
+    const char *p = obj->debug_addr.ptr;
+
+    header->ptr = p;
+
+    if (!p) return true;
+
+    header->unit_length = *(uint32_t *)p;
+    p += sizeof(uint32_t);
+
+    header->format = 4;
+    if (header->unit_length == 0xffffffff) {
+        header->unit_length = *(uint64_t *)p;
+        p += sizeof(uint64_t);
+        header->format = 8;
+    }
+
+    p += 2; /* version */
+    header->address_size = *p++;
+    if (header->address_size != 4 && header->address_size != 8) {
+        kprintf("unknown address_size:%d", header->address_size);
+        return false;
+    }
+    p++; /* segment_selector_size */
+    return true;
+}
+
+static uint64_t
+read_addr(addr_header_t *header, uint64_t addr_base, uint64_t idx) {
+    if (header->address_size == 4) {
+        return ((uint32_t*)(header->ptr + addr_base))[idx];
+    }
+    else {
+        return ((uint64_t*)(header->ptr + addr_base))[idx];
+    }
+}
+
+typedef struct rnglists_header {
+    uint64_t unit_length;
+    uint8_t format;
+    uint8_t address_size;
+    uint32_t offset_entry_count;
+} rnglists_header_t;
+
+static bool
+rnglists_header_init(obj_info_t *obj, rnglists_header_t *header, FILE *errout)
+{
+    const char *p = obj->debug_rnglists.ptr;
+
+    if (!p) return true;
+
+    header->unit_length = *(uint32_t *)p;
+    p += sizeof(uint32_t);
+
+    header->format = 4;
+    if (header->unit_length == 0xffffffff) {
+        header->unit_length = *(uint64_t *)p;
+        p += sizeof(uint64_t);
+        header->format = 8;
+    }
+
+    p += 2; /* version */
+    header->address_size = *p++;
+    if (header->address_size != 4 && header->address_size != 8) {
+        kprintf("unknown address_size:%d", header->address_size);
+        return false;
     }
+    p++; /* segment_selector_size */
+    header->offset_entry_count = *(uint32_t *)p;
+    return true;
 }
 
 typedef struct {
@@ -1383,50 +1578,54 @@ typedef struct {
 } ranges_t;
 
 static void
-ranges_set(ranges_t *ptr, DebugInfoValue *v)
+ranges_set(ranges_t *ptr, DebugInfoValue *v, addr_header_t *addr_header, uint64_t addr_base)
 {
+    uint64_t n = 0;
+    if (v->type == VAL_uint) {
+        n = v->as.uint64;
+    }
+    else if (v->type == VAL_addr) {
+        n = read_addr(addr_header, addr_base, v->as.addr_idx);
+    }
     switch (v->at) {
       case DW_AT_low_pc:
-        ptr->low_pc = v->as.uint64;
+        ptr->low_pc = n;
         ptr->low_pc_set = true;
         break;
       case DW_AT_high_pc:
         if (v->form == DW_FORM_addr) {
-            ptr->high_pc = v->as.uint64;
+            ptr->high_pc = n;
         }
         else {
-            ptr->high_pc = ptr->low_pc + v->as.uint64;
+            ptr->high_pc = ptr->low_pc + n;
         }
         ptr->high_pc_set = true;
         break;
       case DW_AT_ranges:
-        ptr->ranges = v->as.uint64;
+        ptr->ranges = n;
         ptr->ranges_set = true;
         break;
     }
 }
 
 static uint64_t
-read_dw_form_addr(DebugInfoReader *reader, const char **ptr)
+read_dw_form_addr(DebugInfoReader *reader, const char **ptr, FILE *errout)
 {
     const char *p = *ptr;
     *ptr = p + reader->address_size;
     if (reader->address_size == 4) {
         return read_uint32(&p);
-    } else if (reader->address_size == 8) {
-        return read_uint64(&p);
     } else {
-        fprintf(stderr,"unknown address_size:%d", reader->address_size);
-        abort();
+        return read_uint64(&p);
     }
 }
 
 static uintptr_t
-ranges_include(DebugInfoReader *reader, ranges_t *ptr, uint64_t addr)
+ranges_include(DebugInfoReader *reader, ranges_t *ptr, uint64_t addr, rnglists_header_t *rnglists_header, FILE *errout)
 {
     if (ptr->high_pc_set) {
         if (ptr->ranges_set || !ptr->low_pc_set) {
-            exit(1);
+            return UINTPTR_MAX;
         }
         if (ptr->low_pc <= addr && addr <= ptr->high_pc) {
             return (uintptr_t)ptr->low_pc;
@@ -1437,8 +1636,21 @@ ranges_include(DebugInfoReader *reader, ranges_t *ptr, uint64_t addr)
         const char *p;
         uint64_t base = ptr->low_pc_set ? ptr->low_pc : reader->current_low_pc;
         bool base_valid = true;
-        if (reader->obj->debug_rnglists.ptr) {
-            p = reader->obj->debug_rnglists.ptr + ptr->ranges;
+        if (reader->current_version >= 5) {
+            if (rnglists_header->offset_entry_count == 0) {
+                // DW_FORM_sec_offset
+                p = reader->obj->debug_rnglists.ptr + ptr->ranges + reader->current_rnglists_base;
+            }
+            else {
+                // DW_FORM_rnglistx
+                const char *offset_array = reader->obj->debug_rnglists.ptr + reader->current_rnglists_base;
+                if (rnglists_header->format == 4) {
+                    p = offset_array + ((uint32_t *)offset_array)[ptr->ranges];
+                }
+                else {
+                    p = offset_array + ((uint64_t *)offset_array)[ptr->ranges];
+                }
+            }
             for (;;) {
                 uint8_t rle = read_uint8(&p);
                 uintptr_t from = 0, to = 0;
@@ -1462,15 +1674,15 @@ ranges_include(DebugInfoReader *reader, ranges_t *ptr, uint64_t addr)
                     to = (uintptr_t)base + uleb128(&p);
                     break;
                   case DW_RLE_base_address:
-                    base = read_dw_form_addr(reader, &p);
+                    base = read_dw_form_addr(reader, &p, errout);
                     base_valid = true;
                     break;
                   case DW_RLE_start_end:
-                    from = (uintptr_t)read_dw_form_addr(reader, &p);
-                    to = (uintptr_t)read_dw_form_addr(reader, &p);
+                    from = (uintptr_t)read_dw_form_addr(reader, &p, errout);
+                    to = (uintptr_t)read_dw_form_addr(reader, &p, errout);
                     break;
                   case DW_RLE_start_length:
-                    from = (uintptr_t)read_dw_form_addr(reader, &p);
+                    from = (uintptr_t)read_dw_form_addr(reader, &p, errout);
                     to = from + uleb128(&p);
                     break;
                 }
@@ -1478,7 +1690,7 @@ ranges_include(DebugInfoReader *reader, ranges_t *ptr, uint64_t addr)
                     return from;
                 }
             }
-            return false;
+            return 0;
         }
         p = reader->obj->debug_ranges.ptr + ptr->ranges;
         for (;;) {
@@ -1499,42 +1711,42 @@ ranges_include(DebugInfoReader *reader, ranges_t *ptr, uint64_t addr)
             return (uintptr_t)ptr->low_pc;
         }
     }
-    return false;
+    return 0;
 }
 
 #if 0
 static void
-ranges_inspect(DebugInfoReader *reader, ranges_t *ptr)
+ranges_inspect(DebugInfoReader *reader, ranges_t *ptr, FILE *errout)
 {
     if (ptr->high_pc_set) {
         if (ptr->ranges_set || !ptr->low_pc_set) {
-            fprintf(stderr,"low_pc_set:%d high_pc_set:%d ranges_set:%d\n",ptr->low_pc_set,ptr->high_pc_set,ptr->ranges_set);
-            exit(1);
+            kprintf("low_pc_set:%d high_pc_set:%d ranges_set:%d\n",ptr->low_pc_set,ptr->high_pc_set,ptr->ranges_set);
+            return;
         }
-        fprintf(stderr,"low_pc:%"PRIx64" high_pc:%"PRIx64"\n",ptr->low_pc,ptr->high_pc);
+        kprintf("low_pc:%"PRIx64" high_pc:%"PRIx64"\n",ptr->low_pc,ptr->high_pc);
     }
     else if (ptr->ranges_set) {
         char *p = reader->obj->debug_ranges.ptr + ptr->ranges;
-        fprintf(stderr,"low_pc:%"PRIx64" ranges:%"PRIx64" %lx ",ptr->low_pc,ptr->ranges, p-reader->obj->mapped);
+        kprintf("low_pc:%"PRIx64" ranges:%"PRIx64" %lx ",ptr->low_pc,ptr->ranges, p-reader->obj->mapped);
         for (;;) {
             uintptr_t from = read_uintptr(&p);
             uintptr_t to = read_uintptr(&p);
             if (!from && !to) break;
-            fprintf(stderr,"%"PRIx64"-%"PRIx64" ",ptr->low_pc+from,ptr->low_pc+to);
+            kprintf("%"PRIx64"-%"PRIx64" ",ptr->low_pc+from,ptr->low_pc+to);
         }
-        fprintf(stderr,"\n");
+        kprintf("\n");
     }
     else if (ptr->low_pc_set) {
-        fprintf(stderr,"low_pc:%"PRIx64"\n",ptr->low_pc);
+        kprintf("low_pc:%"PRIx64"\n",ptr->low_pc);
     }
     else {
-        fprintf(stderr,"empty\n");
+        kprintf("empty\n");
     }
 }
 #endif
 
 static int
-di_read_cu(DebugInfoReader *reader)
+di_read_cu(DebugInfoReader *reader, FILE *errout)
 {
     uint64_t unit_length;
     uint16_t version;
@@ -1548,6 +1760,7 @@ di_read_cu(DebugInfoReader *reader)
     }
     reader->cu_end = reader->p + unit_length;
     version = read_uint16(&reader->p);
+    reader->current_version = version;
     if (version > 5) {
         return -1;
     }
@@ -1560,43 +1773,72 @@ di_read_cu(DebugInfoReader *reader)
         debug_abbrev_offset = read_uint(reader);
         reader->address_size = read_uint8(&reader->p);
     }
+    if (reader->address_size != 4 && reader->address_size != 8) {
+        kprintf("unknown address_size:%d", reader->address_size);
+        return -1;
+    }
     reader->q0 = reader->obj->debug_abbrev.ptr + debug_abbrev_offset;
 
     reader->level = 0;
     di_read_debug_abbrev_cu(reader);
-    if (di_read_debug_line_cu(reader)) return -1;
+    if (di_read_debug_line_cu(reader, errout)) return -1;
 
-#if defined(__GNUC__) && !defined(__clang__) && !defined(__INTEL_COMPILER_BUILD_DATE)
-    /* Though DWARF specifies "the applicable base address defaults to the base
-       address of the compilation unit", but GCC seems to use zero as default */
-#else
     do {
         DIE die;
 
-        if (!di_read_die(reader, &die)) continue;
+        if (!di_read_die(reader, &die, errout)) continue;
 
         if (die.tag != DW_TAG_compile_unit) {
-            di_skip_records(reader);
+            if (!di_skip_records(reader, errout)) return -1;
             break;
         }
 
+        reader->current_str_offsets_base = 0;
+        reader->current_addr_base = 0;
+        reader->current_rnglists_base = 0;
+
+        DebugInfoValue low_pc = {{0}};
         /* enumerate abbrev */
         for (;;) {
-            DebugInfoValue v = {{}};
-            if (!di_read_record(reader, &v)) break;
+            DebugInfoValue v = {{0}};
+            if (!di_read_record(reader, &v, errout)) break;
             switch (v.at) {
               case DW_AT_low_pc:
-                reader->current_low_pc = v.as.uint64;
+                // clang may output DW_AT_addr_base after DW_AT_low_pc.
+                // We need to resolve the DW_FORM_addr* after DW_AT_addr_base is parsed.
+                low_pc = v;
+                break;
+              case DW_AT_str_offsets_base:
+                reader->current_str_offsets_base = v.as.uint64;
+                break;
+              case DW_AT_addr_base:
+                reader->current_addr_base = v.as.uint64;
+                break;
+              case DW_AT_rnglists_base:
+                reader->current_rnglists_base = v.as.uint64;
                 break;
             }
         }
+        // Resolve the DW_FORM_addr of DW_AT_low_pc
+        switch (low_pc.type) {
+            case VAL_uint:
+                reader->current_low_pc = low_pc.as.uint64;
+                break;
+            case VAL_addr:
+                {
+                    addr_header_t header = {0};
+                    if (!addr_header_init(reader->obj, &header, errout)) return -1;
+                    reader->current_low_pc = read_addr(&header, reader->current_addr_base, low_pc.as.addr_idx);
+                }
+                break;
+        }
     } while (0);
-#endif
+
     return 0;
 }
 
 static void
-read_abstract_origin(DebugInfoReader *reader, uint64_t form, uint64_t abstract_origin, line_info_t *line)
+read_abstract_origin(DebugInfoReader *reader, uint64_t form, uint64_t abstract_origin, line_info_t *line, FILE *errout)
 {
     const char *p = reader->p;
     const char *q = reader->q;
@@ -1621,12 +1863,12 @@ read_abstract_origin(DebugInfoReader *reader, uint64_t form, uint64_t abstract_o
       default:
         goto finish;
     }
-    if (!di_read_die(reader, &die)) goto finish;
+    if (!di_read_die(reader, &die, errout)) goto finish;
 
     /* enumerate abbrev */
     for (;;) {
-        DebugInfoValue v = {{}};
-        if (!di_read_record(reader, &v)) break;
+        DebugInfoValue v = {{0}};
+        if (!di_read_record(reader, &v, errout)) break;
         switch (v.at) {
           case DW_AT_name:
             line->sname = get_cstr_value(&v);
@@ -1640,36 +1882,44 @@ read_abstract_origin(DebugInfoReader *reader, uint64_t form, uint64_t abstract_o
     reader->level = level;
 }
 
-static void
+static bool
 debug_info_read(DebugInfoReader *reader, int num_traces, void **traces,
-         line_info_t *lines, int offset) {
+                line_info_t *lines, int offset, FILE *errout)
+{
+
+    addr_header_t addr_header = {0};
+    if (!addr_header_init(reader->obj, &addr_header, errout)) return false;
+
+    rnglists_header_t rnglists_header = {0};
+    if (!rnglists_header_init(reader->obj, &rnglists_header, errout)) return false;
+
     while (reader->p < reader->cu_end) {
         DIE die;
-        ranges_t ranges = {};
-        line_info_t line = {};
+        ranges_t ranges = {0};
+        line_info_t line = {0};
 
-        if (!di_read_die(reader, &die)) continue;
-        /* fprintf(stderr,"%d:%tx: <%d>\n",__LINE__,die.pos,reader->level,die.tag); */
+        if (!di_read_die(reader, &die, errout)) continue;
+        /* kprintf("%d:%tx: <%d>\n",__LINE__,die.pos,reader->level,die.tag); */
 
         if (die.tag != DW_TAG_subprogram && die.tag != DW_TAG_inlined_subroutine) {
           skip_die:
-            di_skip_records(reader);
+            if (!di_skip_records(reader, errout)) return false;
             continue;
         }
 
         /* enumerate abbrev */
         for (;;) {
-            DebugInfoValue v = {{}};
+            DebugInfoValue v = {{0}};
             /* ptrdiff_t pos = reader->p - reader->p0; */
-            if (!di_read_record(reader, &v)) break;
-            /* fprintf(stderr,"\n%d:%tx: AT:%lx FORM:%lx\n",__LINE__,pos,v.at,v.form); */
-            /* div_inspect(&v); */
+            if (!di_read_record(reader, &v, errout)) break;
+            /* kprintf("\n%d:%tx: AT:%lx FORM:%lx\n",__LINE__,pos,v.at,v.form); */
+            /* div_inspect(&v, errout); */
             switch (v.at) {
               case DW_AT_name:
                 line.sname = get_cstr_value(&v);
                 break;
               case DW_AT_call_file:
-                fill_filename((int)v.as.uint64, reader->debug_line_directories, reader->debug_line_files, &line, reader->obj);
+                fill_filename((int)v.as.uint64, reader->debug_line_format, reader->debug_line_version, reader->debug_line_directories, reader->debug_line_files, &line, reader->obj, errout);
                 break;
               case DW_AT_call_line:
                 line.line = (int)v.as.uint64;
@@ -1677,7 +1927,7 @@ debug_info_read(DebugInfoReader *reader, int num_traces, void **traces,
               case DW_AT_low_pc:
               case DW_AT_high_pc:
               case DW_AT_ranges:
-                ranges_set(&ranges, &v);
+                ranges_set(&ranges, &v, &addr_header, reader->current_addr_base);
                 break;
               case DW_AT_declaration:
                 goto skip_die;
@@ -1685,18 +1935,19 @@ debug_info_read(DebugInfoReader *reader, int num_traces, void **traces,
                 /* 1 or 3 */
                 break; /* goto skip_die; */
               case DW_AT_abstract_origin:
-                read_abstract_origin(reader, v.form, v.as.uint64, &line);
+                read_abstract_origin(reader, v.form, v.as.uint64, &line, errout);
                 break; /* goto skip_die; */
             }
         }
-        /* ranges_inspect(reader, &ranges); */
-        /* fprintf(stderr,"%d:%tx: %x ",__LINE__,diepos,die.tag); */
+        /* ranges_inspect(reader, &ranges, errout); */
+        /* kprintf("%d:%tx: %x ",__LINE__,diepos,die.tag); */
         for (int i=offset; i < num_traces; i++) {
             uintptr_t addr = (uintptr_t)traces[i];
             uintptr_t offset = addr - reader->obj->base_addr + reader->obj->vmaddr;
-            uintptr_t saddr = ranges_include(reader, &ranges, offset);
+            uintptr_t saddr = ranges_include(reader, &ranges, offset, &rnglists_header, errout);
+            if (saddr == UINTPTR_MAX) return false;
             if (saddr) {
-                /* fprintf(stderr, "%d:%tx: %d %lx->%lx %x %s: %s/%s %d %s %s %s\n",__LINE__,die.pos, i,addr,offset, die.tag,line.sname,line.dirname,line.filename,line.line,reader->obj->path,line.sname,lines[i].sname); */
+                /* kprintf("%d:%tx: %d %lx->%lx %x %s: %s/%s %d %s %s %s\n",__LINE__,die.pos, i,addr,offset, die.tag,line.sname,line.dirname,line.filename,line.line,reader->obj->path,line.sname,lines[i].sname); */
                 if (lines[i].sname) {
                     line_info_t *lp = malloc(sizeof(line_info_t));
                     memcpy(lp, &lines[i], sizeof(line_info_t));
@@ -1713,6 +1964,58 @@ debug_info_read(DebugInfoReader *reader, int num_traces, void **traces,
             }
         }
     }
+    return true;
+}
+
+// This function parses the following attributes of Line Number Program Header in DWARF 5:
+//
+// * directory_entry_format_count
+// * directory_entry_format
+// * directories_count
+// * directories
+//
+// or
+//
+// * file_name_entry_format_count
+// * file_name_entry_format
+// * file_names_count
+// * file_names
+//
+// It records DW_LNCT_path and DW_LNCT_directory_index at the index "idx".
+static const char *
+parse_ver5_debug_line_header(const char *p, int idx, uint8_t format,
+                             obj_info_t *obj, const char **out_path,
+                             uint64_t *out_directory_index, FILE *errout)
+{
+    int i, j;
+    int entry_format_count = *(uint8_t *)p++;
+    const char *entry_format = p;
+
+    /* skip the part of entry_format */
+    for (i = 0; i < entry_format_count * 2; i++) uleb128(&p);
+
+    int entry_count = (int)uleb128(&p);
+
+    DebugInfoReader reader = {0};
+    debug_info_reader_init(&reader, obj);
+    reader.format = format;
+    reader.p = p;
+    for (j = 0; j < entry_count; j++) {
+        const char *format = entry_format;
+        for (i = 0; i < entry_format_count; i++) {
+            DebugInfoValue v = {{0}};
+            unsigned long dw_lnct = uleb128(&format);
+            unsigned long dw_form = uleb128(&format);
+            if (!debug_info_reader_read_value(&reader, dw_form, &v, errout)) return 0;
+            if (dw_lnct == 1 /* DW_LNCT_path */ && v.type == VAL_cstr && out_path)
+                *out_path = v.as.ptr + v.off;
+            if (dw_lnct == 2 /* DW_LNCT_directory_index */ && v.type == VAL_uint && out_directory_index)
+                *out_directory_index = v.as.uint64;
+        }
+        if (j == idx) return 0;
+    }
+
+    return reader.p;
 }
 
 #ifdef USE_ELF
@@ -1726,14 +2029,14 @@ uncompress_debug_section(ElfW(Shdr) *shdr, char *file, char **ptr)
     int ret = 0;
 
     if (chdr->ch_type != ELFCOMPRESS_ZLIB) {
-	/* unsupported compression type */
-	return 0;
+        /* unsupported compression type */
+        return 0;
     }
 
     *ptr = malloc(destsize);
     if (!*ptr) return 0;
     ret = uncompress((Bytef *)*ptr, &destsize,
-	    (const Bytef*)chdr + sizeof(ElfW(Chdr)),
+            (const Bytef*)chdr + sizeof(ElfW(Chdr)),
             shdr->sh_size - sizeof(ElfW(Chdr)));
     if (ret != Z_OK) goto fail;
     return destsize;
@@ -1748,7 +2051,7 @@ fail:
 /* read file and fill lines */
 static uintptr_t
 fill_lines(int num_traces, void **traces, int check_debuglink,
-	   obj_info_t **objp, line_info_t *lines, int offset)
+           obj_info_t **objp, line_info_t *lines, int offset, FILE *errout)
 {
     int i, j;
     char *shstr;
@@ -1766,40 +2069,40 @@ fill_lines(int num_traces, void **traces, int check_debuglink,
 
     fd = open(binary_filename, O_RDONLY);
     if (fd < 0) {
-	goto fail;
+        goto fail;
     }
     filesize = lseek(fd, 0, SEEK_END);
     if (filesize < 0) {
-	int e = errno;
-	close(fd);
-	kprintf("lseek: %s\n", strerror(e));
-	goto fail;
+        int e = errno;
+        close(fd);
+        kprintf("lseek: %s\n", strerror(e));
+        goto fail;
     }
 #if SIZEOF_OFF_T > SIZEOF_SIZE_T
     if (filesize > (off_t)SIZE_MAX) {
-	close(fd);
-	kprintf("Too large file %s\n", binary_filename);
-	goto fail;
+        close(fd);
+        kprintf("Too large file %s\n", binary_filename);
+        goto fail;
     }
 #endif
     lseek(fd, 0, SEEK_SET);
     /* async-signal unsafe */
     file = (char *)mmap(NULL, (size_t)filesize, PROT_READ, MAP_SHARED, fd, 0);
     if (file == MAP_FAILED) {
-	int e = errno;
-	close(fd);
-	kprintf("mmap: %s\n", strerror(e));
-	goto fail;
+        int e = errno;
+        close(fd);
+        kprintf("mmap: %s\n", strerror(e));
+        goto fail;
     }
     close(fd);
 
     ehdr = (ElfW(Ehdr) *)file;
     if (memcmp(ehdr->e_ident, "\177ELF", 4) != 0) {
-	/*
-	 * Huh? Maybe filename was overridden by setproctitle() and
-	 * it match non-elf file.
-	 */
-	goto fail;
+        /*
+         * Huh? Maybe filename was overridden by setproctitle() and
+         * it match non-elf file.
+         */
+        goto fail;
     }
     obj->mapped = file;
     obj->mapped_size = (size_t)filesize;
@@ -1811,40 +2114,43 @@ fill_lines(int num_traces, void **traces, int check_debuglink,
 
     for (i = 0; i < ehdr->e_shnum; i++) {
         char *section_name = shstr + shdr[i].sh_name;
-	switch (shdr[i].sh_type) {
-	  case SHT_STRTAB:
-	    if (!strcmp(section_name, ".strtab")) {
-		strtab_shdr = shdr + i;
-	    }
-	    else if (!strcmp(section_name, ".dynstr")) {
-		dynstr_shdr = shdr + i;
-	    }
-	    break;
-	  case SHT_SYMTAB:
-	    /* if (!strcmp(section_name, ".symtab")) */
-	    symtab_shdr = shdr + i;
-	    break;
-	  case SHT_DYNSYM:
-	    /* if (!strcmp(section_name, ".dynsym")) */
-	    dynsym_shdr = shdr + i;
-	    break;
+        switch (shdr[i].sh_type) {
+          case SHT_STRTAB:
+            if (!strcmp(section_name, ".strtab")) {
+                strtab_shdr = shdr + i;
+            }
+            else if (!strcmp(section_name, ".dynstr")) {
+                dynstr_shdr = shdr + i;
+            }
+            break;
+          case SHT_SYMTAB:
+            /* if (!strcmp(section_name, ".symtab")) */
+            symtab_shdr = shdr + i;
+            break;
+          case SHT_DYNSYM:
+            /* if (!strcmp(section_name, ".dynsym")) */
+            dynsym_shdr = shdr + i;
+            break;
           case SHT_NOTE:
             if (!strcmp(section_name, ".note.gnu.build-id")) {
                 note_gnu_build_id = shdr + i;
             }
             break;
-	  case SHT_PROGBITS:
-	    if (!strcmp(section_name, ".gnu_debuglink")) {
-		gnu_debuglink_shdr = shdr + i;
-	    }
+          case SHT_PROGBITS:
+            if (!strcmp(section_name, ".gnu_debuglink")) {
+                gnu_debuglink_shdr = shdr + i;
+            }
             else {
                 const char *debug_section_names[] = {
                     ".debug_abbrev",
                     ".debug_info",
                     ".debug_line",
                     ".debug_ranges",
+                    ".debug_str_offsets",
+                    ".debug_addr",
                     ".debug_rnglists",
-                    ".debug_str"
+                    ".debug_str",
+                    ".debug_line_str"
                 };
 
                 for (j=0; j < DWARF_SECTION_COUNT; j++) {
@@ -1863,17 +2169,17 @@ fill_lines(int num_traces, void **traces, int check_debuglink,
                     break;
                 }
             }
-	    break;
-	}
+            break;
+        }
     }
 
     if (offset == -1) {
-	/* main executable */
-	offset = 0;
-	if (dynsym_shdr && dynstr_shdr) {
-	    char *strtab = file + dynstr_shdr->sh_offset;
-	    ElfW(Sym) *symtab = (ElfW(Sym) *)(file + dynsym_shdr->sh_offset);
-	    int symtab_count = (int)(dynsym_shdr->sh_size / sizeof(ElfW(Sym)));
+        /* main executable */
+        offset = 0;
+        if (dynsym_shdr && dynstr_shdr) {
+            char *strtab = file + dynstr_shdr->sh_offset;
+            ElfW(Sym) *symtab = (ElfW(Sym) *)(file + dynsym_shdr->sh_offset);
+            int symtab_count = (int)(dynsym_shdr->sh_size / sizeof(ElfW(Sym)));
             void *handle = dlopen(NULL, RTLD_NOW|RTLD_LOCAL);
             if (handle) {
                 for (j = 0; j < symtab_count; j++) {
@@ -1890,14 +2196,14 @@ fill_lines(int num_traces, void **traces, int check_debuglink,
                 }
                 dlclose(handle);
             }
-	    if (ehdr->e_type == ET_EXEC) {
-		obj->base_addr = 0;
-	    }
-	    else {
-		/* PIE (position-independent executable) */
-		obj->base_addr = dladdr_fbase;
-	    }
-	}
+            if (ehdr->e_type == ET_EXEC) {
+                obj->base_addr = 0;
+            }
+            else {
+                /* PIE (position-independent executable) */
+                obj->base_addr = dladdr_fbase;
+            }
+        }
     }
 
     if (obj->debug_info.ptr && obj->debug_abbrev.ptr) {
@@ -1905,9 +2211,10 @@ fill_lines(int num_traces, void **traces, int check_debuglink,
         debug_info_reader_init(&reader, obj);
         i = 0;
         while (reader.p < reader.pend) {
-            /* fprintf(stderr, "%d:%tx: CU[%d]\n", __LINE__, reader.p - reader.obj->debug_info.ptr, i++); */
-            if (di_read_cu(&reader)) goto use_symtab;
-            debug_info_read(&reader, num_traces, traces, lines, offset);
+            /* kprintf("%d:%tx: CU[%d]\n", __LINE__, reader.p - reader.obj->debug_info.ptr, i++); */
+            if (di_read_cu(&reader, errout)) goto use_symtab;
+            if (!debug_info_read(&reader, num_traces, traces, lines, offset, errout))
+                goto use_symtab;
         }
     }
     else {
@@ -1942,27 +2249,27 @@ use_symtab:
     }
 
     if (!obj->debug_line.ptr) {
-	/* This file doesn't have .debug_line section,
-	   let's check .gnu_debuglink section instead. */
-	if (gnu_debuglink_shdr && check_debuglink) {
-	    follow_debuglink(file + gnu_debuglink_shdr->sh_offset,
-			     num_traces, traces,
-			     objp, lines, offset);
-	}
+        /* This file doesn't have .debug_line section,
+           let's check .gnu_debuglink section instead. */
+        if (gnu_debuglink_shdr && check_debuglink) {
+            follow_debuglink(file + gnu_debuglink_shdr->sh_offset,
+                             num_traces, traces,
+                             objp, lines, offset, errout);
+        }
         if (note_gnu_build_id && check_debuglink) {
             ElfW(Nhdr) *nhdr = (ElfW(Nhdr)*) (file + note_gnu_build_id->sh_offset);
             const char *build_id = (char *)(nhdr + 1) + nhdr->n_namesz;
             follow_debuglink_build_id(build_id, nhdr->n_descsz,
-			       num_traces, traces,
-			       objp, lines, offset);
+                               num_traces, traces,
+                               objp, lines, offset, errout);
         }
-	goto finish;
+        goto finish;
     }
 
     if (parse_debug_line(num_traces, traces,
             obj->debug_line.ptr,
             obj->debug_line.size,
-            obj, lines, offset) == -1)
+            obj, lines, offset, errout) == -1)
         goto fail;
 
 finish:
@@ -1974,7 +2281,7 @@ fail:
 /* read file and fill lines */
 static uintptr_t
 fill_lines(int num_traces, void **traces, int check_debuglink,
-        obj_info_t **objp, line_info_t *lines, int offset)
+        obj_info_t **objp, line_info_t *lines, int offset, FILE *errout)
 {
 # ifdef __LP64__
 #  define LP(x) x##_64
@@ -2053,13 +2360,13 @@ fill_lines(int num_traces, void **traces, int check_debuglink,
         struct fat_header *fat = (struct fat_header *)file;
         char *q = file + sizeof(*fat);
         uint32_t nfat_arch = __builtin_bswap32(fat->nfat_arch);
-        /* fprintf(stderr,"%d: fat:%s %d\n",__LINE__, binary_filename,nfat_arch); */
+        /* kprintf("%d: fat:%s %d\n",__LINE__, binary_filename,nfat_arch); */
         for (uint32_t i = 0; i < nfat_arch; i++) {
             struct fat_arch *arch = (struct fat_arch *)q;
             cpu_type_t cputype = __builtin_bswap32(arch->cputype);
             cpu_subtype_t cpusubtype = __builtin_bswap32(arch->cpusubtype);
             uint32_t offset = __builtin_bswap32(arch->offset);
-            /* fprintf(stderr,"%d: fat %d %x/%x %x/%x\n",__LINE__, i, mhp->cputype,mhp->cpusubtype, cputype,cpusubtype); */
+            /* kprintf("%d: fat %d %x/%x %x/%x\n",__LINE__, i, mhp->cputype,mhp->cpusubtype, cputype,cpusubtype); */
             if (mhp->cputype == cputype &&
                     (cpu_subtype_t)(mhp->cpusubtype & ~CPU_SUBTYPE_MASK) == cpusubtype) {
                 p = file + offset;
@@ -2077,13 +2384,14 @@ fill_lines(int num_traces, void **traces, int check_debuglink,
         goto fail;
     }
     else {
-        kprintf("'%s' is not a "
 # ifdef __LP64__
-                "64"
+#   define bitsize "64"
 # else
-                "32"
+#   define bitsize "32"
 # endif
+        kprintf("'%s' is not a " bitsize
                 "-bit Mach-O file!\n",binary_filename);
+# undef bitsize
         close(fd);
         goto fail;
     }
@@ -2100,8 +2408,11 @@ found_mach_header:
                     "__debug_info",
                     "__debug_line",
                     "__debug_ranges",
+                    "__debug_str_offsets",
+                    "__debug_addr",
                     "__debug_rnglists",
-                    "__debug_str"
+                    "__debug_str",
+                    "__debug_line_str",
                 };
                 struct LP(segment_command) *scmd = (struct LP(segment_command) *)lcmd;
                 if (strcmp(scmd->segname, "__TEXT") == 0) {
@@ -2115,7 +2426,17 @@ found_mach_header:
                         for (int j=0; j < DWARF_SECTION_COUNT; j++) {
                             struct dwarf_section *s = obj_dwarf_section_at(obj, j);
 
-                            if (strcmp(sect->sectname, debug_section_names[j]) != 0)
+                            if (strcmp(sect->sectname, debug_section_names[j]) != 0
+#ifdef __APPLE__
+                                    /* macOS clang 16 generates DWARF5, which have Mach-O
+                                     * section names that are limited to 16 characters,
+                                     * which causes sections with long names to be truncated
+                                     * and not match above.
+                                     * See: https://wiki.dwarfstd.org/Best_Practices.md#Mach-2d-O
+                                     */
+                                    && strncmp(sect->sectname, debug_section_names[j], 16) != 0
+#endif
+                                )
                                 continue;
 
                             s->ptr = file + sect->offset;
@@ -2172,15 +2493,16 @@ found_mach_header:
         DebugInfoReader reader;
         debug_info_reader_init(&reader, obj);
         while (reader.p < reader.pend) {
-            if (di_read_cu(&reader)) goto fail;
-            debug_info_read(&reader, num_traces, traces, lines, offset);
+            if (di_read_cu(&reader, errout)) goto fail;
+            if (!debug_info_read(&reader, num_traces, traces, lines, offset, errout))
+                goto fail;
         }
     }
 
     if (parse_debug_line(num_traces, traces,
             obj->debug_line.ptr,
             obj->debug_line.size,
-            obj, lines, offset) == -1)
+            obj, lines, offset, errout) == -1)
         goto fail;
 
     return dladdr_fbase;
@@ -2193,7 +2515,7 @@ fail:
 #if defined(__FreeBSD__) || defined(__DragonFly__)
 # include <sys/sysctl.h>
 #endif
-/* ssize_t main_exe_path(void)
+/* ssize_t main_exe_path(FILE *errout)
  *
  * store the path of the main executable to `binary_filename`,
  * and returns strlen(binary_filename).
@@ -2201,7 +2523,7 @@ fail:
  */
 #if defined(__linux__) || defined(__NetBSD__)
 static ssize_t
-main_exe_path(void)
+main_exe_path(FILE *errout)
 {
 # if defined(__linux__)
 #  define PROC_SELF_EXE "/proc/self/exe"
@@ -2215,21 +2537,21 @@ main_exe_path(void)
 }
 #elif defined(__FreeBSD__) || defined(__DragonFly__)
 static ssize_t
-main_exe_path(void)
+main_exe_path(FILE *errout)
 {
     int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
     size_t len = PATH_MAX;
     int err = sysctl(mib, 4, binary_filename, &len, NULL, 0);
     if (err) {
-	kprintf("Can't get the path of ruby");
-	return -1;
+        kprintf("Can't get the path of ruby");
+        return -1;
     }
     len--; /* sysctl sets strlen+1 */
     return len;
 }
 #elif defined(HAVE_LIBPROC_H)
 static ssize_t
-main_exe_path(void)
+main_exe_path(FILE *errout)
 {
     int len = proc_pidpath(getpid(), binary_filename, PATH_MAX);
     if (len == 0) return 0;
@@ -2241,7 +2563,7 @@ main_exe_path(void)
 #endif
 
 static void
-print_line0(line_info_t *line, void *address)
+print_line0(line_info_t *line, void *address, FILE *errout)
 {
     uintptr_t addr = (uintptr_t)address;
     uintptr_t d = addr - line->saddr;
@@ -2257,9 +2579,12 @@ print_line0(line_info_t *line, void *address)
     else if (!line->path) {
         kprintf("[0x%"PRIxPTR"]\n", addr);
     }
-    else if (!line->saddr || !line->sname) {
+    else if (!line->sname) {
         kprintf("%s(0x%"PRIxPTR") [0x%"PRIxPTR"]\n", line->path, addr-line->base_addr, addr);
     }
+    else if (!line->saddr) {
+        kprintf("%s(%s) [0x%"PRIxPTR"]\n", line->path, line->sname, addr);
+    }
     else if (line->line <= 0) {
         kprintf("%s(%s+0x%"PRIxPTR") [0x%"PRIxPTR"]\n", line->path, line->sname,
                 d, addr);
@@ -2279,16 +2604,16 @@ print_line0(line_info_t *line, void *address)
 }
 
 static void
-print_line(line_info_t *line, void *address)
+print_line(line_info_t *line, void *address, FILE *errout)
 {
-    print_line0(line, address);
+    print_line0(line, address, errout);
     if (line->next) {
-        print_line(line->next, NULL);
+        print_line(line->next, NULL, errout);
     }
 }
 
 void
-rb_dump_backtrace_with_lines(int num_traces, void **traces)
+rb_dump_backtrace_with_lines(int num_traces, void **traces, FILE *errout)
 {
     int i;
     /* async-signal unsafe */
@@ -2296,81 +2621,84 @@ rb_dump_backtrace_with_lines(int num_traces, void **traces)
     obj_info_t *obj = NULL;
     /* 2 is NULL + main executable */
     void **dladdr_fbases = (void **)calloc(num_traces+2, sizeof(void *));
+
 #ifdef HAVE_MAIN_EXE_PATH
     char *main_path = NULL; /* used on printing backtrace */
     ssize_t len;
-    if ((len = main_exe_path()) > 0) {
-	main_path = (char *)alloca(len + 1);
-	if (main_path) {
-	    uintptr_t addr;
-	    memcpy(main_path, binary_filename, len+1);
-	    append_obj(&obj);
-	    obj->path = main_path;
-	    addr = fill_lines(num_traces, traces, 1, &obj, lines, -1);
-	    if (addr != (uintptr_t)-1) {
-		dladdr_fbases[0] = (void *)addr;
-	    }
-	}
+    if ((len = main_exe_path(errout)) > 0) {
+        main_path = (char *)alloca(len + 1);
+        if (main_path) {
+            uintptr_t addr;
+            memcpy(main_path, binary_filename, len+1);
+            append_obj(&obj);
+            obj->path = main_path;
+            addr = fill_lines(num_traces, traces, 1, &obj, lines, 0, errout);
+            if (addr != (uintptr_t)-1) {
+                dladdr_fbases[0] = (void *)addr;
+            }
+        }
     }
 #endif
 
     /* fill source lines by reading dwarf */
     for (i = 0; i < num_traces; i++) {
-	Dl_info info;
-	if (lines[i].line) continue;
-	if (dladdr(traces[i], &info)) {
-	    const char *path;
-	    void **p;
-
-	    /* skip symbols which is in already checked objects */
-	    /* if the binary is strip-ed, this may effect */
-	    for (p=dladdr_fbases; *p; p++) {
-		if (*p == info.dli_fbase) {
-		    lines[i].path = info.dli_fname;
-		    lines[i].sname = info.dli_sname;
-		    goto next_line;
-		}
-	    }
-	    *p = info.dli_fbase;
-
-	    append_obj(&obj);
-	    obj->base_addr = (uintptr_t)info.dli_fbase;
-	    path = info.dli_fname;
-	    obj->path = path;
-	    lines[i].path = path;
-            lines[i].sname = info.dli_sname;
-            lines[i].saddr = (uintptr_t)info.dli_saddr;
-	    strlcpy(binary_filename, path, PATH_MAX);
-	    if (fill_lines(num_traces, traces, 1, &obj, lines, i) == (uintptr_t)-1)
-		break;
-	}
+        Dl_info info;
+        if (lines[i].line) continue;
+        if (dladdr(traces[i], &info)) {
+            const char *path;
+            void **p;
+
+            /* skip symbols which is in already checked objects */
+            /* if the binary is strip-ed, this may effect */
+            for (p=dladdr_fbases; *p; p++) {
+                if (*p == info.dli_fbase) {
+                    if (info.dli_fname) lines[i].path = info.dli_fname;
+                    if (info.dli_sname) lines[i].sname = info.dli_sname;
+                    goto next_line;
+                }
+            }
+            *p = info.dli_fbase;
+
+            append_obj(&obj);
+            obj->base_addr = (uintptr_t)info.dli_fbase;
+            path = info.dli_fname;
+            obj->path = path;
+            if (path) lines[i].path = path;
+            if (info.dli_sname) {
+                lines[i].sname = info.dli_sname;
+                lines[i].saddr = (uintptr_t)info.dli_saddr;
+            }
+            strlcpy(binary_filename, path, PATH_MAX);
+            if (fill_lines(num_traces, traces, 1, &obj, lines, i, errout) == (uintptr_t)-1)
+                break;
+        }
 next_line:
-	continue;
+        continue;
     }
 
     /* output */
     for (i = 0; i < num_traces; i++) {
-        print_line(&lines[i], traces[i]);
+        print_line(&lines[i], traces[i], errout);
 
-	/* FreeBSD's backtrace may show _start and so on */
-	if (lines[i].sname && strcmp("main", lines[i].sname) == 0)
-	    break;
+        /* FreeBSD's backtrace may show _start and so on */
+        if (lines[i].sname && strcmp("main", lines[i].sname) == 0)
+            break;
     }
 
     /* free */
     while (obj) {
-	obj_info_t *o = obj;
+        obj_info_t *o = obj;
         for (i=0; i < DWARF_SECTION_COUNT; i++) {
             struct dwarf_section *s = obj_dwarf_section_at(obj, i);
             if (s->flags & SHF_COMPRESSED) {
                 free(s->ptr);
             }
         }
-	if (obj->mapped_size) {
-	    munmap(obj->mapped, obj->mapped_size);
-	}
-	obj = o->next;
-	free(o);
+        if (obj->mapped_size) {
+            munmap(obj->mapped, obj->mapped_size);
+        }
+        obj = o->next;
+        free(o);
     }
     for (i = 0; i < num_traces; i++) {
         line_info_t *line = lines[i].next;
@@ -2384,435 +2712,8 @@ next_line:
     free(dladdr_fbases);
 }
 
-/* From FreeBSD's lib/libstand/printf.c */
-/*-
- * Copyright (c) 1986, 1988, 1991, 1993
- *	The Regents of the University of California.  All rights reserved.
- * (c) UNIX System Laboratories, Inc.
- * All or some portions of this file are derived from material licensed
- * to the University of California by American Telephone and Telegraph
- * Co. or Unix System Laboratories, Inc. and are reproduced herein with
- * the permission of UNIX System Laboratories, Inc.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- * 4. Neither the name of the University nor the names of its contributors
- *    may be used to endorse or promote products derived from this software
- *    without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- *	@(#)subr_prf.c	8.3 (Berkeley) 1/21/94
- */
-
-#include <stdarg.h>
-#define MAXNBUF (sizeof(intmax_t) * CHAR_BIT + 1)
-static inline int toupper(int c) { return ('A' <= c && c <= 'Z') ? (c&0x5f) : c; }
-#define    hex2ascii(hex)  (hex2ascii_data[hex])
-static const char hex2ascii_data[] = "0123456789abcdefghijklmnopqrstuvwxyz";
-static inline int imax(int a, int b) { return (a > b ? a : b); }
-static int kvprintf(char const *fmt, void (*func)(int), void *arg, int radix, va_list ap);
-
-static void putce(int c)
-{
-    char s[1];
-    ssize_t ret;
-
-    s[0] = (char)c;
-    ret = write(2, s, 1);
-    (void)ret;
-}
-
-static int
-kprintf(const char *fmt, ...)
-{
-	va_list ap;
-	int retval;
-
-	va_start(ap, fmt);
-	retval = kvprintf(fmt, putce, NULL, 10, ap);
-	va_end(ap);
-	return retval;
-}
-
-/*
- * Put a NUL-terminated ASCII number (base <= 36) in a buffer in reverse
- * order; return an optional length and a pointer to the last character
- * written in the buffer (i.e., the first character of the string).
- * The buffer pointed to by `nbuf' must have length >= MAXNBUF.
- */
-static char *
-ksprintn(char *nbuf, uintmax_t num, int base, int *lenp, int upper)
-{
-	char *p, c;
-
-	p = nbuf;
-	*p = '\0';
-	do {
-		c = hex2ascii(num % base);
-		*++p = upper ? toupper(c) : c;
-	} while (num /= base);
-	if (lenp)
-		*lenp = (int)(p - nbuf);
-	return (p);
-}
+#undef kprintf
 
-/*
- * Scaled down version of printf(3).
- *
- * Two additional formats:
- *
- * The format %b is supported to decode error registers.
- * Its usage is:
- *
- *	printf("reg=%b\n", regval, "<base><arg>*");
- *
- * where <base> is the output base expressed as a control character, e.g.
- * \10 gives octal; \20 gives hex.  Each arg is a sequence of characters,
- * the first of which gives the bit number to be inspected (origin 1), and
- * the next characters (up to a control character, i.e. a character <= 32),
- * give the name of the register.  Thus:
- *
- *	kvprintf("reg=%b\n", 3, "\10\2BITTWO\1BITONE\n");
- *
- * would produce output:
- *
- *	reg=3<BITTWO,BITONE>
- *
- * XXX:  %D  -- Hexdump, takes pointer and separator string:
- *		("%6D", ptr, ":")   -> XX:XX:XX:XX:XX:XX
- *		("%*D", len, ptr, " " -> XX XX XX XX ...
- */
-static int
-kvprintf(char const *fmt, void (*func)(int), void *arg, int radix, va_list ap)
-{
-#define PCHAR(c) {int cc=(c); if (func) (*func)(cc); else *d++ = cc; retval++; }
-	char nbuf[MAXNBUF];
-	char *d;
-	const char *p, *percent, *q;
-	unsigned char *up;
-	int ch, n;
-	uintmax_t num;
-	int base, lflag, qflag, tmp, width, ladjust, sharpflag, neg, sign, dot;
-	int cflag, hflag, jflag, tflag, zflag;
-	int dwidth, upper;
-	char padc;
-	int stop = 0, retval = 0;
-
-	num = 0;
-	if (!func)
-		d = (char *) arg;
-	else
-		d = NULL;
-
-	if (fmt == NULL)
-		fmt = "(fmt null)\n";
-
-	if (radix < 2 || radix > 36)
-		radix = 10;
-
-	for (;;) {
-		padc = ' ';
-		width = 0;
-		while ((ch = (unsigned char)*fmt++) != '%' || stop) {
-			if (ch == '\0')
-				return (retval);
-			PCHAR(ch);
-		}
-		percent = fmt - 1;
-		qflag = 0; lflag = 0; ladjust = 0; sharpflag = 0; neg = 0;
-		sign = 0; dot = 0; dwidth = 0; upper = 0;
-		cflag = 0; hflag = 0; jflag = 0; tflag = 0; zflag = 0;
-reswitch:	switch (ch = (unsigned char)*fmt++) {
-		case '.':
-			dot = 1;
-			goto reswitch;
-		case '#':
-			sharpflag = 1;
-			goto reswitch;
-		case '+':
-			sign = 1;
-			goto reswitch;
-		case '-':
-			ladjust = 1;
-			goto reswitch;
-		case '%':
-			PCHAR(ch);
-			break;
-		case '*':
-			if (!dot) {
-				width = va_arg(ap, int);
-				if (width < 0) {
-					ladjust = !ladjust;
-					width = -width;
-				}
-			} else {
-				dwidth = va_arg(ap, int);
-			}
-			goto reswitch;
-		case '0':
-			if (!dot) {
-				padc = '0';
-				goto reswitch;
-			}
-		case '1': case '2': case '3': case '4':
-		case '5': case '6': case '7': case '8': case '9':
-				for (n = 0;; ++fmt) {
-					n = n * 10 + ch - '0';
-					ch = *fmt;
-					if (ch < '0' || ch > '9')
-						break;
-				}
-			if (dot)
-				dwidth = n;
-			else
-				width = n;
-			goto reswitch;
-		case 'b':
-			num = (unsigned int)va_arg(ap, int);
-			p = va_arg(ap, char *);
-			for (q = ksprintn(nbuf, num, *p++, NULL, 0); *q;)
-				PCHAR(*q--);
-
-			if (num == 0)
-				break;
-
-			for (tmp = 0; *p;) {
-				n = *p++;
-				if (num & (1 << (n - 1))) {
-					PCHAR(tmp ? ',' : '<');
-					for (; (n = *p) > ' '; ++p)
-						PCHAR(n);
-					tmp = 1;
-				} else
-					for (; *p > ' '; ++p)
-						continue;
-			}
-			if (tmp)
-				PCHAR('>');
-			break;
-		case 'c':
-			PCHAR(va_arg(ap, int));
-			break;
-		case 'D':
-			up = va_arg(ap, unsigned char *);
-			p = va_arg(ap, char *);
-			if (!width)
-				width = 16;
-			while(width--) {
-				PCHAR(hex2ascii(*up >> 4));
-				PCHAR(hex2ascii(*up & 0x0f));
-				up++;
-				if (width)
-					for (q=p;*q;q++)
-						PCHAR(*q);
-			}
-			break;
-		case 'd':
-		case 'i':
-			base = 10;
-			sign = 1;
-			goto handle_sign;
-		case 'h':
-			if (hflag) {
-				hflag = 0;
-				cflag = 1;
-			} else
-				hflag = 1;
-			goto reswitch;
-		case 'j':
-			jflag = 1;
-			goto reswitch;
-		case 'l':
-			if (lflag) {
-				lflag = 0;
-				qflag = 1;
-			} else
-				lflag = 1;
-			goto reswitch;
-		case 'n':
-			if (jflag)
-				*(va_arg(ap, intmax_t *)) = retval;
-			else if (qflag)
-				*(va_arg(ap, int64_t *)) = retval;
-			else if (lflag)
-				*(va_arg(ap, long *)) = retval;
-			else if (zflag)
-				*(va_arg(ap, size_t *)) = retval;
-			else if (hflag)
-				*(va_arg(ap, short *)) = retval;
-			else if (cflag)
-				*(va_arg(ap, char *)) = retval;
-			else
-				*(va_arg(ap, int *)) = retval;
-			break;
-		case 'o':
-			base = 8;
-			goto handle_nosign;
-		case 'p':
-			base = 16;
-			sharpflag = (width == 0);
-			sign = 0;
-			num = (uintptr_t)va_arg(ap, void *);
-			goto number;
-		case 'q':
-			qflag = 1;
-			goto reswitch;
-		case 'r':
-			base = radix;
-			if (sign)
-				goto handle_sign;
-			goto handle_nosign;
-		case 's':
-			p = va_arg(ap, char *);
-			if (p == NULL)
-				p = "(null)";
-			if (!dot)
-				n = (int)strlen (p);
-			else
-				for (n = 0; n < dwidth && p[n]; n++)
-					continue;
-
-			width -= n;
-
-			if (!ladjust && width > 0)
-				while (width--)
-					PCHAR(padc);
-			while (n--)
-				PCHAR(*p++);
-			if (ladjust && width > 0)
-				while (width--)
-					PCHAR(padc);
-			break;
-		case 't':
-			tflag = 1;
-			goto reswitch;
-		case 'u':
-			base = 10;
-			goto handle_nosign;
-		case 'X':
-			upper = 1;
-		case 'x':
-			base = 16;
-			goto handle_nosign;
-		case 'y':
-			base = 16;
-			sign = 1;
-			goto handle_sign;
-		case 'z':
-			zflag = 1;
-			goto reswitch;
-handle_nosign:
-			sign = 0;
-			if (jflag)
-				num = va_arg(ap, uintmax_t);
-			else if (qflag)
-				num = va_arg(ap, uint64_t);
-			else if (tflag)
-				num = va_arg(ap, ptrdiff_t);
-			else if (lflag)
-				num = va_arg(ap, unsigned long);
-			else if (zflag)
-				num = va_arg(ap, size_t);
-			else if (hflag)
-				num = (unsigned short)va_arg(ap, int);
-			else if (cflag)
-				num = (unsigned char)va_arg(ap, int);
-			else
-				num = va_arg(ap, unsigned int);
-			goto number;
-handle_sign:
-			if (jflag)
-				num = va_arg(ap, intmax_t);
-			else if (qflag)
-				num = va_arg(ap, int64_t);
-			else if (tflag)
-				num = va_arg(ap, ptrdiff_t);
-			else if (lflag)
-				num = va_arg(ap, long);
-			else if (zflag)
-				num = va_arg(ap, ssize_t);
-			else if (hflag)
-				num = (short)va_arg(ap, int);
-			else if (cflag)
-				num = (char)va_arg(ap, int);
-			else
-				num = va_arg(ap, int);
-number:
-			if (sign && (intmax_t)num < 0) {
-				neg = 1;
-				num = -(intmax_t)num;
-			}
-			p = ksprintn(nbuf, num, base, &n, upper);
-			tmp = 0;
-			if (sharpflag && num != 0) {
-				if (base == 8)
-					tmp++;
-				else if (base == 16)
-					tmp += 2;
-			}
-			if (neg)
-				tmp++;
-
-			if (!ladjust && padc == '0')
-				dwidth = width - tmp;
-			width -= tmp + imax(dwidth, n);
-			dwidth -= n;
-			if (!ladjust)
-				while (width-- > 0)
-					PCHAR(' ');
-			if (neg)
-				PCHAR('-');
-			if (sharpflag && num != 0) {
-				if (base == 8) {
-					PCHAR('0');
-				} else if (base == 16) {
-					PCHAR('0');
-					PCHAR('x');
-				}
-			}
-			while (dwidth-- > 0)
-				PCHAR('0');
-
-			while (*p)
-				PCHAR(*p--);
-
-			if (ladjust)
-				while (width-- > 0)
-					PCHAR(' ');
-
-			break;
-		default:
-			while (percent < fmt)
-				PCHAR(*percent++);
-			/*
-			 * Since we ignore an formatting argument it is no
-			 * longer safe to obey the remaining formatting
-			 * arguments as the arguments will no longer match
-			 * the format specs.
-			 */
-			stop = 1;
-			break;
-		}
-	}
-#undef PCHAR
-}
 #else /* defined(USE_ELF) */
 #error not supported
 #endif
diff --git a/addr2line.h b/addr2line.h
index f09b665800..ff8e476b92 100644
--- a/addr2line.h
+++ b/addr2line.h
@@ -12,8 +12,10 @@
 
 #if (defined(USE_ELF) || defined(HAVE_MACH_O_LOADER_H))
 
+#include <stdio.h>
+
 void
-rb_dump_backtrace_with_lines(int num_traces, void **traces);
+rb_dump_backtrace_with_lines(int num_traces, void **traces, FILE *errout);
 
 #endif /* USE_ELF */
 
diff --git a/array.c b/array.c
index 8f79761b7b..5a4daf3e73 100644
--- a/array.c
+++ b/array.c
@@ -28,7 +28,7 @@
 #include "ruby/encoding.h"
 #include "ruby/st.h"
 #include "ruby/util.h"
-#include "transient_heap.h"
+#include "vm_core.h"
 #include "builtin.h"
 
 #if !ARRAY_DEBUG
@@ -38,6 +38,31 @@
 #include "ruby_assert.h"
 
 VALUE rb_cArray;
+VALUE rb_cArray_empty_frozen;
+
+/* Flags of RArray
+ *
+ * 0:   RARRAY_SHARED_FLAG (equal to ELTS_SHARED)
+ *          The array is shared. The buffer this array points to is owned by
+ *          another array (the shared root).
+ * 1:   RARRAY_EMBED_FLAG
+ *          The array is embedded (its contents follow the header, rather than
+ *          being on a separately allocated buffer).
+ * 3-9: RARRAY_EMBED_LEN
+ *          The length of the array when RARRAY_EMBED_FLAG is set.
+ * 12:  RARRAY_SHARED_ROOT_FLAG
+ *          The array is a shared root that does reference counting. The buffer
+ *          this array points to is owned by this array but may be pointed to
+ *          by other arrays.
+ *          Note: Frozen arrays may be a shared root without this flag being
+ *                set. Frozen arrays do not have reference counting because
+ *                they cannot be modified. Not updating the reference count
+ *                improves copy-on-write performance. Their reference count is
+ *                assumed to be infinity.
+ * 14:  RARRAY_PTR_IN_USE_FLAG
+ *          The buffer of the array is in use. This is only used during
+ *          debugging.
+ */
 
 /* for OPTIMIZED_CMP: */
 #define id_cmp idCmp
@@ -53,66 +78,47 @@ should_be_T_ARRAY(VALUE ary)
     return RB_TYPE_P(ary, T_ARRAY);
 }
 
-RBIMPL_ATTR_MAYBE_UNUSED()
-static int
-should_not_be_shared_and_embedded(VALUE ary)
-{
-    return !FL_TEST((ary), ELTS_SHARED) || !FL_TEST((ary), RARRAY_EMBED_FLAG);
-}
-
-#define ARY_SHARED_P(ary) \
-  (assert(should_be_T_ARRAY((VALUE)(ary))), \
-   assert(should_not_be_shared_and_embedded((VALUE)ary)), \
-   FL_TEST_RAW((ary),ELTS_SHARED)!=0)
-
-#define ARY_EMBED_P(ary) \
-  (assert(should_be_T_ARRAY((VALUE)(ary))), \
-   assert(should_not_be_shared_and_embedded((VALUE)ary)), \
-   FL_TEST_RAW((ary), RARRAY_EMBED_FLAG) != 0)
-
-#define ARY_HEAP_PTR(a) (assert(!ARY_EMBED_P(a)), RARRAY(a)->as.heap.ptr)
-#define ARY_HEAP_LEN(a) (assert(!ARY_EMBED_P(a)), RARRAY(a)->as.heap.len)
-#define ARY_HEAP_CAPA(a) (assert(!ARY_EMBED_P(a)), assert(!ARY_SHARED_ROOT_P(a)), \
+#define ARY_HEAP_PTR(a) (RUBY_ASSERT(!ARY_EMBED_P(a)), RARRAY(a)->as.heap.ptr)
+#define ARY_HEAP_LEN(a) (RUBY_ASSERT(!ARY_EMBED_P(a)), RARRAY(a)->as.heap.len)
+#define ARY_HEAP_CAPA(a) (RUBY_ASSERT(!ARY_EMBED_P(a)), RUBY_ASSERT(!ARY_SHARED_ROOT_P(a)), \
                           RARRAY(a)->as.heap.aux.capa)
 
-#define ARY_EMBED_PTR(a) (assert(ARY_EMBED_P(a)), RARRAY(a)->as.ary)
+#define ARY_EMBED_PTR(a) (RUBY_ASSERT(ARY_EMBED_P(a)), RARRAY(a)->as.ary)
 #define ARY_EMBED_LEN(a) \
-    (assert(ARY_EMBED_P(a)), \
+    (RUBY_ASSERT(ARY_EMBED_P(a)), \
      (long)((RBASIC(a)->flags >> RARRAY_EMBED_LEN_SHIFT) & \
-	 (RARRAY_EMBED_LEN_MASK >> RARRAY_EMBED_LEN_SHIFT)))
-#define ARY_HEAP_SIZE(a) (assert(!ARY_EMBED_P(a)), assert(ARY_OWNS_HEAP_P(a)), ARY_CAPA(a) * sizeof(VALUE))
+         (RARRAY_EMBED_LEN_MASK >> RARRAY_EMBED_LEN_SHIFT)))
+#define ARY_HEAP_SIZE(a) (RUBY_ASSERT(!ARY_EMBED_P(a)), RUBY_ASSERT(ARY_OWNS_HEAP_P(a)), ARY_CAPA(a) * sizeof(VALUE))
 
-#define ARY_OWNS_HEAP_P(a) (assert(should_be_T_ARRAY((VALUE)(a))), \
-                            !FL_TEST_RAW((a), ELTS_SHARED|RARRAY_EMBED_FLAG))
+#define ARY_OWNS_HEAP_P(a) (RUBY_ASSERT(should_be_T_ARRAY((VALUE)(a))), \
+                            !FL_TEST_RAW((a), RARRAY_SHARED_FLAG|RARRAY_EMBED_FLAG))
 
 #define FL_SET_EMBED(a) do { \
-    assert(!ARY_SHARED_P(a)); \
+    RUBY_ASSERT(!ARY_SHARED_P(a)); \
     FL_SET((a), RARRAY_EMBED_FLAG); \
-    RARY_TRANSIENT_UNSET(a); \
     ary_verify(a); \
 } while (0)
 
 #define FL_UNSET_EMBED(ary) FL_UNSET((ary), RARRAY_EMBED_FLAG|RARRAY_EMBED_LEN_MASK)
 #define FL_SET_SHARED(ary) do { \
-    assert(!ARY_EMBED_P(ary)); \
-    FL_SET((ary), ELTS_SHARED); \
+    RUBY_ASSERT(!ARY_EMBED_P(ary)); \
+    FL_SET((ary), RARRAY_SHARED_FLAG); \
 } while (0)
-#define FL_UNSET_SHARED(ary) FL_UNSET((ary), ELTS_SHARED)
+#define FL_UNSET_SHARED(ary) FL_UNSET((ary), RARRAY_SHARED_FLAG)
 
 #define ARY_SET_PTR(ary, p) do { \
-    assert(!ARY_EMBED_P(ary)); \
-    assert(!OBJ_FROZEN(ary)); \
+    RUBY_ASSERT(!ARY_EMBED_P(ary)); \
+    RUBY_ASSERT(!OBJ_FROZEN(ary)); \
     RARRAY(ary)->as.heap.ptr = (p); \
 } while (0)
 #define ARY_SET_EMBED_LEN(ary, n) do { \
     long tmp_n = (n); \
-    assert(ARY_EMBED_P(ary)); \
-    assert(!OBJ_FROZEN(ary)); \
+    RUBY_ASSERT(ARY_EMBED_P(ary)); \
     RBASIC(ary)->flags &= ~RARRAY_EMBED_LEN_MASK; \
     RBASIC(ary)->flags |= (tmp_n) << RARRAY_EMBED_LEN_SHIFT; \
 } while (0)
 #define ARY_SET_HEAP_LEN(ary, n) do { \
-    assert(!ARY_EMBED_P(ary)); \
+    RUBY_ASSERT(!ARY_EMBED_P(ary)); \
     RARRAY(ary)->as.heap.len = (n); \
 } while (0)
 #define ARY_SET_LEN(ary, n) do { \
@@ -122,15 +128,15 @@ should_not_be_shared_and_embedded(VALUE ary)
     else { \
         ARY_SET_HEAP_LEN((ary), (n)); \
     } \
-    assert(RARRAY_LEN(ary) == (n)); \
+    RUBY_ASSERT(RARRAY_LEN(ary) == (n)); \
 } while (0)
 #define ARY_INCREASE_PTR(ary, n) do  { \
-    assert(!ARY_EMBED_P(ary)); \
-    assert(!OBJ_FROZEN(ary)); \
+    RUBY_ASSERT(!ARY_EMBED_P(ary)); \
+    RUBY_ASSERT(!OBJ_FROZEN(ary)); \
     RARRAY(ary)->as.heap.ptr += (n); \
 } while (0)
 #define ARY_INCREASE_LEN(ary, n) do  { \
-    assert(!OBJ_FROZEN(ary)); \
+    RUBY_ASSERT(!OBJ_FROZEN(ary)); \
     if (ARY_EMBED_P(ary)) { \
         ARY_SET_EMBED_LEN((ary), RARRAY_LEN(ary)+(n)); \
     } \
@@ -142,43 +148,30 @@ should_not_be_shared_and_embedded(VALUE ary)
 #define ARY_CAPA(ary) (ARY_EMBED_P(ary) ? ary_embed_capa(ary) : \
                        ARY_SHARED_ROOT_P(ary) ? RARRAY_LEN(ary) : ARY_HEAP_CAPA(ary))
 #define ARY_SET_CAPA(ary, n) do { \
-    assert(!ARY_EMBED_P(ary)); \
-    assert(!ARY_SHARED_P(ary)); \
-    assert(!OBJ_FROZEN(ary)); \
+    RUBY_ASSERT(!ARY_EMBED_P(ary)); \
+    RUBY_ASSERT(!ARY_SHARED_P(ary)); \
+    RUBY_ASSERT(!OBJ_FROZEN(ary)); \
     RARRAY(ary)->as.heap.aux.capa = (n); \
 } while (0)
 
-#define ARY_SHARED_ROOT(ary) (assert(ARY_SHARED_P(ary)), RARRAY(ary)->as.heap.aux.shared_root)
-#define ARY_SET_SHARED(ary, value) do { \
-    const VALUE _ary_ = (ary); \
-    const VALUE _value_ = (value); \
-    assert(!ARY_EMBED_P(_ary_)); \
-    assert(ARY_SHARED_P(_ary_)); \
-    assert(ARY_SHARED_ROOT_P(_value_)); \
-    RB_OBJ_WRITE(_ary_, &RARRAY(_ary_)->as.heap.aux.shared_root, _value_); \
-} while (0)
-#define RARRAY_SHARED_ROOT_FLAG FL_USER12
-#define ARY_SHARED_ROOT_P(ary) (assert(should_be_T_ARRAY((VALUE)(ary))), \
-                                FL_TEST_RAW((ary), RARRAY_SHARED_ROOT_FLAG))
-#define ARY_SHARED_ROOT_REFCNT(ary) \
-    (assert(ARY_SHARED_ROOT_P(ary)), RARRAY(ary)->as.heap.aux.capa)
-#define ARY_SHARED_ROOT_OCCUPIED(ary) (ARY_SHARED_ROOT_REFCNT(ary) == 1)
+#define ARY_SHARED_ROOT_OCCUPIED(ary) (!OBJ_FROZEN(ary) && ARY_SHARED_ROOT_REFCNT(ary) == 1)
 #define ARY_SET_SHARED_ROOT_REFCNT(ary, value) do { \
-    assert(ARY_SHARED_ROOT_P(ary)); \
-    assert((value) >= 0); \
+    RUBY_ASSERT(ARY_SHARED_ROOT_P(ary)); \
+    RUBY_ASSERT(!OBJ_FROZEN(ary)); \
+    RUBY_ASSERT((value) >= 0); \
     RARRAY(ary)->as.heap.aux.capa = (value); \
 } while (0)
 #define FL_SET_SHARED_ROOT(ary) do { \
-    assert(!ARY_EMBED_P(ary)); \
-    assert(!RARRAY_TRANSIENT_P(ary)); \
+    RUBY_ASSERT(!OBJ_FROZEN(ary)); \
+    RUBY_ASSERT(!ARY_EMBED_P(ary)); \
     FL_SET((ary), RARRAY_SHARED_ROOT_FLAG); \
 } while (0)
 
 static inline void
 ARY_SET(VALUE a, long i, VALUE v)
 {
-    assert(!ARY_SHARED_P(a));
-    assert(!OBJ_FROZEN(a));
+    RUBY_ASSERT(!ARY_SHARED_P(a));
+    RUBY_ASSERT(!OBJ_FROZEN(a));
 
     RARRAY_ASET(a, i, v);
 }
@@ -187,13 +180,9 @@ ARY_SET(VALUE a, long i, VALUE v)
 static long
 ary_embed_capa(VALUE ary)
 {
-#if USE_RVARGC
     size_t size = rb_gc_obj_slot_size(ary) - offsetof(struct RArray, as.ary);
-    assert(size % sizeof(VALUE) == 0);
+    RUBY_ASSERT(size % sizeof(VALUE) == 0);
     return size / sizeof(VALUE);
-#else
-    return RARRAY_EMBED_LEN_MAX;
-#endif
 }
 
 static size_t
@@ -205,11 +194,38 @@ ary_embed_size(long capa)
 static bool
 ary_embeddable_p(long capa)
 {
-#if USE_RVARGC
     return rb_gc_size_allocatable_p(ary_embed_size(capa));
-#else
-    return capa <= RARRAY_EMBED_LEN_MAX;
-#endif
+}
+
+bool
+rb_ary_embeddable_p(VALUE ary)
+{
+    /* An array cannot be turned embeddable when the array is:
+     *  - Shared root: other objects may point to the buffer of this array
+     *    so we cannot make it embedded.
+     *  - Frozen: this array may also be a shared root without the shared root
+     *    flag.
+     *  - Shared: we don't want to re-embed an array that points to a shared
+     *    root (to save memory).
+     */
+    return !(ARY_SHARED_ROOT_P(ary) || OBJ_FROZEN(ary) || ARY_SHARED_P(ary));
+}
+
+size_t
+rb_ary_size_as_embedded(VALUE ary)
+{
+    size_t real_size;
+
+    if (ARY_EMBED_P(ary)) {
+        real_size = ary_embed_size(ARY_EMBED_LEN(ary));
+    }
+    else if (rb_ary_embeddable_p(ary)) {
+        real_size = ary_embed_size(ARY_HEAP_CAPA(ary));
+    }
+    else {
+        real_size = sizeof(struct RArray);
+    }
+    return real_size;
 }
 
 
@@ -219,25 +235,23 @@ ary_embeddable_p(long capa)
 static VALUE
 ary_verify_(VALUE ary, const char *file, int line)
 {
-    assert(RB_TYPE_P(ary, T_ARRAY));
+    RUBY_ASSERT(RB_TYPE_P(ary, T_ARRAY));
 
-    if (FL_TEST(ary, ELTS_SHARED)) {
-        VALUE root = RARRAY(ary)->as.heap.aux.shared_root;
+    if (ARY_SHARED_P(ary)) {
+        VALUE root = ARY_SHARED_ROOT(ary);
         const VALUE *ptr = ARY_HEAP_PTR(ary);
-        const VALUE *root_ptr = RARRAY_CONST_PTR_TRANSIENT(root);
+        const VALUE *root_ptr = RARRAY_CONST_PTR(root);
         long len = ARY_HEAP_LEN(ary), root_len = RARRAY_LEN(root);
-        assert(FL_TEST(root, RARRAY_SHARED_ROOT_FLAG));
-        assert(root_ptr <= ptr && ptr + len <= root_ptr + root_len);
+        RUBY_ASSERT(ARY_SHARED_ROOT_P(root) || OBJ_FROZEN(root));
+        RUBY_ASSERT(root_ptr <= ptr && ptr + len <= root_ptr + root_len);
         ary_verify(root);
     }
     else if (ARY_EMBED_P(ary)) {
-        assert(!RARRAY_TRANSIENT_P(ary));
-        assert(!ARY_SHARED_P(ary));
-        assert(RARRAY_LEN(ary) <= ary_embed_capa(ary));
+        RUBY_ASSERT(!ARY_SHARED_P(ary));
+        RUBY_ASSERT(RARRAY_LEN(ary) <= ary_embed_capa(ary));
     }
     else {
-#if 1
-        const VALUE *ptr = RARRAY_CONST_PTR_TRANSIENT(ary);
+        const VALUE *ptr = RARRAY_CONST_PTR(ary);
         long i, len = RARRAY_LEN(ary);
         volatile VALUE v;
         if (len > 1) len = 1; /* check only HEAD */
@@ -245,25 +259,10 @@ ary_verify_(VALUE ary, const char *file, int line)
             v = ptr[i]; /* access check */
         }
         v = v;
-#endif
-    }
-
-#if USE_TRANSIENT_HEAP
-    if (RARRAY_TRANSIENT_P(ary)) {
-        assert(rb_transient_heap_managed_ptr_p(RARRAY_CONST_PTR_TRANSIENT(ary)));
     }
-#endif
-
-    rb_transient_heap_verify();
 
     return ary;
 }
-
-void
-rb_ary_verify(VALUE ary)
-{
-    ary_verify(ary);
-}
 #else
 #define ary_verify(ary) ((void)0)
 #endif
@@ -274,7 +273,7 @@ rb_ary_ptr_use_start(VALUE ary)
 #if ARRAY_DEBUG
     FL_SET_RAW(ary, RARRAY_PTR_IN_USE_FLAG);
 #endif
-    return (VALUE *)RARRAY_CONST_PTR_TRANSIENT(ary);
+    return (VALUE *)RARRAY_CONST_PTR(ary);
 }
 
 void
@@ -289,15 +288,15 @@ void
 rb_mem_clear(VALUE *mem, long size)
 {
     while (size--) {
-	*mem++ = Qnil;
+        *mem++ = Qnil;
     }
 }
 
 static void
 ary_mem_clear(VALUE ary, long beg, long size)
 {
-    RARRAY_PTR_USE_TRANSIENT(ary, ptr, {
-	rb_mem_clear(ptr + beg, size);
+    RARRAY_PTR_USE(ary, ptr, {
+        rb_mem_clear(ptr + beg, size);
     });
 }
 
@@ -305,33 +304,33 @@ static inline void
 memfill(register VALUE *mem, register long size, register VALUE val)
 {
     while (size--) {
-	*mem++ = val;
+        *mem++ = val;
     }
 }
 
 static void
 ary_memfill(VALUE ary, long beg, long size, VALUE val)
 {
-    RARRAY_PTR_USE_TRANSIENT(ary, ptr, {
-	memfill(ptr + beg, size, val);
-	RB_OBJ_WRITTEN(ary, Qundef, val);
+    RARRAY_PTR_USE(ary, ptr, {
+        memfill(ptr + beg, size, val);
+        RB_OBJ_WRITTEN(ary, Qundef, val);
     });
 }
 
 static void
 ary_memcpy0(VALUE ary, long beg, long argc, const VALUE *argv, VALUE buff_owner_ary)
 {
-    assert(!ARY_SHARED_P(buff_owner_ary));
+    RUBY_ASSERT(!ARY_SHARED_P(buff_owner_ary));
 
     if (argc > (int)(128/sizeof(VALUE)) /* is magic number (cache line size) */) {
         rb_gc_writebarrier_remember(buff_owner_ary);
-        RARRAY_PTR_USE_TRANSIENT(ary, ptr, {
+        RARRAY_PTR_USE(ary, ptr, {
             MEMCPY(ptr+beg, argv, VALUE, argc);
         });
     }
     else {
         int i;
-        RARRAY_PTR_USE_TRANSIENT(ary, ptr, {
+        RARRAY_PTR_USE(ary, ptr, {
             for (i=0; i<argc; i++) {
                 RB_OBJ_WRITE(buff_owner_ary, &ptr[i+beg], argv[i]);
             }
@@ -346,140 +345,62 @@ ary_memcpy(VALUE ary, long beg, long argc, const VALUE *argv)
 }
 
 static VALUE *
-ary_heap_alloc(VALUE ary, size_t capa)
+ary_heap_alloc_buffer(size_t capa)
 {
-    VALUE *ptr = rb_transient_heap_alloc(ary, sizeof(VALUE) * capa);
-
-    if (ptr != NULL) {
-        RARY_TRANSIENT_SET(ary);
-    }
-    else {
-        RARY_TRANSIENT_UNSET(ary);
-        ptr = ALLOC_N(VALUE, capa);
-    }
-
-    return ptr;
+    return ALLOC_N(VALUE, capa);
 }
 
 static void
 ary_heap_free_ptr(VALUE ary, const VALUE *ptr, long size)
 {
-    if (RARRAY_TRANSIENT_P(ary)) {
-        /* ignore it */
-    }
-    else {
-        ruby_sized_xfree((void *)ptr, size);
-    }
+    ruby_sized_xfree((void *)ptr, size);
 }
 
 static void
 ary_heap_free(VALUE ary)
 {
-    if (RARRAY_TRANSIENT_P(ary)) {
-        RARY_TRANSIENT_UNSET(ary);
-    }
-    else {
-        ary_heap_free_ptr(ary, ARY_HEAP_PTR(ary), ARY_HEAP_SIZE(ary));
-    }
+    ary_heap_free_ptr(ary, ARY_HEAP_PTR(ary), ARY_HEAP_SIZE(ary));
 }
 
 static size_t
 ary_heap_realloc(VALUE ary, size_t new_capa)
 {
-    size_t alloc_capa = new_capa;
-    size_t old_capa = ARY_HEAP_CAPA(ary);
-
-    if (RARRAY_TRANSIENT_P(ary)) {
-        if (new_capa <= old_capa) {
-            /* do nothing */
-            alloc_capa = old_capa;
-        }
-        else {
-            VALUE *new_ptr = rb_transient_heap_alloc(ary, sizeof(VALUE) * new_capa);
-
-            if (new_ptr == NULL) {
-                new_ptr = ALLOC_N(VALUE, new_capa);
-                RARY_TRANSIENT_UNSET(ary);
-            }
-
-            MEMCPY(new_ptr, ARY_HEAP_PTR(ary), VALUE, old_capa);
-            ARY_SET_PTR(ary, new_ptr);
-        }
-    }
-    else {
-        SIZED_REALLOC_N(RARRAY(ary)->as.heap.ptr, VALUE, new_capa, old_capa);
-    }
+    RUBY_ASSERT(!OBJ_FROZEN(ary));
+    SIZED_REALLOC_N(RARRAY(ary)->as.heap.ptr, VALUE, new_capa, ARY_HEAP_CAPA(ary));
     ary_verify(ary);
 
-    return alloc_capa;
+    return new_capa;
 }
 
-#if USE_TRANSIENT_HEAP
-static inline void
-rb_ary_transient_heap_evacuate_(VALUE ary, int transient, int promote)
+void
+rb_ary_make_embedded(VALUE ary)
 {
-    if (transient) {
-        VALUE *new_ptr;
-        const VALUE *old_ptr = ARY_HEAP_PTR(ary);
-        long capa = ARY_HEAP_CAPA(ary);
-        long len  = ARY_HEAP_LEN(ary);
+    RUBY_ASSERT(rb_ary_embeddable_p(ary));
+    if (!ARY_EMBED_P(ary)) {
+        const VALUE *buf = ARY_HEAP_PTR(ary);
+        long len = ARY_HEAP_LEN(ary);
 
-        if (ARY_SHARED_ROOT_P(ary)) {
-            capa = len;
-        }
-
-        assert(ARY_OWNS_HEAP_P(ary));
-        assert(RARRAY_TRANSIENT_P(ary));
-        assert(!ARY_PTR_USING_P(ary));
+        FL_SET_EMBED(ary);
+        ARY_SET_EMBED_LEN(ary, len);
 
-        if (promote) {
-            new_ptr = ALLOC_N(VALUE, capa);
-            RARY_TRANSIENT_UNSET(ary);
-        }
-        else {
-            new_ptr = ary_heap_alloc(ary, capa);
-        }
+        MEMCPY((void *)ARY_EMBED_PTR(ary), (void *)buf, VALUE, len);
 
-        MEMCPY(new_ptr, old_ptr, VALUE, capa);
-        /* do not use ARY_SET_PTR() because they assert !frozen */
-        RARRAY(ary)->as.heap.ptr = new_ptr;
+        ary_heap_free_ptr(ary, buf, len * sizeof(VALUE));
     }
-
-    ary_verify(ary);
-}
-
-void
-rb_ary_transient_heap_evacuate(VALUE ary, int promote)
-{
-    rb_ary_transient_heap_evacuate_(ary, RARRAY_TRANSIENT_P(ary), promote);
 }
 
-void
-rb_ary_detransient(VALUE ary)
-{
-    assert(RARRAY_TRANSIENT_P(ary));
-    rb_ary_transient_heap_evacuate_(ary, TRUE, TRUE);
-}
-#else
-void
-rb_ary_detransient(VALUE ary)
-{
-    /* do nothing */
-}
-#endif
-
 static void
 ary_resize_capa(VALUE ary, long capacity)
 {
-    assert(RARRAY_LEN(ary) <= capacity);
-    assert(!OBJ_FROZEN(ary));
-    assert(!ARY_SHARED_P(ary));
+    RUBY_ASSERT(RARRAY_LEN(ary) <= capacity);
+    RUBY_ASSERT(!OBJ_FROZEN(ary));
+    RUBY_ASSERT(!ARY_SHARED_P(ary));
 
     if (capacity > ary_embed_capa(ary)) {
         size_t new_capa = capacity;
         if (ARY_EMBED_P(ary)) {
             long len = ARY_EMBED_LEN(ary);
-            VALUE *ptr = ary_heap_alloc(ary, capacity);
+            VALUE *ptr = ary_heap_alloc_buffer(capacity);
 
             MEMCPY(ptr, ARY_EMBED_PTR(ary), VALUE, len);
             FL_UNSET_EMBED(ary);
@@ -514,9 +435,12 @@ ary_shrink_capa(VALUE ary)
 {
     long capacity = ARY_HEAP_LEN(ary);
     long old_capa = ARY_HEAP_CAPA(ary);
-    assert(!ARY_SHARED_P(ary));
-    assert(old_capa >= capacity);
-    if (old_capa > capacity) ary_heap_realloc(ary, capacity);
+    RUBY_ASSERT(!ARY_SHARED_P(ary));
+    RUBY_ASSERT(old_capa >= capacity);
+    if (old_capa > capacity) {
+        size_t new_capa = ary_heap_realloc(ary, capacity);
+        ARY_SET_CAPA(ary, new_capa);
+    }
 
     ary_verify(ary);
 }
@@ -527,10 +451,10 @@ ary_double_capa(VALUE ary, long min)
     long new_capa = ARY_CAPA(ary) / 2;
 
     if (new_capa < ARY_DEFAULT_SIZE) {
-	new_capa = ARY_DEFAULT_SIZE;
+        new_capa = ARY_DEFAULT_SIZE;
     }
     if (new_capa >= ARY_MAX_SIZE - min) {
-	new_capa = (ARY_MAX_SIZE - min) / 2;
+        new_capa = (ARY_MAX_SIZE - min) / 2;
     }
     new_capa += min;
     ary_resize_capa(ary, new_capa);
@@ -541,14 +465,16 @@ ary_double_capa(VALUE ary, long min)
 static void
 rb_ary_decrement_share(VALUE shared_root)
 {
-    long num = ARY_SHARED_ROOT_REFCNT(shared_root);
-    ARY_SET_SHARED_ROOT_REFCNT(shared_root, num - 1);
+    if (!OBJ_FROZEN(shared_root)) {
+        long num = ARY_SHARED_ROOT_REFCNT(shared_root);
+        ARY_SET_SHARED_ROOT_REFCNT(shared_root, num - 1);
+    }
 }
 
 static void
 rb_ary_unshare(VALUE ary)
 {
-    VALUE shared_root = RARRAY(ary)->as.heap.aux.shared_root;
+    VALUE shared_root = ARY_SHARED_ROOT(ary);
     rb_ary_decrement_share(shared_root);
     FL_UNSET_SHARED(ary);
 }
@@ -570,19 +496,26 @@ rb_ary_reset(VALUE ary)
 static VALUE
 rb_ary_increment_share(VALUE shared_root)
 {
-    long num = ARY_SHARED_ROOT_REFCNT(shared_root);
-    assert(num >= 0);
-    ARY_SET_SHARED_ROOT_REFCNT(shared_root, num + 1);
+    if (!OBJ_FROZEN(shared_root)) {
+        long num = ARY_SHARED_ROOT_REFCNT(shared_root);
+        RUBY_ASSERT(num >= 0);
+        ARY_SET_SHARED_ROOT_REFCNT(shared_root, num + 1);
+    }
     return shared_root;
 }
 
 static void
 rb_ary_set_shared(VALUE ary, VALUE shared_root)
 {
+    RUBY_ASSERT(!ARY_EMBED_P(ary));
+    RUBY_ASSERT(!OBJ_FROZEN(ary));
+    RUBY_ASSERT(ARY_SHARED_ROOT_P(shared_root) || OBJ_FROZEN(shared_root));
+
     rb_ary_increment_share(shared_root);
     FL_SET_SHARED(ary);
+    RB_OBJ_WRITE(ary, &RARRAY(ary)->as.heap.aux.shared_root, shared_root);
+
     RB_DEBUG_COUNTER_INC(obj_ary_shared_create);
-    ARY_SET_SHARED(ary, shared_root);
 }
 
 static inline void
@@ -610,18 +543,18 @@ rb_ary_cancel_sharing(VALUE ary)
             ARY_SET_EMBED_LEN(ary, len);
         }
         else if (ARY_SHARED_ROOT_OCCUPIED(shared_root) && len > ((shared_len = RARRAY_LEN(shared_root))>>1)) {
-            long shift = RARRAY_CONST_PTR_TRANSIENT(ary) - RARRAY_CONST_PTR_TRANSIENT(shared_root);
+            long shift = RARRAY_CONST_PTR(ary) - RARRAY_CONST_PTR(shared_root);
             FL_UNSET_SHARED(ary);
-            ARY_SET_PTR(ary, RARRAY_CONST_PTR_TRANSIENT(shared_root));
+            ARY_SET_PTR(ary, RARRAY_CONST_PTR(shared_root));
             ARY_SET_CAPA(ary, shared_len);
-            RARRAY_PTR_USE_TRANSIENT(ary, ptr, {
+            RARRAY_PTR_USE(ary, ptr, {
                 MEMMOVE(ptr, ptr+shift, VALUE, len);
             });
             FL_SET_EMBED(shared_root);
             rb_ary_decrement_share(shared_root);
         }
         else {
-            VALUE *ptr = ary_heap_alloc(ary, len);
+            VALUE *ptr = ary_heap_alloc_buffer(len);
             MEMCPY(ptr, ARY_HEAP_PTR(ary), VALUE, len);
             rb_ary_unshare(ary);
             ARY_SET_CAPA(ary, len);
@@ -648,40 +581,40 @@ ary_ensure_room_for_push(VALUE ary, long add_len)
     long capa;
 
     if (old_len > ARY_MAX_SIZE - add_len) {
-	rb_raise(rb_eIndexError, "index %ld too big", new_len);
+        rb_raise(rb_eIndexError, "index %ld too big", new_len);
     }
     if (ARY_SHARED_P(ary)) {
-	if (new_len > ary_embed_capa(ary)) {
+        if (new_len > ary_embed_capa(ary)) {
             VALUE shared_root = ARY_SHARED_ROOT(ary);
             if (ARY_SHARED_ROOT_OCCUPIED(shared_root)) {
-                if (ARY_HEAP_PTR(ary) - RARRAY_CONST_PTR_TRANSIENT(shared_root) + new_len <= RARRAY_LEN(shared_root)) {
-		    rb_ary_modify_check(ary);
+                if (ARY_HEAP_PTR(ary) - RARRAY_CONST_PTR(shared_root) + new_len <= RARRAY_LEN(shared_root)) {
+                    rb_ary_modify_check(ary);
 
                     ary_verify(ary);
                     ary_verify(shared_root);
                     return shared_root;
-		}
-		else {
-		    /* if array is shared, then it is likely it participate in push/shift pattern */
-		    rb_ary_modify(ary);
-		    capa = ARY_CAPA(ary);
-		    if (new_len > capa - (capa >> 6)) {
-			ary_double_capa(ary, new_len);
-		    }
+                }
+                else {
+                    /* if array is shared, then it is likely it participate in push/shift pattern */
+                    rb_ary_modify(ary);
+                    capa = ARY_CAPA(ary);
+                    if (new_len > capa - (capa >> 6)) {
+                        ary_double_capa(ary, new_len);
+                    }
                     ary_verify(ary);
-		    return ary;
-		}
-	    }
-	}
+                    return ary;
+                }
+            }
+        }
         ary_verify(ary);
         rb_ary_modify(ary);
     }
     else {
-	rb_ary_modify_check(ary);
+        rb_ary_modify_check(ary);
     }
     capa = ARY_CAPA(ary);
     if (new_len > capa) {
-	ary_double_capa(ary, new_len);
+        ary_double_capa(ary, new_len);
     }
 
     ary_verify(ary);
@@ -690,20 +623,32 @@ ary_ensure_room_for_push(VALUE ary, long add_len)
 
 /*
  *  call-seq:
- *    array.freeze -> self
+ *    freeze -> self
+ *
+ *  Freezes +self+ (if not already frozen); returns +self+:
  *
- *  Freezes +self+; returns +self+:
  *    a = []
  *    a.frozen? # => false
  *    a.freeze
  *    a.frozen? # => true
  *
- *  An attempt to modify a frozen \Array raises FrozenError.
+ *  No further changes may be made to +self+;
+ *  raises FrozenError if a change is attempted.
+ *
+ *  Related: Kernel#frozen?.
  */
 
 VALUE
 rb_ary_freeze(VALUE ary)
 {
+    RUBY_ASSERT(RB_TYPE_P(ary, T_ARRAY));
+
+    if (OBJ_FROZEN(ary)) return ary;
+
+    if (!ARY_EMBED_P(ary) && !ARY_SHARED_P(ary) && !ARY_SHARED_ROOT_P(ary)) {
+        ary_shrink_capa(ary);
+    }
+
     return rb_obj_freeze(ary);
 }
 
@@ -718,10 +663,10 @@ VALUE
 rb_ary_shared_with_p(VALUE ary1, VALUE ary2)
 {
     if (!ARY_EMBED_P(ary1) && ARY_SHARED_P(ary1) &&
-	!ARY_EMBED_P(ary2) && ARY_SHARED_P(ary2) &&
-        RARRAY(ary1)->as.heap.aux.shared_root == RARRAY(ary2)->as.heap.aux.shared_root &&
-	RARRAY(ary1)->as.heap.len == RARRAY(ary2)->as.heap.len) {
-	return Qtrue;
+            !ARY_EMBED_P(ary2) && ARY_SHARED_P(ary2) &&
+            ARY_SHARED_ROOT(ary1) == ARY_SHARED_ROOT(ary2) &&
+            ARY_HEAP_LEN(ary1) == ARY_HEAP_LEN(ary2)) {
+        return Qtrue;
     }
     return Qfalse;
 }
@@ -730,13 +675,10 @@ static VALUE
 ary_alloc_embed(VALUE klass, long capa)
 {
     size_t size = ary_embed_size(capa);
-    assert(rb_gc_size_allocatable_p(size));
-#if !USE_RVARGC
-    assert(size <= sizeof(struct RArray));
-#endif
-    RVARGC_NEWOBJ_OF(ary, struct RArray, klass,
+    RUBY_ASSERT(rb_gc_size_allocatable_p(size));
+    NEWOBJ_OF(ary, struct RArray, klass,
                      T_ARRAY | RARRAY_EMBED_FLAG | (RGENGC_WB_PROTECTED_ARRAY ? FL_WB_PROTECTED : 0),
-                     size);
+                     size, 0);
     /* Created array is:
      *   FL_SET_EMBED((VALUE)ary);
      *   ARY_SET_EMBED_LEN((VALUE)ary, 0);
@@ -747,9 +689,9 @@ ary_alloc_embed(VALUE klass, long capa)
 static VALUE
 ary_alloc_heap(VALUE klass)
 {
-    RVARGC_NEWOBJ_OF(ary, struct RArray, klass,
+    NEWOBJ_OF(ary, struct RArray, klass,
                      T_ARRAY | (RGENGC_WB_PROTECTED_ARRAY ? FL_WB_PROTECTED : 0),
-                     sizeof(struct RArray));
+                     sizeof(struct RArray), 0);
     return (VALUE)ary;
 }
 
@@ -763,13 +705,13 @@ empty_ary_alloc(VALUE klass)
 static VALUE
 ary_new(VALUE klass, long capa)
 {
-    VALUE ary,*ptr;
+    VALUE ary;
 
     if (capa < 0) {
-	rb_raise(rb_eArgError, "negative array size (or size too big)");
+        rb_raise(rb_eArgError, "negative array size (or size too big)");
     }
     if (capa > ARY_MAX_SIZE) {
-	rb_raise(rb_eArgError, "array size too big");
+        rb_raise(rb_eArgError, "array size too big");
     }
 
     RUBY_DTRACE_CREATE_HOOK(ARRAY, capa);
@@ -779,11 +721,10 @@ ary_new(VALUE klass, long capa)
     }
     else {
         ary = ary_alloc_heap(klass);
-        assert(!ARY_EMBED_P(ary));
-
-        ptr = ary_heap_alloc(ary, capa);
-        ARY_SET_PTR(ary, ptr);
         ARY_SET_CAPA(ary, capa);
+        RUBY_ASSERT(!ARY_EMBED_P(ary));
+
+        ARY_SET_PTR(ary, ary_heap_alloc_buffer(capa));
         ARY_SET_HEAP_LEN(ary, 0);
     }
 
@@ -813,7 +754,7 @@ VALUE
 
     va_start(ar, n);
     for (i=0; i<n; i++) {
-	ARY_SET(ary, i, va_arg(ar, VALUE));
+        ARY_SET(ary, i, va_arg(ar, VALUE));
     }
     va_end(ar);
 
@@ -821,15 +762,15 @@ VALUE
     return ary;
 }
 
-MJIT_FUNC_EXPORTED VALUE
+VALUE
 rb_ary_tmp_new_from_values(VALUE klass, long n, const VALUE *elts)
 {
     VALUE ary;
 
     ary = ary_new(klass, n);
     if (n > 0 && elts) {
-	ary_memcpy(ary, 0, n, elts);
-	ARY_SET_LEN(ary, n);
+        ary_memcpy(ary, 0, n, elts);
+        ARY_SET_LEN(ary, n);
     }
 
     return ary;
@@ -845,13 +786,10 @@ static VALUE
 ec_ary_alloc_embed(rb_execution_context_t *ec, VALUE klass, long capa)
 {
     size_t size = ary_embed_size(capa);
-    assert(rb_gc_size_allocatable_p(size));
-#if !USE_RVARGC
-    assert(size <= sizeof(struct RArray));
-#endif
-    RB_RVARGC_EC_NEWOBJ_OF(ec, ary, struct RArray, klass,
-                           T_ARRAY | RARRAY_EMBED_FLAG | (RGENGC_WB_PROTECTED_ARRAY ? FL_WB_PROTECTED : 0),
-                           size);
+    RUBY_ASSERT(rb_gc_size_allocatable_p(size));
+    NEWOBJ_OF(ary, struct RArray, klass,
+            T_ARRAY | RARRAY_EMBED_FLAG | (RGENGC_WB_PROTECTED_ARRAY ? FL_WB_PROTECTED : 0),
+            size, ec);
     /* Created array is:
      *   FL_SET_EMBED((VALUE)ary);
      *   ARY_SET_EMBED_LEN((VALUE)ary, 0);
@@ -862,22 +800,22 @@ ec_ary_alloc_embed(rb_execution_context_t *ec, VALUE klass, long capa)
 static VALUE
 ec_ary_alloc_heap(rb_execution_context_t *ec, VALUE klass)
 {
-    RB_RVARGC_EC_NEWOBJ_OF(ec, ary, struct RArray, klass,
-                           T_ARRAY | (RGENGC_WB_PROTECTED_ARRAY ? FL_WB_PROTECTED : 0),
-                           sizeof(struct RArray));
+    NEWOBJ_OF(ary, struct RArray, klass,
+            T_ARRAY | (RGENGC_WB_PROTECTED_ARRAY ? FL_WB_PROTECTED : 0),
+            sizeof(struct RArray), ec);
     return (VALUE)ary;
 }
 
 static VALUE
 ec_ary_new(rb_execution_context_t *ec, VALUE klass, long capa)
 {
-    VALUE ary,*ptr;
+    VALUE ary;
 
     if (capa < 0) {
-	rb_raise(rb_eArgError, "negative array size (or size too big)");
+        rb_raise(rb_eArgError, "negative array size (or size too big)");
     }
     if (capa > ARY_MAX_SIZE) {
-	rb_raise(rb_eArgError, "array size too big");
+        rb_raise(rb_eArgError, "array size too big");
     }
 
     RUBY_DTRACE_CREATE_HOOK(ARRAY, capa);
@@ -887,11 +825,10 @@ ec_ary_new(rb_execution_context_t *ec, VALUE klass, long capa)
     }
     else {
         ary = ec_ary_alloc_heap(ec, klass);
-        assert(!ARY_EMBED_P(ary));
-
-        ptr = ary_heap_alloc(ary, capa);
-        ARY_SET_PTR(ary, ptr);
         ARY_SET_CAPA(ary, capa);
+        RUBY_ASSERT(!ARY_EMBED_P(ary));
+
+        ARY_SET_PTR(ary, ary_heap_alloc_buffer(capa));
         ARY_SET_HEAP_LEN(ary, 0);
     }
 
@@ -905,28 +842,26 @@ rb_ec_ary_new_from_values(rb_execution_context_t *ec, long n, const VALUE *elts)
 
     ary = ec_ary_new(ec, rb_cArray, n);
     if (n > 0 && elts) {
-	ary_memcpy(ary, 0, n, elts);
-	ARY_SET_LEN(ary, n);
+        ary_memcpy(ary, 0, n, elts);
+        ARY_SET_LEN(ary, n);
     }
 
     return ary;
 }
 
 VALUE
-rb_ary_tmp_new(long capa)
+rb_ary_hidden_new(long capa)
 {
     VALUE ary = ary_new(0, capa);
-    rb_ary_transient_heap_evacuate(ary, TRUE);
     return ary;
 }
 
 VALUE
-rb_ary_tmp_new_fill(long capa)
+rb_ary_hidden_new_fill(long capa)
 {
-    VALUE ary = ary_new(0, capa);
+    VALUE ary = rb_ary_hidden_new(capa);
     ary_memfill(ary, 0, capa, Qnil);
     ARY_SET_LEN(ary, capa);
-    rb_ary_transient_heap_evacuate(ary, TRUE);
     return ary;
 }
 
@@ -940,13 +875,8 @@ rb_ary_free(VALUE ary)
             RB_DEBUG_COUNTER_INC(obj_ary_extracapa);
         }
 
-        if (RARRAY_TRANSIENT_P(ary)) {
-            RB_DEBUG_COUNTER_INC(obj_ary_transient);
-        }
-        else {
-            RB_DEBUG_COUNTER_INC(obj_ary_ptr);
-            ary_heap_free(ary);
-        }
+        RB_DEBUG_COUNTER_INC(obj_ary_ptr);
+        ary_heap_free(ary);
     }
     else {
         RB_DEBUG_COUNTER_INC(obj_ary_embed);
@@ -960,68 +890,86 @@ rb_ary_free(VALUE ary)
     }
 }
 
-RUBY_FUNC_EXPORTED size_t
+static VALUE fake_ary_flags;
+
+static VALUE
+init_fake_ary_flags(void)
+{
+    struct RArray fake_ary = {0};
+    fake_ary.basic.flags = T_ARRAY;
+    VALUE ary = (VALUE)&fake_ary;
+    rb_ary_freeze(ary);
+    return fake_ary.basic.flags;
+}
+
+VALUE
+rb_setup_fake_ary(struct RArray *fake_ary, const VALUE *list, long len)
+{
+    fake_ary->basic.flags = fake_ary_flags;
+    RBASIC_CLEAR_CLASS((VALUE)fake_ary);
+
+    // bypass frozen checks
+    fake_ary->as.heap.ptr = list;
+    fake_ary->as.heap.len = len;
+    fake_ary->as.heap.aux.capa = len;
+    return (VALUE)fake_ary;
+}
+
+size_t
 rb_ary_memsize(VALUE ary)
 {
     if (ARY_OWNS_HEAP_P(ary)) {
-	return ARY_CAPA(ary) * sizeof(VALUE);
+        return ARY_CAPA(ary) * sizeof(VALUE);
     }
     else {
-	return 0;
+        return 0;
     }
 }
 
-static inline void
-ary_discard(VALUE ary)
-{
-    rb_ary_free(ary);
-    RBASIC(ary)->flags |= RARRAY_EMBED_FLAG;
-    RBASIC(ary)->flags &= ~(RARRAY_EMBED_LEN_MASK | RARRAY_TRANSIENT_FLAG);
-}
-
 static VALUE
 ary_make_shared(VALUE ary)
 {
-    assert(!ARY_EMBED_P(ary));
     ary_verify(ary);
 
     if (ARY_SHARED_P(ary)) {
         return ARY_SHARED_ROOT(ary);
     }
     else if (ARY_SHARED_ROOT_P(ary)) {
-	return ary;
+        return ary;
     }
     else if (OBJ_FROZEN(ary)) {
-        rb_ary_transient_heap_evacuate(ary, TRUE);
-	ary_shrink_capa(ary);
-	FL_SET_SHARED_ROOT(ary);
-        ARY_SET_SHARED_ROOT_REFCNT(ary, 1);
-	return ary;
+        return ary;
     }
     else {
-	long capa = ARY_CAPA(ary), len = RARRAY_LEN(ary);
-        const VALUE *ptr;
+        long capa = ARY_CAPA(ary);
+        long len = RARRAY_LEN(ary);
+
+        /* Shared roots cannot be embedded because the reference count
+         * (refcnt) is stored in as.heap.aux.capa. */
         VALUE shared = ary_alloc_heap(0);
-        VALUE vshared = (VALUE)shared;
-
-        rb_ary_transient_heap_evacuate(ary, TRUE);
-        ptr = ARY_HEAP_PTR(ary);
-
-        FL_UNSET_EMBED(vshared);
-        ARY_SET_LEN(vshared, capa);
-        ARY_SET_PTR(vshared, ptr);
-        ary_mem_clear(vshared, len, capa - len);
-        FL_SET_SHARED_ROOT(vshared);
-        ARY_SET_SHARED_ROOT_REFCNT(vshared, 1);
-	FL_SET_SHARED(ary);
-        RB_DEBUG_COUNTER_INC(obj_ary_shared_create);
-        ARY_SET_SHARED(ary, vshared);
-        OBJ_FREEZE(vshared);
-
-        ary_verify(vshared);
+        FL_SET_SHARED_ROOT(shared);
+
+        if (ARY_EMBED_P(ary)) {
+            VALUE *ptr = ary_heap_alloc_buffer(capa);
+            ARY_SET_PTR(shared, ptr);
+            ary_memcpy(shared, 0, len, RARRAY_CONST_PTR(ary));
+
+            FL_UNSET_EMBED(ary);
+            ARY_SET_HEAP_LEN(ary, len);
+            ARY_SET_PTR(ary, ptr);
+        }
+        else {
+            ARY_SET_PTR(shared, RARRAY_CONST_PTR(ary));
+        }
+
+        ARY_SET_LEN(shared, capa);
+        ary_mem_clear(shared, len, capa - len);
+        rb_ary_set_shared(ary, shared);
+
+        ary_verify(shared);
         ary_verify(ary);
 
-        return vshared;
+        return shared;
     }
 }
 
@@ -1032,9 +980,9 @@ ary_make_substitution(VALUE ary)
 
     if (ary_embeddable_p(len)) {
         VALUE subst = rb_ary_new_capa(len);
-        assert(ARY_EMBED_P(subst));
+        RUBY_ASSERT(ARY_EMBED_P(subst));
 
-        ary_memcpy(subst, 0, len, RARRAY_CONST_PTR_TRANSIENT(ary));
+        ary_memcpy(subst, 0, len, RARRAY_CONST_PTR(ary));
         ARY_SET_EMBED_LEN(subst, len);
         return subst;
     }
@@ -1062,7 +1010,7 @@ rb_check_array_type(VALUE ary)
     return rb_check_convert_type_with_id(ary, T_ARRAY, "Array", idTo_ary);
 }
 
-MJIT_FUNC_EXPORTED VALUE
+VALUE
 rb_check_to_array(VALUE ary)
 {
     return rb_check_convert_type_with_id(ary, T_ARRAY, "Array", idTo_a);
@@ -1078,14 +1026,18 @@ rb_to_array(VALUE ary)
  *  call-seq:
  *    Array.try_convert(object) -> object, new_array, or nil
  *
- *  If +object+ is an \Array object, returns +object+.
+ *  Attempts to return an array, based on the given +object+.
  *
- *  Otherwise if +object+ responds to <tt>:to_ary</tt>,
- *  calls <tt>object.to_ary</tt> and returns the result.
+ *  If +object+ is an array, returns +object+.
  *
- *  Returns +nil+ if +object+ does not respond to <tt>:to_ary</tt>
+ *  Otherwise if +object+ responds to <tt>:to_ary</tt>.
+ *  calls <tt>object.to_ary</tt>:
+ *  if the return value is an array or +nil+, returns that value;
+ *  if not, raises TypeError.
  *
- *  Raises an exception unless <tt>object.to_ary</tt> returns an \Array object.
+ *  Otherwise returns +nil+.
+ *
+ *  Related: see {Methods for Creating an Array}[rdoc-ref:Array@Methods+for+Creating+an+Array].
  */
 
 static VALUE
@@ -1122,44 +1074,51 @@ rb_ary_s_new(int argc, VALUE *argv, VALUE klass)
  *  call-seq:
  *    Array.new -> new_empty_array
  *    Array.new(array) -> new_array
- *    Array.new(size) -> new_array
- *    Array.new(size, default_value) -> new_array
- *    Array.new(size) {|index| ... } -> new_array
+ *    Array.new(size, default_value = nil) -> new_array
+ *    Array.new(size = 0) {|index| ... } -> new_array
  *
- *  Returns a new \Array.
+ *  Returns a new array.
  *
- *  With no block and no arguments, returns a new empty \Array object.
+ *  With no block and no argument given, returns a new empty array:
  *
- *  With no block and a single \Array argument +array+,
- *  returns a new \Array formed from +array+:
- *    a = Array.new([:foo, 'bar', 2])
- *    a.class # => Array
- *    a # => [:foo, "bar", 2]
+ *    Array.new # => []
+ *
+ *  With no block and array argument given, returns a new array with the same elements:
+ *
+ *    Array.new([:foo, 'bar', 2]) # => [:foo, "bar", 2]
+ *
+ *  With no block and integer argument given, returns a new array containing
+ *  that many instances of the given +default_value+:
+ *
+ *    Array.new(0)    # => []
+ *    Array.new(3)    # => [nil, nil, nil]
+ *    Array.new(2, 3) # => [3, 3]
+ *
+ *  With a block given, returns an array of the given +size+;
+ *  calls the block with each +index+ in the range <tt>(0...size)</tt>;
+ *  the element at that +index+ in the returned array is the blocks return value:
+ *
+ *    Array.new(3)  {|index| "Element #{index}" } # => ["Element 0", "Element 1", "Element 2"]
+ *
+ *  A common pitfall for new Rubyists is providing an expression as +default_value+:
+ *
+ *    array = Array.new(2, {})
+ *    array # => [{}, {}]
+ *    array[0][:a] = 1
+ *    array # => [{a: 1}, {a: 1}], as array[0] and array[1] are same object
  *
- *  With no block and a single \Integer argument +size+,
- *  returns a new \Array of the given size
- *  whose elements are all +nil+:
- *    a = Array.new(3)
- *    a # => [nil, nil, nil]
- *
- *  With no block and arguments +size+ and +default_value+,
- *  returns an \Array of the given size;
- *  each element is that same +default_value+:
- *    a = Array.new(3, 'x')
- *    a # => ['x', 'x', 'x']
- *
- *  With a block and argument +size+,
- *  returns an \Array of the given size;
- *  the block is called with each successive integer +index+;
- *  the element for that +index+ is the return value from the block:
- *    a = Array.new(3) {|index| "Element #{index}" }
- *    a # => ["Element 0", "Element 1", "Element 2"]
- *
- *  Raises ArgumentError if +size+ is negative.
- *
- *  With a block and no argument,
- *  or a single argument +0+,
- *  ignores the block and returns a new empty \Array.
+ *  If you want the elements of the array to be distinct, you should pass a block:
+ *
+ *    array = Array.new(2) { {} }
+ *    array # => [{}, {}]
+ *    array[0][:a] = 1
+ *    array # => [{a: 1}, {}], as array[0] and array[1] are different objects
+ *
+ *  Raises TypeError if the first argument is not either an array
+ *  or an {integer-convertible object}[rdoc-ref:implicit_conversion.rdoc@Integer-Convertible+Objects]).
+ *  Raises ArgumentError if the first argument is a negative integer.
+ *
+ *  Related: see {Methods for Creating an Array}[rdoc-ref:Array@Methods+for+Creating+an+Array].
  */
 
 static VALUE
@@ -1171,57 +1130,59 @@ rb_ary_initialize(int argc, VALUE *argv, VALUE ary)
     rb_ary_modify(ary);
     if (argc == 0) {
         rb_ary_reset(ary);
-        assert(ARY_EMBED_P(ary));
-        assert(ARY_EMBED_LEN(ary) == 0);
-	if (rb_block_given_p()) {
-	    rb_warning("given block not used");
-	}
-	return ary;
+        RUBY_ASSERT(ARY_EMBED_P(ary));
+        RUBY_ASSERT(ARY_EMBED_LEN(ary) == 0);
+        if (rb_block_given_p()) {
+            rb_warning("given block not used");
+        }
+        return ary;
     }
     rb_scan_args(argc, argv, "02", &size, &val);
     if (argc == 1 && !FIXNUM_P(size)) {
-	val = rb_check_array_type(size);
-	if (!NIL_P(val)) {
-	    rb_ary_replace(ary, val);
-	    return ary;
-	}
+        val = rb_check_array_type(size);
+        if (!NIL_P(val)) {
+            rb_ary_replace(ary, val);
+            return ary;
+        }
     }
 
     len = NUM2LONG(size);
     /* NUM2LONG() may call size.to_int, ary can be frozen, modified, etc */
     if (len < 0) {
-	rb_raise(rb_eArgError, "negative array size");
+        rb_raise(rb_eArgError, "negative array size");
     }
     if (len > ARY_MAX_SIZE) {
-	rb_raise(rb_eArgError, "array size too big");
+        rb_raise(rb_eArgError, "array size too big");
     }
     /* recheck after argument conversion */
     rb_ary_modify(ary);
     ary_resize_capa(ary, len);
     if (rb_block_given_p()) {
-	long i;
+        long i;
 
-	if (argc == 2) {
-	    rb_warn("block supersedes default value argument");
-	}
-	for (i=0; i<len; i++) {
-	    rb_ary_store(ary, i, rb_yield(LONG2NUM(i)));
-	    ARY_SET_LEN(ary, i + 1);
-	}
+        if (argc == 2) {
+            rb_warn("block supersedes default value argument");
+        }
+        for (i=0; i<len; i++) {
+            rb_ary_store(ary, i, rb_yield(LONG2NUM(i)));
+            ARY_SET_LEN(ary, i + 1);
+        }
     }
     else {
-	ary_memfill(ary, 0, len, val);
-	ARY_SET_LEN(ary, len);
+        ary_memfill(ary, 0, len, val);
+        ARY_SET_LEN(ary, len);
     }
     return ary;
 }
 
 /*
- * Returns a new array populated with the given objects.
+ * Returns a new array, populated with the given objects:
+ *
+ *   Array[1, 'a', /^A/]    # => [1, "a", /^A/]
+ *   Array[]                # => []
+ *   Array.[](1, 'a', /^A/) # => [1, "a", /^A/]
  *
- *   Array.[]( 1, 'a', /^A/)  # => [1, "a", /^A/]
- *   Array[ 1, 'a', /^A/ ]    # => [1, "a", /^A/]
- *   [ 1, 'a', /^A/ ]         # => [1, "a", /^A/]
+ * Related: see {Methods for Creating an Array}[rdoc-ref:Array@Methods+for+Creating+an+Array].
  */
 
 static VALUE
@@ -1242,26 +1203,26 @@ rb_ary_store(VALUE ary, long idx, VALUE val)
     long len = RARRAY_LEN(ary);
 
     if (idx < 0) {
-	idx += len;
-	if (idx < 0) {
-	    rb_raise(rb_eIndexError, "index %ld too small for array; minimum: %ld",
-		     idx - len, -len);
-	}
+        idx += len;
+        if (idx < 0) {
+            rb_raise(rb_eIndexError, "index %ld too small for array; minimum: %ld",
+                     idx - len, -len);
+        }
     }
     else if (idx >= ARY_MAX_SIZE) {
-	rb_raise(rb_eIndexError, "index %ld too big", idx);
+        rb_raise(rb_eIndexError, "index %ld too big", idx);
     }
 
     rb_ary_modify(ary);
     if (idx >= ARY_CAPA(ary)) {
-	ary_double_capa(ary, idx);
+        ary_double_capa(ary, idx);
     }
     if (idx > len) {
-	ary_mem_clear(ary, len, idx - len + 1);
+        ary_mem_clear(ary, len, idx - len + 1);
     }
 
     if (idx >= len) {
-	ARY_SET_LEN(ary, idx + 1);
+        ARY_SET_LEN(ary, idx + 1);
     }
     ARY_SET(ary, idx, val);
 }
@@ -1269,22 +1230,26 @@ rb_ary_store(VALUE ary, long idx, VALUE val)
 static VALUE
 ary_make_partial(VALUE ary, VALUE klass, long offset, long len)
 {
-    assert(offset >= 0);
-    assert(len >= 0);
-    assert(offset+len <= RARRAY_LEN(ary));
+    RUBY_ASSERT(offset >= 0);
+    RUBY_ASSERT(len >= 0);
+    RUBY_ASSERT(offset+len <= RARRAY_LEN(ary));
 
-    if (ary_embeddable_p(len)) {
-        VALUE result = ary_alloc_embed(klass, len);
-        ary_memcpy(result, 0, len, RARRAY_CONST_PTR_TRANSIENT(ary) + offset);
+    VALUE result = ary_alloc_heap(klass);
+    size_t embed_capa = ary_embed_capa(result);
+    if ((size_t)len <= embed_capa) {
+        FL_SET_EMBED(result);
+        ary_memcpy(result, 0, len, RARRAY_CONST_PTR(ary) + offset);
         ARY_SET_EMBED_LEN(result, len);
-        return result;
     }
     else {
-        VALUE shared, result = ary_alloc_heap(klass);
-        assert(!ARY_EMBED_P(result));
+        VALUE shared = ary_make_shared(ary);
+
+        /* The ary_make_shared call may allocate, which can trigger a GC
+         * compaction. This can cause the array to be embedded because it has
+         * a length of 0. */
+        FL_UNSET_EMBED(result);
 
-        shared = ary_make_shared(ary);
-        ARY_SET_PTR(result, RARRAY_CONST_PTR_TRANSIENT(ary));
+        ARY_SET_PTR(result, RARRAY_CONST_PTR(ary));
         ARY_SET_LEN(result, RARRAY_LEN(ary));
         rb_ary_set_shared(result, shared);
 
@@ -1292,32 +1257,37 @@ ary_make_partial(VALUE ary, VALUE klass, long offset, long len)
         ARY_SET_LEN(result, len);
 
         ary_verify(shared);
-        ary_verify(result);
-        return result;
     }
+
+    ary_verify(result);
+    return result;
 }
 
 static VALUE
 ary_make_partial_step(VALUE ary, VALUE klass, long offset, long len, long step)
 {
-    assert(offset >= 0);
-    assert(len >= 0);
-    assert(offset+len <= RARRAY_LEN(ary));
-    assert(step != 0);
+    RUBY_ASSERT(offset >= 0);
+    RUBY_ASSERT(len >= 0);
+    RUBY_ASSERT(offset+len <= RARRAY_LEN(ary));
+    RUBY_ASSERT(step != 0);
 
-    const VALUE *values = RARRAY_CONST_PTR_TRANSIENT(ary);
     const long orig_len = len;
 
-    if ((step > 0 && step >= len) || (step < 0 && (step < -len))) {
+    if (step > 0 && step >= len) {
         VALUE result = ary_new(klass, 1);
         VALUE *ptr = (VALUE *)ARY_EMBED_PTR(result);
+        const VALUE *values = RARRAY_CONST_PTR(ary);
+
         RB_OBJ_WRITE(result, ptr, values[offset]);
         ARY_SET_EMBED_LEN(result, 1);
         return result;
     }
+    else if (step < 0 && step < -len) {
+        step = -len;
+    }
 
     long ustep = (step < 0) ? -step : step;
-    len = (len + ustep - 1) / ustep;
+    len = roomof(len, ustep);
 
     long i;
     long j = offset + ((step > 0) ? 0 : (orig_len - 1));
@@ -1325,6 +1295,8 @@ ary_make_partial_step(VALUE ary, VALUE klass, long offset, long len, long step)
     VALUE result = ary_new(klass, len);
     if (ARY_EMBED_P(result)) {
         VALUE *ptr = (VALUE *)ARY_EMBED_PTR(result);
+        const VALUE *values = RARRAY_CONST_PTR(ary);
+
         for (i = 0; i < len; ++i) {
             RB_OBJ_WRITE(result, ptr+i, values[j]);
             j += step;
@@ -1332,7 +1304,9 @@ ary_make_partial_step(VALUE ary, VALUE klass, long offset, long len, long step)
         ARY_SET_EMBED_LEN(result, len);
     }
     else {
-        RARRAY_PTR_USE_TRANSIENT(result, ptr, {
+        const VALUE *values = RARRAY_CONST_PTR(ary);
+
+        RARRAY_PTR_USE(result, ptr, {
             for (i = 0; i < len; ++i) {
                 RB_OBJ_WRITE(result, ptr+i, values[j]);
                 j += step;
@@ -1357,44 +1331,47 @@ enum ary_take_pos_flags
 };
 
 static VALUE
-ary_take_first_or_last(int argc, const VALUE *argv, VALUE ary, enum ary_take_pos_flags last)
+ary_take_first_or_last_n(VALUE ary, long n, enum ary_take_pos_flags last)
 {
-    long n;
-    long len;
+    long len = RARRAY_LEN(ary);
     long offset = 0;
 
-    argc = rb_check_arity(argc, 0, 1);
-    /* the case optional argument is omitted should be handled in
-     * callers of this function.  if another arity case is added,
-     * this arity check needs to rewrite. */
-    RUBY_ASSERT_ALWAYS(argc == 1);
-
-    n = NUM2LONG(argv[0]);
-    len = RARRAY_LEN(ary);
     if (n > len) {
-	n = len;
+        n = len;
     }
     else if (n < 0) {
-	rb_raise(rb_eArgError, "negative array size");
+        rb_raise(rb_eArgError, "negative array size");
     }
     if (last) {
-	offset = len - n;
+        offset = len - n;
     }
     return ary_make_partial(ary, rb_cArray, offset, n);
 }
 
+static VALUE
+ary_take_first_or_last(int argc, const VALUE *argv, VALUE ary, enum ary_take_pos_flags last)
+{
+    argc = rb_check_arity(argc, 0, 1);
+    /* the case optional argument is omitted should be handled in
+     * callers of this function.  if another arity case is added,
+     * this arity check needs to rewrite. */
+    RUBY_ASSERT_ALWAYS(argc == 1);
+    return ary_take_first_or_last_n(ary, NUM2LONG(argv[0]), last);
+}
+
 /*
  *  call-seq:
- *    array << object -> self
+ *    self << object -> self
  *
- *  Appends +object+ to +self+; returns +self+:
- *    a = [:foo, 'bar', 2]
- *    a << :baz # => [:foo, "bar", 2, :baz]
+ *  Appends +object+ as the last element in +self+; returns +self+:
  *
- *  Appends +object+ as one element, even if it is another \Array:
- *    a = [:foo, 'bar', 2]
- *    a1 = a << [3, 4]
- *    a1 # => [:foo, "bar", 2, [3, 4]]
+ *    [:foo, 'bar', 2] << :baz # => [:foo, "bar", 2, :baz]
+ *
+ *  Appends +object+ as a single element, even if it is another array:
+ *
+ *    [:foo, 'bar', 2] << [3, 4] # => [:foo, "bar", 2, [3, 4]]
+ *
+ *  Related: see {Methods for Assigning}[rdoc-ref:Array@Methods+for+Assigning].
  */
 
 VALUE
@@ -1402,8 +1379,8 @@ rb_ary_push(VALUE ary, VALUE item)
 {
     long idx = RARRAY_LEN((ary_verify(ary), ary));
     VALUE target_ary = ary_ensure_room_for_push(ary, 1);
-    RARRAY_PTR_USE_TRANSIENT(ary, ptr, {
-	RB_OBJ_WRITE(target_ary, &ptr[idx], item);
+    RARRAY_PTR_USE(ary, ptr, {
+        RB_OBJ_WRITE(target_ary, &ptr[idx], item);
     });
     ARY_SET_LEN(ary, idx + 1);
     ary_verify(ary);
@@ -1422,22 +1399,20 @@ rb_ary_cat(VALUE ary, const VALUE *argv, long len)
 
 /*
  *  call-seq:
- *    array.push(*objects) -> self
+ *    push(*objects) -> self
+ *    append(*objects) -> self
  *
- *  Appends trailing elements.
+ *  Appends each argument in +objects+ to +self+; returns +self+:
  *
- *  Appends each argument in +objects+ to +self+;  returns +self+:
- *    a = [:foo, 'bar', 2]
- *    a.push(:baz, :bat) # => [:foo, "bar", 2, :baz, :bat]
+ *    a = [:foo, 'bar', 2] # => [:foo, "bar", 2]
+ *    a.push(:baz, :bat)   # => [:foo, "bar", 2, :baz, :bat]
  *
- *  Appends each argument as one element, even if it is another \Array:
- *    a = [:foo, 'bar', 2]
- *    a1 = a.push([:baz, :bat], [:bam, :bad])
- *    a1 # => [:foo, "bar", 2, [:baz, :bat], [:bam, :bad]]
+ *  Appends each argument as a single element, even if it is another array:
  *
- *  Array#append is an alias for Array#push.
+ *    a = [:foo, 'bar', 2]               # => [:foo, "bar", 2]
+      a.push([:baz, :bat], [:bam, :bad]) # => [:foo, "bar", 2, [:baz, :bat], [:bam, :bad]]
  *
- *  Related: #pop, #shift, #unshift.
+ *  Related: see {Methods for Assigning}[rdoc-ref:Array@Methods+for+Assigning].
  */
 
 static VALUE
@@ -1454,10 +1429,10 @@ rb_ary_pop(VALUE ary)
     n = RARRAY_LEN(ary);
     if (n == 0) return Qnil;
     if (ARY_OWNS_HEAP_P(ary) &&
-	n * 3 < ARY_CAPA(ary) &&
-	ARY_CAPA(ary) > ARY_DEFAULT_SIZE)
+        n * 3 < ARY_CAPA(ary) &&
+        ARY_CAPA(ary) > ARY_DEFAULT_SIZE)
     {
-	ary_resize_capa(ary, n * 2);
+        ary_resize_capa(ary, n * 2);
     }
     --n;
     ARY_SET_LEN(ary, n);
@@ -1467,30 +1442,32 @@ rb_ary_pop(VALUE ary)
 
 /*
  *  call-seq:
- *    array.pop -> object or nil
- *    array.pop(n) -> new_array
+ *    pop -> object or nil
+ *    pop(count) -> new_array
  *
- *  Removes and returns trailing elements.
+ *  Removes and returns trailing elements of +self+.
+ *
+ *  With no argument given, removes and returns the last element, if available;
+ *  otherwise returns +nil+:
  *
- *  When no argument is given and +self+ is not empty,
- *  removes and returns the last element:
  *    a = [:foo, 'bar', 2]
- *    a.pop # => 2
- *    a # => [:foo, "bar"]
+ *    a.pop  # => 2
+ *    a      # => [:foo, "bar"]
+ *    [].pop # => nil
  *
- *  Returns +nil+ if the array is empty.
+ *  With non-negative integer argument +count+ given,
+ *  returns a new array containing the trailing +count+ elements of +self+, as available:
  *
- *  When a non-negative \Integer argument +n+ is given and is in range,
- *  removes and returns the last +n+ elements in a new \Array:
  *    a = [:foo, 'bar', 2]
  *    a.pop(2) # => ["bar", 2]
+ *    a        # => [:foo]
  *
- *  If +n+ is positive and out of range,
- *  removes and returns all elements:
  *    a = [:foo, 'bar', 2]
  *    a.pop(50) # => [:foo, "bar", 2]
+ *    a         # => []
  *
- *  Related: #push, #shift, #unshift.
+ *  Related: Array#push;
+ *  see also {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
 
 static VALUE
@@ -1499,7 +1476,7 @@ rb_ary_pop_m(int argc, VALUE *argv, VALUE ary)
     VALUE result;
 
     if (argc == 0) {
-	return rb_ary_pop(ary);
+        return rb_ary_pop(ary);
     }
 
     rb_ary_modify_check(ary);
@@ -1529,32 +1506,40 @@ rb_ary_shift(VALUE ary)
 
 /*
  *  call-seq:
- *     array.shift -> object or nil
- *     array.shift(n) -> new_array
+ *    shift -> object or nil
+ *    shift(count) -> new_array or nil
  *
- *  Removes and returns leading elements.
+ *  Removes and returns leading elements from +self+.
  *
- *  When no argument is given, removes and returns the first element:
- *    a = [:foo, 'bar', 2]
- *    a.shift # => :foo
- *    a # => ['bar', 2]
+ *  With no argument, removes and returns one element, if available,
+ *  or +nil+ otherwise:
  *
- *  Returns +nil+ if +self+ is empty.
+ *    a = [0, 1, 2, 3]
+ *    a.shift  # => 0
+ *    a        # => [1, 2, 3]
+ *    [].shift # => nil
  *
- *  When positive \Integer argument +n+ is given, removes the first +n+ elements;
- *  returns those elements in a new \Array:
- *    a = [:foo, 'bar', 2]
- *    a.shift(2) # => [:foo, 'bar']
- *    a # => [2]
+ *  With non-negative numeric argument +count+ given,
+ *  removes and returns the first +count+ elements:
  *
- *  If +n+ is as large as or larger than <tt>self.length</tt>,
- *  removes all elements; returns those elements in a new \Array:
- *    a = [:foo, 'bar', 2]
- *    a.shift(3) # => [:foo, 'bar', 2]
+ *    a = [0, 1, 2, 3]
+ *    a.shift(2)   # => [0, 1]
+ *    a            # => [2, 3]
+ *    a.shift(1.1) # => [2]
+ *    a            # => [3]
+ *    a.shift(0)   # => []
+ *    a            # => [3]
+ *
+ *  If +count+ is large,
+ *  removes and returns all elements:
+ *
+ *    a = [0, 1, 2, 3]
+ *    a.shift(50) # => [0, 1, 2, 3]
+ *    a           # => []
  *
- *  If +n+ is zero, returns a new empty \Array; +self+ is unmodified.
+ *  If +self+ is empty, returns a new empty array.
  *
- *  Related: #push, #pop, #unshift.
+ *  Related: see {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
 
 static VALUE
@@ -1564,7 +1549,7 @@ rb_ary_shift_m(int argc, VALUE *argv, VALUE ary)
     long n;
 
     if (argc == 0) {
-	return rb_ary_shift(ary);
+        return rb_ary_shift(ary);
     }
 
     rb_ary_modify_check(ary);
@@ -1575,7 +1560,7 @@ rb_ary_shift_m(int argc, VALUE *argv, VALUE ary)
     return result;
 }
 
-MJIT_FUNC_EXPORTED VALUE
+VALUE
 rb_ary_behead(VALUE ary, long n)
 {
     if (n <= 0) {
@@ -1586,7 +1571,7 @@ rb_ary_behead(VALUE ary, long n)
 
     if (!ARY_SHARED_P(ary)) {
         if (ARY_EMBED_P(ary) || RARRAY_LEN(ary) < ARY_DEFAULT_SIZE) {
-            RARRAY_PTR_USE_TRANSIENT(ary, ptr, {
+            RARRAY_PTR_USE(ary, ptr, {
                 MEMMOVE(ptr, ptr + n, VALUE, RARRAY_LEN(ary) - n);
             }); /* WB: no new reference */
             ARY_INCREASE_LEN(ary, -n);
@@ -1619,7 +1604,7 @@ make_room_for_unshift(VALUE ary, const VALUE *head, VALUE *sharedp, int argc, lo
         head = sharedp + argc + room;
     }
     ARY_SET_PTR(ary, head - argc);
-    assert(ARY_SHARED_ROOT_OCCUPIED(ARY_SHARED_ROOT(ary)));
+    RUBY_ASSERT(ARY_SHARED_ROOT_OCCUPIED(ARY_SHARED_ROOT(ary)));
 
     ary_verify(ary);
     return ARY_SHARED_ROOT(ary);
@@ -1636,7 +1621,7 @@ ary_modify_for_unshift(VALUE ary, int argc)
     rb_ary_modify(ary);
     capa = ARY_CAPA(ary);
     if (capa - (capa >> 6) <= new_len) {
-	ary_double_capa(ary, new_len);
+        ary_double_capa(ary, new_len);
     }
 
     /* use shared array for big "queues" */
@@ -1644,20 +1629,20 @@ ary_modify_for_unshift(VALUE ary, int argc)
         ary_verify(ary);
 
         /* make a room for unshifted items */
-	capa = ARY_CAPA(ary);
-	ary_make_shared(ary);
+        capa = ARY_CAPA(ary);
+        ary_make_shared(ary);
 
-        head = sharedp = RARRAY_CONST_PTR_TRANSIENT(ary);
+        head = sharedp = RARRAY_CONST_PTR(ary);
         return make_room_for_unshift(ary, head, (void *)sharedp, argc, capa, len);
     }
     else {
-	/* sliding items */
-        RARRAY_PTR_USE_TRANSIENT(ary, ptr, {
-	    MEMMOVE(ptr + argc, ptr, VALUE, len);
-	});
+        /* sliding items */
+        RARRAY_PTR_USE(ary, ptr, {
+            MEMMOVE(ptr + argc, ptr, VALUE, len);
+        });
 
         ary_verify(ary);
-	return ary;
+        return ary;
     }
 }
 
@@ -1684,8 +1669,8 @@ ary_ensure_room_for_unshift(VALUE ary, int argc)
             return ary_modify_for_unshift(ary, argc);
         }
         else {
-            const VALUE * head = RARRAY_CONST_PTR_TRANSIENT(ary);
-            void *sharedp = (void *)RARRAY_CONST_PTR_TRANSIENT(shared_root);
+            const VALUE * head = RARRAY_CONST_PTR(ary);
+            void *sharedp = (void *)RARRAY_CONST_PTR(shared_root);
 
             rb_ary_modify_check(ary);
             return make_room_for_unshift(ary, head, sharedp, argc, capa, len);
@@ -1695,26 +1680,27 @@ ary_ensure_room_for_unshift(VALUE ary, int argc)
 
 /*
  *  call-seq:
- *    array.unshift(*objects) -> self
+ *    unshift(*objects) -> self
+ *    prepend(*objects) -> self
  *
  *  Prepends the given +objects+ to +self+:
+ *
  *    a = [:foo, 'bar', 2]
  *    a.unshift(:bam, :bat) # => [:bam, :bat, :foo, "bar", 2]
  *
- *  Array#prepend is an alias for Array#unshift.
- *
- *  Related: #push, #pop, #shift.
+ *  Related: Array#shift;
+ *  see also {Methods for Assigning}[rdoc-ref:Array@Methods+for+Assigning].
  */
 
-static VALUE
+VALUE
 rb_ary_unshift_m(int argc, VALUE *argv, VALUE ary)
 {
     long len = RARRAY_LEN(ary);
     VALUE target_ary;
 
     if (argc == 0) {
-	rb_ary_modify_check(ary);
-	return ary;
+        rb_ary_modify_check(ary);
+        return ary;
     }
 
     target_ary = ary_ensure_room_for_unshift(ary, argc);
@@ -1726,7 +1712,7 @@ rb_ary_unshift_m(int argc, VALUE *argv, VALUE ary)
 VALUE
 rb_ary_unshift(VALUE ary, VALUE item)
 {
-    return rb_ary_unshift_m(1,&item,ary);
+    return rb_ary_unshift_m(1, &item, ary);
 }
 
 /* faster version - use this if you don't need to treat negative offset */
@@ -1736,7 +1722,7 @@ rb_ary_elt(VALUE ary, long offset)
     long len = RARRAY_LEN(ary);
     if (len == 0) return Qnil;
     if (offset < 0 || len <= offset) {
-	return Qnil;
+        return Qnil;
     }
     return RARRAY_AREF(ary, offset);
 }
@@ -1757,7 +1743,7 @@ rb_ary_subseq_step(VALUE ary, long beg, long len, long step)
     if (beg < 0 || len < 0) return Qnil;
 
     if (alen < len || alen < beg + len) {
-	len = alen - beg;
+        len = alen - beg;
     }
     klass = rb_cArray;
     if (len == 0) return ary_new(klass, 0);
@@ -1779,83 +1765,110 @@ static VALUE rb_ary_aref2(VALUE ary, VALUE b, VALUE e);
 
 /*
  *  call-seq:
- *    array[index] -> object or nil
- *    array[start, length] -> object or nil
- *    array[range] -> object or nil
- *    array[aseq] -> object or nil
- *    array.slice(index) -> object or nil
- *    array.slice(start, length) -> object or nil
- *    array.slice(range) -> object or nil
- *    array.slice(aseq) -> object or nil
+ *    self[index] -> object or nil
+ *    self[start, length] -> object or nil
+ *    self[range] -> object or nil
+ *    self[aseq] -> object or nil
+ *    slice(index) -> object or nil
+ *    slice(start, length) -> object or nil
+ *    slice(range) -> object or nil
+ *    slice(aseq) -> object or nil
  *
  *  Returns elements from +self+; does not modify +self+.
  *
- *  When a single \Integer argument +index+ is given, returns the element at offset +index+:
+ *  In brief:
+ *
+ *    a = [:foo, 'bar', 2]
+ *
+ *    # Single argument index: returns one element.
+ *    a[0]     # => :foo          # Zero-based index.
+ *    a[-1]    # => 2             # Negative index counts backwards from end.
+ *
+ *    # Arguments start and length: returns an array.
+ *    a[1, 2]  # => ["bar", 2]
+ *    a[-2, 2] # => ["bar", 2]    # Negative start counts backwards from end.
+ *
+ *    # Single argument range: returns an array.
+ *    a[0..1]  # => [:foo, "bar"]
+ *    a[0..-2] # => [:foo, "bar"] # Negative range-begin counts backwards from end.
+ *    a[-2..2] # => ["bar", 2]    # Negative range-end counts backwards from end.
+ *
+ *  When a single integer argument +index+ is given, returns the element at offset +index+:
+ *
  *    a = [:foo, 'bar', 2]
  *    a[0] # => :foo
  *    a[2] # => 2
  *    a # => [:foo, "bar", 2]
  *
- *  If +index+ is negative, counts relative to the end of +self+:
+ *  If +index+ is negative, counts backwards from the end of +self+:
+ *
  *    a = [:foo, 'bar', 2]
  *    a[-1] # => 2
  *    a[-2] # => "bar"
  *
  *  If +index+ is out of range, returns +nil+.
  *
- *  When two \Integer arguments +start+ and +length+ are given,
- *  returns a new \Array of size +length+ containing successive elements beginning at offset +start+:
+ *  When two Integer arguments +start+ and +length+ are given,
+ *  returns a new +Array+ of size +length+ containing successive elements beginning at offset +start+:
+ *
  *    a = [:foo, 'bar', 2]
  *    a[0, 2] # => [:foo, "bar"]
  *    a[1, 2] # => ["bar", 2]
  *
  *  If <tt>start + length</tt> is greater than <tt>self.length</tt>,
  *  returns all elements from offset +start+ to the end:
+ *
  *    a = [:foo, 'bar', 2]
  *    a[0, 4] # => [:foo, "bar", 2]
  *    a[1, 3] # => ["bar", 2]
  *    a[2, 2] # => [2]
  *
  *  If <tt>start == self.size</tt> and <tt>length >= 0</tt>,
- *  returns a new empty \Array.
+ *  returns a new empty +Array+.
  *
  *  If +length+ is negative, returns +nil+.
  *
- *  When a single \Range argument +range+ is given,
+ *  When a single Range argument +range+ is given,
  *  treats <tt>range.min</tt> as +start+ above
  *  and <tt>range.size</tt> as +length+ above:
+ *
  *    a = [:foo, 'bar', 2]
  *    a[0..1] # => [:foo, "bar"]
  *    a[1..2] # => ["bar", 2]
  *
- *  Special case: If <tt>range.start == a.size</tt>, returns a new empty \Array.
+ *  Special case: If <tt>range.start == a.size</tt>, returns a new empty +Array+.
  *
  *  If <tt>range.end</tt> is negative, calculates the end index from the end:
+ *
  *    a = [:foo, 'bar', 2]
  *    a[0..-1] # => [:foo, "bar", 2]
  *    a[0..-2] # => [:foo, "bar"]
  *    a[0..-3] # => [:foo]
  *
  *  If <tt>range.start</tt> is negative, calculates the start index from the end:
+ *
  *    a = [:foo, 'bar', 2]
  *    a[-1..2] # => [2]
  *    a[-2..2] # => ["bar", 2]
  *    a[-3..2] # => [:foo, "bar", 2]
  *
  *  If <tt>range.start</tt> is larger than the array size, returns +nil+.
+ *
  *    a = [:foo, 'bar', 2]
  *    a[4..1] # => nil
  *    a[4..0] # => nil
  *    a[4..-1] # => nil
  *
  *  When a single Enumerator::ArithmeticSequence argument +aseq+ is given,
- *  returns an \Array of elements corresponding to the indexes produced by
+ *  returns an +Array+ of elements corresponding to the indexes produced by
  *  the sequence.
+ *
  *    a = ['--', 'data1', '--', 'data2', '--', 'data3']
  *    a[(1..).step(2)] # => ["data1", "data2", "data3"]
  *
  *  Unlike slicing with range, if the start or the end of the arithmetic sequence
  *  is larger than array size, throws RangeError.
+ *
  *    a = ['--', 'data1', '--', 'data2', '--', 'data3']
  *    a[(1..11).step(2)]
  *    # RangeError (((1..11).step(2)) out of range)
@@ -1864,11 +1877,12 @@ static VALUE rb_ary_aref2(VALUE ary, VALUE b, VALUE e);
  *
  *  If given a single argument, and its type is not one of the listed, tries to
  *  convert it to Integer, and raises if it is impossible:
+ *
  *    a = [:foo, 'bar', 2]
  *    # Raises TypeError (no implicit conversion of Symbol into Integer):
  *    a[:foo]
  *
- *  Array#slice is an alias for Array#[].
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 VALUE
@@ -1876,7 +1890,7 @@ rb_ary_aref(int argc, const VALUE *argv, VALUE ary)
 {
     rb_check_arity(argc, 1, 2);
     if (argc == 2) {
-	return rb_ary_aref2(ary, argv[0], argv[1]);
+        return rb_ary_aref2(ary, argv[0], argv[1]);
     }
     return rb_ary_aref1(ary, argv[0]);
 }
@@ -1887,19 +1901,19 @@ rb_ary_aref2(VALUE ary, VALUE b, VALUE e)
     long beg = NUM2LONG(b);
     long len = NUM2LONG(e);
     if (beg < 0) {
-	beg += RARRAY_LEN(ary);
+        beg += RARRAY_LEN(ary);
     }
     return rb_ary_subseq(ary, beg, len);
 }
 
-MJIT_FUNC_EXPORTED VALUE
+VALUE
 rb_ary_aref1(VALUE ary, VALUE arg)
 {
     long beg, len, step;
 
     /* special case - speeding up */
     if (FIXNUM_P(arg)) {
-	return rb_ary_entry(ary, FIX2LONG(arg));
+        return rb_ary_entry(ary, FIX2LONG(arg));
     }
     /* check if idx is Range or ArithmeticSequence */
     switch (rb_arithmetic_sequence_beg_len_step(arg, &beg, &len, &step, RARRAY_LEN(ary), 0)) {
@@ -1916,12 +1930,26 @@ rb_ary_aref1(VALUE ary, VALUE arg)
 
 /*
  *  call-seq:
- *    array.at(index) -> object
+ *    at(index) -> object or nil
+ *
+ *  Returns the element of +self+ specified by the given +index+
+ *  or +nil+ if there is no such element;
+ *  +index+ must be an
+ *  {integer-convertible object}[rdoc-ref:implicit_conversion.rdoc@Integer-Convertible+Objects].
+ *
+ *  For non-negative +index+, returns the element of +self+ at offset +index+:
  *
- *  Returns the element at \Integer offset +index+; does not modify +self+.
  *    a = [:foo, 'bar', 2]
- *    a.at(0) # => :foo
- *    a.at(2) # => 2
+ *    a.at(0)   # => :foo
+ *    a.at(2)   # => 2
+ *    a.at(2.0) # => 2
+ *
+ *  For negative +index+, counts backwards from the end of +self+:
+ *
+ *    a.at(-2) # => "bar"
+ *
+ *  Related: Array#[];
+ *  see also {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 VALUE
@@ -1930,113 +1958,72 @@ rb_ary_at(VALUE ary, VALUE pos)
     return rb_ary_entry(ary, NUM2LONG(pos));
 }
 
-/*
- *  call-seq:
- *    array.first -> object or nil
- *    array.first(n) -> new_array
- *
- *  Returns elements from +self+; does not modify +self+.
- *
- *  When no argument is given, returns the first element:
- *    a = [:foo, 'bar', 2]
- *    a.first # => :foo
- *    a # => [:foo, "bar", 2]
- *
- *  If +self+ is empty, returns +nil+.
- *
- *  When non-negative \Integer argument +n+ is given,
- *  returns the first +n+ elements in a new \Array:
- *    a = [:foo, 'bar', 2]
- *    a.first(2) # => [:foo, "bar"]
- *
- *  If <tt>n >= array.size</tt>, returns all elements:
- *    a = [:foo, 'bar', 2]
- *    a.first(50) # => [:foo, "bar", 2]
- *
- *  If <tt>n == 0</tt> returns an new empty \Array:
- *    a = [:foo, 'bar', 2]
- *    a.first(0) # []
- *
- *  Related: #last.
- */
+#if 0
 static VALUE
 rb_ary_first(int argc, VALUE *argv, VALUE ary)
 {
     if (argc == 0) {
-	if (RARRAY_LEN(ary) == 0) return Qnil;
-	return RARRAY_AREF(ary, 0);
+        if (RARRAY_LEN(ary) == 0) return Qnil;
+        return RARRAY_AREF(ary, 0);
     }
     else {
-	return ary_take_first_or_last(argc, argv, ary, ARY_TAKE_FIRST);
+        return ary_take_first_or_last(argc, argv, ary, ARY_TAKE_FIRST);
     }
 }
+#endif
 
-/*
- *  call-seq:
- *    array.last  -> object or nil
- *    array.last(n) -> new_array
- *
- *  Returns elements from +self+; +self+ is not modified.
- *
- *  When no argument is given, returns the last element:
- *    a = [:foo, 'bar', 2]
- *    a.last # => 2
- *    a # => [:foo, "bar", 2]
- *
- *  If +self+ is empty, returns +nil+.
- *
- *  When non-negative \Innteger argument +n+ is given,
- *  returns the last +n+ elements in a new \Array:
- *    a = [:foo, 'bar', 2]
- *    a.last(2) # => ["bar", 2]
- *
- *  If <tt>n >= array.size</tt>, returns all elements:
- *    a = [:foo, 'bar', 2]
- *    a.last(50) # => [:foo, "bar", 2]
- *
- *  If <tt>n == 0</tt>, returns an new empty \Array:
- *    a = [:foo, 'bar', 2]
- *    a.last(0) # []
- *
- *  Related: #first.
- */
+static VALUE
+ary_first(VALUE self)
+{
+    return (RARRAY_LEN(self) == 0) ? Qnil : RARRAY_AREF(self, 0);
+}
+
+static VALUE
+ary_last(VALUE self)
+{
+    long len = RARRAY_LEN(self);
+    return (len == 0) ? Qnil : RARRAY_AREF(self, len-1);
+}
 
 VALUE
-rb_ary_last(int argc, const VALUE *argv, VALUE ary)
+rb_ary_last(int argc, const VALUE *argv, VALUE ary) // used by parse.y
 {
     if (argc == 0) {
-	long len = RARRAY_LEN(ary);
-	if (len == 0) return Qnil;
-	return RARRAY_AREF(ary, len-1);
+        return ary_last(ary);
     }
     else {
-	return ary_take_first_or_last(argc, argv, ary, ARY_TAKE_LAST);
+        return ary_take_first_or_last(argc, argv, ary, ARY_TAKE_LAST);
     }
 }
 
 /*
  *  call-seq:
- *    array.fetch(index) -> element
- *    array.fetch(index, default_value) -> element
- *    array.fetch(index) {|index| ... } -> element
+ *    fetch(index) -> element
+ *    fetch(index, default_value) -> element or default_value
+ *    fetch(index) {|index| ... } -> element or block_return_value
  *
- *  Returns the element at offset  +index+.
+ *  Returns the element of +self+ at offset +index+ if +index+ is in range; +index+ must be an
+ *  {integer-convertible object}[rdoc-ref:implicit_conversion.rdoc@Integer-Convertible+Objects].
  *
- *  With the single \Integer argument +index+,
+ *  With the single argument +index+ and no block,
  *  returns the element at offset +index+:
+ *
  *    a = [:foo, 'bar', 2]
- *    a.fetch(1) # => "bar"
+ *    a.fetch(1)   # => "bar"
+ *    a.fetch(1.1) # => "bar"
  *
  *  If +index+ is negative, counts from the end of the array:
+ *
  *    a = [:foo, 'bar', 2]
  *    a.fetch(-1) # => 2
  *    a.fetch(-2) # => "bar"
  *
- *  With arguments +index+ and +default_value+,
- *  returns the element at offset +index+ if index is in range,
- *  otherwise returns +default_value+:
+ *  With arguments +index+ and +default_value+ (which may be any object) and no block,
+ *  returns +default_value+ if +index+ is out-of-range:
+ *
  *    a = [:foo, 'bar', 2]
- *    a.fetch(1, nil) # => "bar"
+ *    a.fetch(1, nil)  # => "bar"
+ *    a.fetch(3, :foo) # => :foo
  *
  *  With argument +index+ and a block,
  *  returns the element at offset +index+ if index is in range
@@ -2045,6 +2032,8 @@ rb_ary_last(int argc, const VALUE *argv, VALUE ary)
  *    a = [:foo, 'bar', 2]
  *    a.fetch(1) {|index| raise 'Cannot happen' } # => "bar"
  *    a.fetch(50) {|index| "Value for #{index}" } # => "Value for 50"
+ *
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 static VALUE
@@ -2057,57 +2046,56 @@ rb_ary_fetch(int argc, VALUE *argv, VALUE ary)
     rb_scan_args(argc, argv, "11", &pos, &ifnone);
     block_given = rb_block_given_p();
     if (block_given && argc == 2) {
-	rb_warn("block supersedes default value argument");
+        rb_warn("block supersedes default value argument");
     }
     idx = NUM2LONG(pos);
 
     if (idx < 0) {
-	idx +=  RARRAY_LEN(ary);
+        idx +=  RARRAY_LEN(ary);
     }
     if (idx < 0 || RARRAY_LEN(ary) <= idx) {
-	if (block_given) return rb_yield(pos);
-	if (argc == 1) {
-	    rb_raise(rb_eIndexError, "index %ld outside of array bounds: %ld...%ld",
-			idx - (idx < 0 ? RARRAY_LEN(ary) : 0), -RARRAY_LEN(ary), RARRAY_LEN(ary));
-	}
-	return ifnone;
+        if (block_given) return rb_yield(pos);
+        if (argc == 1) {
+            rb_raise(rb_eIndexError, "index %ld outside of array bounds: %ld...%ld",
+                        idx - (idx < 0 ? RARRAY_LEN(ary) : 0), -RARRAY_LEN(ary), RARRAY_LEN(ary));
+        }
+        return ifnone;
     }
     return RARRAY_AREF(ary, idx);
 }
 
 /*
  *  call-seq:
- *    array.index(object) -> integer or nil
- *    array.index {|element| ... } -> integer or nil
- *    array.index -> new_enumerator
+ *    find_index(object) -> integer or nil
+ *    find_index {|element| ... } -> integer or nil
+ *    find_index -> new_enumerator
+ *    index(object) -> integer or nil
+ *    index {|element| ... } -> integer or nil
+ *    index -> new_enumerator
  *
- *  Returns the index of a specified element.
+ *  Returns the zero-based integer index of a specified element, or +nil+.
  *
- *  When argument +object+ is given but no block,
+ *  With only argument +object+ given,
  *  returns the index of the first element +element+
  *  for which <tt>object == element</tt>:
+ *
  *    a = [:foo, 'bar', 2, 'bar']
  *    a.index('bar') # => 1
  *
  *  Returns +nil+ if no such element found.
  *
- *  When both argument +object+ and a block are given,
+ *  With only a block given,
  *  calls the block with each successive element;
  *  returns the index of the first element for which the block returns a truthy value:
+ *
  *    a = [:foo, 'bar', 2, 'bar']
  *    a.index {|element| element == 'bar' } # => 1
  *
  *  Returns +nil+ if the block never returns a truthy value.
  *
- *  When neither an argument nor a block is given, returns a new Enumerator:
- *    a = [:foo, 'bar', 2]
- *    e = a.index
- *    e # => #<Enumerator: [:foo, "bar", 2]:index>
- *    e.each {|element| element == 'bar' } # => 1
- *
- *  Array#find_index is an alias for Array#index.
+ *  With neither an argument nor a block given, returns a new Enumerator.
  *
- *  Related: #rindex.
+ *  Related: see {Methods for Querying}[rdoc-ref:Array@Methods+for+Querying].
  */
 
 static VALUE
@@ -2117,56 +2105,53 @@ rb_ary_index(int argc, VALUE *argv, VALUE ary)
     long i;
 
     if (argc == 0) {
-	RETURN_ENUMERATOR(ary, 0, 0);
-	for (i=0; i<RARRAY_LEN(ary); i++) {
-	    if (RTEST(rb_yield(RARRAY_AREF(ary, i)))) {
-		return LONG2NUM(i);
-	    }
-	}
-	return Qnil;
+        RETURN_ENUMERATOR(ary, 0, 0);
+        for (i=0; i<RARRAY_LEN(ary); i++) {
+            if (RTEST(rb_yield(RARRAY_AREF(ary, i)))) {
+                return LONG2NUM(i);
+            }
+        }
+        return Qnil;
     }
     rb_check_arity(argc, 0, 1);
     val = argv[0];
     if (rb_block_given_p())
-	rb_warn("given block not used");
+        rb_warn("given block not used");
     for (i=0; i<RARRAY_LEN(ary); i++) {
-	VALUE e = RARRAY_AREF(ary, i);
-	if (rb_equal(e, val)) {
-	    return LONG2NUM(i);
-	}
+        VALUE e = RARRAY_AREF(ary, i);
+        if (rb_equal(e, val)) {
+            return LONG2NUM(i);
+        }
     }
     return Qnil;
 }
 
 /*
  *  call-seq:
- *    array.rindex(object) -> integer or nil
- *    array.rindex {|element| ... } -> integer or nil
- *    array.rindex -> new_enumerator
+ *    rindex(object) -> integer or nil
+ *    rindex {|element| ... } -> integer or nil
+ *    rindex -> new_enumerator
  *
  *  Returns the index of the last element for which <tt>object == element</tt>.
  *
- *  When argument +object+ is given but no block, returns the index of the last such element found:
+ *  With argument +object+ given, returns the index of the last such element found:
+ *
  *    a = [:foo, 'bar', 2, 'bar']
  *    a.rindex('bar') # => 3
  *
  *  Returns +nil+ if no such object found.
  *
- *  When a block is given but no argument, calls the block with each successive element;
+ *  With a block given, calls the block with each successive element;
  *  returns the index of the last element for which the block returns a truthy value:
+ *
  *    a = [:foo, 'bar', 2, 'bar']
  *    a.rindex {|element| element == 'bar' } # => 3
  *
  *  Returns +nil+ if the block never returns a truthy value.
  *
- *  When neither an argument nor a block is given, returns a new \Enumerator:
- *
- *    a = [:foo, 'bar', 2, 'bar']
- *    e = a.rindex
- *    e # => #<Enumerator: [:foo, "bar", 2, "bar"]:rindex>
- *    e.each {|element| element == 'bar' } # => 3
+ *  When neither an argument nor a block is given, returns a new Enumerator.
  *
- *  Related: #index.
+ *  Related: see {Methods for Querying}[rdoc-ref:Array@Methods+for+Querying].
  */
 
 static VALUE
@@ -2176,25 +2161,25 @@ rb_ary_rindex(int argc, VALUE *argv, VALUE ary)
     long i = RARRAY_LEN(ary), len;
 
     if (argc == 0) {
-	RETURN_ENUMERATOR(ary, 0, 0);
-	while (i--) {
-	    if (RTEST(rb_yield(RARRAY_AREF(ary, i))))
-		return LONG2NUM(i);
-	    if (i > (len = RARRAY_LEN(ary))) {
-		i = len;
-	    }
-	}
-	return Qnil;
+        RETURN_ENUMERATOR(ary, 0, 0);
+        while (i--) {
+            if (RTEST(rb_yield(RARRAY_AREF(ary, i))))
+                return LONG2NUM(i);
+            if (i > (len = RARRAY_LEN(ary))) {
+                i = len;
+            }
+        }
+        return Qnil;
     }
     rb_check_arity(argc, 0, 1);
     val = argv[0];
     if (rb_block_given_p())
-	rb_warn("given block not used");
+        rb_warn("given block not used");
     while (i--) {
-	VALUE e = RARRAY_AREF(ary, i);
-	if (rb_equal(e, val)) {
-	    return LONG2NUM(i);
-	}
+        VALUE e = RARRAY_AREF(ary, i);
+        if (rb_equal(e, val)) {
+            return LONG2NUM(i);
+        }
         if (i > RARRAY_LEN(ary)) {
             break;
         }
@@ -2220,64 +2205,69 @@ rb_ary_splice(VALUE ary, long beg, long len, const VALUE *rptr, long rlen)
     if (len < 0) rb_raise(rb_eIndexError, "negative length (%ld)", len);
     olen = RARRAY_LEN(ary);
     if (beg < 0) {
-	beg += olen;
-	if (beg < 0) {
-	    rb_raise(rb_eIndexError, "index %ld too small for array; minimum: %ld",
-		     beg - olen, -olen);
-	}
+        beg += olen;
+        if (beg < 0) {
+            rb_raise(rb_eIndexError, "index %ld too small for array; minimum: %ld",
+                     beg - olen, -olen);
+        }
     }
     if (olen < len || olen < beg + len) {
-	len = olen - beg;
+        len = olen - beg;
     }
 
     {
-        const VALUE *optr = RARRAY_CONST_PTR_TRANSIENT(ary);
-	rofs = (rptr >= optr && rptr < optr + olen) ? rptr - optr : -1;
+        const VALUE *optr = RARRAY_CONST_PTR(ary);
+        rofs = (rptr >= optr && rptr < optr + olen) ? rptr - optr : -1;
     }
 
     if (beg >= olen) {
-	VALUE target_ary;
-	if (beg > ARY_MAX_SIZE - rlen) {
-	    rb_raise(rb_eIndexError, "index %ld too big", beg);
-	}
-	target_ary = ary_ensure_room_for_push(ary, rlen-len); /* len is 0 or negative */
-	len = beg + rlen;
-	ary_mem_clear(ary, olen, beg - olen);
-	if (rlen > 0) {
-            if (rofs != -1) rptr = RARRAY_CONST_PTR_TRANSIENT(ary) + rofs;
-	    ary_memcpy0(ary, beg, rlen, rptr, target_ary);
-	}
-	ARY_SET_LEN(ary, len);
+        VALUE target_ary;
+        if (beg > ARY_MAX_SIZE - rlen) {
+            rb_raise(rb_eIndexError, "index %ld too big", beg);
+        }
+        target_ary = ary_ensure_room_for_push(ary, rlen-len); /* len is 0 or negative */
+        len = beg + rlen;
+        ary_mem_clear(ary, olen, beg - olen);
+        if (rlen > 0) {
+            if (rofs != -1) rptr = RARRAY_CONST_PTR(ary) + rofs;
+            ary_memcpy0(ary, beg, rlen, rptr, target_ary);
+        }
+        ARY_SET_LEN(ary, len);
     }
     else {
-	long alen;
-
-	if (olen - len > ARY_MAX_SIZE - rlen) {
-	    rb_raise(rb_eIndexError, "index %ld too big", olen + rlen - len);
-	}
-	rb_ary_modify(ary);
-	alen = olen + rlen - len;
-	if (alen >= ARY_CAPA(ary)) {
-	    ary_double_capa(ary, alen);
-	}
-
-	if (len != rlen) {
-            RARRAY_PTR_USE_TRANSIENT(ary, ptr,
+        long alen;
+
+        if (olen - len > ARY_MAX_SIZE - rlen) {
+            rb_raise(rb_eIndexError, "index %ld too big", olen + rlen - len);
+        }
+        rb_ary_modify(ary);
+        alen = olen + rlen - len;
+        if (alen >= ARY_CAPA(ary)) {
+            ary_double_capa(ary, alen);
+        }
+
+        if (len != rlen) {
+            RARRAY_PTR_USE(ary, ptr,
                                      MEMMOVE(ptr + beg + rlen, ptr + beg + len,
                                              VALUE, olen - (beg + len)));
-	    ARY_SET_LEN(ary, alen);
-	}
-	if (rlen > 0) {
-            if (rofs != -1) rptr = RARRAY_CONST_PTR_TRANSIENT(ary) + rofs;
-            /* give up wb-protected ary */
-            RB_OBJ_WB_UNPROTECT_FOR(ARRAY, ary);
+            ARY_SET_LEN(ary, alen);
+        }
+        if (rlen > 0) {
+            if (rofs == -1) {
+                rb_gc_writebarrier_remember(ary);
+            }
+            else {
+                /* In this case, we're copying from a region in this array, so
+                 * we don't need to fire the write barrier. */
+                rptr = RARRAY_CONST_PTR(ary) + rofs;
+            }
 
             /* do not use RARRAY_PTR() because it can causes GC.
              * ary can contain T_NONE object because it is not cleared.
              */
-            RARRAY_PTR_USE_TRANSIENT(ary, ptr,
+            RARRAY_PTR_USE(ary, ptr,
                                      MEMMOVE(ptr + beg, rptr, VALUE, rlen));
-	}
+        }
     }
 }
 
@@ -2288,10 +2278,10 @@ rb_ary_set_len(VALUE ary, long len)
 
     rb_ary_modify_check(ary);
     if (ARY_SHARED_P(ary)) {
-	rb_raise(rb_eRuntimeError, "can't set length of shared ");
+        rb_raise(rb_eRuntimeError, "can't set length of shared ");
     }
     if (len > (capa = (long)ARY_CAPA(ary))) {
-	rb_bug("probable buffer overflow: %ld for %ld", len, capa);
+        rb_bug("probable buffer overflow: %ld for %ld", len, capa);
     }
     ARY_SET_LEN(ary, len);
 }
@@ -2305,14 +2295,14 @@ rb_ary_resize(VALUE ary, long len)
     olen = RARRAY_LEN(ary);
     if (len == olen) return ary;
     if (len > ARY_MAX_SIZE) {
-	rb_raise(rb_eIndexError, "index %ld too big", len);
+        rb_raise(rb_eIndexError, "index %ld too big", len);
     }
     if (len > olen) {
-	if (len >= ARY_CAPA(ary)) {
-	    ary_double_capa(ary, len);
-	}
-	ary_mem_clear(ary, olen, len - olen);
-	ARY_SET_LEN(ary, len);
+        if (len > ARY_CAPA(ary)) {
+            ary_double_capa(ary, len);
+        }
+        ary_mem_clear(ary, olen, len - olen);
+        ARY_SET_LEN(ary, len);
     }
     else if (ARY_EMBED_P(ary)) {
         ARY_SET_EMBED_LEN(ary, len);
@@ -2320,9 +2310,8 @@ rb_ary_resize(VALUE ary, long len)
     else if (len <= ary_embed_capa(ary)) {
         const VALUE *ptr = ARY_HEAP_PTR(ary);
         long ptr_capa = ARY_HEAP_SIZE(ary);
-        bool is_malloc_ptr = !ARY_SHARED_P(ary) && !RARRAY_TRANSIENT_P(ary);
+        bool is_malloc_ptr = !ARY_SHARED_P(ary);
 
-        FL_UNSET(ary, RARRAY_TRANSIENT_FLAG);
         FL_SET_EMBED(ary);
 
         MEMCPY((VALUE *)ARY_EMBED_PTR(ary), ptr, VALUE, len); /* WB: no new reference */
@@ -2331,11 +2320,11 @@ rb_ary_resize(VALUE ary, long len)
         if (is_malloc_ptr) ruby_sized_xfree((void *)ptr, ptr_capa);
     }
     else {
-	if (olen > len + ARY_DEFAULT_SIZE) {
+        if (olen > len + ARY_DEFAULT_SIZE) {
             size_t new_capa = ary_heap_realloc(ary, len);
             ARY_SET_CAPA(ary, new_capa);
-	}
-	ARY_SET_HEAP_LEN(ary, len);
+        }
+        ARY_SET_HEAP_LEN(ary, len);
     }
     ary_verify(ary);
     return ary;
@@ -2352,44 +2341,77 @@ static VALUE
 ary_aset_by_rb_ary_splice(VALUE ary, long beg, long len, VALUE val)
 {
     VALUE rpl = rb_ary_to_ary(val);
-    rb_ary_splice(ary, beg, len, RARRAY_CONST_PTR_TRANSIENT(rpl), RARRAY_LEN(rpl));
+    rb_ary_splice(ary, beg, len, RARRAY_CONST_PTR(rpl), RARRAY_LEN(rpl));
     RB_GC_GUARD(rpl);
     return val;
 }
 
 /*
  *  call-seq:
- *    array[index] = object -> object
- *    array[start, length] = object -> object
- *    array[range] = object -> object
- *
- *  Assigns elements in +self+; returns the given +object+.
- *
- *  When \Integer argument +index+ is given, assigns +object+ to an element in +self+.
+ *    self[index] = object -> object
+ *    self[start, length] = object -> object
+ *    self[range] = object -> object
+ *
+ *  Assigns elements in +self+, based on the given +object+; returns +object+.
+ *
+ *  In brief:
+ *
+ *      a_orig = [:foo, 'bar', 2]
+ *
+ *      # With argument index.
+ *      a = a_orig.dup
+ *      a[0] = 'foo' # => "foo"
+ *      a # => ["foo", "bar", 2]
+ *      a = a_orig.dup
+ *      a[7] = 'foo' # => "foo"
+ *      a # => [:foo, "bar", 2, nil, nil, nil, nil, "foo"]
+ *
+ *      # With arguments start and length.
+ *      a = a_orig.dup
+ *      a[0, 2] = 'foo' # => "foo"
+ *      a # => ["foo", 2]
+ *      a = a_orig.dup
+ *      a[6, 50] = 'foo' # => "foo"
+ *      a # => [:foo, "bar", 2, nil, nil, nil, "foo"]
+ *
+ *      # With argument range.
+ *      a = a_orig.dup
+ *      a[0..1] = 'foo' # => "foo"
+ *      a # => ["foo", 2]
+ *      a = a_orig.dup
+ *      a[6..50] = 'foo' # => "foo"
+ *      a # => [:foo, "bar", 2, nil, nil, nil, "foo"]
+ *
+ *  When Integer argument +index+ is given, assigns +object+ to an element in +self+.
  *
  *  If +index+ is non-negative, assigns +object+ the element at offset +index+:
+ *
  *    a = [:foo, 'bar', 2]
  *    a[0] = 'foo' # => "foo"
  *    a # => ["foo", "bar", 2]
  *
  *  If +index+ is greater than <tt>self.length</tt>, extends the array:
+ *
  *    a = [:foo, 'bar', 2]
  *    a[7] = 'foo' # => "foo"
  *    a # => [:foo, "bar", 2, nil, nil, nil, nil, "foo"]
  *
  *  If +index+ is negative, counts backwards from the end of the array:
+ *
  *    a = [:foo, 'bar', 2]
  *    a[-1] = 'two' # => "two"
  *    a # => [:foo, "bar", "two"]
  *
- *  When \Integer arguments +start+ and +length+ are given and +object+ is not an \Array,
+ *  When Integer arguments +start+ and +length+ are given and +object+ is not an +Array+,
  *  removes <tt>length - 1</tt> elements beginning at offset +start+,
  *  and assigns +object+ at offset +start+:
+ *
  *    a = [:foo, 'bar', 2]
  *    a[0, 2] = 'foo' # => "foo"
  *    a # => ["foo", 2]
  *
  *  If +start+ is negative, counts backwards from the end of the array:
+ *
  *    a = [:foo, 'bar', 2]
  *    a[-2, 2] = 'foo' # => "foo"
  *    a # => [:foo, "foo"]
@@ -2397,47 +2419,56 @@ ary_aset_by_rb_ary_splice(VALUE ary, long beg, long len, VALUE val)
  *  If +start+ is non-negative and outside the array (<tt> >= self.size</tt>),
  *  extends the array with +nil+, assigns +object+ at offset +start+,
  *  and ignores +length+:
+ *
  *    a = [:foo, 'bar', 2]
  *    a[6, 50] = 'foo' # => "foo"
  *    a # => [:foo, "bar", 2, nil, nil, nil, "foo"]
  *
  *  If +length+ is zero, shifts elements at and following offset +start+
  *  and assigns +object+ at offset +start+:
+ *
  *    a = [:foo, 'bar', 2]
  *    a[1, 0] = 'foo' # => "foo"
  *    a # => [:foo, "foo", "bar", 2]
  *
  *  If +length+ is too large for the existing array, does not extend the array:
+ *
  *    a = [:foo, 'bar', 2]
  *    a[1, 5] = 'foo' # => "foo"
  *    a # => [:foo, "foo"]
  *
- *  When \Range argument +range+ is given and +object+ is an \Array,
+ *  When Range argument +range+ is given and +object+ is not an +Array+,
  *  removes <tt>length - 1</tt> elements beginning at offset +start+,
  *  and assigns +object+ at offset +start+:
+ *
  *    a = [:foo, 'bar', 2]
  *    a[0..1] = 'foo' # => "foo"
  *    a # => ["foo", 2]
  *
  *  if <tt>range.begin</tt> is negative, counts backwards from the end of the array:
+ *
  *    a = [:foo, 'bar', 2]
  *    a[-2..2] = 'foo' # => "foo"
  *    a # => [:foo, "foo"]
  *
  *  If the array length is less than <tt>range.begin</tt>,
- *  assigns +object+ at offset <tt>range.begin</tt>, and ignores +length+:
+ *  extends the array with +nil+, assigns +object+ at offset <tt>range.begin</tt>,
+ *  and ignores +length+:
+ *
  *    a = [:foo, 'bar', 2]
  *    a[6..50] = 'foo' # => "foo"
  *    a # => [:foo, "bar", 2, nil, nil, nil, "foo"]
  *
  *  If <tt>range.end</tt> is zero, shifts elements at and following offset +start+
  *  and assigns +object+ at offset +start+:
+ *
  *    a = [:foo, 'bar', 2]
  *    a[1..0] = 'foo' # => "foo"
  *    a # => [:foo, "foo", "bar", 2]
  *
  *  If <tt>range.end</tt> is negative, assigns +object+ at offset +start+,
  *  retains <tt>range.end.abs -1</tt> elements past that, and removes those beyond:
+ *
  *    a = [:foo, 'bar', 2]
  *    a[1..-1] = 'foo' # => "foo"
  *    a # => [:foo, "foo"]
@@ -2451,9 +2482,12 @@ ary_aset_by_rb_ary_splice(VALUE ary, long beg, long len, VALUE val)
  *
  *  If <tt>range.end</tt> is too large for the existing array,
  *  replaces array elements, but does not extend the array with +nil+ values:
+ *
  *    a = [:foo, 'bar', 2]
  *    a[1..5] = 'foo' # => "foo"
  *    a # => [:foo, "foo"]
+ *
+ *  Related: see {Methods for Assigning}[rdoc-ref:Array@Methods+for+Assigning].
  */
 
 static VALUE
@@ -2464,16 +2498,16 @@ rb_ary_aset(int argc, VALUE *argv, VALUE ary)
     rb_check_arity(argc, 2, 3);
     rb_ary_modify_check(ary);
     if (argc == 3) {
-	beg = NUM2LONG(argv[0]);
-	len = NUM2LONG(argv[1]);
+        beg = NUM2LONG(argv[0]);
+        len = NUM2LONG(argv[1]);
         return ary_aset_by_rb_ary_splice(ary, beg, len, argv[2]);
     }
     if (FIXNUM_P(argv[0])) {
-	offset = FIX2LONG(argv[0]);
+        offset = FIX2LONG(argv[0]);
         return ary_aset_by_rb_ary_store(ary, offset, argv[1]);
     }
     if (rb_range_beg_len(argv[0], &beg, &len, RARRAY_LEN(ary), 1)) {
-	/* check if idx is Range */
+        /* check if idx is Range */
         return ary_aset_by_rb_ary_splice(ary, beg, len, argv[1]);
     }
 
@@ -2483,33 +2517,38 @@ rb_ary_aset(int argc, VALUE *argv, VALUE ary)
 
 /*
  *  call-seq:
- *    array.insert(index, *objects) -> self
+ *    insert(index, *objects) -> self
  *
- *  Inserts given +objects+ before or after the element at \Integer index +offset+;
+ *  Inserts the given +objects+ as elements of +self+;
  *  returns +self+.
  *
- *  When +index+ is non-negative, inserts all given +objects+
- *  before the element at offset +index+:
- *    a = [:foo, 'bar', 2]
- *    a.insert(1, :bat, :bam) # => [:foo, :bat, :bam, "bar", 2]
+ *  When +index+ is non-negative, inserts +objects+
+ *  _before_ the element at offset +index+:
+ *
+ *    a = ['a', 'b', 'c']     # => ["a", "b", "c"]
+ *    a.insert(1, :x, :y, :z) # => ["a", :x, :y, :z, "b", "c"]
  *
  *  Extends the array if +index+ is beyond the array (<tt>index >= self.size</tt>):
- *    a = [:foo, 'bar', 2]
- *    a.insert(5, :bat, :bam)
- *    a # => [:foo, "bar", 2, nil, nil, :bat, :bam]
  *
- *  Does nothing if no objects given:
- *    a = [:foo, 'bar', 2]
- *    a.insert(1)
- *    a.insert(50)
- *    a.insert(-50)
- *    a # => [:foo, "bar", 2]
+ *    a = ['a', 'b', 'c']     # => ["a", "b", "c"]
+ *    a.insert(5, :x, :y, :z) # => ["a", "b", "c", nil, nil, :x, :y, :z]
  *
- *  When +index+ is negative, inserts all given +objects+
- *  _after_ the element at offset <tt>index+self.size</tt>:
- *    a = [:foo, 'bar', 2]
- *    a.insert(-2, :bat, :bam)
- *    a # => [:foo, "bar", :bat, :bam, 2]
+ *  When +index+ is negative, inserts +objects+
+ *  _after_ the element at offset <tt>index + self.size</tt>:
+ *
+ *    a = ['a', 'b', 'c']      # => ["a", "b", "c"]
+ *    a.insert(-2, :x, :y, :z) # => ["a", "b", :x, :y, :z, "c"]
+ *
+ *  With no +objects+ given, does nothing:
+ *
+ *    a = ['a', 'b', 'c'] # => ["a", "b", "c"]
+ *    a.insert(1)         # => ["a", "b", "c"]
+ *    a.insert(50)        # => ["a", "b", "c"]
+ *    a.insert(-50)       # => ["a", "b", "c"]
+ *
+ *  Raises IndexError if +objects+ are given and +index+ is negative and out of range.
+ *
+ *  Related: see {Methods for Assigning}[rdoc-ref:Array@Methods+for+Assigning].
  */
 
 static VALUE
@@ -2522,15 +2561,15 @@ rb_ary_insert(int argc, VALUE *argv, VALUE ary)
     pos = NUM2LONG(argv[0]);
     if (argc == 1) return ary;
     if (pos == -1) {
-	pos = RARRAY_LEN(ary);
+        pos = RARRAY_LEN(ary);
     }
     else if (pos < 0) {
-	long minpos = -RARRAY_LEN(ary) - 1;
-	if (pos < minpos) {
-	    rb_raise(rb_eIndexError, "index %ld too small for array; minimum: %ld",
-		     pos, minpos);
-	}
-	pos++;
+        long minpos = -RARRAY_LEN(ary) - 1;
+        if (pos < minpos) {
+            rb_raise(rb_eIndexError, "index %ld too small for array; minimum: %ld",
+                     pos, minpos);
+        }
+        pos++;
     }
     rb_ary_splice(ary, pos, 0, argv + 1, argc - 1);
     return ary;
@@ -2545,43 +2584,51 @@ ary_enum_length(VALUE ary, VALUE args, VALUE eobj)
     return rb_ary_length(ary);
 }
 
+// Primitive to avoid a race condition in Array#each.
+// Return `true` and write `value` and `index` if the element exists.
+static VALUE
+ary_fetch_next(VALUE self, VALUE *index, VALUE *value)
+{
+    long i = NUM2LONG(*index);
+    if (i >= RARRAY_LEN(self)) {
+        return Qfalse;
+    }
+    *value = RARRAY_AREF(self, i);
+    *index = LONG2NUM(i + 1);
+    return Qtrue;
+}
+
 /*
  *  call-seq:
- *    array.each {|element| ... } -> self
- *    array.each -> Enumerator
+ *    each {|element| ... } -> self
+ *    each -> new_enumerator
  *
- *  Iterates over array elements.
- *
- *  When a block given, passes each successive array element to the block;
+ *  With a block given, iterates over the elements of +self+,
+ *  passing each element to the block;
  *  returns +self+:
+ *
  *    a = [:foo, 'bar', 2]
  *    a.each {|element|  puts "#{element.class} #{element}" }
  *
  *  Output:
+ *
  *    Symbol foo
  *    String bar
  *    Integer 2
  *
  *  Allows the array to be modified during iteration:
+ *
  *    a = [:foo, 'bar', 2]
  *    a.each {|element| puts element; a.clear if element.to_s.start_with?('b') }
  *
  *  Output:
+ *
  *    foo
  *    bar
  *
- *  When no block given, returns a new \Enumerator:
- *    a = [:foo, 'bar', 2]
- *    e = a.each
- *    e # => #<Enumerator: [:foo, "bar", 2]:each>
- *    a1 = e.each {|element|  puts "#{element.class} #{element}" }
+ *  With no block given, returns a new Enumerator.
  *
- *  Output:
- *    Symbol foo
- *    String bar
- *    Integer 2
- *
- *  Related: #each_index, #reverse_each.
+ *  Related: see {Methods for Iterating}[rdoc-ref:Array@Methods+for+Iterating].
  */
 
 VALUE
@@ -2591,48 +2638,43 @@ rb_ary_each(VALUE ary)
     ary_verify(ary);
     RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
     for (i=0; i<RARRAY_LEN(ary); i++) {
-	rb_yield(RARRAY_AREF(ary, i));
+        rb_yield(RARRAY_AREF(ary, i));
     }
     return ary;
 }
 
 /*
  *  call-seq:
- *    array.each_index {|index| ... } -> self
- *    array.each_index -> Enumerator
- *
- *  Iterates over array indexes.
+ *    each_index {|index| ... } -> self
+ *    each_index -> new_enumerator
  *
- *  When a block given, passes each successive array index to the block;
+ *  With a block given, iterates over the elements of +self+,
+ *  passing each <i>array index</i> to the block;
  *  returns +self+:
+ *
  *    a = [:foo, 'bar', 2]
  *    a.each_index {|index|  puts "#{index} #{a[index]}" }
  *
  *  Output:
+ *
  *    0 foo
  *    1 bar
  *    2 2
  *
  *  Allows the array to be modified during iteration:
+ *
  *    a = [:foo, 'bar', 2]
  *    a.each_index {|index| puts index; a.clear if index > 0 }
+ *    a # => []
  *
  *  Output:
+ *
  *    0
  *    1
  *
- *  When no block given, returns a new \Enumerator:
- *    a = [:foo, 'bar', 2]
- *    e = a.each_index
- *    e # => #<Enumerator: [:foo, "bar", 2]:each_index>
- *    a1 = e.each {|index|  puts "#{index} #{a[index]}"}
+ *  With no block given, returns a new Enumerator.
  *
- *  Output:
- *    0 foo
- *    1 bar
- *    2 2
- *
- *  Related: #each, #reverse_each.
+ *  Related: see {Methods for Iterating}[rdoc-ref:Array@Methods+for+Iterating].
  */
 
 static VALUE
@@ -2642,47 +2684,33 @@ rb_ary_each_index(VALUE ary)
     RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
 
     for (i=0; i<RARRAY_LEN(ary); i++) {
-	rb_yield(LONG2NUM(i));
+        rb_yield(LONG2NUM(i));
     }
     return ary;
 }
 
 /*
  *  call-seq:
- *    array.reverse_each {|element| ... } -> self
- *    array.reverse_each -> Enumerator
+ *    reverse_each {|element| ... } -> self
+ *    reverse_each -> Enumerator
  *
- *  Iterates backwards over array elements.
- *
- *  When a block given, passes, in reverse order, each element to the block;
+ *  When a block given, iterates backwards over the elements of +self+,
+ *  passing, in reverse order, each element to the block;
  *  returns +self+:
- *    a = [:foo, 'bar', 2]
- *    a.reverse_each {|element|  puts "#{element.class} #{element}" }
  *
- *  Output:
- *    Integer 2
- *    String bar
- *    Symbol foo
+ *    a = []
+ *    [0, 1, 2].reverse_each {|element| a.push(element) }
+ *    a # => [2, 1, 0]
  *
  *  Allows the array to be modified during iteration:
- *    a = [:foo, 'bar', 2]
- *    a.reverse_each {|element| puts element; a.clear if element.to_s.start_with?('b') }
  *
- *  Output:
- *    2
- *    bar
+ *    a = ['a', 'b', 'c']
+ *    a.reverse_each {|element| a.clear if element.start_with?('b') }
+ *    a # => []
  *
- *  When no block given, returns a new \Enumerator:
- *    a = [:foo, 'bar', 2]
- *    e = a.reverse_each
- *    e # => #<Enumerator: [:foo, "bar", 2]:reverse_each>
- *    a1 = e.each {|element|  puts "#{element.class} #{element}" }
- *  Output:
- *    Integer 2
- *    String bar
- *    Symbol foo
+ *  When no block given, returns a new Enumerator.
  *
- *  Related: #each, #each_index.
+ *  Related: see {Methods for Iterating}[rdoc-ref:Array@Methods+for+Iterating].
  */
 
 static VALUE
@@ -2693,21 +2721,27 @@ rb_ary_reverse_each(VALUE ary)
     RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
     len = RARRAY_LEN(ary);
     while (len--) {
-	long nlen;
-	rb_yield(RARRAY_AREF(ary, len));
-	nlen = RARRAY_LEN(ary);
-	if (nlen < len) {
-	    len = nlen;
-	}
+        long nlen;
+        rb_yield(RARRAY_AREF(ary, len));
+        nlen = RARRAY_LEN(ary);
+        if (nlen < len) {
+            len = nlen;
+        }
     }
     return ary;
 }
 
 /*
  *  call-seq:
- *    array.length -> an_integer
+ *    length -> integer
+ *    size -> integer
+ *
+ *  Returns the count of elements in +self+:
+ *
+ *    [0, 1, 2].length # => 3
+ *    [].length        # => 0
  *
- *  Returns the count of elements in +self+.
+ *  Related: see {Methods for Querying}[rdoc-ref:Array@Methods+for+Querying].
  */
 
 static VALUE
@@ -2723,6 +2757,8 @@ rb_ary_length(VALUE ary)
  *
  *  Returns +true+ if the count of elements in +self+ is zero,
  *  +false+ otherwise.
+ *
+ *  Related: see {Methods for Querying}[rdoc-ref:Array@Methods+for+Querying].
  */
 
 static VALUE
@@ -2736,7 +2772,7 @@ rb_ary_dup(VALUE ary)
 {
     long len = RARRAY_LEN(ary);
     VALUE dup = rb_ary_new2(len);
-    ary_memcpy(dup, 0, len, RARRAY_CONST_PTR_TRANSIENT(ary));
+    ary_memcpy(dup, 0, len, RARRAY_CONST_PTR(ary));
     ARY_SET_LEN(dup, len);
 
     ary_verify(ary);
@@ -2764,10 +2800,10 @@ recursive_join(VALUE obj, VALUE argp, int recur)
     int *first = (int *)arg[3];
 
     if (recur) {
-	rb_raise(rb_eArgError, "recursive array join");
+        rb_raise(rb_eArgError, "recursive array join");
     }
     else {
-	ary_join_1(obj, ary, sep, 0, result, first);
+        ary_join_1(obj, ary, sep, 0, result, first);
     }
     return Qnil;
 }
@@ -2780,11 +2816,11 @@ ary_join_0(VALUE ary, VALUE sep, long max, VALUE result)
 
     if (max > 0) rb_enc_copy(result, RARRAY_AREF(ary, 0));
     for (i=0; i<max; i++) {
-	val = RARRAY_AREF(ary, i);
+        val = RARRAY_AREF(ary, i);
         if (!RB_TYPE_P(val, T_STRING)) break;
-	if (i > 0 && !NIL_P(sep))
-	    rb_str_buf_append(result, sep);
-	rb_str_buf_append(result, val);
+        if (i > 0 && !NIL_P(sep))
+            rb_str_buf_append(result, sep);
+        rb_str_buf_append(result, val);
     }
     return i;
 }
@@ -2823,16 +2859,16 @@ ary_join_1(VALUE obj, VALUE ary, VALUE sep, long i, VALUE result, int *first)
     VALUE val, tmp;
 
     for (; i<RARRAY_LEN(ary); i++) {
-	if (i > 0 && !NIL_P(sep))
-	    rb_str_buf_append(result, sep);
+        if (i > 0 && !NIL_P(sep))
+            rb_str_buf_append(result, sep);
 
-	val = RARRAY_AREF(ary, i);
-	if (RB_TYPE_P(val, T_STRING)) {
+        val = RARRAY_AREF(ary, i);
+        if (RB_TYPE_P(val, T_STRING)) {
             ary_join_1_str(result, val, first);
-	}
-	else if (RB_TYPE_P(val, T_ARRAY)) {
+        }
+        else if (RB_TYPE_P(val, T_ARRAY)) {
             ary_join_1_ary(val, ary, sep, result, val, first);
-	}
+        }
         else if (!NIL_P(tmp = rb_check_string_type(val))) {
             ary_join_1_str(result, tmp, first);
         }
@@ -2841,7 +2877,7 @@ ary_join_1(VALUE obj, VALUE ary, VALUE sep, long i, VALUE result, int *first)
         }
         else {
             ary_join_1_str(result, rb_obj_as_string(val), first);
-	}
+        }
     }
 }
 
@@ -2854,26 +2890,26 @@ rb_ary_join(VALUE ary, VALUE sep)
     if (RARRAY_LEN(ary) == 0) return rb_usascii_str_new(0, 0);
 
     if (!NIL_P(sep)) {
-	StringValue(sep);
-	len += RSTRING_LEN(sep) * (RARRAY_LEN(ary) - 1);
+        StringValue(sep);
+        len += RSTRING_LEN(sep) * (RARRAY_LEN(ary) - 1);
     }
     for (i=0; i<RARRAY_LEN(ary); i++) {
-	val = RARRAY_AREF(ary, i);
-	tmp = rb_check_string_type(val);
+        val = RARRAY_AREF(ary, i);
+        tmp = rb_check_string_type(val);
 
-	if (NIL_P(tmp) || tmp != val) {
-	    int first;
+        if (NIL_P(tmp) || tmp != val) {
+            int first;
             long n = RARRAY_LEN(ary);
             if (i > n) i = n;
             result = rb_str_buf_new(len + (n-i)*10);
-	    rb_enc_associate(result, rb_usascii_encoding());
+            rb_enc_associate(result, rb_usascii_encoding());
             i = ary_join_0(ary, sep, i, result);
-	    first = i == 0;
-	    ary_join_1(ary, ary, sep, i, result, &first);
-	    return result;
-	}
+            first = i == 0;
+            ary_join_1(ary, ary, sep, i, result, &first);
+            return result;
+        }
 
-	len += RSTRING_LEN(tmp);
+        len += RSTRING_LEN(tmp);
     }
 
     result = rb_str_new(0, len);
@@ -2886,26 +2922,32 @@ rb_ary_join(VALUE ary, VALUE sep)
 
 /*
  *  call-seq:
- *    array.join ->new_string
  *    array.join(separator = $,) -> new_string
  *
- *  Returns the new \String formed by joining the array elements after conversion.
- *  For each element +element+
- *  - Uses <tt>element.to_s</tt> if +element+ is not a <tt>kind_of?(Array)</tt>.
- *  - Uses recursive <tt>element.join(separator)</tt> if +element+ is a <tt>kind_of?(Array)</tt>.
+ *  Returns the new string formed by joining the converted elements of +self+;
+ *  for each element +element+:
+ *
+ *  - Converts recursively using <tt>element.join(separator)</tt>
+ *    if +element+ is a <tt>kind_of?(Array)</tt>.
+ *  - Otherwise, converts using <tt>element.to_s</tt>.
+ *
+ *  With no argument given, joins using the output field separator, <tt>$,</tt>:
  *
- *  With no argument, joins using the output field separator, <tt>$,</tt>:
  *    a = [:foo, 'bar', 2]
  *    $, # => nil
  *    a.join # => "foobar2"
  *
- *  With \string argument +separator+, joins using that separator:
+ *  With string argument +separator+ given, joins using that separator:
+ *
  *    a = [:foo, 'bar', 2]
  *    a.join("\n") # => "foo\nbar\n2"
  *
- *  Joins recursively for nested Arrays:
+ *  Joins recursively for nested arrays:
+ *
  *   a = [:foo, [:bar, [:baz, :bat]]]
  *   a.join # => "foobarbazbat"
+ *
+ *  Related: see {Methods for Converting}[rdoc-ref:Array@Methods+for+Converting].
  */
 static VALUE
 rb_ary_join_m(int argc, VALUE *argv, VALUE ary)
@@ -2931,10 +2973,10 @@ inspect_ary(VALUE ary, VALUE dummy, int recur)
     if (recur) return rb_usascii_str_new_cstr("[...]");
     str = rb_str_buf_new2("[");
     for (i=0; i<RARRAY_LEN(ary); i++) {
-	s = rb_inspect(RARRAY_AREF(ary, i));
-	if (i > 0) rb_str_buf_cat2(str, ", ");
-	else rb_enc_copy(str, s);
-	rb_str_buf_append(str, s);
+        s = rb_inspect(RARRAY_AREF(ary, i));
+        if (i > 0) rb_str_buf_cat2(str, ", ");
+        else rb_enc_copy(str, s);
+        rb_str_buf_append(str, s);
     }
     rb_str_buf_cat2(str, "]");
     return str;
@@ -2942,14 +2984,16 @@ inspect_ary(VALUE ary, VALUE dummy, int recur)
 
 /*
  *  call-seq:
- *    array.inspect -> new_string
+ *    inspect -> new_string
+ *    to_s -> new_string
  *
- *  Returns the new \String formed by calling method <tt>#inspect</tt>
+ *  Returns the new string formed by calling method <tt>#inspect</tt>
  *  on each array element:
+ *
  *    a = [:foo, 'bar', 2]
  *    a.inspect # => "[:foo, \"bar\", 2]"
  *
- *  Array#to_s is an alias for Array#inspect.
+ *  Related: see {Methods for Converting}[rdoc-ref:Array@Methods+for+Converting].
  */
 
 static VALUE
@@ -2969,51 +3013,53 @@ rb_ary_to_s(VALUE ary)
  *  call-seq:
  *    to_a -> self or new_array
  *
- *  When +self+ is an instance of \Array, returns +self+:
- *    a = [:foo, 'bar', 2]
- *    a.to_a # => [:foo, "bar", 2]
+ *  When +self+ is an instance of +Array+, returns +self+.
+ *
+ *  Otherwise, returns a new array containing the elements of +self+:
  *
- *  Otherwise, returns a new \Array containing the elements of +self+:
  *    class MyArray < Array; end
- *    a = MyArray.new(['foo', 'bar', 'two'])
- *    a.instance_of?(Array) # => false
- *    a.kind_of?(Array) # => true
- *    a1 = a.to_a
- *    a1 # => ["foo", "bar", "two"]
- *    a1.class # => Array # Not MyArray
+ *    my_a = MyArray.new(['foo', 'bar', 'two'])
+ *    a = my_a.to_a
+ *    a # => ["foo", "bar", "two"]
+ *    a.class # => Array # Not MyArray.
+ *
+ *  Related: see {Methods for Converting}[rdoc-ref:Array@Methods+for+Converting].
  */
 
 static VALUE
 rb_ary_to_a(VALUE ary)
 {
     if (rb_obj_class(ary) != rb_cArray) {
-	VALUE dup = rb_ary_new2(RARRAY_LEN(ary));
-	rb_ary_replace(dup, ary);
-	return dup;
+        VALUE dup = rb_ary_new2(RARRAY_LEN(ary));
+        rb_ary_replace(dup, ary);
+        return dup;
     }
     return ary;
 }
 
 /*
  *  call-seq:
- *    array.to_h -> new_hash
- *    array.to_h {|item| ... } -> new_hash
+ *    to_h -> new_hash
+ *    to_h {|element| ... } -> new_hash
  *
- *  Returns a new \Hash formed from +self+.
+ *  Returns a new hash formed from +self+.
  *
- *  When a block is given, calls the block with each array element;
- *  the block must return a 2-element \Array whose two elements
- *  form a key-value pair in the returned \Hash:
- *    a = ['foo', :bar, 1, [2, 3], {baz: 4}]
- *    h = a.to_h {|item| [item, item] }
- *    h # => {"foo"=>"foo", :bar=>:bar, 1=>1, [2, 3]=>[2, 3], {:baz=>4}=>{:baz=>4}}
+ *  With no block given, each element of +self+ must be a 2-element sub-array;
+ *  forms each sub-array into a key-value pair in the new hash:
  *
- *  When no block is given, +self+ must be an \Array of 2-element sub-arrays,
- *  each sub-array is formed into a key-value pair in the new \Hash:
- *    [].to_h # => {}
  *    a = [['foo', 'zero'], ['bar', 'one'], ['baz', 'two']]
- *    h = a.to_h
- *    h # => {"foo"=>"zero", "bar"=>"one", "baz"=>"two"}
+ *    a.to_h # => {"foo"=>"zero", "bar"=>"one", "baz"=>"two"}
+ *    [].to_h # => {}
+ *
+ *  With a block given, the block must return a 2-element array;
+ *  calls the block with each element of +self+;
+ *  forms each returned array into a key-value pair in the returned hash:
+ *
+ *    a = ['foo', :bar, 1, [2, 3], {baz: 4}]
+ *    a.to_h {|element| [element, element.class] }
+ *    # => {"foo"=>String, :bar=>Symbol, 1=>Integer, [2, 3]=>Array, {:baz=>4}=>Hash}
+ *
+ *  Related: see {Methods for Converting}[rdoc-ref:Array@Methods+for+Converting].
  */
 
 static VALUE
@@ -3024,18 +3070,18 @@ rb_ary_to_h(VALUE ary)
     int block_given = rb_block_given_p();
 
     for (i=0; i<RARRAY_LEN(ary); i++) {
-	const VALUE e = rb_ary_elt(ary, i);
-	const VALUE elt = block_given ? rb_yield_force_blockarg(e) : e;
-	const VALUE key_value_pair = rb_check_array_type(elt);
-	if (NIL_P(key_value_pair)) {
-	    rb_raise(rb_eTypeError, "wrong element type %"PRIsVALUE" at %ld (expected array)",
-		     rb_obj_class(elt), i);
-	}
-	if (RARRAY_LEN(key_value_pair) != 2) {
-	    rb_raise(rb_eArgError, "wrong array length at %ld (expected 2, was %ld)",
-		i, RARRAY_LEN(key_value_pair));
-	}
-	rb_hash_aset(hash, RARRAY_AREF(key_value_pair, 0), RARRAY_AREF(key_value_pair, 1));
+        const VALUE e = rb_ary_elt(ary, i);
+        const VALUE elt = block_given ? rb_yield_force_blockarg(e) : e;
+        const VALUE key_value_pair = rb_check_array_type(elt);
+        if (NIL_P(key_value_pair)) {
+            rb_raise(rb_eTypeError, "wrong element type %"PRIsVALUE" at %ld (expected array)",
+                     rb_obj_class(elt), i);
+        }
+        if (RARRAY_LEN(key_value_pair) != 2) {
+            rb_raise(rb_eArgError, "wrong array length at %ld (expected 2, was %ld)",
+                i, RARRAY_LEN(key_value_pair));
+        }
+        rb_hash_aset(hash, RARRAY_AREF(key_value_pair, 0), RARRAY_AREF(key_value_pair, 1));
     }
     return hash;
 }
@@ -3057,9 +3103,9 @@ static void
 ary_reverse(VALUE *p1, VALUE *p2)
 {
     while (p1 < p2) {
-	VALUE tmp = *p1;
-	*p1++ = *p2;
-	*p2-- = tmp;
+        VALUE tmp = *p1;
+        *p1++ = *p2;
+        *p2-- = tmp;
     }
 }
 
@@ -3071,21 +3117,26 @@ rb_ary_reverse(VALUE ary)
 
     rb_ary_modify(ary);
     if (len > 1) {
-        RARRAY_PTR_USE_TRANSIENT(ary, p1, {
+        RARRAY_PTR_USE(ary, p1, {
             p2 = p1 + len - 1;	/* points last item */
             ary_reverse(p1, p2);
-	}); /* WB: no new reference */
+        }); /* WB: no new reference */
     }
     return ary;
 }
 
 /*
  *  call-seq:
- *    array.reverse! -> self
+ *    reverse! -> self
  *
- *  Reverses +self+ in place:
- *    a = ['foo', 'bar', 'two']
- *    a.reverse! # => ["two", "bar", "foo"]
+ *  Reverses the order of the elements of +self+;
+ *  returns +self+:
+ *
+ *    a = [0, 1, 2]
+ *    a.reverse! # => [2, 1, 0]
+ *    a          # => [2, 1, 0]
+ *
+ *  Related: see {Methods for Assigning}[rdoc-ref:Array@Methods+for+Assigning].
  */
 
 static VALUE
@@ -3096,12 +3147,13 @@ rb_ary_reverse_bang(VALUE ary)
 
 /*
  *  call-seq:
- *    array.reverse -> new_array
+ *    reverse -> new_array
+ *
+ *  Returns a new array containing the elements of +self+ in reverse order:
  *
- *  Returns a new \Array with the elements of +self+ in reverse order.
- *    a = ['foo', 'bar', 'two']
- *    a1 = a.reverse
- *    a1 # => ["two", "bar", "foo"]
+ *    [0, 1, 2].reverse # => [2, 1, 0]
+ *
+ *  Related: see {Methods for Combining}[rdoc-ref:Array@Methods+for+Combining].
  */
 
 static VALUE
@@ -3111,9 +3163,9 @@ rb_ary_reverse_m(VALUE ary)
     VALUE dup = rb_ary_new2(len);
 
     if (len > 0) {
-        const VALUE *p1 = RARRAY_CONST_PTR_TRANSIENT(ary);
-        VALUE *p2 = (VALUE *)RARRAY_CONST_PTR_TRANSIENT(dup) + len - 1;
-	do *p2-- = *p1++; while (--len > 0);
+        const VALUE *p1 = RARRAY_CONST_PTR(ary);
+        VALUE *p2 = (VALUE *)RARRAY_CONST_PTR(dup) + len - 1;
+        do *p2-- = *p1++; while (--len > 0);
     }
     ARY_SET_LEN(dup, RARRAY_LEN(ary));
     return dup;
@@ -3154,7 +3206,7 @@ rb_ary_rotate(VALUE ary, long cnt)
     if (cnt != 0) {
         long len = RARRAY_LEN(ary);
         if (len > 1 && (cnt = rotate_count(cnt, len)) > 0) {
-            RARRAY_PTR_USE_TRANSIENT(ary, ptr, ary_rotate_ptr(ptr, len, cnt));
+            RARRAY_PTR_USE(ary, ptr, ary_rotate_ptr(ptr, len, cnt));
             return ary;
         }
     }
@@ -3163,41 +3215,34 @@ rb_ary_rotate(VALUE ary, long cnt)
 
 /*
  *  call-seq:
- *    array.rotate! -> self
- *    array.rotate!(count) -> self
+ *    rotate!(count = 1) -> self
  *
  *  Rotates +self+ in place by moving elements from one end to the other; returns +self+.
  *
- *  When no argument given, rotates the first element to the last position:
- *    a = [:foo, 'bar', 2, 'bar']
- *    a.rotate! # => ["bar", 2, "bar", :foo]
- *
- *  When given a non-negative \Integer +count+,
+ *  With non-negative numeric +count+,
  *  rotates +count+ elements from the beginning to the end:
- *    a = [:foo, 'bar', 2]
- *    a.rotate!(2)
- *    a # => [2, :foo, "bar"]
+ *
+ *    [0, 1, 2, 3].rotate!(2)   # => [2, 3, 0, 1]
+      [0, 1, 2, 3].rotate!(2.1) # => [2, 3, 0, 1]
  *
  *  If +count+ is large, uses <tt>count % array.size</tt> as the count:
- *    a = [:foo, 'bar', 2]
- *    a.rotate!(20)
- *    a # => [2, :foo, "bar"]
  *
- *  If +count+ is zero, returns +self+ unmodified:
- *    a = [:foo, 'bar', 2]
- *    a.rotate!(0)
- *    a # => [:foo, "bar", 2]
+ *    [0, 1, 2, 3].rotate!(21) # => [1, 2, 3, 0]
+ *
+ *  If +count+ is zero, rotates no elements:
  *
- *  When given a negative Integer +count+, rotates in the opposite direction,
+ *    [0, 1, 2, 3].rotate!(0) # => [0, 1, 2, 3]
+ *
+ *  With a negative numeric +count+, rotates in the opposite direction,
  *  from end to beginning:
- *    a = [:foo, 'bar', 2]
- *    a.rotate!(-2)
- *    a # => ["bar", 2, :foo]
+ *
+ *    [0, 1, 2, 3].rotate!(-1) # => [3, 0, 1, 2]
  *
  *  If +count+ is small (far from zero), uses <tt>count % array.size</tt> as the count:
- *    a = [:foo, 'bar', 2]
- *    a.rotate!(-5)
- *    a # => ["bar", 2, :foo]
+ *
+ *    [0, 1, 2, 3].rotate!(-21) # => [3, 0, 1, 2]
+ *
+ *  Related: see {Methods for Assigning}[rdoc-ref:Array@Methods+for+Assigning].
  */
 
 static VALUE
@@ -3210,44 +3255,35 @@ rb_ary_rotate_bang(int argc, VALUE *argv, VALUE ary)
 
 /*
  *  call-seq:
- *    array.rotate -> new_array
- *    array.rotate(count) -> new_array
+ *    rotate(count = 1) -> new_array
  *
- *  Returns a new \Array formed from +self+ with elements
+ *  Returns a new array formed from +self+ with elements
  *  rotated from one end to the other.
  *
- *  When no argument given, returns a new \Array that is like +self+,
- *  except that the first element has been rotated to the last position:
- *    a = [:foo, 'bar', 2, 'bar']
- *    a1 = a.rotate
- *    a1 # => ["bar", 2, "bar", :foo]
+ *  With non-negative numeric +count+,
+ *  rotates elements from the beginning to the end:
  *
- *  When given a non-negative \Integer +count+,
- *  returns a new \Array with +count+ elements rotated from the beginning to the end:
- *    a = [:foo, 'bar', 2]
- *    a1 = a.rotate(2)
- *    a1 # => [2, :foo, "bar"]
+ *    [0, 1, 2, 3].rotate(2)   # => [2, 3, 0, 1]
+ *    [0, 1, 2, 3].rotate(2.1) # => [2, 3, 0, 1]
  *
  *  If +count+ is large, uses <tt>count % array.size</tt> as the count:
- *    a = [:foo, 'bar', 2]
- *    a1 = a.rotate(20)
- *    a1 # => [2, :foo, "bar"]
  *
- *  If +count+ is zero, returns a copy of +self+, unmodified:
- *    a = [:foo, 'bar', 2]
- *    a1 = a.rotate(0)
- *    a1 # => [:foo, "bar", 2]
+ *    [0, 1, 2, 3].rotate(22) # => [2, 3, 0, 1]
  *
- *  When given a negative \Integer +count+, rotates in the opposite direction,
- *  from end to beginning:
- *    a = [:foo, 'bar', 2]
- *    a1 = a.rotate(-2)
- *    a1 # => ["bar", 2, :foo]
+ *  With a +count+ of zero, rotates no elements:
+ *
+ *    [0, 1, 2, 3].rotate(0) # => [0, 1, 2, 3]
+ *
+ *  With negative numeric +count+, rotates in the opposite direction,
+ *  from the end to the beginning:
+ *
+ *    [0, 1, 2, 3].rotate(-1) # => [3, 0, 1, 2]
  *
  *  If +count+ is small (far from zero), uses <tt>count % array.size</tt> as the count:
- *    a = [:foo, 'bar', 2]
- *    a1 = a.rotate(-5)
- *    a1 # => ["bar", 2, :foo]
+ *
+ *    [0, 1, 2, 3].rotate(-21) # => [3, 0, 1, 2]
+ *
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 static VALUE
@@ -3261,11 +3297,11 @@ rb_ary_rotate_m(int argc, VALUE *argv, VALUE ary)
     len = RARRAY_LEN(ary);
     rotated = rb_ary_new2(len);
     if (len > 0) {
-	cnt = rotate_count(cnt, len);
-        ptr = RARRAY_CONST_PTR_TRANSIENT(ary);
-	len -= cnt;
-	ary_memcpy(rotated, 0, len, ptr + cnt);
-	ary_memcpy(rotated, len, cnt, ptr);
+        cnt = rotate_count(cnt, len);
+        ptr = RARRAY_CONST_PTR(ary);
+        len -= cnt;
+        ary_memcpy(rotated, 0, len, ptr + cnt);
+        ary_memcpy(rotated, len, cnt, ptr);
     }
     ARY_SET_LEN(rotated, RARRAY_LEN(ary));
     return rotated;
@@ -3274,14 +3310,13 @@ rb_ary_rotate_m(int argc, VALUE *argv, VALUE ary)
 struct ary_sort_data {
     VALUE ary;
     VALUE receiver;
-    struct cmp_opt_data cmp_opt;
 };
 
 static VALUE
 sort_reentered(VALUE ary)
 {
     if (RBASIC(ary)->klass) {
-	rb_raise(rb_eRuntimeError, "sort reentered");
+        rb_raise(rb_eRuntimeError, "sort reentered");
     }
     return Qnil;
 }
@@ -3320,16 +3355,16 @@ sort_2(const void *ap, const void *bp, void *dummy)
     VALUE a = *(const VALUE *)ap, b = *(const VALUE *)bp;
     int n;
 
-    if (FIXNUM_P(a) && FIXNUM_P(b) && CMP_OPTIMIZABLE(data->cmp_opt, Integer)) {
-	if ((long)a > (long)b) return 1;
-	if ((long)a < (long)b) return -1;
-	return 0;
+    if (FIXNUM_P(a) && FIXNUM_P(b) && CMP_OPTIMIZABLE(INTEGER)) {
+        if ((long)a > (long)b) return 1;
+        if ((long)a < (long)b) return -1;
+        return 0;
     }
-    if (STRING_P(a) && STRING_P(b) && CMP_OPTIMIZABLE(data->cmp_opt, String)) {
-	return rb_str_cmp(a, b);
+    if (STRING_P(a) && STRING_P(b) && CMP_OPTIMIZABLE(STRING)) {
+        return rb_str_cmp(a, b);
     }
-    if (RB_FLOAT_TYPE_P(a) && CMP_OPTIMIZABLE(data->cmp_opt, Float)) {
-	return rb_float_cmp(a, b);
+    if (RB_FLOAT_TYPE_P(a) && CMP_OPTIMIZABLE(FLOAT)) {
+        return rb_float_cmp(a, b);
     }
 
     retval = rb_funcallv(a, id_cmp, 1, &b);
@@ -3341,65 +3376,40 @@ sort_2(const void *ap, const void *bp, void *dummy)
 
 /*
  *  call-seq:
- *    array.sort! -> self
- *    array.sort! {|a, b| ... } -> self
- *
- *  Returns +self+ with its elements sorted in place.
- *
- *  With no block, compares elements using operator <tt><=></tt>
- *  (see Comparable):
- *    a = 'abcde'.split('').shuffle
- *    a # => ["e", "b", "d", "a", "c"]
- *    a.sort!
- *    a # => ["a", "b", "c", "d", "e"]
- *
- *  With a block, calls the block with each element pair;
- *  for each element pair +a+ and +b+, the block should return an integer:
- *  - Negative when +b+ is to follow +a+.
- *  - Zero when +a+ and +b+ are equivalent.
- *  - Positive when +a+ is to follow +b+.
+ *    sort! -> self
+ *    sort! {|a, b| ... } -> self
  *
- *  Example:
- *    a = 'abcde'.split('').shuffle
- *    a # => ["e", "b", "d", "a", "c"]
- *    a.sort! {|a, b| a <=> b }
- *    a # => ["a", "b", "c", "d", "e"]
- *    a.sort! {|a, b| b <=> a }
- *    a # => ["e", "d", "c", "b", "a"]
+ *  Like Array#sort, but returns +self+ with its elements sorted in place.
  *
- *  When the block returns zero, the order for +a+ and +b+ is indeterminate,
- *  and may be unstable:
- *    a = 'abcde'.split('').shuffle
- *    a # => ["e", "b", "d", "a", "c"]
- *    a.sort! {|a, b| 0 }
- *    a # => ["d", "e", "c", "a", "b"]
+ *  Related: see {Methods for Assigning}[rdoc-ref:Array@Methods+for+Assigning].
  */
 
 VALUE
 rb_ary_sort_bang(VALUE ary)
 {
     rb_ary_modify(ary);
-    assert(!ARY_SHARED_P(ary));
+    RUBY_ASSERT(!ARY_SHARED_P(ary));
     if (RARRAY_LEN(ary) > 1) {
-	VALUE tmp = ary_make_substitution(ary); /* only ary refers tmp */
-	struct ary_sort_data data;
-	long len = RARRAY_LEN(ary);
-	RBASIC_CLEAR_CLASS(tmp);
-	data.ary = tmp;
+        VALUE tmp = ary_make_substitution(ary); /* only ary refers tmp */
+        struct ary_sort_data data;
+        long len = RARRAY_LEN(ary);
+        RBASIC_CLEAR_CLASS(tmp);
+        data.ary = tmp;
         data.receiver = ary;
-	data.cmp_opt.opt_methods = 0;
-	data.cmp_opt.opt_inited = 0;
-	RARRAY_PTR_USE(tmp, ptr, {
+        RARRAY_PTR_USE(tmp, ptr, {
             ruby_qsort(ptr, len, sizeof(VALUE),
                        rb_block_given_p()?sort_1:sort_2, &data);
-	}); /* WB: no new reference */
-	rb_ary_modify(ary);
+        }); /* WB: no new reference */
+        rb_ary_modify(ary);
         if (ARY_EMBED_P(tmp)) {
             if (ARY_SHARED_P(ary)) { /* ary might be destructively operated in the given block */
                 rb_ary_unshare(ary);
-		FL_SET_EMBED(ary);
+                FL_SET_EMBED(ary);
             }
-	    ary_memcpy(ary, 0, ARY_EMBED_LEN(tmp), ARY_EMBED_PTR(tmp));
+            if (ARY_EMBED_LEN(tmp) > ARY_CAPA(ary)) {
+                ary_resize_capa(ary, ARY_EMBED_LEN(tmp));
+            }
+            ary_memcpy(ary, 0, ARY_EMBED_LEN(tmp), ARY_EMBED_PTR(tmp));
             ARY_SET_LEN(ary, ARY_EMBED_LEN(tmp));
         }
         else {
@@ -3408,7 +3418,7 @@ rb_ary_sort_bang(VALUE ary)
                 ARY_SET_CAPA(ary, RARRAY_LEN(tmp));
             }
             else {
-                assert(!ARY_SHARED_P(tmp));
+                RUBY_ASSERT(!ARY_SHARED_P(tmp));
                 if (ARY_EMBED_P(ary)) {
                     FL_UNSET_EMBED(ary);
                 }
@@ -3438,40 +3448,33 @@ rb_ary_sort_bang(VALUE ary)
 
 /*
  *  call-seq:
- *    array.sort -> new_array
- *    array.sort {|a, b| ... } -> new_array
+ *    sort -> new_array
+ *    sort {|a, b| ... } -> new_array
+ *
+ *  Returns a new array containing the elements of +self+, sorted.
  *
- *  Returns a new \Array whose elements are those from +self+, sorted.
+ *  With no block given, compares elements using operator <tt>#<=></tt>
+ *  (see Object#<=>):
  *
- *  With no block, compares elements using operator <tt><=></tt>
- *  (see Comparable):
- *    a = 'abcde'.split('').shuffle
- *    a # => ["e", "b", "d", "a", "c"]
- *    a1 = a.sort
- *    a1 # => ["a", "b", "c", "d", "e"]
+ *    [0, 2, 3, 1].sort # => [0, 1, 2, 3]
+ *
+ *  With a block given, calls the block with each combination of pairs of elements from +self+;
+ *  for each pair +a+ and +b+, the block should return a numeric:
  *
- *  With a block, calls the block with each element pair;
- *  for each element pair +a+ and +b+, the block should return an integer:
  *  - Negative when +b+ is to follow +a+.
  *  - Zero when +a+ and +b+ are equivalent.
  *  - Positive when +a+ is to follow +b+.
  *
  *  Example:
- *    a = 'abcde'.split('').shuffle
- *    a # => ["e", "b", "d", "a", "c"]
- *    a1 = a.sort {|a, b| a <=> b }
- *    a1 # => ["a", "b", "c", "d", "e"]
- *    a2 = a.sort {|a, b| b <=> a }
- *    a2 # => ["e", "d", "c", "b", "a"]
+ *
+ *    a = [3, 2, 0, 1]
+ *    a.sort {|a, b| a <=> b } # => [0, 1, 2, 3]
+ *    a.sort {|a, b| b <=> a } # => [3, 2, 1, 0]
  *
  *  When the block returns zero, the order for +a+ and +b+ is indeterminate,
- *  and may be unstable:
- *    a = 'abcde'.split('').shuffle
- *    a # => ["e", "b", "d", "a", "c"]
- *    a1 = a.sort {|a, b| 0 }
- *    a1 # =>  ["c", "e", "b", "d", "a"]
+ *  and may be unstable.
  *
- *  Related: Enumerable#sort_by.
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 VALUE
@@ -3486,12 +3489,15 @@ static VALUE rb_ary_bsearch_index(VALUE ary);
 
 /*
  *  call-seq:
- *    array.bsearch {|element| ... } -> object
- *    array.bsearch -> new_enumerator
+ *    bsearch {|element| ... } -> found_element or nil
+ *    bsearch -> new_enumerator
  *
- *  Returns an element from +self+ selected by a binary search.
+ *  Returns the element from +self+ found by a binary search,
+ *  or +nil+ if the search found no suitable element.
  *
  *  See {Binary Searching}[rdoc-ref:bsearch.rdoc].
+ *
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 static VALUE
@@ -3500,18 +3506,22 @@ rb_ary_bsearch(VALUE ary)
     VALUE index_result = rb_ary_bsearch_index(ary);
 
     if (FIXNUM_P(index_result)) {
-	return rb_ary_entry(ary, FIX2LONG(index_result));
+        return rb_ary_entry(ary, FIX2LONG(index_result));
     }
     return index_result;
 }
 
 /*
  *  call-seq:
- *    array.bsearch_index {|element| ... } -> integer or nil
- *    array.bsearch_index -> new_enumerator
+ *    bsearch_index {|element| ... } -> integer or nil
+ *    bsearch_index -> new_enumerator
+ *
+ *  Returns the integer index of the element from +self+ found by a binary search,
+ *  or +nil+ if the search found no suitable element.
  *
- *  Searches +self+ as described at method #bsearch,
- *  but returns the _index_ of the found element instead of the element itself.
+ *  See {Binary Searching}[rdoc-ref:bsearch.rdoc].
+ *
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 static VALUE
@@ -3523,39 +3533,39 @@ rb_ary_bsearch_index(VALUE ary)
 
     RETURN_ENUMERATOR(ary, 0, 0);
     while (low < high) {
-	mid = low + ((high - low) / 2);
-	val = rb_ary_entry(ary, mid);
-	v = rb_yield(val);
-	if (FIXNUM_P(v)) {
-	    if (v == INT2FIX(0)) return INT2FIX(mid);
-	    smaller = (SIGNED_VALUE)v < 0; /* Fixnum preserves its sign-bit */
-	}
-	else if (v == Qtrue) {
-	    satisfied = 1;
-	    smaller = 1;
-	}
-	else if (!RTEST(v)) {
-	    smaller = 0;
-	}
-	else if (rb_obj_is_kind_of(v, rb_cNumeric)) {
-	    const VALUE zero = INT2FIX(0);
-	    switch (rb_cmpint(rb_funcallv(v, id_cmp, 1, &zero), v, zero)) {
-	      case 0: return INT2FIX(mid);
-	      case 1: smaller = 1; break;
-	      case -1: smaller = 0;
-	    }
-	}
-	else {
-	    rb_raise(rb_eTypeError, "wrong argument type %"PRIsVALUE
-		     " (must be numeric, true, false or nil)",
-		     rb_obj_class(v));
-	}
-	if (smaller) {
-	    high = mid;
-	}
-	else {
-	    low = mid + 1;
-	}
+        mid = low + ((high - low) / 2);
+        val = rb_ary_entry(ary, mid);
+        v = rb_yield(val);
+        if (FIXNUM_P(v)) {
+            if (v == INT2FIX(0)) return INT2FIX(mid);
+            smaller = (SIGNED_VALUE)v < 0; /* Fixnum preserves its sign-bit */
+        }
+        else if (v == Qtrue) {
+            satisfied = 1;
+            smaller = 1;
+        }
+        else if (!RTEST(v)) {
+            smaller = 0;
+        }
+        else if (rb_obj_is_kind_of(v, rb_cNumeric)) {
+            const VALUE zero = INT2FIX(0);
+            switch (rb_cmpint(rb_funcallv(v, id_cmp, 1, &zero), v, zero)) {
+              case 0: return INT2FIX(mid);
+              case 1: smaller = 0; break;
+              case -1: smaller = 1;
+            }
+        }
+        else {
+            rb_raise(rb_eTypeError, "wrong argument type %"PRIsVALUE
+                     " (must be numeric, true, false or nil)",
+                     rb_obj_class(v));
+        }
+        if (smaller) {
+            high = mid;
+        }
+        else {
+            low = mid + 1;
+        }
     }
     if (!satisfied) return Qnil;
     return INT2FIX(low);
@@ -3570,26 +3580,24 @@ sort_by_i(RB_BLOCK_CALL_FUNC_ARGLIST(i, dummy))
 
 /*
  *  call-seq:
- *    array.sort_by! {|element| ... } -> self
- *    array.sort_by! -> new_enumerator
+ *    sort_by! {|element| ... } -> self
+ *    sort_by! -> new_enumerator
  *
- *  Sorts the elements of +self+ in place,
- *  using an ordering determined by the block; returns self.
+ *  With a block given, sorts the elements of +self+ in place;
+ *  returns self.
  *
  *  Calls the block with each successive element;
- *  sorts elements based on the values returned from the block.
- *
- *  For duplicates returned by the block, the ordering is indeterminate, and may be unstable.
+ *  sorts elements based on the values returned from the block:
  *
- *  This example sorts strings based on their sizes:
  *    a = ['aaaa', 'bbb', 'cc', 'd']
  *    a.sort_by! {|element| element.size }
  *    a # => ["d", "cc", "bbb", "aaaa"]
  *
- *  Returns a new \Enumerator if no block given:
+ *  For duplicate values returned by the block, the ordering is indeterminate, and may be unstable.
  *
- *    a = ['aaaa', 'bbb', 'cc', 'd']
- *    a.sort_by! # => #<Enumerator: ["aaaa", "bbb", "cc", "d"]:sort_by!>
+ *  With no block given, returns a new Enumerator.
+ *
+ *  Related: see {Methods for Assigning}[rdoc-ref:Array@Methods+for+Assigning].
  */
 
 static VALUE
@@ -3607,21 +3615,22 @@ rb_ary_sort_by_bang(VALUE ary)
 
 /*
  *  call-seq:
- *    array.map {|element| ... } -> new_array
- *    array.map -> new_enumerator
+ *    collect {|element| ... } -> new_array
+ *    collect -> new_enumerator
+ *    map {|element| ... } -> new_array
+ *    map -> new_enumerator
+ *
+ *  With a block given, calls the block with each element of +self+;
+ *  returns a new array whose elements are the return values from the block:
  *
- *  Calls the block, if given, with each element of +self+;
- *  returns a new \Array whose elements are the return values from the block:
  *    a = [:foo, 'bar', 2]
  *    a1 = a.map {|element| element.class }
  *    a1 # => [Symbol, String, Integer]
  *
- *  Returns a new \Enumerator if no block given:
- *    a = [:foo, 'bar', 2]
- *    a1 = a.map
- *    a1 # => #<Enumerator: [:foo, "bar", 2]:map>
+ *  With no block given, returns a new Enumerator.
  *
- *  Array#collect is an alias for Array#map.
+ *  Related: #collect!;
+ *  see also {Methods for Converting}[rdoc-ref:Array@Methods+for+Converting].
  */
 
 static VALUE
@@ -3641,20 +3650,22 @@ rb_ary_collect(VALUE ary)
 
 /*
  *  call-seq:
- *    array.map! {|element| ... } -> self
- *    array.map! -> new_enumerator
+ *    collect! {|element| ... } -> new_array
+ *    collect! -> new_enumerator
+ *    map! {|element| ... } -> new_array
+ *    map! -> new_enumerator
+ *
+ *  With a block given, calls the block with each element of +self+
+ *  and replaces the element with the block's return value;
+ *  returns +self+:
  *
- *  Calls the block, if given, with each element;
- *  replaces the element with the block's return value:
  *    a = [:foo, 'bar', 2]
  *    a.map! { |element| element.class } # => [Symbol, String, Integer]
  *
- *  Returns a new \Enumerator if no block given:
- *    a = [:foo, 'bar', 2]
- *    a1 = a.map!
- *    a1 # => #<Enumerator: [:foo, "bar", 2]:map!>
+ *  With no block given, returns a new Enumerator.
  *
- *  Array#collect! is an alias for Array#map!.
+ *  Related: #collect;
+ *  see also {Methods for Converting}[rdoc-ref:Array@Methods+for+Converting].
  */
 
 static VALUE
@@ -3665,7 +3676,7 @@ rb_ary_collect_bang(VALUE ary)
     RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
     rb_ary_modify(ary);
     for (i = 0; i < RARRAY_LEN(ary); i++) {
-	rb_ary_store(ary, i, rb_yield(RARRAY_AREF(ary, i)));
+        rb_ary_store(ary, i, rb_yield(RARRAY_AREF(ary, i)));
     }
     return ary;
 }
@@ -3677,21 +3688,21 @@ rb_get_values_at(VALUE obj, long olen, int argc, const VALUE *argv, VALUE (*func
     long beg, len, i, j;
 
     for (i=0; i<argc; i++) {
-	if (FIXNUM_P(argv[i])) {
-	    rb_ary_push(result, (*func)(obj, FIX2LONG(argv[i])));
-	    continue;
-	}
-	/* check if idx is Range */
-	if (rb_range_beg_len(argv[i], &beg, &len, olen, 1)) {
-	    long end = olen < beg+len ? olen : beg+len;
-	    for (j = beg; j < end; j++) {
-		rb_ary_push(result, (*func)(obj, j));
-	    }
-	    if (beg + len > j)
-		rb_ary_resize(result, RARRAY_LEN(result) + (beg + len) - j);
-	    continue;
-	}
-	rb_ary_push(result, (*func)(obj, NUM2LONG(argv[i])));
+        if (FIXNUM_P(argv[i])) {
+            rb_ary_push(result, (*func)(obj, FIX2LONG(argv[i])));
+            continue;
+        }
+        /* check if idx is Range */
+        if (rb_range_beg_len(argv[i], &beg, &len, olen, 1)) {
+            long end = olen < beg+len ? olen : beg+len;
+            for (j = beg; j < end; j++) {
+                rb_ary_push(result, (*func)(obj, j));
+            }
+            if (beg + len > j)
+                rb_ary_resize(result, RARRAY_LEN(result) + (beg + len) - j);
+            continue;
+        }
+        rb_ary_push(result, (*func)(obj, NUM2LONG(argv[i])));
     }
     return result;
 }
@@ -3701,63 +3712,133 @@ append_values_at_single(VALUE result, VALUE ary, long olen, VALUE idx)
 {
     long beg, len;
     if (FIXNUM_P(idx)) {
-	beg = FIX2LONG(idx);
+        beg = FIX2LONG(idx);
     }
     /* check if idx is Range */
     else if (rb_range_beg_len(idx, &beg, &len, olen, 1)) {
-	if (len > 0) {
-            const VALUE *const src = RARRAY_CONST_PTR_TRANSIENT(ary);
-	    const long end = beg + len;
-	    const long prevlen = RARRAY_LEN(result);
-	    if (beg < olen) {
-		rb_ary_cat(result, src + beg, end > olen ? olen-beg : len);
-	    }
-	    if (end > olen) {
-		rb_ary_store(result, prevlen + len - 1, Qnil);
-	    }
-	}
-	return result;
+        if (len > 0) {
+            const VALUE *const src = RARRAY_CONST_PTR(ary);
+            const long end = beg + len;
+            const long prevlen = RARRAY_LEN(result);
+            if (beg < olen) {
+                rb_ary_cat(result, src + beg, end > olen ? olen-beg : len);
+            }
+            if (end > olen) {
+                rb_ary_store(result, prevlen + len - 1, Qnil);
+            }
+        }
+        return result;
     }
     else {
-	beg = NUM2LONG(idx);
+        beg = NUM2LONG(idx);
     }
     return rb_ary_push(result, rb_ary_entry(ary, beg));
 }
 
 /*
  *  call-seq:
- *    array.values_at(*indexes) -> new_array
+ *    values_at(*specifiers) -> new_array
  *
- *  Returns a new \Array whose elements are the elements
- *  of +self+ at the given \Integer or \Range +indexes+.
+ *  Returns elements from +self+ in a new array; does not modify +self+.
  *
- *  For each positive +index+, returns the element at offset +index+:
- *    a = [:foo, 'bar', 2]
- *    a.values_at(0, 2) # => [:foo, 2]
- *    a.values_at(0..1) # => [:foo, "bar"]
+ *  The objects included in the returned array are the elements of +self+
+ *  selected by the given +specifiers+,
+ *  each of which must be a numeric index or a Range.
  *
- *  The given +indexes+ may be in any order, and may repeat:
- *    a = [:foo, 'bar', 2]
- *    a.values_at(2, 0, 1, 0, 2) # => [2, :foo, "bar", :foo, 2]
- *    a.values_at(1, 0..2) # => ["bar", :foo, "bar", 2]
+ *  In brief:
  *
- *  Assigns +nil+ for an +index+ that is too large:
- *    a = [:foo, 'bar', 2]
- *    a.values_at(0, 3, 1, 3) # => [:foo, nil, "bar", nil]
+ *    a = ['a', 'b', 'c', 'd']
  *
- *  Returns a new empty \Array if no arguments given.
+ *    # Index specifiers.
+ *    a.values_at(2, 0, 2, 0)     # => ["c", "a", "c", "a"] # May repeat.
+ *    a.values_at(-4, -3, -2, -1) # => ["a", "b", "c", "d"] # Counts backwards if negative.
+ *    a.values_at(-50, 50)        # => [nil, nil]           # Outside of self.
  *
- *  For each negative +index+, counts backward from the end of the array:
- *    a = [:foo, 'bar', 2]
- *    a.values_at(-1, -3) # => [2, :foo]
+ *    # Range specifiers.
+ *    a.values_at(1..3)       # => ["b", "c", "d"] # From range.begin to range.end.
+ *    a.values_at(1...3)      # => ["b", "c"]      # End excluded.
+ *    a.values_at(3..1)       # => []              # No such elements.
  *
- *  Assigns +nil+ for an +index+ that is too small:
- *    a = [:foo, 'bar', 2]
- *    a.values_at(0, -5, 1, -6, 2) # => [:foo, nil, "bar", nil, 2]
+ *    a.values_at(-3..3)  # => ["b", "c", "d"]     # Negative range.begin counts backwards.
+ *    a.values_at(-50..3)                          # Raises RangeError.
  *
- *  The given +indexes+ may have a mixture of signs:
- *    a = [:foo, 'bar', 2]
- *    a.values_at(0, -2, 1, -1) # => [:foo, "bar", "bar", 2]
+ *    a.values_at(1..-2)  # => ["b", "c"]          # Negative range.end counts backwards.
+ *    a.values_at(1..-50) # => []                  # No such elements.
+ *
+ *    # Mixture of specifiers.
+ *    a.values_at(2..3, 3, 0..1, 0) # => ["c", "d", "d", "a", "b", "a"]
+ *
+ *  With no +specifiers+ given, returns a new empty array:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.values_at # => []
+ *
+ *  For each numeric specifier +index+, includes an element:
+ *
+ *  - For each non-negative numeric specifier +index+ that is in-range (less than <tt>self.size</tt>),
+ *    includes the element at offset +index+:
+ *
+ *      a.values_at(0, 2)     # => ["a", "c"]
+ *      a.values_at(0.1, 2.9) # => ["a", "c"]
+ *
+ *  - For each negative numeric +index+ that is in-range (greater than or equal to <tt>- self.size</tt>),
+ *    counts backwards from the end of +self+:
+ *
+ *      a.values_at(-1, -4) # => ["d", "a"]
+ *
+ *  The given indexes may be in any order, and may repeat:
+ *
+ *    a.values_at(2, 0, 1, 0, 2) # => ["c", "a", "b", "a", "c"]
+ *
+ *  For each +index+ that is out-of-range, includes +nil+:
+ *
+ *    a.values_at(4, -5) # => [nil, nil]
+ *
+ *  For each Range specifier +range+, includes elements
+ *  according to <tt>range.begin</tt> and <tt>range.end</tt>:
+ *
+ *  - If both <tt>range.begin</tt> and <tt>range.end</tt>
+ *    are non-negative and in-range (less than <tt>self.size</tt>),
+ *    includes elements from index <tt>range.begin</tt>
+ *    through <tt>range.end - 1</tt> (if <tt>range.exclude_end?</tt>),
+ *    or through <tt>range.end</tt> (otherwise):
+ *
+ *      a.values_at(1..2)  # => ["b", "c"]
+ *      a.values_at(1...2) # => ["b"]
+ *
+ *  - If <tt>range.begin</tt> is negative and in-range (greater than or equal to <tt>- self.size</tt>),
+ *    counts backwards from the end of +self+:
+ *
+ *      a.values_at(-2..3) # => ["c", "d"]
+ *
+ *  - If <tt>range.begin</tt> is negative and out-of-range, raises an exception:
+ *
+ *      a.values_at(-5..3) # Raises RangeError.
+ *
+ *  - If <tt>range.end</tt> is positive and out-of-range,
+ *    extends the returned array with +nil+ elements:
+ *
+ *      a.values_at(1..5) # => ["b", "c", "d", nil, nil]
+ *
+ *  - If <tt>range.end</tt> is negative and in-range,
+ *    counts backwards from the end of +self+:
+ *
+ *      a.values_at(1..-2) # => ["b", "c"]
+ *
+ *  - If <tt>range.end</tt> is negative and out-of-range,
+ *    returns an empty array:
+ *
+ *      a.values_at(1..-5) # => []
+ *
+ *  The given ranges may be in any order and may repeat:
+ *
+ *    a.values_at(2..3, 0..1, 2..3) # => ["c", "d", "a", "b", "c", "d"]
+ *
+ *  The given specifiers may be any mixture of indexes and ranges:
+ *
+ *    a.values_at(3, 1..2, 0, 2..3) # => ["d", "b", "c", "a", "c", "d"]
+ *
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 static VALUE
@@ -3766,7 +3847,7 @@ rb_ary_values_at(int argc, VALUE *argv, VALUE ary)
     long i, olen = RARRAY_LEN(ary);
     VALUE result = rb_ary_new_capa(argc);
     for (i = 0; i < argc; ++i) {
-	append_values_at_single(result, ary, olen, argv[i]);
+        append_values_at_single(result, ary, olen, argv[i]);
     }
     RB_GC_GUARD(ary);
     return result;
@@ -3775,21 +3856,22 @@ rb_ary_values_at(int argc, VALUE *argv, VALUE ary)
 
 /*
  *  call-seq:
- *    array.select {|element| ... } -> new_array
- *    array.select -> new_enumerator
+ *    select {|element| ... } -> new_array
+ *    select -> new_enumerator
+ *    filter {|element| ... } -> new_array
+ *    filter -> new_enumerator
  *
- *  Calls the block, if given, with each element of +self+;
- *  returns a new \Array containing those elements of +self+
+ *  With a block given, calls the block with each element of +self+;
+ *  returns a new array containing those elements of +self+
  *  for which the block returns a truthy value:
- *    a = [:foo, 'bar', 2, :bam]
- *    a1 = a.select {|element| element.to_s.start_with?('b') }
- *    a1 # => ["bar", :bam]
  *
- *  Returns a new \Enumerator if no block given:
  *    a = [:foo, 'bar', 2, :bam]
- *    a.select # => #<Enumerator: [:foo, "bar", 2, :bam]:select>
+ *    a.select {|element| element.to_s.start_with?('b') }
+ *    # => ["bar", :bam]
  *
- *  Array#filter is an alias for Array#select.
+ *  With no block given, returns a new Enumerator.
+ *
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 static VALUE
@@ -3801,9 +3883,9 @@ rb_ary_select(VALUE ary)
     RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
     result = rb_ary_new2(RARRAY_LEN(ary));
     for (i = 0; i < RARRAY_LEN(ary); i++) {
-	if (RTEST(rb_yield(RARRAY_AREF(ary, i)))) {
-	    rb_ary_push(result, rb_ary_elt(ary, i));
-	}
+        if (RTEST(rb_yield(RARRAY_AREF(ary, i)))) {
+            rb_ary_push(result, rb_ary_elt(ary, i));
+        }
     }
     return result;
 }
@@ -3821,12 +3903,12 @@ select_bang_i(VALUE a)
     long i1, i2;
 
     for (i1 = i2 = 0; i1 < RARRAY_LEN(ary); arg->len[0] = ++i1) {
-	VALUE v = RARRAY_AREF(ary, i1);
-	if (!RTEST(rb_yield(v))) continue;
-	if (i1 != i2) {
-	    rb_ary_store(ary, i2, v);
-	}
-	arg->len[1] = ++i2;
+        VALUE v = RARRAY_AREF(ary, i1);
+        if (!RTEST(rb_yield(v))) continue;
+        if (i1 != i2) {
+            rb_ary_store(ary, i2, v);
+        }
+        arg->len[1] = ++i2;
     }
     return (i1 == i2) ? Qnil : ary;
 }
@@ -3840,38 +3922,39 @@ select_bang_ensure(VALUE a)
     long i1 = arg->len[0], i2 = arg->len[1];
 
     if (i2 < len && i2 < i1) {
-	long tail = 0;
+        long tail = 0;
         rb_ary_modify(ary);
-	if (i1 < len) {
-	    tail = len - i1;
-            RARRAY_PTR_USE_TRANSIENT(ary, ptr, {
-		    MEMMOVE(ptr + i2, ptr + i1, VALUE, tail);
-		});
-	}
-	ARY_SET_LEN(ary, i2 + tail);
+        if (i1 < len) {
+            tail = len - i1;
+            RARRAY_PTR_USE(ary, ptr, {
+                    MEMMOVE(ptr + i2, ptr + i1, VALUE, tail);
+                });
+        }
+        ARY_SET_LEN(ary, i2 + tail);
     }
     return ary;
 }
 
 /*
  *  call-seq:
- *    array.select! {|element| ... } -> self or nil
- *    array.select! -> new_enumerator
+ *    select! {|element| ... } -> self or nil
+ *    select! -> new_enumerator
+ *    filter! {|element| ... } -> self or nil
+ *    filter! -> new_enumerator
  *
- *  Calls the block, if given  with each element of +self+;
+ *  With a block given, calls the block with each element of +self+;
  *  removes from +self+ those elements for which the block returns +false+ or +nil+.
  *
  *  Returns +self+ if any elements were removed:
+ *
  *    a = [:foo, 'bar', 2, :bam]
  *    a.select! {|element| element.to_s.start_with?('b') } # => ["bar", :bam]
  *
  *  Returns +nil+ if no elements were removed.
  *
- *  Returns a new \Enumerator if no block given:
- *    a = [:foo, 'bar', 2, :bam]
- *    a.select! # => #<Enumerator: [:foo, "bar", 2, :bam]:select!>
+ *  With no block given, returns a new Enumerator.
  *
- *  Array#filter! is an alias for Array#select!.
+ *  Related: see {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
 
 static VALUE
@@ -3889,17 +3972,18 @@ rb_ary_select_bang(VALUE ary)
 
 /*
  *  call-seq:
- *    array.keep_if {|element| ... } -> self
- *    array.keep_if -> new_enumeration
+ *    keep_if {|element| ... } -> self
+ *    keep_if -> new_enumerator
+ *
+ *  With a block given, calls the block with each element of +self+;
+ *  removes the element from +self+ if the block does not return a truthy value:
  *
- *  Retains those elements for which the block returns a truthy value;
- *  deletes all other elements; returns +self+:
  *    a = [:foo, 'bar', 2, :bam]
  *    a.keep_if {|element| element.to_s.start_with?('b') } # => ["bar", :bam]
  *
- *  Returns a new \Enumerator if no block given:
- *    a = [:foo, 'bar', 2, :bam]
- *    a.keep_if # => #<Enumerator: [:foo, "bar", 2, :bam]:keep_if>
+ *  With no block given, returns a new Enumerator.
+ *
+ *  Related: see {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
 
 static VALUE
@@ -3915,44 +3999,49 @@ ary_resize_smaller(VALUE ary, long len)
 {
     rb_ary_modify(ary);
     if (RARRAY_LEN(ary) > len) {
-	ARY_SET_LEN(ary, len);
-	if (len * 2 < ARY_CAPA(ary) &&
-	    ARY_CAPA(ary) > ARY_DEFAULT_SIZE) {
-	    ary_resize_capa(ary, len * 2);
-	}
+        ARY_SET_LEN(ary, len);
+        if (len * 2 < ARY_CAPA(ary) &&
+            ARY_CAPA(ary) > ARY_DEFAULT_SIZE) {
+            ary_resize_capa(ary, len * 2);
+        }
     }
 }
 
 /*
  *  call-seq:
- *    array.delete(obj) -> deleted_object
- *    array.delete(obj) {|nosuch| ... } -> deleted_object or block_return
+ *    delete(object) -> last_removed_object
+ *    delete(object) {|element| ... } -> last_removed_object or block_return
  *
  *  Removes zero or more elements from +self+.
  *
- *  When no block is given,
- *  removes from +self+ each element +ele+ such that <tt>ele == obj</tt>;
- *  returns the last deleted element:
- *    s1 = 'bar'; s2 = 'bar'
- *    a = [:foo, s1, 2, s2]
- *    a.delete('bar') # => "bar"
- *    a # => [:foo, 2]
+ *  With no block given,
+ *  removes from +self+ each element +ele+ such that <tt>ele == object</tt>;
+ *  returns the last removed element:
  *
- *  Returns +nil+ if no elements removed.
+ *    a = [0, 1, 2, 2.0]
+ *    a.delete(2) # => 2.0
+ *    a           # => [0, 1]
+ *
+ *  Returns +nil+ if no elements removed:
  *
- *  When a block is given,
- *  removes from +self+ each element +ele+ such that <tt>ele == obj</tt>.
+ *    a.delete(2) # => nil
+ *
+ *  With a block given,
+ *  removes from +self+ each element +ele+ such that <tt>ele == object</tt>.
  *
  *  If any such elements are found, ignores the block
- *  and returns the last deleted element:
- *    s1 = 'bar'; s2 = 'bar'
- *    a = [:foo, s1, 2, s2]
- *    deleted_obj = a.delete('bar') {|obj| fail 'Cannot happen' }
- *    a # => [:foo, 2]
+ *  and returns the last removed element:
  *
- *  If no such elements are found, returns the block's return value:
- *    a = [:foo, 'bar', 2]
- *    a.delete(:nosuch) {|obj| "#{obj} not found" } # => "nosuch not found"
+ *    a = [0, 1, 2, 2.0]
+ *    a.delete(2) {|element| fail 'Cannot happen' } # => 2.0
+ *    a                                             # => [0, 1]
+ *
+ *  If no such element is found, returns the block's return value:
+ *
+ *    a.delete(2) {|element| "Element #{element} not found." }
+ *    # => "Element 2 not found."
+ *
+ *  Related: see {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
 
 VALUE
@@ -3962,22 +4051,22 @@ rb_ary_delete(VALUE ary, VALUE item)
     long i1, i2;
 
     for (i1 = i2 = 0; i1 < RARRAY_LEN(ary); i1++) {
-	VALUE e = RARRAY_AREF(ary, i1);
+        VALUE e = RARRAY_AREF(ary, i1);
 
-	if (rb_equal(e, item)) {
-	    v = e;
-	    continue;
-	}
-	if (i1 != i2) {
-	    rb_ary_store(ary, i2, e);
-	}
-	i2++;
+        if (rb_equal(e, item)) {
+            v = e;
+            continue;
+        }
+        if (i1 != i2) {
+            rb_ary_store(ary, i2, e);
+        }
+        i2++;
     }
     if (RARRAY_LEN(ary) == i2) {
-	if (rb_block_given_p()) {
-	    return rb_yield(item);
-	}
-	return Qnil;
+        if (rb_block_given_p()) {
+            return rb_yield(item);
+        }
+        return Qnil;
     }
 
     ary_resize_smaller(ary, i2);
@@ -3992,18 +4081,18 @@ rb_ary_delete_same(VALUE ary, VALUE item)
     long i1, i2;
 
     for (i1 = i2 = 0; i1 < RARRAY_LEN(ary); i1++) {
-	VALUE e = RARRAY_AREF(ary, i1);
+        VALUE e = RARRAY_AREF(ary, i1);
 
-	if (e == item) {
-	    continue;
-	}
-	if (i1 != i2) {
-	    rb_ary_store(ary, i2, e);
-	}
-	i2++;
+        if (e == item) {
+            continue;
+        }
+        if (i1 != i2) {
+            rb_ary_store(ary, i2, e);
+        }
+        i2++;
     }
     if (RARRAY_LEN(ary) == i2) {
-	return;
+        return;
     }
 
     ary_resize_smaller(ary, i2);
@@ -4017,13 +4106,13 @@ rb_ary_delete_at(VALUE ary, long pos)
 
     if (pos >= len) return Qnil;
     if (pos < 0) {
-	pos += len;
-	if (pos < 0) return Qnil;
+        pos += len;
+        if (pos < 0) return Qnil;
     }
 
     rb_ary_modify(ary);
     del = RARRAY_AREF(ary, pos);
-    RARRAY_PTR_USE_TRANSIENT(ary, ptr, {
+    RARRAY_PTR_USE(ary, ptr, {
         MEMMOVE(ptr+pos, ptr+pos+1, VALUE, len-pos-1);
     });
     ARY_INCREASE_LEN(ary, -1);
@@ -4033,23 +4122,30 @@ rb_ary_delete_at(VALUE ary, long pos)
 
 /*
  *  call-seq:
- *    array.delete_at(index) -> deleted_object or nil
+ *    delete_at(index) -> removed_object or nil
  *
- *  Deletes an element from +self+, per the given \Integer +index+.
+ *  Removes the element of +self+ at the given +index+, which must be an
+ *  {integer-convertible object}[rdoc-ref:implicit_conversion.rdoc@Integer-Convertible+Objects].
  *
  *  When +index+ is non-negative, deletes the element at offset +index+:
+ *
  *    a = [:foo, 'bar', 2]
  *    a.delete_at(1) # => "bar"
  *    a # => [:foo, 2]
  *
- *  If index is too large, returns +nil+.
- *
  *  When +index+ is negative, counts backward from the end of the array:
+ *
  *    a = [:foo, 'bar', 2]
  *    a.delete_at(-2) # => "bar"
  *    a # => [:foo, 2]
  *
- *  If +index+ is too small (far from zero), returns nil.
+ *  When +index+ is out of range, returns +nil+.
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.delete_at(3)  # => nil
+ *    a.delete_at(-4) # => nil
+ *
+ *  Related: see {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
 
 static VALUE
@@ -4082,7 +4178,7 @@ ary_slice_bang_by_rb_ary_splice(VALUE ary, long pos, long len)
         return rb_ary_new2(0);
     }
     else {
-        VALUE arg2 = rb_ary_new4(len, RARRAY_CONST_PTR_TRANSIENT(ary)+pos);
+        VALUE arg2 = rb_ary_new4(len, RARRAY_CONST_PTR(ary)+pos);
         rb_ary_splice(ary, pos, len, 0, 0);
         return arg2;
     }
@@ -4090,63 +4186,94 @@ ary_slice_bang_by_rb_ary_splice(VALUE ary, long pos, long len)
 
 /*
  *  call-seq:
- *    array.slice!(n) -> object or nil
- *    array.slice!(start, length) -> new_array or nil
- *    array.slice!(range) -> new_array or nil
+ *    slice!(index) -> object or nil
+ *    slice!(start, length) -> new_array or nil
+ *    slice!(range) -> new_array or nil
  *
  *  Removes and returns elements from +self+.
  *
- *  When the only argument is an \Integer +n+,
- *  removes and returns the _nth_ element in +self+:
- *    a = [:foo, 'bar', 2]
- *    a.slice!(1) # => "bar"
- *    a # => [:foo, 2]
+ *  With numeric argument +index+ given,
+ *  removes and returns the element at offset +index+:
  *
- *  If +n+ is negative, counts backwards from the end of +self+:
- *    a = [:foo, 'bar', 2]
- *    a.slice!(-1) # => 2
- *    a # => [:foo, "bar"]
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.slice!(2)   # => "c"
+ *    a             # => ["a", "b", "d"]
+ *    a.slice!(2.1) # => "d"
+ *    a             # => ["a", "b"]
  *
- *  If +n+ is out of range, returns +nil+.
+ *  If +index+ is negative, counts backwards from the end of +self+:
  *
- *  When the only arguments are Integers +start+ and +length+,
- *  removes +length+ elements from +self+ beginning at offset  +start+;
- *  returns the deleted objects in a new \Array:
- *    a = [:foo, 'bar', 2]
- *    a.slice!(0, 2) # => [:foo, "bar"]
- *    a # => [2]
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.slice!(-2) # => "c"
+ *    a            # => ["a", "b", "d"]
+ *
+ *  If +index+ is out of range, returns +nil+.
+ *
+ *  With numeric arguments +start+ and +length+ given,
+ *  removes +length+ elements from +self+ beginning at zero-based offset +start+;
+ *  returns the removed objects in a new array:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.slice!(1, 2)     # => ["b", "c"]
+ *    a                  # => ["a", "d"]
+ *    a.slice!(0.1, 1.1) # => ["a"]
+ *    a                  # => ["d"]
+ *
+ *  If +start+ is negative, counts backwards from the end of +self+:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.slice!(-2, 1) # => ["c"]
+ *    a               # => ["a", "b", "d"]
+ *
+ *  If +start+ is out-of-range, returns +nil+:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.slice!(5, 1)  # => nil
+ *    a.slice!(-5, 1) # => nil
  *
  *  If <tt>start + length</tt> exceeds the array size,
  *  removes and returns all elements from offset +start+ to the end:
- *    a = [:foo, 'bar', 2]
- *    a.slice!(1, 50) # => ["bar", 2]
- *    a # => [:foo]
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.slice!(2, 50) # => ["c", "d"]
+ *    a               # => ["a", "b"]
  *
  *  If <tt>start == a.size</tt> and +length+ is non-negative,
- *  returns a new empty \Array.
+ *  returns a new empty array.
  *
  *  If +length+ is negative, returns +nil+.
  *
- *  When the only argument is a \Range object +range+,
- *  treats <tt>range.min</tt> as +start+ above and <tt>range.size</tt> as +length+ above:
- *    a = [:foo, 'bar', 2]
- *     a.slice!(1..2) # => ["bar", 2]
- *    a # => [:foo]
+ *  With Range argument +range+ given,
+ *  treats <tt>range.min</tt> as +start+ (as above)
+ *  and <tt>range.size</tt> as +length+ (as above):
  *
- *  If <tt>range.start == a.size</tt>, returns a new empty \Array.
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.slice!(1..2) # => ["b", "c"]
+ *    a              # => ["a", "d"]
  *
- *  If <tt>range.start</tt> is larger than the array size, returns +nil+.
+ *  If <tt>range.start == a.size</tt>, returns a new empty array:
  *
- *  If <tt>range.end</tt> is negative, counts backwards from the end of the array:
- *    a = [:foo, 'bar', 2]
- *    a.slice!(0..-2) # => [:foo, "bar"]
- *    a # => [2]
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.slice!(4..5) # => []
+ *
+ *  If <tt>range.start</tt> is larger than the array size, returns +nil+:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+      a.slice!(5..6) # => nil
  *
  *  If <tt>range.start</tt> is negative,
- *  calculates the start index backwards from the end of the array:
- *    a = [:foo, 'bar', 2]
- *    a.slice!(-2..2) # => ["bar", 2]
- *    a # => [:foo]
+ *  calculates the start index by counting backwards from the end of +self+:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.slice!(-2..2) # => ["c"]
+ *
+ *  If <tt>range.end</tt> is negative,
+ *  calculates the end index by counting backwards from the end of +self+:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.slice!(0..-2) # => ["a", "b", "c"]
+ *
+ *  Related: see {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
 
 static VALUE
@@ -4160,23 +4287,23 @@ rb_ary_slice_bang(int argc, VALUE *argv, VALUE ary)
     arg1 = argv[0];
 
     if (argc == 2) {
-	pos = NUM2LONG(argv[0]);
-	len = NUM2LONG(argv[1]);
+        pos = NUM2LONG(argv[0]);
+        len = NUM2LONG(argv[1]);
         return ary_slice_bang_by_rb_ary_splice(ary, pos, len);
     }
 
     if (!FIXNUM_P(arg1)) {
-	switch (rb_range_beg_len(arg1, &pos, &len, RARRAY_LEN(ary), 0)) {
-	  case Qtrue:
-	    /* valid range */
+        switch (rb_range_beg_len(arg1, &pos, &len, RARRAY_LEN(ary), 0)) {
+          case Qtrue:
+            /* valid range */
             return ary_slice_bang_by_rb_ary_splice(ary, pos, len);
-	  case Qnil:
-	    /* invalid range */
-	    return Qnil;
-	  default:
-	    /* not a range */
-	    break;
-	}
+          case Qnil:
+            /* invalid range */
+            return Qnil;
+          default:
+            /* not a range */
+            break;
+        }
     }
 
     return rb_ary_delete_at(ary, NUM2LONG(arg1));
@@ -4188,11 +4315,11 @@ ary_reject(VALUE orig, VALUE result)
     long i;
 
     for (i = 0; i < RARRAY_LEN(orig); i++) {
-	VALUE v = RARRAY_AREF(orig, i);
+        VALUE v = RARRAY_AREF(orig, i);
 
         if (!RTEST(rb_yield(v))) {
-	    rb_ary_push(result, v);
-	}
+            rb_ary_push(result, v);
+        }
     }
     return result;
 }
@@ -4205,12 +4332,12 @@ reject_bang_i(VALUE a)
     long i1, i2;
 
     for (i1 = i2 = 0; i1 < RARRAY_LEN(ary); arg->len[0] = ++i1) {
-	VALUE v = RARRAY_AREF(ary, i1);
-	if (RTEST(rb_yield(v))) continue;
-	if (i1 != i2) {
-	    rb_ary_store(ary, i2, v);
-	}
-	arg->len[1] = ++i2;
+        VALUE v = RARRAY_AREF(ary, i1);
+        if (RTEST(rb_yield(v))) continue;
+        if (i1 != i2) {
+            rb_ary_store(ary, i2, v);
+        }
+        arg->len[1] = ++i2;
     }
     return (i1 == i2) ? Qnil : ary;
 }
@@ -4227,20 +4354,22 @@ ary_reject_bang(VALUE ary)
 
 /*
  *  call-seq:
- *    array.reject! {|element| ... } -> self or nil
- *    array.reject! -> new_enumerator
+ *    reject! {|element| ... } -> self or nil
+ *    reject! -> new_enumerator
  *
- *  Removes each element for which the block returns a truthy value.
+ *  With a block given, calls the block with each element of +self+;
+ *  removes each element for which the block returns a truthy value.
  *
  *  Returns +self+ if any elements removed:
+ *
  *    a = [:foo, 'bar', 2, 'bat']
  *    a.reject! {|element| element.to_s.start_with?('b') } # => [:foo, 2]
  *
  *  Returns +nil+ if no elements removed.
  *
- *  Returns a new \Enumerator if no block given:
- *    a = [:foo, 'bar', 2]
- *    a.reject! # => #<Enumerator: [:foo, "bar", 2]:reject!>
+ *  With no block given, returns a new Enumerator.
+ *
+ *  Related: see {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
 
 static VALUE
@@ -4253,18 +4382,19 @@ rb_ary_reject_bang(VALUE ary)
 
 /*
  *  call-seq:
- *    array.reject {|element| ... } -> new_array
- *    array.reject -> new_enumerator
+ *    reject {|element| ... } -> new_array
+ *    reject -> new_enumerator
  *
- *  Returns a new \Array whose elements are all those from +self+
+ *  With a block given, returns a new array whose elements are all those from +self+
  *  for which the block returns +false+ or +nil+:
+ *
  *    a = [:foo, 'bar', 2, 'bat']
  *    a1 = a.reject {|element| element.to_s.start_with?('b') }
  *    a1 # => [:foo, 2]
  *
- *  Returns a new \Enumerator if no block given:
- *     a = [:foo, 'bar', 2]
- *     a.reject # => #<Enumerator: [:foo, "bar", 2]:reject>
+ *  With no block given, returns a new Enumerator.
+ *
+ *  Related: {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 static VALUE
@@ -4280,17 +4410,19 @@ rb_ary_reject(VALUE ary)
 
 /*
  *  call-seq:
- *    array.delete_if {|element| ... } -> self
- *    array.delete_if -> Enumerator
+ *    delete_if {|element| ... } -> self
+ *    delete_if -> new_numerator
  *
- *  Removes each element in +self+ for which the block returns a truthy value;
+ *  With a block given, calls the block with each element of +self+;
+ *  removes the element if the block returns a truthy value;
  *  returns +self+:
+ *
  *    a = [:foo, 'bar', 2, 'bat']
  *    a.delete_if {|element| element.to_s.start_with?('b') } # => [:foo, 2]
  *
- *  Returns a new \Enumerator if no block given:
- *    a = [:foo, 'bar', 2]
- *    a.delete_if # => #<Enumerator: [:foo, "bar", 2]:delete_if>
+ *  With no block given, returns a new Enumerator.
+ *
+ *  Related: see {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
 
 static VALUE
@@ -4322,60 +4454,104 @@ take_items(VALUE obj, long n)
     if (!NIL_P(result)) return rb_ary_subseq(result, 0, n);
     result = rb_ary_new2(n);
     args[0] = result; args[1] = (VALUE)n;
-    if (rb_check_block_call(obj, idEach, 0, 0, take_i, (VALUE)args) == Qundef)
-	rb_raise(rb_eTypeError, "wrong argument type %"PRIsVALUE" (must respond to :each)",
-		 rb_obj_class(obj));
+    if (UNDEF_P(rb_check_block_call(obj, idEach, 0, 0, take_i, (VALUE)args)))
+        rb_raise(rb_eTypeError, "wrong argument type %"PRIsVALUE" (must respond to :each)",
+                 rb_obj_class(obj));
     return result;
 }
 
 
 /*
  *  call-seq:
- *    array.zip(*other_arrays) -> new_array
- *    array.zip(*other_arrays) {|other_array| ... } -> nil
+ *    zip(*other_arrays) -> new_array
+ *    zip(*other_arrays) {|sub_array| ... } -> nil
+ *
+ *  With no block given, combines +self+ with the collection of +other_arrays+;
+ *  returns a new array of sub-arrays:
+ *
+ *    [0, 1].zip(['zero', 'one'], [:zero, :one])
+ *    # => [[0, "zero", :zero], [1, "one", :one]]
  *
- *  When no block given, returns a new \Array +new_array+ of size <tt>self.size</tt>
- *  whose elements are Arrays.
+ *  Returned:
  *
- *  Each nested array <tt>new_array[n]</tt> is of size <tt>other_arrays.size+1</tt>,
- *  and contains:
- *  - The _nth_ element of +self+.
- *  - The _nth_ element of each of the +other_arrays+.
+ *  - The outer array is of size <tt>self.size</tt>.
+ *  - Each sub-array is of size <tt>other_arrays.size + 1</tt>.
+ *  - The _nth_ sub-array contains (in order):
+ *
+ *    - The _nth_ element of +self+.
+ *    - The _nth_ element of each of the other arrays, as available.
+ *
+ *  Example:
+ *
+ *    a = [0, 1]
+ *    zipped = a.zip(['zero', 'one'], [:zero, :one])
+ *    # => [[0, "zero", :zero], [1, "one", :one]]
+ *    zipped.size       # => 2 # Same size as a.
+ *    zipped.first.size # => 3 # Size of other arrays plus 1.
+ *
+ *  When the other arrays are all the same size as +self+,
+ *  the returned sub-arrays are a rearrangement containing exactly elements of all the arrays
+ *  (including +self+), with no omissions or additions:
  *
- *  If all +other_arrays+ and +self+ are the same size:
  *    a = [:a0, :a1, :a2, :a3]
  *    b = [:b0, :b1, :b2, :b3]
  *    c = [:c0, :c1, :c2, :c3]
  *    d = a.zip(b, c)
- *    d # => [[:a0, :b0, :c0], [:a1, :b1, :c1], [:a2, :b2, :c2], [:a3, :b3, :c3]]
+ *    pp d
+ *    # =>
+ *    [[:a0, :b0, :c0],
+ *     [:a1, :b1, :c1],
+ *     [:a2, :b2, :c2],
+ *     [:a3, :b3, :c3]]
+ *
+ *  When one of the other arrays is smaller than +self+,
+ *  pads the corresponding sub-array with +nil+ elements:
  *
- *  If any array in +other_arrays+ is smaller than +self+,
- *  fills to <tt>self.size</tt> with +nil+:
  *    a = [:a0, :a1, :a2, :a3]
  *    b = [:b0, :b1, :b2]
  *    c = [:c0, :c1]
  *    d = a.zip(b, c)
- *    d # => [[:a0, :b0, :c0], [:a1, :b1, :c1], [:a2, :b2, nil], [:a3, nil, nil]]
+ *    pp d
+ *    # =>
+ *    [[:a0, :b0, :c0],
+ *     [:a1, :b1, :c1],
+ *     [:a2, :b2, nil],
+ *     [:a3, nil, nil]]
+ *
+ *  When one of the other arrays is larger than +self+,
+ *  _ignores_ its trailing elements:
  *
- *  If any array in +other_arrays+ is larger than +self+,
- *  its trailing elements are ignored:
  *    a = [:a0, :a1, :a2, :a3]
  *    b = [:b0, :b1, :b2, :b3, :b4]
  *    c = [:c0, :c1, :c2, :c3, :c4, :c5]
  *    d = a.zip(b, c)
- *    d # => [[:a0, :b0, :c0], [:a1, :b1, :c1], [:a2, :b2, :c2], [:a3, :b3, :c3]]
+ *    pp d
+ *    # =>
+ *    [[:a0, :b0, :c0],
+ *     [:a1, :b1, :c1],
+ *     [:a2, :b2, :c2],
+ *     [:a3, :b3, :c3]]
  *
- *  When a block is given, calls the block with each of the sub-arrays (formed as above); returns nil
+ *  With a block given, calls the block with each of the other arrays;
+ *  returns +nil+:
+ *
+ *    d = []
  *    a = [:a0, :a1, :a2, :a3]
  *    b = [:b0, :b1, :b2, :b3]
  *    c = [:c0, :c1, :c2, :c3]
- *    a.zip(b, c) {|sub_array| p sub_array} # => nil
- *
- *  Output:
- *    [:a0, :b0, :c0]
- *    [:a1, :b1, :c1]
- *    [:a2, :b2, :c2]
- *    [:a3, :b3, :c3]
+ *    a.zip(b, c) {|sub_array| d.push(sub_array.reverse) } # => nil
+ *    pp d
+ *    # =>
+ *    [[:c0, :b0, :a0],
+ *     [:c1, :b1, :a1],
+ *     [:c2, :b2, :a2],
+ *     [:c3, :b3, :a3]]
+ *
+ *  For an *object* in *other_arrays* that is not actually an array,
+ *  forms the the "other array" as <tt>object.to_ary</tt>, if defined,
+ *  or as <tt>object.each.to_a</tt> otherwise.
+ *
+ *  Related: see {Methods for Converting}[rdoc-ref:Array@Methods+for+Converting].
  */
 
 static VALUE
@@ -4386,51 +4562,51 @@ rb_ary_zip(int argc, VALUE *argv, VALUE ary)
     VALUE result = Qnil;
 
     for (i=0; i<argc; i++) {
-	argv[i] = take_items(argv[i], len);
+        argv[i] = take_items(argv[i], len);
     }
 
     if (rb_block_given_p()) {
-	int arity = rb_block_arity();
-
-	if (arity > 1) {
-	    VALUE work, *tmp;
-
-	    tmp = ALLOCV_N(VALUE, work, argc+1);
-
-	    for (i=0; i<RARRAY_LEN(ary); i++) {
-		tmp[0] = RARRAY_AREF(ary, i);
-		for (j=0; j<argc; j++) {
-		    tmp[j+1] = rb_ary_elt(argv[j], i);
-		}
-		rb_yield_values2(argc+1, tmp);
-	    }
-
-	    if (work) ALLOCV_END(work);
-	}
-	else {
-	    for (i=0; i<RARRAY_LEN(ary); i++) {
-		VALUE tmp = rb_ary_new2(argc+1);
-
-		rb_ary_push(tmp, RARRAY_AREF(ary, i));
-		for (j=0; j<argc; j++) {
-		    rb_ary_push(tmp, rb_ary_elt(argv[j], i));
-		}
-		rb_yield(tmp);
-	    }
-	}
+        int arity = rb_block_arity();
+
+        if (arity > 1) {
+            VALUE work, *tmp;
+
+            tmp = ALLOCV_N(VALUE, work, argc+1);
+
+            for (i=0; i<RARRAY_LEN(ary); i++) {
+                tmp[0] = RARRAY_AREF(ary, i);
+                for (j=0; j<argc; j++) {
+                    tmp[j+1] = rb_ary_elt(argv[j], i);
+                }
+                rb_yield_values2(argc+1, tmp);
+            }
+
+            if (work) ALLOCV_END(work);
+        }
+        else {
+            for (i=0; i<RARRAY_LEN(ary); i++) {
+                VALUE tmp = rb_ary_new2(argc+1);
+
+                rb_ary_push(tmp, RARRAY_AREF(ary, i));
+                for (j=0; j<argc; j++) {
+                    rb_ary_push(tmp, rb_ary_elt(argv[j], i));
+                }
+                rb_yield(tmp);
+            }
+        }
     }
     else {
-	result = rb_ary_new_capa(len);
+        result = rb_ary_new_capa(len);
 
-	for (i=0; i<len; i++) {
-	    VALUE tmp = rb_ary_new_capa(argc+1);
+        for (i=0; i<len; i++) {
+            VALUE tmp = rb_ary_new_capa(argc+1);
 
-	    rb_ary_push(tmp, RARRAY_AREF(ary, i));
-	    for (j=0; j<argc; j++) {
-		rb_ary_push(tmp, rb_ary_elt(argv[j], i));
-	    }
-	    rb_ary_push(result, tmp);
-	}
+            rb_ary_push(tmp, RARRAY_AREF(ary, i));
+            for (j=0; j<argc; j++) {
+                rb_ary_push(tmp, rb_ary_elt(argv[j], i));
+            }
+            rb_ary_push(result, tmp);
+        }
     }
 
     return result;
@@ -4438,12 +4614,17 @@ rb_ary_zip(int argc, VALUE *argv, VALUE ary)
 
 /*
  *  call-seq:
- *    array.transpose -> new_array
+ *    transpose -> new_array
+ *
+ *  Returns a new array that is +self+
+ *  as a {transposed matrix}[https://en.wikipedia.org/wiki/Transpose]:
  *
- *  Transposes the rows and columns in an \Array of Arrays;
- *  the nested Arrays must all be the same size:
  *    a = [[:a0, :a1], [:b0, :b1], [:c0, :c1]]
  *    a.transpose # => [[:a0, :b0, :c0], [:a1, :b1, :c1]]
+ *
+ *  The elements of +self+ must all be the same size.
+ *
+ *  Related: see {Methods for Converting}[rdoc-ref:Array@Methods+for+Converting].
  */
 
 static VALUE
@@ -4455,32 +4636,38 @@ rb_ary_transpose(VALUE ary)
     alen = RARRAY_LEN(ary);
     if (alen == 0) return rb_ary_dup(ary);
     for (i=0; i<alen; i++) {
-	tmp = to_ary(rb_ary_elt(ary, i));
-	if (elen < 0) {		/* first element */
-	    elen = RARRAY_LEN(tmp);
-	    result = rb_ary_new2(elen);
-	    for (j=0; j<elen; j++) {
-		rb_ary_store(result, j, rb_ary_new2(alen));
-	    }
-	}
-	else if (elen != RARRAY_LEN(tmp)) {
-	    rb_raise(rb_eIndexError, "element size differs (%ld should be %ld)",
-		     RARRAY_LEN(tmp), elen);
-	}
-	for (j=0; j<elen; j++) {
-	    rb_ary_store(rb_ary_elt(result, j), i, rb_ary_elt(tmp, j));
-	}
+        tmp = to_ary(rb_ary_elt(ary, i));
+        if (elen < 0) {		/* first element */
+            elen = RARRAY_LEN(tmp);
+            result = rb_ary_new2(elen);
+            for (j=0; j<elen; j++) {
+                rb_ary_store(result, j, rb_ary_new2(alen));
+            }
+        }
+        else if (elen != RARRAY_LEN(tmp)) {
+            rb_raise(rb_eIndexError, "element size differs (%ld should be %ld)",
+                     RARRAY_LEN(tmp), elen);
+        }
+        for (j=0; j<elen; j++) {
+            rb_ary_store(rb_ary_elt(result, j), i, rb_ary_elt(tmp, j));
+        }
     }
     return result;
 }
 
 /*
  *  call-seq:
- *    array.replace(other_array) -> self
+ *    initialize_copy(other_array) -> self
+ *    replace(other_array) -> self
  *
- *  Replaces the content of +self+ with the content of +other_array+; returns +self+:
- *    a = [:foo, 'bar', 2]
- *    a.replace(['foo', :bar, 3]) # => ["foo", :bar, 3]
+ *  Replaces the elements of +self+ with the elements of +other_array+, which must be an
+ *  {array-convertible object}[rdoc-ref:implicit_conversion.rdoc@Array-Convertible+Objects];
+ *  returns +self+:
+ *
+ *    a = ['a', 'b', 'c']   # => ["a", "b", "c"]
+ *    a.replace(['d', 'e']) # => ["d", "e"]
+ *
+ *  Related: see {Methods for Assigning}[rdoc-ref:Array@Methods+for+Assigning].
  */
 
 VALUE
@@ -4494,25 +4681,25 @@ rb_ary_replace(VALUE copy, VALUE orig)
 
     /* orig has enough space to embed the contents of orig. */
     if (RARRAY_LEN(orig) <= ary_embed_capa(copy)) {
-        assert(ARY_EMBED_P(copy));
-        ary_memcpy(copy, 0, RARRAY_LEN(orig), RARRAY_CONST_PTR_TRANSIENT(orig));
+        RUBY_ASSERT(ARY_EMBED_P(copy));
+        ary_memcpy(copy, 0, RARRAY_LEN(orig), RARRAY_CONST_PTR(orig));
         ARY_SET_EMBED_LEN(copy, RARRAY_LEN(orig));
     }
-#if USE_RVARGC
     /* orig is embedded but copy does not have enough space to embed the
      * contents of orig. */
     else if (ARY_EMBED_P(orig)) {
         long len = ARY_EMBED_LEN(orig);
-
-        VALUE *ptr = ary_heap_alloc(copy, len);
-        MEMCPY(ptr, ARY_EMBED_PTR(orig), VALUE, len);
+        VALUE *ptr = ary_heap_alloc_buffer(len);
 
         FL_UNSET_EMBED(copy);
         ARY_SET_PTR(copy, ptr);
         ARY_SET_LEN(copy, len);
         ARY_SET_CAPA(copy, len);
+
+        // No allocation and exception expected that could leave `copy` in a
+        // bad state from the edits above.
+        ary_memcpy(copy, 0, len, RARRAY_CONST_PTR(orig));
     }
-#endif
     /* Otherwise, orig is on heap and copy does not have enough space to embed
      * the contents of orig. */
     else {
@@ -4528,11 +4715,14 @@ rb_ary_replace(VALUE copy, VALUE orig)
 
 /*
  *  call-seq:
- *     array.clear -> self
+ *    clear -> self
+ *
+ *  Removes all elements from +self+; returns +self+:
  *
- *  Removes all elements from +self+:
  *    a = [:foo, 'bar', 2]
  *    a.clear # => []
+ *
+ *  Related: see {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
 
 VALUE
@@ -4540,11 +4730,9 @@ rb_ary_clear(VALUE ary)
 {
     rb_ary_modify_check(ary);
     if (ARY_SHARED_P(ary)) {
-	if (!ARY_EMBED_P(ary)) {
-	    rb_ary_unshare(ary);
-	    FL_SET_EMBED(ary);
-            ARY_SET_EMBED_LEN(ary, 0);
-	}
+        rb_ary_unshare(ary);
+        FL_SET_EMBED(ary);
+        ARY_SET_EMBED_LEN(ary, 0);
     }
     else {
         ARY_SET_LEN(ary, 0);
@@ -4558,171 +4746,182 @@ rb_ary_clear(VALUE ary)
 
 /*
  *  call-seq:
- *    array.fill(obj) -> self
- *    array.fill(obj, start) -> self
- *    array.fill(obj, start, length) -> self
- *    array.fill(obj, range) -> self
- *    array.fill {|index| ... } -> self
- *    array.fill(start) {|index| ... } -> self
- *    array.fill(start, length) {|index| ... } -> self
- *    array.fill(range) {|index| ... } -> self
- *
- *  Replaces specified elements in +self+ with specified objects; returns +self+.
- *
- *  With argument +obj+ and no block given, replaces all elements with that one object:
- *    a = ['a', 'b', 'c', 'd']
- *    a # => ["a", "b", "c", "d"]
- *    a.fill(:X) # => [:X, :X, :X, :X]
+ *    fill(object, start = nil, count = nil) -> new_array
+ *    fill(object, range) -> new_array
+ *    fill(start = nil, count = nil) {|element| ... } -> new_array
+ *    fill(range) {|element| ... } -> new_array
  *
- *  With arguments +obj+ and \Integer +start+, and no block given,
- *  replaces elements based on the given start.
+ *  Replaces selected elements in +self+;
+ *  may add elements to +self+;
+ *  always returns +self+ (never a new array).
  *
- *  If +start+ is in range (<tt>0 <= start < array.size</tt>),
- *  replaces all elements from offset +start+ through the end:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(:X, 2) # => ["a", "b", :X, :X]
+ *  In brief:
  *
- *  If +start+ is too large (<tt>start >= array.size</tt>), does nothing:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(:X, 4) # => ["a", "b", "c", "d"]
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(:X, 5) # => ["a", "b", "c", "d"]
+ *    # Non-negative start.
+ *    ['a', 'b', 'c', 'd'].fill('-', 1, 2)          # => ["a", "-", "-", "d"]
+ *    ['a', 'b', 'c', 'd'].fill(1, 2) {|e| e.to_s } # => ["a", "1", "2", "d"]
  *
- *  If +start+ is negative, counts from the end (starting index is <tt>start + array.size</tt>):
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(:X, -2) # => ["a", "b", :X, :X]
+ *    # Extends with specified values if necessary.
+ *    ['a', 'b', 'c', 'd'].fill('-', 3, 2)          # => ["a", "b", "c", "-", "-"]
+ *    ['a', 'b', 'c', 'd'].fill(3, 2) {|e| e.to_s } # => ["a", "b", "c", "3", "4"]
  *
- *  If +start+ is too small (less than and far from zero), replaces all elements:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(:X, -6) # => [:X, :X, :X, :X]
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(:X, -50) # => [:X, :X, :X, :X]
+ *    # Fills with nils if necessary.
+ *    ['a', 'b', 'c', 'd'].fill('-', 6, 2)          # => ["a", "b", "c", "d", nil, nil, "-", "-"]
+ *    ['a', 'b', 'c', 'd'].fill(6, 2) {|e| e.to_s } # => ["a", "b", "c", "d", nil, nil, "6", "7"]
  *
- *  With arguments +obj+, \Integer +start+, and \Integer +length+, and no block given,
- *  replaces elements based on the given +start+ and +length+.
+ *    # For negative start, counts backwards from the end.
+ *    ['a', 'b', 'c', 'd'].fill('-', -3, 3)          # => ["a", "-", "-", "-"]
+ *    ['a', 'b', 'c', 'd'].fill(-3, 3) {|e| e.to_s } # => ["a", "1", "2", "3"]
  *
- *  If +start+ is in range, replaces +length+ elements beginning at offset +start+:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(:X, 1, 1) # => ["a", :X, "c", "d"]
+ *    # Range.
+ *    ['a', 'b', 'c', 'd'].fill('-', 1..2)          # => ["a", "-", "-", "d"]
+ *    ['a', 'b', 'c', 'd'].fill(1..2) {|e| e.to_s } # => ["a", "1", "2", "d"]
  *
- *  If +start+ is negative, counts from the end:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(:X, -2, 1) # => ["a", "b", :X, "d"]
+ *  When arguments +start+ and +count+ are given,
+ *  they select the elements of +self+ to be replaced;
+ *  each must be an
+ *  {integer-convertible object}[rdoc-ref:implicit_conversion.rdoc@Integer-Convertible+Objects]
+ *  (or +nil+):
  *
- *  If +start+ is large (<tt>start >= array.size</tt>), extends +self+ with +nil+:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(:X, 5, 0) # => ["a", "b", "c", "d", nil]
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(:X, 5, 2) # => ["a", "b", "c", "d", nil, :X, :X]
+ *  - +start+ specifies the zero-based offset of the first element to be replaced;
+ *    +nil+ means zero.
+ *  - +count+ is the number of consecutive elements to be replaced;
+ *    +nil+ means "all the rest."
  *
- *  If +length+ is zero or negative, replaces no elements:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(:X, 1, 0) # => ["a", "b", "c", "d"]
- *    a.fill(:X, 1, -1) # => ["a", "b", "c", "d"]
+ *  With argument +object+ given,
+ *  that one object is used for all replacements:
  *
- *  With arguments +obj+ and \Range +range+, and no block given,
- *  replaces elements based on the given range.
+ *    o = Object.new           # => #<Object:0x0000014e7bff7600>
+ *    a = ['a', 'b', 'c', 'd'] # => ["a", "b", "c", "d"]
+ *    a.fill(o, 1, 2)
+ *    # => ["a", #<Object:0x0000014e7bff7600>, #<Object:0x0000014e7bff7600>, "d"]
  *
- *  If the range is positive and ascending (<tt>0 < range.begin <= range.end</tt>),
- *  replaces elements from <tt>range.begin</tt> to <tt>range.end</tt>:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(:X, (1..1)) # => ["a", :X, "c", "d"]
+ *  With a block given, the block is called once for each element to be replaced;
+ *  the value passed to the block is the _index_ of the element to be replaced
+ *  (not the element itself);
+ *  the block's return value replaces the element:
  *
- *  If <tt>range.first</tt> is negative, replaces no elements:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(:X, (-1..1)) # => ["a", "b", "c", "d"]
+ *    a = ['a', 'b', 'c', 'd']               # => ["a", "b", "c", "d"]
+ *    a.fill(1, 2) {|element| element.to_s } # => ["a", "1", "2", "d"]
  *
- *  If <tt>range.last</tt> is negative, counts from the end:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(:X, (0..-2)) # => [:X, :X, :X, "d"]
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(:X, (1..-2)) # => ["a", :X, :X, "d"]
+ *  For arguments +start+ and +count+:
  *
- *  If <tt>range.last</tt> and <tt>range.last</tt> are both negative,
- *  both count from the end of the array:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(:X, (-1..-1)) # => ["a", "b", "c", :X]
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(:X, (-2..-2)) # => ["a", "b", :X, "d"]
+ *  - If +start+ is non-negative,
+ *    replaces +count+ elements beginning at offset +start+:
  *
- *  With no arguments and a block given, calls the block with each index;
- *  replaces the corresponding element with the block's return value:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill { |index| "new_#{index}" } # => ["new_0", "new_1", "new_2", "new_3"]
+ *      ['a', 'b', 'c', 'd'].fill('-', 0, 2) # => ["-", "-", "c", "d"]
+ *      ['a', 'b', 'c', 'd'].fill('-', 1, 2) # => ["a", "-", "-", "d"]
+ *      ['a', 'b', 'c', 'd'].fill('-', 2, 2) # => ["a", "b", "-", "-"]
  *
- *  With argument +start+ and a block given, calls the block with each index
- *  from offset +start+ to the end; replaces the corresponding element
- *  with the block's return value:
+ *      ['a', 'b', 'c', 'd'].fill(0, 2) {|e| e.to_s } # => ["0", "1", "c", "d"]
+ *      ['a', 'b', 'c', 'd'].fill(1, 2) {|e| e.to_s } # => ["a", "1", "2", "d"]
+ *      ['a', 'b', 'c', 'd'].fill(2, 2) {|e| e.to_s } # => ["a", "b", "2", "3"]
  *
- *  If start is in range (<tt>0 <= start < array.size</tt>),
- *  replaces from offset +start+ to the end:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(1) { |index| "new_#{index}" } # => ["a", "new_1", "new_2", "new_3"]
+ *    Extends +self+ if necessary:
  *
- *  If +start+ is too large(<tt>start >= array.size</tt>), does nothing:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(4) { |index| fail 'Cannot happen' } # => ["a", "b", "c", "d"]
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(4) { |index| fail 'Cannot happen' } # => ["a", "b", "c", "d"]
+ *      ['a', 'b', 'c', 'd'].fill('-', 3, 2) # => ["a", "b", "c", "-", "-"]
+ *      ['a', 'b', 'c', 'd'].fill('-', 4, 2) # => ["a", "b", "c", "d", "-", "-"]
  *
- *  If +start+ is negative, counts from the end:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(-2) { |index| "new_#{index}" } # => ["a", "b", "new_2", "new_3"]
+ *      ['a', 'b', 'c', 'd'].fill(3, 2) {|e| e.to_s } # => ["a", "b", "c", "3", "4"]
+ *      ['a', 'b', 'c', 'd'].fill(4, 2) {|e| e.to_s } # => ["a", "b", "c", "d", "4", "5"]
  *
- *  If start is too small (<tt>start <= -array.size</tt>, replaces all elements:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(-6) { |index| "new_#{index}" } # => ["new_0", "new_1", "new_2", "new_3"]
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(-50) { |index| "new_#{index}" } # => ["new_0", "new_1", "new_2", "new_3"]
+ *    Fills with +nil+ if necessary:
  *
- *  With arguments +start+ and +length+, and a block given,
- *  calls the block for each index specified by start length;
- *  replaces the corresponding element with the block's return value.
+ *      ['a', 'b', 'c', 'd'].fill('-', 5, 2) # => ["a", "b", "c", "d", nil, "-", "-"]
+ *      ['a', 'b', 'c', 'd'].fill('-', 6, 2) # => ["a", "b", "c", "d", nil, nil, "-", "-"]
  *
- *  If +start+ is in range, replaces +length+ elements beginning at offset +start+:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(1, 1) { |index| "new_#{index}" } # => ["a", "new_1", "c", "d"]
+ *      ['a', 'b', 'c', 'd'].fill(5, 2) {|e| e.to_s } # => ["a", "b", "c", "d", nil, "5", "6"]
+ *      ['a', 'b', 'c', 'd'].fill(6, 2) {|e| e.to_s } # => ["a", "b", "c", "d", nil, nil, "6", "7"]
  *
- *  If start is negative, counts from the end:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(-2, 1) { |index| "new_#{index}" } # => ["a", "b", "new_2", "d"]
+ *    Does nothing if +count+ is non-positive:
  *
- *  If +start+ is large (<tt>start >= array.size</tt>), extends +self+ with +nil+:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(5, 0) { |index| "new_#{index}" } # => ["a", "b", "c", "d", nil]
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(5, 2) { |index| "new_#{index}" } # => ["a", "b", "c", "d", nil, "new_5", "new_6"]
+ *      ['a', 'b', 'c', 'd'].fill('-', 2, 0)    # => ["a", "b", "c", "d"]
+ *      ['a', 'b', 'c', 'd'].fill('-', 2, -100) # => ["a", "b", "c", "d"]
+ *      ['a', 'b', 'c', 'd'].fill('-', 6, -100) # => ["a", "b", "c", "d"]
  *
- *  If +length+ is zero or less, replaces no elements:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(1, 0) { |index| "new_#{index}" } # => ["a", "b", "c", "d"]
- *    a.fill(1, -1) { |index| "new_#{index}" } # => ["a", "b", "c", "d"]
+ *      ['a', 'b', 'c', 'd'].fill(2, 0) {|e| fail 'Cannot happen' }    # => ["a", "b", "c", "d"]
+ *      ['a', 'b', 'c', 'd'].fill(2, -100) {|e| fail 'Cannot happen' } # => ["a", "b", "c", "d"]
+ *      ['a', 'b', 'c', 'd'].fill(6, -100) {|e| fail 'Cannot happen' } # => ["a", "b", "c", "d"]
  *
- *  With arguments +obj+ and +range+, and a block given,
- *  calls the block with each index in the given range;
- *  replaces the corresponding element with the block's return value.
+ *  - If +start+ is negative, counts backwards from the end of +self+:
  *
- *  If the range is positive and ascending (<tt>range 0 < range.begin <= range.end</tt>,
- *  replaces elements from <tt>range.begin</tt> to <tt>range.end</tt>:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(1..1) { |index| "new_#{index}" } # => ["a", "new_1", "c", "d"]
+ *      ['a', 'b', 'c', 'd'].fill('-', -4, 3) # => ["-", "-", "-", "d"]
+ *      ['a', 'b', 'c', 'd'].fill('-', -3, 3) # => ["a", "-", "-", "-"]
  *
- *  If +range.first+ is negative, does nothing:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(-1..1) { |index| fail 'Cannot happen' } # => ["a", "b", "c", "d"]
+ *      ['a', 'b', 'c', 'd'].fill(-4, 3) {|e| e.to_s } # => ["0", "1", "2", "d"]
+ *      ['a', 'b', 'c', 'd'].fill(-3, 3) {|e| e.to_s } # => ["a", "1", "2", "3"]
  *
- *  If <tt>range.last</tt> is negative, counts from the end:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(0..-2) { |index| "new_#{index}" } # => ["new_0", "new_1", "new_2", "d"]
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(1..-2) { |index| "new_#{index}" } # => ["a", "new_1", "new_2", "d"]
+ *    Extends +self+ if necessary:
  *
- *  If <tt>range.first</tt> and <tt>range.last</tt> are both negative,
- *  both count from the end:
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(-1..-1) { |index| "new_#{index}" } # => ["a", "b", "c", "new_3"]
- *    a = ['a', 'b', 'c', 'd']
- *    a.fill(-2..-2) { |index| "new_#{index}" } # => ["a", "b", "new_2", "d"]
+ *      ['a', 'b', 'c', 'd'].fill('-', -2, 3) # => ["a", "b", "-", "-", "-"]
+ *      ['a', 'b', 'c', 'd'].fill('-', -1, 3) # => ["a", "b", "c", "-", "-", "-"]
+ *
+ *      ['a', 'b', 'c', 'd'].fill(-2, 3) {|e| e.to_s } # => ["a", "b", "2", "3", "4"]
+ *      ['a', 'b', 'c', 'd'].fill(-1, 3) {|e| e.to_s } # => ["a", "b", "c", "3", "4", "5"]
+ *
+ *    Starts at the beginning of +self+ if +start+ is negative and out-of-range:
+ *
+ *      ['a', 'b', 'c', 'd'].fill('-', -5, 2) # => ["-", "-", "c", "d"]
+ *      ['a', 'b', 'c', 'd'].fill('-', -6, 2) # => ["-", "-", "c", "d"]
+ *
+ *      ['a', 'b', 'c', 'd'].fill(-5, 2) {|e| e.to_s } # => ["0", "1", "c", "d"]
+ *      ['a', 'b', 'c', 'd'].fill(-6, 2) {|e| e.to_s } # => ["0", "1", "c", "d"]
+ *
+ *    Does nothing if +count+ is non-positive:
+ *
+ *      ['a', 'b', 'c', 'd'].fill('-', -2, 0)  # => ["a", "b", "c", "d"]
+ *      ['a', 'b', 'c', 'd'].fill('-', -2, -1) # => ["a", "b", "c", "d"]
+ *
+ *      ['a', 'b', 'c', 'd'].fill(-2, 0) {|e| fail 'Cannot happen' }  # => ["a", "b", "c", "d"]
+ *      ['a', 'b', 'c', 'd'].fill(-2, -1) {|e| fail 'Cannot happen' } # => ["a", "b", "c", "d"]
+ *
+ *  When argument +range+ is given,
+ *  it must be a Range object whose members are numeric;
+ *  its +begin+ and +end+ values determine the elements of +self+
+ *  to be replaced:
+ *
+ *  - If both +begin+ and +end+ are positive, they specify the first and last elements
+ *    to be replaced:
+ *
+ *      ['a', 'b', 'c', 'd'].fill('-', 1..2)          # => ["a", "-", "-", "d"]
+ *      ['a', 'b', 'c', 'd'].fill(1..2) {|e| e.to_s } # => ["a", "1", "2", "d"]
+ *
+ *    If +end+ is smaller than +begin+, replaces no elements:
+ *
+ *      ['a', 'b', 'c', 'd'].fill('-', 2..1)          # => ["a", "b", "c", "d"]
+ *      ['a', 'b', 'c', 'd'].fill(2..1) {|e| e.to_s } # => ["a", "b", "c", "d"]
+ *
+ *  - If either is negative (or both are negative), counts backwards from the end of +self+:
+ *
+ *      ['a', 'b', 'c', 'd'].fill('-', -3..2)  # => ["a", "-", "-", "d"]
+ *      ['a', 'b', 'c', 'd'].fill('-', 1..-2)  # => ["a", "-", "-", "d"]
+ *      ['a', 'b', 'c', 'd'].fill('-', -3..-2) # => ["a", "-", "-", "d"]
+ *
+ *      ['a', 'b', 'c', 'd'].fill(-3..2) {|e| e.to_s }  # => ["a", "1", "2", "d"]
+ *      ['a', 'b', 'c', 'd'].fill(1..-2) {|e| e.to_s }  # => ["a", "1", "2", "d"]
+ *      ['a', 'b', 'c', 'd'].fill(-3..-2) {|e| e.to_s } # => ["a", "1", "2", "d"]
+ *
+ *  - If the +end+ value is excluded (see Range#exclude_end?), omits the last replacement:
+ *
+ *      ['a', 'b', 'c', 'd'].fill('-', 1...2)  # => ["a", "-", "c", "d"]
+ *      ['a', 'b', 'c', 'd'].fill('-', 1...-2) # => ["a", "-", "c", "d"]
+ *
+ *      ['a', 'b', 'c', 'd'].fill(1...2) {|e| e.to_s }  # => ["a", "1", "c", "d"]
+ *      ['a', 'b', 'c', 'd'].fill(1...-2) {|e| e.to_s } # => ["a", "1", "c", "d"]
+ *
+ *  - If the range is endless (see {Endless Ranges}[rdoc-ref:Range@Endless+Ranges]),
+ *    replaces elements to the end of +self+:
+ *
+ *      ['a', 'b', 'c', 'd'].fill('-', 1..)          # => ["a", "-", "-", "-"]
+ *      ['a', 'b', 'c', 'd'].fill(1..) {|e| e.to_s } # => ["a", "1", "2", "3"]
+ *
+ *  - If the range is beginless (see {Beginless Ranges}[rdoc-ref:Range@Beginless+Ranges]),
+ *    replaces elements from the beginning of +self+:
+ *
+ *      ['a', 'b', 'c', 'd'].fill('-', ..2)          # => ["-", "-", "-", "d"]
+ *      ['a', 'b', 'c', 'd'].fill(..2) {|e| e.to_s } # => ["0", "1", "2", "d"]
+ *
+ *  Related: see {Methods for Assigning}[rdoc-ref:Array@Methods+for+Assigning].
  */
 
 static VALUE
@@ -4732,73 +4931,74 @@ rb_ary_fill(int argc, VALUE *argv, VALUE ary)
     long beg = 0, end = 0, len = 0;
 
     if (rb_block_given_p()) {
-	rb_scan_args(argc, argv, "02", &arg1, &arg2);
-	argc += 1;		/* hackish */
+        rb_scan_args(argc, argv, "02", &arg1, &arg2);
+        argc += 1;		/* hackish */
     }
     else {
-	rb_scan_args(argc, argv, "12", &item, &arg1, &arg2);
+        rb_scan_args(argc, argv, "12", &item, &arg1, &arg2);
     }
     switch (argc) {
       case 1:
-	beg = 0;
-	len = RARRAY_LEN(ary);
-	break;
+        beg = 0;
+        len = RARRAY_LEN(ary);
+        break;
       case 2:
-	if (rb_range_beg_len(arg1, &beg, &len, RARRAY_LEN(ary), 1)) {
-	    break;
-	}
-	/* fall through */
+        if (rb_range_beg_len(arg1, &beg, &len, RARRAY_LEN(ary), 1)) {
+            break;
+        }
+        /* fall through */
       case 3:
-	beg = NIL_P(arg1) ? 0 : NUM2LONG(arg1);
-	if (beg < 0) {
-	    beg = RARRAY_LEN(ary) + beg;
-	    if (beg < 0) beg = 0;
-	}
-	len = NIL_P(arg2) ? RARRAY_LEN(ary) - beg : NUM2LONG(arg2);
-	break;
+        beg = NIL_P(arg1) ? 0 : NUM2LONG(arg1);
+        if (beg < 0) {
+            beg = RARRAY_LEN(ary) + beg;
+            if (beg < 0) beg = 0;
+        }
+        len = NIL_P(arg2) ? RARRAY_LEN(ary) - beg : NUM2LONG(arg2);
+        break;
     }
     rb_ary_modify(ary);
     if (len < 0) {
         return ary;
     }
     if (beg >= ARY_MAX_SIZE || len > ARY_MAX_SIZE - beg) {
-	rb_raise(rb_eArgError, "argument too big");
+        rb_raise(rb_eArgError, "argument too big");
     }
     end = beg + len;
     if (RARRAY_LEN(ary) < end) {
-	if (end >= ARY_CAPA(ary)) {
-	    ary_resize_capa(ary, end);
-	}
-	ary_mem_clear(ary, RARRAY_LEN(ary), end - RARRAY_LEN(ary));
-	ARY_SET_LEN(ary, end);
+        if (end >= ARY_CAPA(ary)) {
+            ary_resize_capa(ary, end);
+        }
+        ary_mem_clear(ary, RARRAY_LEN(ary), end - RARRAY_LEN(ary));
+        ARY_SET_LEN(ary, end);
     }
 
-    if (item == Qundef) {
-	VALUE v;
-	long i;
+    if (UNDEF_P(item)) {
+        VALUE v;
+        long i;
 
-	for (i=beg; i<end; i++) {
-	    v = rb_yield(LONG2NUM(i));
-	    if (i>=RARRAY_LEN(ary)) break;
-	    ARY_SET(ary, i, v);
-	}
+        for (i=beg; i<end; i++) {
+            v = rb_yield(LONG2NUM(i));
+            if (i>=RARRAY_LEN(ary)) break;
+            ARY_SET(ary, i, v);
+        }
     }
     else {
-	ary_memfill(ary, beg, len, item);
+        ary_memfill(ary, beg, len, item);
     }
     return ary;
 }
 
 /*
  *  call-seq:
- *    array + other_array -> new_array
+ *    self + other_array -> new_array
  *
- *  Returns a new \Array containing all elements of +array+
+ *  Returns a new array containing all elements of +self+
  *  followed by all elements of +other_array+:
+ *
  *    a = [0, 1] + [2, 3]
  *    a # => [0, 1, 2, 3]
  *
- *  Related: #concat.
+ *  Related: see {Methods for Combining}[rdoc-ref:Array@Methods+for+Combining].
  */
 
 VALUE
@@ -4813,8 +5013,8 @@ rb_ary_plus(VALUE x, VALUE y)
     len = xlen + ylen;
     z = rb_ary_new2(len);
 
-    ary_memcpy(z, 0, xlen, RARRAY_CONST_PTR_TRANSIENT(x));
-    ary_memcpy(z, xlen, ylen, RARRAY_CONST_PTR_TRANSIENT(y));
+    ary_memcpy(z, 0, xlen, RARRAY_CONST_PTR(x));
+    ary_memcpy(z, xlen, ylen, RARRAY_CONST_PTR(y));
     ARY_SET_LEN(z, len);
     return z;
 }
@@ -4824,7 +5024,7 @@ ary_append(VALUE x, VALUE y)
 {
     long n = RARRAY_LEN(y);
     if (n > 0) {
-        rb_ary_splice(x, RARRAY_LEN(x), 0, RARRAY_CONST_PTR_TRANSIENT(y), n);
+        rb_ary_splice(x, RARRAY_LEN(x), 0, RARRAY_CONST_PTR(y), n);
     }
     RB_GC_GUARD(y);
     return x;
@@ -4832,11 +5032,15 @@ ary_append(VALUE x, VALUE y)
 
 /*
  *  call-seq:
- *    array.concat(*other_arrays) -> self
+ *    concat(*other_arrays) -> self
+ *
+ *  Adds to +self+ all elements from each array in +other_arrays+; returns +self+:
  *
- *  Adds to +array+ all elements from each \Array in +other_arrays+; returns +self+:
  *    a = [0, 1]
- *    a.concat([2, 3], [4, 5]) # => [0, 1, 2, 3, 4, 5]
+ *    a.concat(['two', 'three'], [:four, :five], a)
+ *    # => [0, 1, "two", "three", :four, :five, 0, 1]
+ *
+ *  Related: see {Methods for Assigning}[rdoc-ref:Array@Methods+for+Assigning].
  */
 
 static VALUE
@@ -4845,15 +5049,15 @@ rb_ary_concat_multi(int argc, VALUE *argv, VALUE ary)
     rb_ary_modify_check(ary);
 
     if (argc == 1) {
-	rb_ary_concat(ary, argv[0]);
+        rb_ary_concat(ary, argv[0]);
     }
     else if (argc > 1) {
-	int i;
-	VALUE args = rb_ary_tmp_new(argc);
-	for (i = 0; i < argc; i++) {
-	    rb_ary_concat(args, argv[i]);
-	}
-	ary_append(ary, args);
+        int i;
+        VALUE args = rb_ary_hidden_new(argc);
+        for (i = 0; i < argc; i++) {
+            rb_ary_concat(args, argv[i]);
+        }
+        ary_append(ary, args);
     }
 
     ary_verify(ary);
@@ -4868,17 +5072,20 @@ rb_ary_concat(VALUE x, VALUE y)
 
 /*
  *  call-seq:
- *    array * n -> new_array
- *    array * string_separator -> new_string
+ *    self * n -> new_array
+ *    self * string_separator -> new_string
+ *
+ *  When non-negative integer argument +n+ is given,
+ *  returns a new array built by concatenating +n+ copies of +self+:
  *
- *  When non-negative argument \Integer +n+ is given,
- *  returns a new \Array built by concatenating the +n+ copies of +self+:
  *    a = ['x', 'y']
  *    a * 3 # => ["x", "y", "x", "y", "x", "y"]
  *
- *  When \String argument +string_separator+ is given,
- *  equivalent to <tt>array.join(string_separator)</tt>:
- *    [0, [0, 1], {foo: 0}] * ', ' # => "0, 0, 1, {:foo=>0}"
+ *  When string argument +string_separator+ is given,
+ *  equivalent to <tt>self.join(string_separator)</tt>:
+ *
+ *    [0, [0, 1], {foo: 0}] * ', ' # => "0, 0, 1, {foo: 0}"
+ *
  */
 
 static VALUE
@@ -4890,35 +5097,35 @@ rb_ary_times(VALUE ary, VALUE times)
 
     tmp = rb_check_string_type(times);
     if (!NIL_P(tmp)) {
-	return rb_ary_join(ary, tmp);
+        return rb_ary_join(ary, tmp);
     }
 
     len = NUM2LONG(times);
     if (len == 0) {
         ary2 = ary_new(rb_cArray, 0);
-	goto out;
+        goto out;
     }
     if (len < 0) {
-	rb_raise(rb_eArgError, "negative argument");
+        rb_raise(rb_eArgError, "negative argument");
     }
     if (ARY_MAX_SIZE/len < RARRAY_LEN(ary)) {
-	rb_raise(rb_eArgError, "argument too big");
+        rb_raise(rb_eArgError, "argument too big");
     }
     len *= RARRAY_LEN(ary);
 
     ary2 = ary_new(rb_cArray, len);
     ARY_SET_LEN(ary2, len);
 
-    ptr = RARRAY_CONST_PTR_TRANSIENT(ary);
+    ptr = RARRAY_CONST_PTR(ary);
     t = RARRAY_LEN(ary);
     if (0 < t) {
-	ary_memcpy(ary2, 0, t, ptr);
-	while (t <= len/2) {
-            ary_memcpy(ary2, t, t, RARRAY_CONST_PTR_TRANSIENT(ary2));
+        ary_memcpy(ary2, 0, t, ptr);
+        while (t <= len/2) {
+            ary_memcpy(ary2, t, t, RARRAY_CONST_PTR(ary2));
             t *= 2;
         }
         if (t < len) {
-            ary_memcpy(ary2, t, len-t, RARRAY_CONST_PTR_TRANSIENT(ary2));
+            ary_memcpy(ary2, t, len-t, RARRAY_CONST_PTR(ary2));
         }
     }
   out:
@@ -4927,16 +5134,18 @@ rb_ary_times(VALUE ary, VALUE times)
 
 /*
  *  call-seq:
- *    array.assoc(obj) -> found_array or nil
+ *    assoc(object) -> found_array or nil
+ *
+ *  Returns the first element +ele+ in +self+ such that +ele+ is an array
+ *  and <tt>ele[0] == object</tt>:
  *
- *  Returns the first element in +self+ that is an \Array
- *  whose first element <tt>==</tt> +obj+:
  *    a = [{foo: 0}, [2, 4], [4, 5, 6], [4, 5]]
  *    a.assoc(4) # => [4, 5, 6]
  *
  *  Returns +nil+ if no such element is found.
  *
- *  Related: #rassoc.
+ *  Related: Array#rassoc;
+ *  see also {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 VALUE
@@ -4946,26 +5155,29 @@ rb_ary_assoc(VALUE ary, VALUE key)
     VALUE v;
 
     for (i = 0; i < RARRAY_LEN(ary); ++i) {
-	v = rb_check_array_type(RARRAY_AREF(ary, i));
-	if (!NIL_P(v) && RARRAY_LEN(v) > 0 &&
-	    rb_equal(RARRAY_AREF(v, 0), key))
-	    return v;
+        v = rb_check_array_type(RARRAY_AREF(ary, i));
+        if (!NIL_P(v) && RARRAY_LEN(v) > 0 &&
+            rb_equal(RARRAY_AREF(v, 0), key))
+            return v;
     }
     return Qnil;
 }
 
 /*
  *  call-seq:
- *    array.rassoc(obj) -> found_array or nil
+ *    rassoc(object) -> found_array or nil
+ *
+ *  Returns the first element +ele+ in +self+ such that +ele+ is an array
+ *  and <tt>ele[1] == object</tt>:
  *
- *  Returns the first element in +self+ that is an \Array
- *  whose second element <tt>==</tt> +obj+:
  *    a = [{foo: 0}, [2, 4], [4, 5, 6], [4, 5]]
  *    a.rassoc(4) # => [2, 4]
+ *    a.rassoc(5) # => [4, 5, 6]
  *
  *  Returns +nil+ if no such element is found.
  *
- *  Related: #assoc.
+ *  Related: Array#assoc;
+ *  see also {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 VALUE
@@ -4975,11 +5187,11 @@ rb_ary_rassoc(VALUE ary, VALUE value)
     VALUE v;
 
     for (i = 0; i < RARRAY_LEN(ary); ++i) {
-	v = RARRAY_AREF(ary, i);
-	if (RB_TYPE_P(v, T_ARRAY) &&
-	    RARRAY_LEN(v) > 1 &&
-	    rb_equal(RARRAY_AREF(v, 1), value))
-	    return v;
+        v = rb_check_array_type(RARRAY_AREF(ary, i));
+        if (RB_TYPE_P(v, T_ARRAY) &&
+            RARRAY_LEN(v) > 1 &&
+            rb_equal(RARRAY_AREF(v, 1), value))
+            return v;
     }
     return Qnil;
 }
@@ -4998,41 +5210,48 @@ recursive_equal(VALUE ary1, VALUE ary2, int recur)
     len1 = RARRAY_LEN(ary1);
 
     for (i = 0; i < len1; i++) {
-	if (*p1 != *p2) {
-	    if (rb_equal(*p1, *p2)) {
-		len1 = RARRAY_LEN(ary1);
-		if (len1 != RARRAY_LEN(ary2))
-		    return Qfalse;
-		if (len1 < i)
-		    return Qtrue;
+        if (*p1 != *p2) {
+            if (rb_equal(*p1, *p2)) {
+                len1 = RARRAY_LEN(ary1);
+                if (len1 != RARRAY_LEN(ary2))
+                    return Qfalse;
+                if (len1 < i)
+                    return Qtrue;
                 p1 = RARRAY_CONST_PTR(ary1) + i;
                 p2 = RARRAY_CONST_PTR(ary2) + i;
-	    }
-	    else {
-		return Qfalse;
-	    }
-	}
-	p1++;
-	p2++;
+            }
+            else {
+                return Qfalse;
+            }
+        }
+        p1++;
+        p2++;
     }
     return Qtrue;
 }
 
 /*
  *  call-seq:
- *    array == other_array -> true or false
+ *    self == other_array -> true or false
  *
- *  Returns +true+ if both <tt>array.size == other_array.size</tt>
- *  and for each index +i+ in +array+, <tt>array[i] == other_array[i]</tt>:
- *    a0 = [:foo, 'bar', 2]
- *    a1 = [:foo, 'bar', 2.0]
- *    a1 == a0 # => true
- *    [] == [] # => true
+ *  Returns whether both:
  *
- *  Otherwise, returns +false+.
+ *  - +self+ and +other_array+ are the same size.
+ *  - Their corresponding elements are the same;
+ *    that is, for each index +i+ in <tt>(0...self.size)</tt>,
+ *    <tt>self[i] == other_array[i]</tt>.
+ *
+ *  Examples:
+ *
+ *    [:foo, 'bar', 2] == [:foo, 'bar', 2]   # => true
+ *    [:foo, 'bar', 2] == [:foo, 'bar', 2.0] # => true
+ *    [:foo, 'bar', 2] == [:foo, 'bar']      # => false # Different sizes.
+ *    [:foo, 'bar', 2] == [:foo, 'bar', 3]   # => false # Different elements.
  *
  *  This method is different from method Array#eql?,
  *  which compares elements using <tt>Object#eql?</tt>.
+ *
+ *  Related: see {Methods for Comparing}[rdoc-ref:Array@Methods+for+Comparing].
  */
 
 static VALUE
@@ -5040,13 +5259,13 @@ rb_ary_equal(VALUE ary1, VALUE ary2)
 {
     if (ary1 == ary2) return Qtrue;
     if (!RB_TYPE_P(ary2, T_ARRAY)) {
-	if (!rb_respond_to(ary2, idTo_ary)) {
-	    return Qfalse;
-	}
-	return rb_equal(ary2, ary1);
+        if (!rb_respond_to(ary2, idTo_ary)) {
+            return Qfalse;
+        }
+        return rb_equal(ary2, ary1);
     }
     if (RARRAY_LEN(ary1) != RARRAY_LEN(ary2)) return Qfalse;
-    if (RARRAY_CONST_PTR_TRANSIENT(ary1) == RARRAY_CONST_PTR_TRANSIENT(ary2)) return Qtrue;
+    if (RARRAY_CONST_PTR(ary1) == RARRAY_CONST_PTR(ary2)) return Qtrue;
     return rb_exec_recursive_paired(recursive_equal, ary1, ary2, ary2);
 }
 
@@ -5057,18 +5276,19 @@ recursive_eql(VALUE ary1, VALUE ary2, int recur)
 
     if (recur) return Qtrue; /* Subtle! */
     for (i=0; i<RARRAY_LEN(ary1); i++) {
-	if (!rb_eql(rb_ary_elt(ary1, i), rb_ary_elt(ary2, i)))
-	    return Qfalse;
+        if (!rb_eql(rb_ary_elt(ary1, i), rb_ary_elt(ary2, i)))
+            return Qfalse;
     }
     return Qtrue;
 }
 
 /*
  *  call-seq:
- *    array.eql? other_array -> true or false
+ *    eql?(other_array) -> true or false
  *
  *  Returns +true+ if +self+ and +other_array+ are the same size,
- *  and if, for each index +i+ in +self+, <tt>self[i].eql? other_array[i]</tt>:
+ *  and if, for each index +i+ in +self+, <tt>self[i].eql?(other_array[i])</tt>:
+ *
  *    a0 = [:foo, 'bar', 2]
  *    a1 = [:foo, 'bar', 2]
  *    a1.eql?(a0) # => true
@@ -5077,6 +5297,8 @@ recursive_eql(VALUE ary1, VALUE ary2, int recur)
  *
  *  This method is different from method Array#==,
  *  which compares using method <tt>Object#==</tt>.
+ *
+ *  Related: see {Methods for Querying}[rdoc-ref:Array@Methods+for+Querying].
  */
 
 static VALUE
@@ -5085,46 +5307,60 @@ rb_ary_eql(VALUE ary1, VALUE ary2)
     if (ary1 == ary2) return Qtrue;
     if (!RB_TYPE_P(ary2, T_ARRAY)) return Qfalse;
     if (RARRAY_LEN(ary1) != RARRAY_LEN(ary2)) return Qfalse;
-    if (RARRAY_CONST_PTR_TRANSIENT(ary1) == RARRAY_CONST_PTR_TRANSIENT(ary2)) return Qtrue;
+    if (RARRAY_CONST_PTR(ary1) == RARRAY_CONST_PTR(ary2)) return Qtrue;
     return rb_exec_recursive_paired(recursive_eql, ary1, ary2, ary2);
 }
 
+VALUE
+rb_ary_hash_values(long len, const VALUE *elements)
+{
+    long i;
+    st_index_t h;
+    VALUE n;
+
+    h = rb_hash_start(len);
+    h = rb_hash_uint(h, (st_index_t)rb_ary_hash_values);
+    for (i=0; i<len; i++) {
+        n = rb_hash(elements[i]);
+        h = rb_hash_uint(h, NUM2LONG(n));
+    }
+    h = rb_hash_end(h);
+    return ST2FIX(h);
+}
+
 /*
  *  call-seq:
- *    array.hash -> integer
+ *    hash -> integer
  *
  *  Returns the integer hash value for +self+.
  *
- *  Two arrays with the same content will have the same hash code (and will compare using eql?):
- *    [0, 1, 2].hash == [0, 1, 2].hash # => true
- *    [0, 1, 2].hash == [0, 1, 3].hash # => false
+ *  Two arrays with the same content will have the same hash value
+ *  (and will compare using eql?):
+ *
+ *    ['a', 'b'].hash == ['a', 'b'].hash # => true
+ *    ['a', 'b'].hash == ['a', 'c'].hash # => false
+ *    ['a', 'b'].hash == ['a'].hash      # => false
+ *
  */
 
 static VALUE
 rb_ary_hash(VALUE ary)
 {
-    long i;
-    st_index_t h;
-    VALUE n;
-
-    h = rb_hash_start(RARRAY_LEN(ary));
-    h = rb_hash_uint(h, (st_index_t)rb_ary_hash);
-    for (i=0; i<RARRAY_LEN(ary); i++) {
-	n = rb_hash(RARRAY_AREF(ary, i));
-	h = rb_hash_uint(h, NUM2LONG(n));
-    }
-    h = rb_hash_end(h);
-    return ST2FIX(h);
+    return rb_ary_hash_values(RARRAY_LEN(ary), RARRAY_CONST_PTR(ary));
 }
 
 /*
  *  call-seq:
- *    array.include?(obj) -> true or false
+ *    include?(object) -> true or false
+ *
+ *  Returns whether for some element +element+ in +self+,
+ *  <tt>object == element</tt>:
  *
- *  Returns +true+ if for some index +i+ in +self+, <tt>obj == self[i]</tt>;
- *  otherwise +false+:
- *    [0, 1, 2].include?(2) # => true
- *    [0, 1, 2].include?(3) # => false
+ *    [0, 1, 2].include?(2)   # => true
+ *    [0, 1, 2].include?(2.0) # => true
+ *    [0, 1, 2].include?(2.1) # => false
+ *
+ *  Related: see {Methods for Querying}[rdoc-ref:Array@Methods+for+Querying].
  */
 
 VALUE
@@ -5134,10 +5370,10 @@ rb_ary_includes(VALUE ary, VALUE item)
     VALUE e;
 
     for (i=0; i<RARRAY_LEN(ary); i++) {
-	e = RARRAY_AREF(ary, i);
-	if (rb_equal(e, item)) {
-	    return Qtrue;
-	}
+        e = RARRAY_AREF(ary, i);
+        if (rb_equal(e, item)) {
+            return Qtrue;
+        }
     }
     return Qfalse;
 }
@@ -5149,10 +5385,10 @@ rb_ary_includes_by_eql(VALUE ary, VALUE item)
     VALUE e;
 
     for (i=0; i<RARRAY_LEN(ary); i++) {
-	e = RARRAY_AREF(ary, i);
-	if (rb_eql(item, e)) {
-	    return Qtrue;
-	}
+        e = RARRAY_AREF(ary, i);
+        if (rb_eql(item, e)) {
+            return Qtrue;
+        }
     }
     return Qfalse;
 }
@@ -5165,38 +5401,54 @@ recursive_cmp(VALUE ary1, VALUE ary2, int recur)
     if (recur) return Qundef;	/* Subtle! */
     len = RARRAY_LEN(ary1);
     if (len > RARRAY_LEN(ary2)) {
-	len = RARRAY_LEN(ary2);
+        len = RARRAY_LEN(ary2);
     }
     for (i=0; i<len; i++) {
-	VALUE e1 = rb_ary_elt(ary1, i), e2 = rb_ary_elt(ary2, i);
-	VALUE v = rb_funcallv(e1, id_cmp, 1, &e2);
-	if (v != INT2FIX(0)) {
-	    return v;
-	}
+        VALUE e1 = rb_ary_elt(ary1, i), e2 = rb_ary_elt(ary2, i);
+        VALUE v = rb_funcallv(e1, id_cmp, 1, &e2);
+        if (v != INT2FIX(0)) {
+            return v;
+        }
     }
     return Qundef;
 }
 
 /*
  *  call-seq:
- *    array <=> other_array -> -1, 0, or 1
+ *    self <=> other_array -> -1, 0, or 1
+ *
+ *  Returns -1, 0, or 1 as +self+ is determined
+ *  to be less than, equal to, or greater than +other_array+.
+ *
+ *  Iterates over each index +i+ in <tt>(0...self.size)</tt>:
+ *
+ *  - Computes <tt>result[i]</tt> as <tt>self[i] <=> other_array[i]</tt>.
+ *  - Immediately returns 1 if <tt>result[i]</tt> is 1:
+ *
+ *      [0, 1, 2] <=> [0, 0, 2] # => 1
+ *
+ *  - Immediately returns -1 if <tt>result[i]</tt> is -1:
+ *
+ *      [0, 1, 2] <=> [0, 2, 2] # => -1
+ *
+ *  - Continues if <tt>result[i]</tt> is 0.
  *
- *  Returns -1, 0, or 1 as +self+ is less than, equal to, or greater than +other_array+.
- *  For each index +i+ in +self+, evaluates <tt>result = self[i] <=> other_array[i]</tt>.
+ *  When every +result+ is 0,
+ *  returns <tt>self.size <=> other_array.size</tt>
+ *  (see Integer#<=>):
  *
- *  Returns -1 if any result is -1:
- *    [0, 1, 2] <=> [0, 1, 3] # => -1
+ *    [0, 1, 2] <=> [0, 1]        # => 1
+ *    [0, 1, 2] <=> [0, 1, 2]     # => 0
+ *    [0, 1, 2] <=> [0, 1, 2, 3]  # => -1
  *
- *  Returns 1 if any result is 1:
- *    [0, 1, 2] <=> [0, 1, 1] # => 1
+ *  Note that when +other_array+ is larger than +self+,
+ *  its trailing elements do not affect the result:
  *
- *  When all results are zero:
- *  - Returns -1 if +array+ is smaller than +other_array+:
- *      [0, 1, 2] <=> [0, 1, 2, 3] # => -1
- *  - Returns 1 if +array+ is larger than +other_array+:
- *      [0, 1, 2] <=> [0, 1] # => 1
- *  - Returns 0 if +array+ and +other_array+ are the same size:
- *      [0, 1, 2] <=> [0, 1, 2] # => 0
+ *    [0, 1, 2] <=> [0, 1, 2, -3] # => -1
+ *    [0, 1, 2] <=> [0, 1, 2, 0]  # => -1
+ *    [0, 1, 2] <=> [0, 1, 2, 3]  # => -1
+ *
+ *  Related: see {Methods for Comparing}[rdoc-ref:Array@Methods+for+Comparing].
  */
 
 VALUE
@@ -5209,7 +5461,7 @@ rb_ary_cmp(VALUE ary1, VALUE ary2)
     if (NIL_P(ary2)) return Qnil;
     if (ary1 == ary2) return INT2FIX(0);
     v = rb_exec_recursive_paired(recursive_cmp, ary1, ary2, ary2);
-    if (v != Qundef) return v;
+    if (!UNDEF_P(v)) return v;
     len = RARRAY_LEN(ary1) - RARRAY_LEN(ary2);
     if (len == 0) return INT2FIX(0);
     if (len > 0) return INT2FIX(1);
@@ -5222,8 +5474,8 @@ ary_add_hash(VALUE hash, VALUE ary)
     long i;
 
     for (i=0; i<RARRAY_LEN(ary); i++) {
-	VALUE elt = RARRAY_AREF(ary, i);
-	rb_hash_add_new_element(hash, elt, elt);
+        VALUE elt = RARRAY_AREF(ary, i);
+        rb_hash_add_new_element(hash, elt, elt);
     }
     return hash;
 }
@@ -5251,8 +5503,8 @@ ary_add_hash_by(VALUE hash, VALUE ary)
     long i;
 
     for (i = 0; i < RARRAY_LEN(ary); ++i) {
-	VALUE v = rb_ary_elt(ary, i), k = rb_yield(v);
-	rb_hash_add_new_element(hash, k, v);
+        VALUE v = rb_ary_elt(ary, i), k = rb_yield(v);
+        rb_hash_add_new_element(hash, k, v);
     }
     return hash;
 }
@@ -5264,33 +5516,25 @@ ary_make_hash_by(VALUE ary)
     return ary_add_hash_by(hash, ary);
 }
 
-static inline void
-ary_recycle_hash(VALUE hash)
-{
-    assert(RBASIC_CLASS(hash) == 0);
-    if (RHASH_ST_TABLE_P(hash)) {
-        st_table *tbl = RHASH_ST_TABLE(hash);
-	st_free_table(tbl);
-        RHASH_ST_CLEAR(hash);
-    }
-}
-
 /*
  *  call-seq:
- *    array - other_array -> new_array
+ *    self - other_array -> new_array
+ *
+ *  Returns a new array containing only those elements of +self+
+ *  that are not found in +other_array+;
+ *  the order from +self+ is preserved:
  *
- *  Returns a new \Array containing only those elements from +array+
- *  that are not found in \Array +other_array+;
- *  items are compared using <tt>eql?</tt>;
- *  the order from +array+ is preserved:
- *    [0, 1, 1, 2, 1, 1, 3, 1, 1] - [1] # => [0, 2, 3]
- *    [0, 1, 2, 3] - [3, 0] # => [1, 2]
- *    [0, 1, 2] - [4] # => [0, 1, 2]
+ *    [0, 1, 1, 2, 1, 1, 3, 1, 1] - [1]             # => [0, 2, 3]
+ *    [0, 1, 1, 2, 1, 1, 3, 1, 1] - [3, 2, 0, :foo] # => [1, 1, 1, 1, 1, 1]
+ *    [0, 1, 2] - [:foo]                            # => [0, 1, 2]
  *
- *  Related: Array#difference.
+ *  Element are compared using method <tt>#eql?</tt>
+ *  (as defined in each element of +self+).
+ *
+ *  Related: see {Methods for Combining}[rdoc-ref:Array@Methods+for+Combining].
  */
 
-static VALUE
+VALUE
 rb_ary_diff(VALUE ary1, VALUE ary2)
 {
     VALUE ary3;
@@ -5302,37 +5546,40 @@ rb_ary_diff(VALUE ary1, VALUE ary2)
     ary3 = rb_ary_new();
 
     if (RARRAY_LEN(ary1) <= SMALL_ARRAY_LEN || RARRAY_LEN(ary2) <= SMALL_ARRAY_LEN) {
-	for (i=0; i<RARRAY_LEN(ary1); i++) {
-	    VALUE elt = rb_ary_elt(ary1, i);
-	    if (rb_ary_includes_by_eql(ary2, elt)) continue;
-	    rb_ary_push(ary3, elt);
-	}
-	return ary3;
+        for (i=0; i<RARRAY_LEN(ary1); i++) {
+            VALUE elt = rb_ary_elt(ary1, i);
+            if (rb_ary_includes_by_eql(ary2, elt)) continue;
+            rb_ary_push(ary3, elt);
+        }
+        return ary3;
     }
 
     hash = ary_make_hash(ary2);
     for (i=0; i<RARRAY_LEN(ary1); i++) {
         if (rb_hash_stlike_lookup(hash, RARRAY_AREF(ary1, i), NULL)) continue;
-	rb_ary_push(ary3, rb_ary_elt(ary1, i));
+        rb_ary_push(ary3, rb_ary_elt(ary1, i));
     }
-    ary_recycle_hash(hash);
+
     return ary3;
 }
 
 /*
  *  call-seq:
- *    array.difference(*other_arrays) -> new_array
+ *    difference(*other_arrays = []) -> new_array
  *
- *  Returns a new \Array containing only those elements from +self+
- *  that are not found in any of the Arrays +other_arrays+;
+ *  Returns a new array containing only those elements from +self+
+ *  that are not found in any of the given +other_arrays+;
  *  items are compared using <tt>eql?</tt>;  order from +self+ is preserved:
+ *
  *    [0, 1, 1, 2, 1, 1, 3, 1, 1].difference([1]) # => [0, 2, 3]
- *    [0, 1, 2, 3].difference([3, 0], [1, 3]) # => [2]
- *    [0, 1, 2].difference([4]) # => [0, 1, 2]
+ *    [0, 1, 2, 3].difference([3, 0], [1, 3])     # => [2]
+ *    [0, 1, 2].difference([4])                   # => [0, 1, 2]
+ *    [0, 1, 2].difference                        # => [0, 1, 2]
  *
- *  Returns a copy of +self+ if no arguments given.
+ *  Returns a copy of +self+ if no arguments are given.
  *
- *  Related: Array#-.
+ *  Related: Array#-;
+ *  see also {Methods for Combining}[rdoc-ref:Array@Methods+for+Combining].
  */
 
 static VALUE
@@ -5374,17 +5621,25 @@ rb_ary_difference_multi(int argc, VALUE *argv, VALUE ary)
 
 /*
  *  call-seq:
- *    array & other_array -> new_array
+ *    self & other_array -> new_array
+ *
+ *  Returns a new array containing the _intersection_ of +self+ and +other_array+;
+ *  that is, containing those elements found in both +self+ and +other_array+:
  *
- *  Returns a new \Array containing each element found in both +array+ and \Array +other_array+;
- *  duplicates are omitted; items are compared using <tt>eql?</tt>:
  *    [0, 1, 2, 3] & [1, 2] # => [1, 2]
- *    [0, 1, 0, 1] & [0, 1] # => [0, 1]
  *
- *  Preserves order from +array+:
+ *  Omits duplicates:
+ *
+ *    [0, 1, 1, 0] & [0, 1] # => [0, 1]
+ *
+ *  Preserves order from +self+:
+ *
  *    [0, 1, 2] & [3, 2, 1, 0] # => [0, 1, 2]
  *
- *  Related: Array#intersection.
+ *  Identifies common elements using method <tt>#eql?</tt>
+ *  (as defined in each element of +self+).
+ *
+ *  Related: see {Methods for Combining}[rdoc-ref:Array@Methods+for+Combining].
  */
 
 
@@ -5400,45 +5655,47 @@ rb_ary_and(VALUE ary1, VALUE ary2)
     if (RARRAY_LEN(ary1) == 0 || RARRAY_LEN(ary2) == 0) return ary3;
 
     if (RARRAY_LEN(ary1) <= SMALL_ARRAY_LEN && RARRAY_LEN(ary2) <= SMALL_ARRAY_LEN) {
-	for (i=0; i<RARRAY_LEN(ary1); i++) {
-	    v = RARRAY_AREF(ary1, i);
-	    if (!rb_ary_includes_by_eql(ary2, v)) continue;
-	    if (rb_ary_includes_by_eql(ary3, v)) continue;
-	    rb_ary_push(ary3, v);
-	}
-	return ary3;
+        for (i=0; i<RARRAY_LEN(ary1); i++) {
+            v = RARRAY_AREF(ary1, i);
+            if (!rb_ary_includes_by_eql(ary2, v)) continue;
+            if (rb_ary_includes_by_eql(ary3, v)) continue;
+            rb_ary_push(ary3, v);
+        }
+        return ary3;
     }
 
     hash = ary_make_hash(ary2);
 
     for (i=0; i<RARRAY_LEN(ary1); i++) {
-	v = RARRAY_AREF(ary1, i);
-	vv = (st_data_t)v;
+        v = RARRAY_AREF(ary1, i);
+        vv = (st_data_t)v;
         if (rb_hash_stlike_delete(hash, &vv, 0)) {
-	    rb_ary_push(ary3, v);
-	}
+            rb_ary_push(ary3, v);
+        }
     }
-    ary_recycle_hash(hash);
 
     return ary3;
 }
 
 /*
  *  call-seq:
- *    array.intersection(*other_arrays) -> new_array
+ *    intersection(*other_arrays) -> new_array
+ *
+ *  Returns a new array containing each element in +self+ that is +#eql?+
+ *  to at least one element in each of the given +other_arrays+;
+ *  duplicates are omitted:
  *
- *  Returns a new \Array containing each element found both in +self+
- *  and in all of the given Arrays +other_arrays+;
- *  duplicates are omitted; items are compared using <tt>eql?</tt>:
- *    [0, 1, 2, 3].intersection([0, 1, 2], [0, 1, 3]) # => [0, 1]
  *    [0, 0, 1, 1, 2, 3].intersection([0, 1, 2], [0, 1, 3]) # => [0, 1]
  *
- *  Preserves order from +self+:
+ *  Each element must correctly implement method <tt>#hash</tt>.
+ *
+ *  Order from +self+ is preserved:
+ *
  *    [0, 1, 2].intersection([2, 1, 0]) # => [0, 1, 2]
  *
- *  Returns a copy of +self+ if no arguments given.
+ *  Returns a copy of +self+ if no arguments are given.
  *
- *  Related: Array#&.
+ *  Related: see {Methods for Combining}[rdoc-ref:Array@Methods+for+Combining].
  */
 
 static VALUE
@@ -5487,52 +5744,59 @@ rb_ary_union_hash(VALUE hash, VALUE ary2)
 
 /*
  *  call-seq:
- *    array | other_array -> new_array
+ *    self | other_array -> new_array
  *
- *  Returns the union of +array+ and \Array +other_array+;
+ *  Returns the union of +self+ and +other_array+;
  *  duplicates are removed; order is preserved;
  *  items are compared using <tt>eql?</tt>:
+ *
  *    [0, 1] | [2, 3] # => [0, 1, 2, 3]
  *    [0, 1, 1] | [2, 2, 3] # => [0, 1, 2, 3]
  *    [0, 1, 2] | [3, 2, 1, 0] # => [0, 1, 2, 3]
  *
- *  Related: Array#union.
+ *  Related: see {Methods for Combining}[rdoc-ref:Array@Methods+for+Combining].
  */
 
 static VALUE
 rb_ary_or(VALUE ary1, VALUE ary2)
 {
-    VALUE hash, ary3;
+    VALUE hash;
 
     ary2 = to_ary(ary2);
     if (RARRAY_LEN(ary1) + RARRAY_LEN(ary2) <= SMALL_ARRAY_LEN) {
-	ary3 = rb_ary_new();
+        VALUE ary3 = rb_ary_new();
         rb_ary_union(ary3, ary1);
         rb_ary_union(ary3, ary2);
-	return ary3;
+        return ary3;
     }
 
     hash = ary_make_hash(ary1);
     rb_ary_union_hash(hash, ary2);
 
-    ary3 = rb_hash_values(hash);
-    ary_recycle_hash(hash);
-    return ary3;
+    return rb_hash_values(hash);
 }
 
 /*
  *  call-seq:
- *    array.union(*other_arrays) -> new_array
+ *    union(*other_arrays) -> new_array
+ *
+ *  Returns a new array that is the union of the elements of +self+
+ *  and all given arrays +other_arrays+;
+ *  items are compared using <tt>eql?</tt>:
  *
- *  Returns a new \Array that is the union of +self+ and all given Arrays +other_arrays+;
- *  duplicates are removed;  order is preserved;  items are compared using <tt>eql?</tt>:
  *    [0, 1, 2, 3].union([4, 5], [6, 7]) # => [0, 1, 2, 3, 4, 5, 6, 7]
+ *
+ *  Removes duplicates (preserving the first found):
+ *
  *    [0, 1, 1].union([2, 1], [3, 1]) # => [0, 1, 2, 3]
- *    [0, 1, 2, 3].union([3, 2], [1, 0]) # => [0, 1, 2, 3]
  *
- *  Returns a copy of +self+ if no arguments given.
+ *  Preserves order (preserving the position of the first found):
+ *
+ *    [3, 2, 1, 0].union([5, 3], [4, 2]) # => [3, 2, 1, 0, 5, 4]
  *
- *  Related: Array#|.
+ *  With no arguments given, returns a copy of +self+.
+ *
+ *  Related: see {Methods for Combining}[rdoc-ref:Array@Methods+for+Combining].
  */
 
 static VALUE
@@ -5540,7 +5804,7 @@ rb_ary_union_multi(int argc, VALUE *argv, VALUE ary)
 {
     int i;
     long sum;
-    VALUE hash, ary_union;
+    VALUE hash;
 
     sum = RARRAY_LEN(ary);
     for (i = 0; i < argc; i++) {
@@ -5549,7 +5813,7 @@ rb_ary_union_multi(int argc, VALUE *argv, VALUE ary)
     }
 
     if (sum <= SMALL_ARRAY_LEN) {
-        ary_union = rb_ary_new();
+        VALUE ary_union = rb_ary_new();
 
         rb_ary_union(ary_union, ary);
         for (i = 0; i < argc; i++) rb_ary_union(ary_union, argv[i]);
@@ -5560,23 +5824,21 @@ rb_ary_union_multi(int argc, VALUE *argv, VALUE ary)
     hash = ary_make_hash(ary);
     for (i = 0; i < argc; i++) rb_ary_union_hash(hash, argv[i]);
 
-    ary_union = rb_hash_values(hash);
-    ary_recycle_hash(hash);
-    return ary_union;
+    return rb_hash_values(hash);
 }
 
 /*
  *  call-seq:
- *     ary.intersect?(other_ary)   -> true or false
+ *    intersect?(other_array) -> true or false
+ *
+ *  Returns whether +other_array+ has at least one element that is +#eql?+ to some element of +self+:
  *
- *  Returns +true+ if the array and +other_ary+ have at least one element in
- *  common, otherwise returns +false+.
+ *    [1, 2, 3].intersect?([3, 4, 5]) # => true
+ *    [1, 2, 3].intersect?([4, 5, 6]) # => false
  *
- *     a = [ 1, 2, 3 ]
- *     b = [ 3, 4, 5 ]
- *     c = [ 5, 6, 7 ]
- *     a.intersect?(b)   #=> true
- *     a.intersect?(c)   #=> false
+ *  Each element must correctly implement method <tt>#hash</tt>.
+ *
+ *  Related: see {Methods for Querying}[rdoc-ref:Array@Methods+for+Querying].
  */
 
 static VALUE
@@ -5615,7 +5877,6 @@ rb_ary_intersect_p(VALUE ary1, VALUE ary2)
             break;
         }
     }
-    ary_recycle_hash(hash);
 
     return result;
 }
@@ -5711,41 +5972,55 @@ ary_max_opt_string(VALUE ary, long i, VALUE vmax)
 
 /*
  *  call-seq:
- *    array.max -> element
- *    array.max {|a, b| ... } -> element
- *    array.max(n) -> new_array
- *    array.max(n) {|a, b| ... } -> new_array
+ *    max -> element
+ *    max(count) -> new_array
+ *    max {|a, b| ... } -> element
+ *    max(count) {|a, b| ... } -> new_array
  *
  *  Returns one of the following:
+ *
  *  - The maximum-valued element from +self+.
- *  - A new \Array of maximum-valued elements selected from +self+.
+ *  - A new array of maximum-valued elements from +self+.
  *
- *  When no block is given, each element in +self+ must respond to method <tt><=></tt>
- *  with an \Integer.
+ *  Does not modify +self+.
+ *
+ *  With no block given, each element in +self+ must respond to method <tt>#<=></tt>
+ *  with a numeric.
  *
  *  With no argument and no block, returns the element in +self+
- *  having the maximum value per method <tt><=></tt>:
- *    [0, 1, 2].max # => 2
+ *  having the maximum value per method <tt>#<=></tt>:
+ *
+ *    [1, 0, 3, 2].max # => 3
  *
- *  With an argument \Integer +n+ and no block, returns a new \Array with at most +n+ elements,
- *  in descending order per method <tt><=></tt>:
- *    [0, 1, 2, 3].max(3) # => [3, 2, 1]
- *    [0, 1, 2, 3].max(6) # => [3, 2, 1, 0]
+ *  With non-negative numeric argument +count+ and no block,
+ *  returns a new array with at most +count+ elements,
+ *  in descending order, per method <tt>#<=></tt>:
  *
- *  When a block is given, the block must return an \Integer.
+ *    [1, 0, 3, 2].max(3)   # => [3, 2, 1]
+ *    [1, 0, 3, 2].max(3.0) # => [3, 2, 1]
+ *    [1, 0, 3, 2].max(9)   # => [3, 2, 1, 0]
+ *    [1, 0, 3, 2].max(0)   # => []
  *
- *  With a block and no argument, calls the block <tt>self.size-1</tt> times to compare elements;
+ *  With a block given, the block must return a numeric.
+ *
+ *  With a block and no argument, calls the block <tt>self.size - 1</tt> times to compare elements;
  *  returns the element having the maximum value per the block:
- *    ['0', '00', '000'].max {|a, b| a.size <=> b.size } # => "000"
  *
- *  With an argument +n+ and a block, returns a new \Array with at most +n+ elements,
- *  in descending order per the block:
- *    ['0', '00', '000'].max(2) {|a, b| a.size <=> b.size } # => ["000", "00"]
+ *    ['0', '', '000', '00'].max {|a, b| a.size <=> b.size }
+ *    # => "000"
+ *
+ *  With non-negative numeric argument +count+ and a block,
+ *  returns a new array with at most +count+ elements,
+ *  in descending order, per the block:
+ *
+ *    ['0', '', '000', '00'].max(2) {|a, b| a.size <=> b.size }
+ *    # => ["000", "00"]
+ *
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 static VALUE
 rb_ary_max(int argc, VALUE *argv, VALUE ary)
 {
-    struct cmp_opt_data cmp_opt = { 0, 0 };
     VALUE result = Qundef, v;
     VALUE num;
     long i;
@@ -5755,23 +6030,23 @@ rb_ary_max(int argc, VALUE *argv, VALUE ary)
 
     const long n = RARRAY_LEN(ary);
     if (rb_block_given_p()) {
-	for (i = 0; i < RARRAY_LEN(ary); i++) {
-	   v = RARRAY_AREF(ary, i);
-	   if (result == Qundef || rb_cmpint(rb_yield_values(2, v, result), v, result) > 0) {
-	       result = v;
-	   }
-	}
+        for (i = 0; i < RARRAY_LEN(ary); i++) {
+           v = RARRAY_AREF(ary, i);
+           if (UNDEF_P(result) || rb_cmpint(rb_yield_values(2, v, result), v, result) > 0) {
+               result = v;
+           }
+        }
     }
     else if (n > 0) {
         result = RARRAY_AREF(ary, 0);
         if (n > 1) {
-            if (FIXNUM_P(result) && CMP_OPTIMIZABLE(cmp_opt, Integer)) {
+            if (FIXNUM_P(result) && CMP_OPTIMIZABLE(INTEGER)) {
                 return ary_max_opt_fixnum(ary, 1, result);
             }
-            else if (STRING_P(result) && CMP_OPTIMIZABLE(cmp_opt, String)) {
+            else if (STRING_P(result) && CMP_OPTIMIZABLE(STRING)) {
                 return ary_max_opt_string(ary, 1, result);
             }
-            else if (RB_FLOAT_TYPE_P(result) && CMP_OPTIMIZABLE(cmp_opt, Float)) {
+            else if (RB_FLOAT_TYPE_P(result) && CMP_OPTIMIZABLE(FLOAT)) {
                 return ary_max_opt_float(ary, 1, result);
             }
             else {
@@ -5779,7 +6054,7 @@ rb_ary_max(int argc, VALUE *argv, VALUE ary)
             }
         }
     }
-    if (result == Qundef) return Qnil;
+    if (UNDEF_P(result)) return Qnil;
     return result;
 }
 
@@ -5874,41 +6149,55 @@ ary_min_opt_string(VALUE ary, long i, VALUE vmin)
 
 /*
  *  call-seq:
- *    array.min -> element
- *    array.min { |a, b| ... } -> element
- *    array.min(n) -> new_array
- *    array.min(n) { |a, b| ... } -> new_array
+ *    min -> element
+ *    min(count) -> new_array
+ *    min {|a, b| ... } -> element
+ *    min(count) {|a, b| ... } -> new_array
  *
  *  Returns one of the following:
+ *
  *  - The minimum-valued element from +self+.
- *  - A new \Array of minimum-valued elements selected from +self+.
+ *  - A new array of minimum-valued elements from +self+.
+ *
+ *  Does not modify +self+.
  *
- *  When no block is given, each element in +self+ must respond to method <tt><=></tt>
- *  with an \Integer.
+ *  With no block given, each element in +self+ must respond to method <tt>#<=></tt>
+ *  with a numeric.
  *
  *  With no argument and no block, returns the element in +self+
- *  having the minimum value per method <tt><=></tt>:
- *    [0, 1, 2].min # => 0
+ *  having the minimum value per method <tt>#<=></tt>:
  *
- *  With \Integer argument +n+ and no block, returns a new \Array with at most +n+ elements,
- *  in ascending order per method <tt><=></tt>:
- *    [0, 1, 2, 3].min(3) # => [0, 1, 2]
- *    [0, 1, 2, 3].min(6) # => [0, 1, 2, 3]
+ *    [1, 0, 3, 2].min # => 0
  *
- *  When a block is given, the block must return an Integer.
+ *  With non-negative numeric argument +count+ and no block,
+ *  returns a new array with at most +count+ elements,
+ *  in ascending order, per method <tt>#<=></tt>:
  *
- *  With a block and no argument, calls the block <tt>self.size-1</tt> times to compare elements;
+ *    [1, 0, 3, 2].min(3)   # => [0, 1, 2]
+ *    [1, 0, 3, 2].min(3.0) # => [0, 1, 2]
+ *    [1, 0, 3, 2].min(9)   # => [0, 1, 2, 3]
+ *    [1, 0, 3, 2].min(0)   # => []
+ *
+ *  With a block given, the block must return a numeric.
+ *
+ *  With a block and no argument, calls the block <tt>self.size - 1</tt> times to compare elements;
  *  returns the element having the minimum value per the block:
- *    ['0', '00', '000'].min { |a, b| a.size <=> b.size } # => "0"
  *
- *  With an argument +n+ and a block, returns a new \Array with at most +n+ elements,
- *  in ascending order per the block:
- *    ['0', '00', '000'].min(2) {|a, b| a.size <=> b.size } # => ["0", "00"]
+ *    ['0', '', '000', '00'].min {|a, b| a.size <=> b.size }
+ *    # => ""
+ *
+ *  With non-negative numeric argument +count+ and a block,
+ *  returns a new array with at most +count+ elements,
+ *  in ascending order, per the block:
+ *
+ *    ['0', '', '000', '00'].min(2) {|a, b| a.size <=> b.size }
+ *    # => ["", "0"]
+ *
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 static VALUE
 rb_ary_min(int argc, VALUE *argv, VALUE ary)
 {
-    struct cmp_opt_data cmp_opt = { 0, 0 };
     VALUE result = Qundef, v;
     VALUE num;
     long i;
@@ -5918,23 +6207,23 @@ rb_ary_min(int argc, VALUE *argv, VALUE ary)
 
     const long n = RARRAY_LEN(ary);
     if (rb_block_given_p()) {
-	for (i = 0; i < RARRAY_LEN(ary); i++) {
-	   v = RARRAY_AREF(ary, i);
-	   if (result == Qundef || rb_cmpint(rb_yield_values(2, v, result), v, result) < 0) {
-	       result = v;
-	   }
-	}
+        for (i = 0; i < RARRAY_LEN(ary); i++) {
+           v = RARRAY_AREF(ary, i);
+           if (UNDEF_P(result) || rb_cmpint(rb_yield_values(2, v, result), v, result) < 0) {
+               result = v;
+           }
+        }
     }
     else if (n > 0) {
         result = RARRAY_AREF(ary, 0);
         if (n > 1) {
-            if (FIXNUM_P(result) && CMP_OPTIMIZABLE(cmp_opt, Integer)) {
+            if (FIXNUM_P(result) && CMP_OPTIMIZABLE(INTEGER)) {
                 return ary_min_opt_fixnum(ary, 1, result);
             }
-            else if (STRING_P(result) && CMP_OPTIMIZABLE(cmp_opt, String)) {
+            else if (STRING_P(result) && CMP_OPTIMIZABLE(STRING)) {
                 return ary_min_opt_string(ary, 1, result);
             }
-            else if (RB_FLOAT_TYPE_P(result) && CMP_OPTIMIZABLE(cmp_opt, Float)) {
+            else if (RB_FLOAT_TYPE_P(result) && CMP_OPTIMIZABLE(FLOAT)) {
                 return ary_min_opt_float(ary, 1, result);
             }
             else {
@@ -5942,29 +6231,31 @@ rb_ary_min(int argc, VALUE *argv, VALUE ary)
             }
         }
     }
-    if (result == Qundef) return Qnil;
+    if (UNDEF_P(result)) return Qnil;
     return result;
 }
 
 /*
  *  call-seq:
- *    array.minmax -> [min_val, max_val]
- *    array.minmax {|a, b| ... } -> [min_val, max_val]
- *
- *  Returns a new 2-element \Array containing the minimum and maximum values
- *  from +self+, either per method <tt><=></tt> or per a given block:.
- *
- *  When no block is given, each element in +self+ must respond to method <tt><=></tt>
- *  with an \Integer;
- *  returns a new 2-element \Array containing the minimum and maximum values
- *  from +self+, per method <tt><=></tt>:
- *    [0, 1, 2].minmax # => [0, 2]
- *
- *  When a block is given, the block must return an \Integer;
- *  the block is called <tt>self.size-1</tt> times to compare elements;
- *  returns a new 2-element \Array containing the minimum and maximum values
- *  from +self+, per the block:
- *    ['0', '00', '000'].minmax {|a, b| a.size <=> b.size } # => ["0", "000"]
+ *    minmax -> array
+ *    minmax {|a, b| ... } -> array
+ *
+ *  Returns a 2-element array containing the minimum-valued and maximum-valued
+ *  elements from +self+;
+ *  does not modify +self+.
+ *
+ *  With no block given, the minimum and maximum values are determined using method <tt>#<=></tt>:
+ *
+ *    [1, 0, 3, 2].minmax # => [0, 3]
+ *
+ *  With a block given, the block must return a numeric;
+ *  the block is called <tt>self.size - 1</tt> times to compare elements;
+ *  returns the elements having the minimum and maximum values per the block:
+ *
+ *    ['0', '', '000', '00'].minmax {|a, b| a.size <=> b.size }
+ *    # => ["", "000"]
+ *
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 static VALUE
 rb_ary_minmax(VALUE ary)
@@ -5984,30 +6275,30 @@ push_value(st_data_t key, st_data_t val, st_data_t ary)
 
 /*
  *  call-seq:
- *    array.uniq! -> self or nil
- *    array.uniq! {|element| ... } -> self or nil
+ *    uniq! -> self or nil
+ *    uniq! {|element| ... } -> self or nil
  *
  *  Removes duplicate elements from +self+, the first occurrence always being retained;
  *  returns +self+ if any elements removed, +nil+ otherwise.
  *
  *  With no block given, identifies and removes elements using method <tt>eql?</tt>
- *  to compare.
+ *  to compare elements:
  *
- *  Returns +self+ if any elements removed:
  *    a = [0, 0, 1, 1, 2, 2]
  *    a.uniq! # => [0, 1, 2]
- *
- *  Returns +nil+ if no elements removed.
+ *    a.uniq! # => nil
  *
  *  With a block given, calls the block for each element;
- *  identifies (using method <tt>eql?</tt>) and removes
- *  elements for which the block returns duplicate values.
+ *  identifies and omits "duplicate" elements using method <tt>eql?</tt>
+ *  to compare <i>block return values</i>;
+ *  that is, an element is a duplicate if its block return value
+ *  is the same as that of a previous element:
  *
- *  Returns +self+ if any elements removed:
  *    a = ['a', 'aa', 'aaa', 'b', 'bb', 'bbb']
- *    a.uniq! {|element| element.size } # => ['a', 'aa', 'aaa']
+ *    a.uniq! {|element| element.size } # => ["a", "aa", "aaa"]
+ *    a.uniq! {|element| element.size } # => nil
  *
- *  Returns +nil+ if no elements removed.
+ *  Related: see {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
 static VALUE
 rb_ary_uniq_bang(VALUE ary)
@@ -6019,45 +6310,50 @@ rb_ary_uniq_bang(VALUE ary)
     if (RARRAY_LEN(ary) <= 1)
         return Qnil;
     if (rb_block_given_p())
-	hash = ary_make_hash_by(ary);
+        hash = ary_make_hash_by(ary);
     else
-	hash = ary_make_hash(ary);
+        hash = ary_make_hash(ary);
 
     hash_size = RHASH_SIZE(hash);
     if (RARRAY_LEN(ary) == hash_size) {
-	return Qnil;
+        return Qnil;
     }
     rb_ary_modify_check(ary);
     ARY_SET_LEN(ary, 0);
-    if (ARY_SHARED_P(ary) && !ARY_EMBED_P(ary)) {
-	rb_ary_unshare(ary);
-	FL_SET_EMBED(ary);
+    if (ARY_SHARED_P(ary)) {
+        rb_ary_unshare(ary);
+        FL_SET_EMBED(ary);
     }
     ary_resize_capa(ary, hash_size);
     rb_hash_foreach(hash, push_value, ary);
-    ary_recycle_hash(hash);
 
     return ary;
 }
 
 /*
  *  call-seq:
- *    array.uniq -> new_array
- *    array.uniq {|element| ... } -> new_array
+ *    uniq -> new_array
+ *    uniq {|element| ... } -> new_array
  *
- *  Returns a new \Array containing those elements from +self+ that are not duplicates,
+ *  Returns a new array containing those elements from +self+ that are not duplicates,
  *  the first occurrence always being retained.
  *
- *  With no block given, identifies and omits duplicates using method <tt>eql?</tt>
- *  to compare.
+ *  With no block given, identifies and omits duplicate elements using method <tt>eql?</tt>
+ *  to compare elements:
+ *
  *    a = [0, 0, 1, 1, 2, 2]
  *    a.uniq # => [0, 1, 2]
  *
  *  With a block given, calls the block for each element;
- *  identifies (using method <tt>eql?</tt>) and omits duplicate values,
- *  that is, those elements for which the block returns the same value:
+ *  identifies and omits "duplicate" elements using method <tt>eql?</tt>
+ *  to compare <i>block return values</i>;
+ *  that is, an element is a duplicate if its block return value
+ *  is the same as that of a previous element:
+ *
  *    a = ['a', 'aa', 'aaa', 'b', 'bb', 'bbb']
  *    a.uniq {|element| element.size } # => ["a", "aa", "aaa"]
+ *
+ *  Related: {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 static VALUE
@@ -6070,15 +6366,12 @@ rb_ary_uniq(VALUE ary)
         uniq = rb_ary_dup(ary);
     }
     else if (rb_block_given_p()) {
-	hash = ary_make_hash_by(ary);
-	uniq = rb_hash_values(hash);
+        hash = ary_make_hash_by(ary);
+        uniq = rb_hash_values(hash);
     }
     else {
-	hash = ary_make_hash(ary);
-	uniq = rb_hash_values(hash);
-    }
-    if (hash) {
-        ary_recycle_hash(hash);
+        hash = ary_make_hash(ary);
+        uniq = rb_hash_values(hash);
     }
 
     return uniq;
@@ -6086,11 +6379,18 @@ rb_ary_uniq(VALUE ary)
 
 /*
  *  call-seq:
- *    array.compact! -> self or nil
+ *    compact! -> self or nil
+ *
+ *  Removes all +nil+ elements from +self+;
+ *  Returns +self+ if any elements are removed, +nil+ otherwise:
  *
- *  Removes all +nil+ elements from +self+.
+ *    a = [nil, 0, nil, false, nil, '', nil, [], nil, {}]
+ *    a.compact! # => [0, false, "", [], {}]
+ *    a          # => [0, false, "", [], {}]
+ *    a.compact! # => nil
  *
- *  Returns +self+ if any elements removed, otherwise +nil+.
+ *  Related: Array#compact;
+ *  see also {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
 
 static VALUE
@@ -6100,16 +6400,16 @@ rb_ary_compact_bang(VALUE ary)
     long n;
 
     rb_ary_modify(ary);
-    p = t = (VALUE *)RARRAY_CONST_PTR_TRANSIENT(ary); /* WB: no new reference */
+    p = t = (VALUE *)RARRAY_CONST_PTR(ary); /* WB: no new reference */
     end = p + RARRAY_LEN(ary);
 
     while (t < end) {
-	if (NIL_P(*t)) t++;
-	else *p++ = *t++;
+        if (NIL_P(*t)) t++;
+        else *p++ = *t++;
     }
-    n = p - RARRAY_CONST_PTR_TRANSIENT(ary);
+    n = p - RARRAY_CONST_PTR(ary);
     if (RARRAY_LEN(ary) == n) {
-	return Qnil;
+        return Qnil;
     }
     ary_resize_smaller(ary, n);
 
@@ -6118,11 +6418,16 @@ rb_ary_compact_bang(VALUE ary)
 
 /*
  *  call-seq:
- *    array.compact -> new_array
+ *    compact -> new_array
+ *
+ *  Returns a new array containing only the non-+nil+ elements from +self+;
+ *  element order is preserved:
  *
- *  Returns a new \Array containing all non-+nil+ elements from +self+:
- *    a = [nil, 0, nil, 1, nil, 2, nil]
- *    a.compact # => [0, 1, 2]
+ *    a = [nil, 0, nil, false, nil, '', nil, [], nil, {}]
+ *    a.compact # => [0, false, "", [], {}]
+ *
+ *  Related: Array#compact!;
+ *  see also {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
 
 static VALUE
@@ -6135,26 +6440,29 @@ rb_ary_compact(VALUE ary)
 
 /*
  *  call-seq:
- *    array.count -> an_integer
- *    array.count(obj) -> an_integer
- *    array.count {|element| ... } -> an_integer
+ *    count -> integer
+ *    count(object) -> integer
+ *    count {|element| ... } -> integer
  *
  *  Returns a count of specified elements.
  *
  *  With no argument and no block, returns the count of all elements:
- *    [0, 1, 2].count # => 3
- *    [].count # => 0
  *
- *  With argument +obj+, returns the count of elements <tt>==</tt> to +obj+:
- *    [0, 1, 2, 0.0].count(0) # => 2
- *    [0, 1, 2].count(3) # => 0
+ *    [0, :one, 'two', 3, 3.0].count # => 5
+ *
+ *  With argument +object+ given, returns the count of elements <tt>==</tt> to +object+:
+ *
+ *    [0, :one, 'two', 3, 3.0].count(3) # => 2
  *
  *  With no argument and a block given, calls the block with each element;
  *  returns the count of elements for which the block returns a truthy value:
- *    [0, 1, 2, 3].count {|element| element > 1} # => 2
  *
- *  With argument +obj+ and a block given, issues a warning, ignores the block,
- *  and returns the count of elements <tt>==</tt> to +obj+:
+ *    [0, 1, 2, 3].count {|element| element > 1 } # => 2
+ *
+ *  With argument +object+ and a block given, issues a warning, ignores the block,
+ *  and returns the count of elements <tt>==</tt> to +object+.
+ *
+ *  Related: see {Methods for Querying}[rdoc-ref:Array@Methods+for+Querying].
  */
 
 static VALUE
@@ -6163,25 +6471,25 @@ rb_ary_count(int argc, VALUE *argv, VALUE ary)
     long i, n = 0;
 
     if (rb_check_arity(argc, 0, 1) == 0) {
-	VALUE v;
+        VALUE v;
 
-	if (!rb_block_given_p())
-	    return LONG2NUM(RARRAY_LEN(ary));
+        if (!rb_block_given_p())
+            return LONG2NUM(RARRAY_LEN(ary));
 
-	for (i = 0; i < RARRAY_LEN(ary); i++) {
-	    v = RARRAY_AREF(ary, i);
-	    if (RTEST(rb_yield(v))) n++;
-	}
+        for (i = 0; i < RARRAY_LEN(ary); i++) {
+            v = RARRAY_AREF(ary, i);
+            if (RTEST(rb_yield(v))) n++;
+        }
     }
     else {
         VALUE obj = argv[0];
 
-	if (rb_block_given_p()) {
-	    rb_warn("given block not used");
-	}
-	for (i = 0; i < RARRAY_LEN(ary); i++) {
-	    if (rb_equal(RARRAY_AREF(ary, i), obj)) n++;
-	}
+        if (rb_block_given_p()) {
+            rb_warn("given block not used");
+        }
+        for (i = 0; i < RARRAY_LEN(ary); i++) {
+            if (rb_equal(RARRAY_AREF(ary, i), obj)) n++;
+        }
     }
 
     return LONG2NUM(n);
@@ -6191,9 +6499,8 @@ static VALUE
 flatten(VALUE ary, int level)
 {
     long i;
-    VALUE stack, result, tmp = 0, elt, vmemo;
-    st_table *memo = 0;
-    st_data_t id;
+    VALUE stack, result, tmp = 0, elt;
+    VALUE memo = Qfalse;
 
     for (i = 0; i < RARRAY_LEN(ary); i++) {
         elt = RARRAY_AREF(ary, i);
@@ -6207,7 +6514,7 @@ flatten(VALUE ary, int level)
     }
 
     result = ary_new(0, RARRAY_LEN(ary));
-    ary_memcpy(result, 0, i, RARRAY_CONST_PTR_TRANSIENT(ary));
+    ary_memcpy(result, 0, i, RARRAY_CONST_PTR(ary));
     ARY_SET_LEN(result, i);
 
     stack = ary_new(0, ARY_DEFAULT_SIZE);
@@ -6215,64 +6522,58 @@ flatten(VALUE ary, int level)
     rb_ary_push(stack, LONG2NUM(i + 1));
 
     if (level < 0) {
-	vmemo = rb_hash_new();
-	RBASIC_CLEAR_CLASS(vmemo);
-	memo = st_init_numtable();
-	rb_hash_st_table_set(vmemo, memo);
-	st_insert(memo, (st_data_t)ary, (st_data_t)Qtrue);
-	st_insert(memo, (st_data_t)tmp, (st_data_t)Qtrue);
+        memo = rb_obj_hide(rb_ident_hash_new());
+        rb_hash_aset(memo, ary, Qtrue);
+        rb_hash_aset(memo, tmp, Qtrue);
     }
 
     ary = tmp;
     i = 0;
 
     while (1) {
-	while (i < RARRAY_LEN(ary)) {
-	    elt = RARRAY_AREF(ary, i++);
-	    if (level >= 0 && RARRAY_LEN(stack) / 2 >= level) {
-		rb_ary_push(result, elt);
-		continue;
-	    }
-	    tmp = rb_check_array_type(elt);
-	    if (RBASIC(result)->klass) {
-		if (memo) {
-		    RB_GC_GUARD(vmemo);
-		    st_clear(memo);
-		}
-		rb_raise(rb_eRuntimeError, "flatten reentered");
-	    }
-	    if (NIL_P(tmp)) {
-		rb_ary_push(result, elt);
-	    }
-	    else {
-		if (memo) {
-		    id = (st_data_t)tmp;
-		    if (st_is_member(memo, id)) {
-			st_clear(memo);
-			rb_raise(rb_eArgError, "tried to flatten recursive array");
-		    }
-		    st_insert(memo, id, (st_data_t)Qtrue);
-		}
-		rb_ary_push(stack, ary);
-		rb_ary_push(stack, LONG2NUM(i));
-		ary = tmp;
-		i = 0;
-	    }
-	}
-	if (RARRAY_LEN(stack) == 0) {
-	    break;
-	}
-	if (memo) {
-	    id = (st_data_t)ary;
-	    st_delete(memo, &id, 0);
-	}
-	tmp = rb_ary_pop(stack);
-	i = NUM2LONG(tmp);
-	ary = rb_ary_pop(stack);
+        while (i < RARRAY_LEN(ary)) {
+            elt = RARRAY_AREF(ary, i++);
+            if (level >= 0 && RARRAY_LEN(stack) / 2 >= level) {
+                rb_ary_push(result, elt);
+                continue;
+            }
+            tmp = rb_check_array_type(elt);
+            if (RBASIC(result)->klass) {
+                if (RTEST(memo)) {
+                    rb_hash_clear(memo);
+                }
+                rb_raise(rb_eRuntimeError, "flatten reentered");
+            }
+            if (NIL_P(tmp)) {
+                rb_ary_push(result, elt);
+            }
+            else {
+                if (memo) {
+                    if (rb_hash_aref(memo, tmp) == Qtrue) {
+                        rb_hash_clear(memo);
+                        rb_raise(rb_eArgError, "tried to flatten recursive array");
+                    }
+                    rb_hash_aset(memo, tmp, Qtrue);
+                }
+                rb_ary_push(stack, ary);
+                rb_ary_push(stack, LONG2NUM(i));
+                ary = tmp;
+                i = 0;
+            }
+        }
+        if (RARRAY_LEN(stack) == 0) {
+            break;
+        }
+        if (memo) {
+            rb_hash_delete(memo, ary);
+        }
+        tmp = rb_ary_pop(stack);
+        i = NUM2LONG(tmp);
+        ary = rb_ary_pop(stack);
     }
 
     if (memo) {
-	st_clear(memo);
+        rb_hash_clear(memo);
     }
 
     RBASIC_SET_CLASS(result, rb_cArray);
@@ -6281,30 +6582,37 @@ flatten(VALUE ary, int level)
 
 /*
  *  call-seq:
- *    array.flatten! -> self or nil
- *    array.flatten!(level) -> self or nil
- *
- *  Replaces each nested \Array in +self+ with the elements from that \Array;
- *  returns +self+ if any changes, +nil+ otherwise.
- *
- *  With non-negative \Integer argument +level+, flattens recursively through +level+ levels:
- *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
- *    a.flatten!(1) # => [0, 1, [2, 3], 4, 5]
- *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
- *    a.flatten!(2) # => [0, 1, 2, 3, 4, 5]
- *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
- *    a.flatten!(3) # => [0, 1, 2, 3, 4, 5]
- *    [0, 1, 2].flatten!(1) # => nil
- *
- *  With no argument, a +nil+ argument, or with negative argument +level+, flattens all levels:
- *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
- *    a.flatten! # => [0, 1, 2, 3, 4, 5]
- *    [0, 1, 2].flatten! # => nil
- *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
- *    a.flatten!(-1) # => [0, 1, 2, 3, 4, 5]
- *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
- *    a.flatten!(-2) # => [0, 1, 2, 3, 4, 5]
- *    [0, 1, 2].flatten!(-1) # => nil
+ *    flatten!(depth = nil) -> self or nil
+ *
+ *  Returns +self+ as a recursively flattening of +self+ to +depth+ levels of recursion;
+ *  +depth+ must be an
+ *  {integer-convertible object}[rdoc-ref:implicit_conversion.rdoc@Integer-Convertible+Objects],
+ *  or +nil+.
+ *  At each level of recursion:
+ *
+ *  - Each element that is an array is "flattened"
+ *    (that is, replaced by its individual array elements).
+ *  - Each element that is not an array is unchanged
+ *    (even if the element is an object that has instance method +flatten+).
+ *
+ *  Returns +nil+ if no elements were flattened.
+ *
+ *  With non-negative integer argument +depth+, flattens recursively through +depth+ levels:
+ *
+ *    a = [ 0, [ 1, [2, 3], 4 ], 5, {foo: 0}, Set.new([6, 7]) ]
+ *    a                   # => [0, [1, [2, 3], 4], 5, {:foo=>0}, #<Set: {6, 7}>]
+ *    a.dup.flatten!(1)   # => [0, 1, [2, 3], 4, 5, {:foo=>0}, #<Set: {6, 7}>]
+ *    a.dup.flatten!(1.1) # => [0, 1, [2, 3], 4, 5, {:foo=>0}, #<Set: {6, 7}>]
+ *    a.dup.flatten!(2)   # => [0, 1, 2, 3, 4, 5, {:foo=>0}, #<Set: {6, 7}>]
+ *    a.dup.flatten!(3)   # => [0, 1, 2, 3, 4, 5, {:foo=>0}, #<Set: {6, 7}>]
+ *
+ *  With +nil+ or negative argument +depth+, flattens all levels:
+ *
+ *    a.dup.flatten!     # => [0, 1, 2, 3, 4, 5, {:foo=>0}, #<Set: {6, 7}>]
+ *    a.dup.flatten!(-1) # => [0, 1, 2, 3, 4, 5, {:foo=>0}, #<Set: {6, 7}>]
+ *
+ *  Related: Array#flatten;
+ *  see also {Methods for Assigning}[rdoc-ref:Array@Methods+for+Assigning].
  */
 
 static VALUE
@@ -6320,9 +6628,9 @@ rb_ary_flatten_bang(int argc, VALUE *argv, VALUE ary)
 
     result = flatten(ary, level);
     if (result == ary) {
-	return Qnil;
+        return Qnil;
     }
-    if (!(mod = ARY_EMBED_P(result))) rb_obj_freeze(result);
+    if (!(mod = ARY_EMBED_P(result))) rb_ary_freeze(result);
     rb_ary_replace(ary, result);
     if (mod) ARY_SET_EMBED_LEN(result, 0);
 
@@ -6331,32 +6639,37 @@ rb_ary_flatten_bang(int argc, VALUE *argv, VALUE ary)
 
 /*
  *  call-seq:
- *    array.flatten -> new_array
- *    array.flatten(level) -> new_array
- *
- *  Returns a new \Array that is a recursive flattening of +self+:
- *  - Each non-Array element is unchanged.
- *  - Each \Array is replaced by its individual elements.
- *
- *  With non-negative \Integer argument +level+, flattens recursively through +level+ levels:
- *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
- *    a.flatten(0) # => [0, [1, [2, 3], 4], 5]
- *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
- *    a.flatten(1) # => [0, 1, [2, 3], 4, 5]
- *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
- *    a.flatten(2) # => [0, 1, 2, 3, 4, 5]
- *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
- *    a.flatten(3) # => [0, 1, 2, 3, 4, 5]
- *
- *  With no argument, a +nil+ argument, or with negative argument +level+, flattens all levels:
- *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
- *    a.flatten # => [0, 1, 2, 3, 4, 5]
- *    [0, 1, 2].flatten # => [0, 1, 2]
- *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
- *    a.flatten(-1) # => [0, 1, 2, 3, 4, 5]
- *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
- *    a.flatten(-2) # => [0, 1, 2, 3, 4, 5]
- *    [0, 1, 2].flatten(-1) # => [0, 1, 2]
+ *    flatten(depth = nil) -> new_array
+ *
+ *  Returns a new array that is a recursive flattening of +self+
+ *  to +depth+ levels of recursion;
+ *  +depth+ must be an
+ *  {integer-convertible object}[rdoc-ref:implicit_conversion.rdoc@Integer-Convertible+Objects]
+ *  or +nil+.
+ *  At each level of recursion:
+ *
+ *  - Each element that is an array is "flattened"
+ *    (that is, replaced by its individual array elements).
+ *  - Each element that is not an array is unchanged
+ *    (even if the element is an object that has instance method +flatten+).
+ *
+ *  With non-negative integer argument +depth+, flattens recursively through +depth+ levels:
+ *
+ *    a = [ 0, [ 1, [2, 3], 4 ], 5, {foo: 0}, Set.new([6, 7]) ]
+ *    a              # => [0, [1, [2, 3], 4], 5, {:foo=>0}, #<Set: {6, 7}>]
+ *    a.flatten(0)   # => [0, [1, [2, 3], 4], 5, {:foo=>0}, #<Set: {6, 7}>]
+ *    a.flatten(1  ) # => [0, 1, [2, 3], 4, 5, {:foo=>0}, #<Set: {6, 7}>]
+ *    a.flatten(1.1) # => [0, 1, [2, 3], 4, 5, {:foo=>0}, #<Set: {6, 7}>]
+ *    a.flatten(2)   # => [0, 1, 2, 3, 4, 5, {:foo=>0}, #<Set: {6, 7}>]
+ *    a.flatten(3)   # => [0, 1, 2, 3, 4, 5, {:foo=>0}, #<Set: {6, 7}>]
+ *
+ *  With +nil+ or negative +depth+, flattens all levels.
+ *
+ *    a.flatten     # => [0, 1, 2, 3, 4, 5, {:foo=>0}, #<Set: {6, 7}>]
+ *    a.flatten(-1) # => [0, 1, 2, 3, 4, 5, {:foo=>0}, #<Set: {6, 7}>]
+ *
+ *  Related: Array#flatten!;
+ *  see also {Methods for Converting}[rdoc-ref:Array@Methods+for+Converting].
  */
 
 static VALUE
@@ -6388,16 +6701,16 @@ rb_ary_shuffle_bang(rb_execution_context_t *ec, VALUE ary, VALUE randgen)
     rb_ary_modify(ary);
     i = len = RARRAY_LEN(ary);
     RARRAY_PTR_USE(ary, ptr, {
-	while (i) {
-	    long j = RAND_UPTO(i);
-	    VALUE tmp;
-            if (len != RARRAY_LEN(ary) || ptr != RARRAY_CONST_PTR_TRANSIENT(ary)) {
+        while (i) {
+            long j = RAND_UPTO(i);
+            VALUE tmp;
+            if (len != RARRAY_LEN(ary) || ptr != RARRAY_CONST_PTR(ary)) {
                 rb_raise(rb_eRuntimeError, "modified during shuffle");
-	    }
-	    tmp = ptr[--i];
-	    ptr[i] = ptr[j];
-	    ptr[j] = tmp;
-	}
+            }
+            tmp = ptr[--i];
+            ptr[i] = ptr[j];
+            ptr[j] = tmp;
+        }
     }); /* WB: no new reference */
     return ary;
 }
@@ -6410,6 +6723,14 @@ rb_ary_shuffle(rb_execution_context_t *ec, VALUE ary, VALUE randgen)
     return ary;
 }
 
+static const rb_data_type_t ary_sample_memo_type = {
+    .wrap_struct_name = "ary_sample_memo",
+    .function = {
+        .dfree = (RUBY_DATA_FUNC)st_free_table,
+    },
+    .flags = RUBY_TYPED_WB_PROTECTED | RUBY_TYPED_FREE_IMMEDIATELY
+};
+
 static VALUE
 ary_sample(rb_execution_context_t *ec, VALUE ary, VALUE randgen, VALUE nv, VALUE to_array)
 {
@@ -6420,120 +6741,119 @@ ary_sample(rb_execution_context_t *ec, VALUE ary, VALUE randgen, VALUE nv, VALUE
 
     len = RARRAY_LEN(ary);
     if (!to_array) {
-	if (len < 2)
-	    i = 0;
-	else
-	    i = RAND_UPTO(len);
+        if (len < 2)
+            i = 0;
+        else
+            i = RAND_UPTO(len);
 
-	return rb_ary_elt(ary, i);
+        return rb_ary_elt(ary, i);
     }
     n = NUM2LONG(nv);
     if (n < 0) rb_raise(rb_eArgError, "negative sample number");
     if (n > len) n = len;
     if (n <= numberof(idx)) {
-	for (i = 0; i < n; ++i) {
-	    rnds[i] = RAND_UPTO(len - i);
-	}
+        for (i = 0; i < n; ++i) {
+            rnds[i] = RAND_UPTO(len - i);
+        }
     }
     k = len;
     len = RARRAY_LEN(ary);
     if (len < k && n <= numberof(idx)) {
-	for (i = 0; i < n; ++i) {
-	    if (rnds[i] >= len) return rb_ary_new_capa(0);
-	}
+        for (i = 0; i < n; ++i) {
+            if (rnds[i] >= len) return rb_ary_new_capa(0);
+        }
     }
     if (n > len) n = len;
     switch (n) {
       case 0:
-	return rb_ary_new_capa(0);
+        return rb_ary_new_capa(0);
       case 1:
-	i = rnds[0];
-	return rb_ary_new_from_args(1, RARRAY_AREF(ary, i));
+        i = rnds[0];
+        return rb_ary_new_from_args(1, RARRAY_AREF(ary, i));
       case 2:
-	i = rnds[0];
-	j = rnds[1];
-	if (j >= i) j++;
-	return rb_ary_new_from_args(2, RARRAY_AREF(ary, i), RARRAY_AREF(ary, j));
+        i = rnds[0];
+        j = rnds[1];
+        if (j >= i) j++;
+        return rb_ary_new_from_args(2, RARRAY_AREF(ary, i), RARRAY_AREF(ary, j));
       case 3:
-	i = rnds[0];
-	j = rnds[1];
-	k = rnds[2];
-	{
-	    long l = j, g = i;
-	    if (j >= i) l = i, g = ++j;
-	    if (k >= l && (++k >= g)) ++k;
-	}
-	return rb_ary_new_from_args(3, RARRAY_AREF(ary, i), RARRAY_AREF(ary, j), RARRAY_AREF(ary, k));
+        i = rnds[0];
+        j = rnds[1];
+        k = rnds[2];
+        {
+            long l = j, g = i;
+            if (j >= i) l = i, g = ++j;
+            if (k >= l && (++k >= g)) ++k;
+        }
+        return rb_ary_new_from_args(3, RARRAY_AREF(ary, i), RARRAY_AREF(ary, j), RARRAY_AREF(ary, k));
     }
     memo_threshold =
-	len < 2560 ? len / 128 :
-	len < 5120 ? len / 64 :
-	len < 10240 ? len / 32 :
-	len / 16;
+        len < 2560 ? len / 128 :
+        len < 5120 ? len / 64 :
+        len < 10240 ? len / 32 :
+        len / 16;
     if (n <= numberof(idx)) {
-	long sorted[numberof(idx)];
-	sorted[0] = idx[0] = rnds[0];
-	for (i=1; i<n; i++) {
-	    k = rnds[i];
-	    for (j = 0; j < i; ++j) {
-		if (k < sorted[j]) break;
-		++k;
-	    }
-	    memmove(&sorted[j+1], &sorted[j], sizeof(sorted[0])*(i-j));
-	    sorted[j] = idx[i] = k;
-	}
-	result = rb_ary_new_capa(n);
-        RARRAY_PTR_USE_TRANSIENT(result, ptr_result, {
-	    for (i=0; i<n; i++) {
-		ptr_result[i] = RARRAY_AREF(ary, idx[i]);
-	    }
-	});
+        long sorted[numberof(idx)];
+        sorted[0] = idx[0] = rnds[0];
+        for (i=1; i<n; i++) {
+            k = rnds[i];
+            for (j = 0; j < i; ++j) {
+                if (k < sorted[j]) break;
+                ++k;
+            }
+            memmove(&sorted[j+1], &sorted[j], sizeof(sorted[0])*(i-j));
+            sorted[j] = idx[i] = k;
+        }
+        result = rb_ary_new_capa(n);
+        RARRAY_PTR_USE(result, ptr_result, {
+            for (i=0; i<n; i++) {
+                ptr_result[i] = RARRAY_AREF(ary, idx[i]);
+            }
+        });
     }
     else if (n <= memo_threshold / 2) {
-	long max_idx = 0;
-#undef RUBY_UNTYPED_DATA_WARNING
-#define RUBY_UNTYPED_DATA_WARNING 0
-	VALUE vmemo = Data_Wrap_Struct(0, 0, st_free_table, 0);
-	st_table *memo = st_init_numtable_with_size(n);
-	DATA_PTR(vmemo) = memo;
-	result = rb_ary_new_capa(n);
-	RARRAY_PTR_USE(result, ptr_result, {
-	    for (i=0; i<n; i++) {
-		long r = RAND_UPTO(len-i) + i;
-		ptr_result[i] = r;
-		if (r > max_idx) max_idx = r;
-	    }
-	    len = RARRAY_LEN(ary);
-	    if (len <= max_idx) n = 0;
-	    else if (n > len) n = len;
-            RARRAY_PTR_USE_TRANSIENT(ary, ptr_ary, {
-		for (i=0; i<n; i++) {
-		    long j2 = j = ptr_result[i];
-		    long i2 = i;
-		    st_data_t value;
-		    if (st_lookup(memo, (st_data_t)i, &value)) i2 = (long)value;
-		    if (st_lookup(memo, (st_data_t)j, &value)) j2 = (long)value;
-		    st_insert(memo, (st_data_t)j, (st_data_t)i2);
-		    ptr_result[i] = ptr_ary[j2];
-		}
-	    });
-	});
-	DATA_PTR(vmemo) = 0;
-	st_free_table(memo);
+        long max_idx = 0;
+        VALUE vmemo = TypedData_Wrap_Struct(0, &ary_sample_memo_type, 0);
+        st_table *memo = st_init_numtable_with_size(n);
+        RTYPEDDATA_DATA(vmemo) = memo;
+        result = rb_ary_new_capa(n);
+        RARRAY_PTR_USE(result, ptr_result, {
+            for (i=0; i<n; i++) {
+                long r = RAND_UPTO(len-i) + i;
+                ptr_result[i] = r;
+                if (r > max_idx) max_idx = r;
+            }
+            len = RARRAY_LEN(ary);
+            if (len <= max_idx) n = 0;
+            else if (n > len) n = len;
+            RARRAY_PTR_USE(ary, ptr_ary, {
+                for (i=0; i<n; i++) {
+                    long j2 = j = ptr_result[i];
+                    long i2 = i;
+                    st_data_t value;
+                    if (st_lookup(memo, (st_data_t)i, &value)) i2 = (long)value;
+                    if (st_lookup(memo, (st_data_t)j, &value)) j2 = (long)value;
+                    st_insert(memo, (st_data_t)j, (st_data_t)i2);
+                    ptr_result[i] = ptr_ary[j2];
+                }
+            });
+        });
+        RTYPEDDATA_DATA(vmemo) = 0;
+        st_free_table(memo);
+        RB_GC_GUARD(vmemo);
     }
     else {
-	result = rb_ary_dup(ary);
-	RBASIC_CLEAR_CLASS(result);
-	RB_GC_GUARD(ary);
-	RARRAY_PTR_USE(result, ptr_result, {
-	    for (i=0; i<n; i++) {
-		j = RAND_UPTO(len-i) + i;
-		nv = ptr_result[j];
-		ptr_result[j] = ptr_result[i];
-		ptr_result[i] = nv;
-	    }
-	});
-	RBASIC_SET_CLASS_RAW(result, rb_cArray);
+        result = rb_ary_dup(ary);
+        RBASIC_CLEAR_CLASS(result);
+        RB_GC_GUARD(ary);
+        RARRAY_PTR_USE(result, ptr_result, {
+            for (i=0; i<n; i++) {
+                j = RAND_UPTO(len-i) + i;
+                nv = ptr_result[j];
+                ptr_result[j] = ptr_result[i];
+                ptr_result[i] = nv;
+            }
+        });
+        RBASIC_SET_CLASS_RAW(result, rb_cArray);
     }
     ARY_SET_LEN(result, n);
 
@@ -6541,6 +6861,12 @@ ary_sample(rb_execution_context_t *ec, VALUE ary, VALUE randgen, VALUE nv, VALUE
 }
 
 static VALUE
+ary_sized_alloc(rb_execution_context_t *ec, VALUE self)
+{
+    return rb_ary_new2(RARRAY_LEN(self));
+}
+
+static VALUE
 ary_sample0(rb_execution_context_t *ec, VALUE ary)
 {
     return ary_sample(ec, ary, rb_cRandom, Qfalse, Qfalse);
@@ -6552,7 +6878,7 @@ rb_ary_cycle_size(VALUE self, VALUE args, VALUE eobj)
     long mul;
     VALUE n = Qnil;
     if (args && (RARRAY_LEN(args) > 0)) {
-	n = RARRAY_AREF(args, 0);
+        n = RARRAY_AREF(args, 0);
     }
     if (RARRAY_LEN(self) == 0) return INT2FIX(0);
     if (NIL_P(n)) return DBL2NUM(HUGE_VAL);
@@ -6564,32 +6890,36 @@ rb_ary_cycle_size(VALUE self, VALUE args, VALUE eobj)
 
 /*
  *  call-seq:
- *    array.cycle {|element| ... } -> nil
- *    array.cycle(count) {|element| ... } -> nil
- *    array.cycle -> new_enumerator
- *    array.cycle(count) -> new_enumerator
+ *    cycle(count = nil) {|element| ... } -> nil
+ *    cycle(count = nil) -> new_enumerator
+ *
+ *  With a block given, may call the block, depending on the value of argument +count+;
+ *  +count+ must be an
+ *  {integer-convertible object}[rdoc-ref:implicit_conversion.rdoc@Integer-Convertible+Objects],
+ *  or +nil+.
  *
- *  When called with positive \Integer argument +count+ and a block,
- *  calls the block with each element, then does so again,
+ *  When +count+ is positive,
+ *  calls the block with each element, then does so repeatedly,
  *  until it has done so +count+ times; returns +nil+:
+ *
  *    output = []
  *    [0, 1].cycle(2) {|element| output.push(element) } # => nil
  *    output # => [0, 1, 0, 1]
  *
- *  If +count+ is zero or negative, does not call the block:
- *    [0, 1].cycle(0) {|element| fail 'Cannot happen' } # => nil
+ *  When +count+ is zero or negative, does not call the block:
+ *
+ *    [0, 1].cycle(0) {|element| fail 'Cannot happen' }  # => nil
  *    [0, 1].cycle(-1) {|element| fail 'Cannot happen' } # => nil
  *
- *  When a block is given, and argument is omitted or +nil+, cycles forever:
+ *  When +count+ is +nil+, cycles forever:
+ *
  *    # Prints 0 and 1 forever.
  *    [0, 1].cycle {|element| puts element }
  *    [0, 1].cycle(nil) {|element| puts element }
  *
- *  When no block is given, returns a new \Enumerator:
+ *  With no block given, returns a new Enumerator.
  *
- *    [0, 1].cycle(2) # => #<Enumerator: [0, 1]:cycle(2)>
- *    [0, 1].cycle # => # => #<Enumerator: [0, 1]:cycle>
- *    [0, 1].cycle.first(5) # => [0, 1, 0, 1, 0]
+ *  Related: see {Methods for Iterating}[rdoc-ref:Array@Methods+for+Iterating].
  */
 static VALUE
 rb_ary_cycle(int argc, VALUE *argv, VALUE ary)
@@ -6615,9 +6945,6 @@ rb_ary_cycle(int argc, VALUE *argv, VALUE ary)
     return Qnil;
 }
 
-#define tmpary(n) rb_ary_tmp_new(n)
-#define tmpary_discard(a) (ary_discard(a), RBASIC_SET_CLASS_RAW(a, rb_cArray))
-
 /*
  * Build a ruby array of the corresponding values and yield it to the
  * associated block.
@@ -6653,32 +6980,32 @@ permute0(const long n, const long r, long *const p, char *const used, const VALU
     long i = 0, index = 0;
 
     for (;;) {
-	const char *const unused = memchr(&used[i], 0, n-i);
-	if (!unused) {
-	    if (!index) break;
-	    i = p[--index];                /* pop index */
-	    used[i++] = 0;                 /* index unused */
-	}
-	else {
-	    i = unused - used;
-	    p[index] = i;
-	    used[i] = 1;                   /* mark index used */
-	    ++index;
-	    if (index < r-1) {             /* if not done yet */
-		p[index] = i = 0;
-		continue;
-	    }
-	    for (i = 0; i < n; ++i) {
-		if (used[i]) continue;
-		p[index] = i;
-		if (!yield_indexed_values(values, r, p)) {
-		    rb_raise(rb_eRuntimeError, "permute reentered");
-		}
-	    }
-	    i = p[--index];                /* pop index */
-	    used[i] = 0;                   /* index unused */
-	    p[index] = ++i;
-	}
+        const char *const unused = memchr(&used[i], 0, n-i);
+        if (!unused) {
+            if (!index) break;
+            i = p[--index];                /* pop index */
+            used[i++] = 0;                 /* index unused */
+        }
+        else {
+            i = unused - used;
+            p[index] = i;
+            used[i] = 1;                   /* mark index used */
+            ++index;
+            if (index < r-1) {             /* if not done yet */
+                p[index] = i = 0;
+                continue;
+            }
+            for (i = 0; i < n; ++i) {
+                if (used[i]) continue;
+                p[index] = i;
+                if (!yield_indexed_values(values, r, p)) {
+                    rb_raise(rb_eRuntimeError, "permute reentered");
+                }
+            }
+            i = p[--index];                /* pop index */
+            used[i] = 0;                   /* index unused */
+            p[index] = ++i;
+        }
     }
 }
 
@@ -6691,14 +7018,14 @@ descending_factorial(long from, long how_many)
 {
     VALUE cnt;
     if (how_many > 0) {
-	cnt = LONG2FIX(from);
-	while (--how_many > 0) {
-	    long v = --from;
-	    cnt = rb_int_mul(cnt, LONG2FIX(v));
-	}
+        cnt = LONG2FIX(from);
+        while (--how_many > 0) {
+            long v = --from;
+            cnt = rb_int_mul(cnt, LONG2FIX(v));
+        }
     }
     else {
-	cnt = LONG2FIX(how_many == 0);
+        cnt = LONG2FIX(how_many == 0);
     }
     return cnt;
 }
@@ -6709,18 +7036,18 @@ binomial_coefficient(long comb, long size)
     VALUE r;
     long i;
     if (comb > size-comb) {
-	comb = size-comb;
+        comb = size-comb;
     }
     if (comb < 0) {
-	return LONG2FIX(0);
+        return LONG2FIX(0);
     }
     else if (comb == 0) {
-	return LONG2FIX(1);
+        return LONG2FIX(1);
     }
     r = LONG2FIX(size);
     for (i = 1; i < comb; ++i) {
-	r = rb_int_mul(r, LONG2FIX(size - i));
-	r = rb_int_idiv(r, LONG2FIX(i + 1));
+        r = rb_int_mul(r, LONG2FIX(size - i));
+        r = rb_int_idiv(r, LONG2FIX(i + 1));
     }
     return r;
 }
@@ -6736,66 +7063,44 @@ rb_ary_permutation_size(VALUE ary, VALUE args, VALUE eobj)
 
 /*
  *  call-seq:
- *    array.permutation {|element| ... } -> self
- *    array.permutation(n) {|element| ... } -> self
- *    array.permutation -> new_enumerator
- *    array.permutation(n) -> new_enumerator
+ *    permutation(count = self.size) {|permutation| ... } -> self
+ *    permutation(count = self.size) -> new_enumerator
  *
- *  When invoked with a block, yield all permutations of elements of +self+; returns +self+.
- *  The order of permutations is indeterminate.
+ *  Iterates over permutations of the elements of +self+;
+ *  the order of permutations is indeterminate.
  *
- *  When a block and an in-range positive \Integer argument +n+ (<tt>0 < n <= self.size</tt>)
- *  are given, calls the block with all +n+-tuple permutations of +self+.
+ *  With a block and an in-range positive integer argument +count+ (<tt>0 < count <= self.size</tt>) given,
+ *  calls the block with each permutation of +self+ of size +count+;
+ *  returns +self+:
  *
- *  Example:
  *    a = [0, 1, 2]
- *    a.permutation(2) {|permutation| p permutation }
- *  Output:
- *    [0, 1]
- *    [0, 2]
- *    [1, 0]
- *    [1, 2]
- *    [2, 0]
- *    [2, 1]
- *  Another example:
- *    a = [0, 1, 2]
- *    a.permutation(3) {|permutation| p permutation }
- *  Output:
- *    [0, 1, 2]
- *    [0, 2, 1]
- *    [1, 0, 2]
- *    [1, 2, 0]
- *    [2, 0, 1]
- *    [2, 1, 0]
- *
- *  When +n+ is zero, calls the block once with a new empty \Array:
- *    a = [0, 1, 2]
- *    a.permutation(0) {|permutation| p permutation }
- *  Output:
- *    []
+ *    perms = []
+ *    a.permutation(1) {|perm| perms.push(perm) }
+ *    perms # => [[0], [1], [2]]
  *
- *  When +n+ is out of range (negative or larger than <tt>self.size</tt>),
+ *    perms = []
+ *    a.permutation(2) {|perm| perms.push(perm) }
+ *    perms # => [[0, 1], [0, 2], [1, 0], [1, 2], [2, 0], [2, 1]]
+ *
+ *    perms = []
+ *    a.permutation(3) {|perm| perms.push(perm) }
+ *    perms # => [[0, 1, 2], [0, 2, 1], [1, 0, 2], [1, 2, 0], [2, 0, 1], [2, 1, 0]]
+ *
+ *  When +count+ is zero, calls the block once with a new empty array:
+ *
+ *    perms = []
+ *    a.permutation(0) {|perm| perms.push(perm) }
+ *    perms # => [[]]
+ *
+ *  When +count+ is out of range (negative or larger than <tt>self.size</tt>),
  *  does not call the block:
- *    a = [0, 1, 2]
+ *
  *    a.permutation(-1) {|permutation| fail 'Cannot happen' }
  *    a.permutation(4) {|permutation| fail 'Cannot happen' }
  *
- *  When a block given but no argument,
- *  behaves the same as <tt>a.permutation(a.size)</tt>:
- *    a = [0, 1, 2]
- *    a.permutation {|permutation| p permutation }
- *  Output:
- *    [0, 1, 2]
- *    [0, 2, 1]
- *    [1, 0, 2]
- *    [1, 2, 0]
- *    [2, 0, 1]
- *    [2, 1, 0]
- *
- *  Returns a new \Enumerator if no block given:
- *    a = [0, 1, 2]
- *    a.permutation # => #<Enumerator: [0, 1, 2]:permutation>
- *    a.permutation(2) # => #<Enumerator: [0, 1, 2]:permutation(2)>
+ *  With no block given, returns a new Enumerator.
+ *
+ *  Related: {Methods for Iterating}[rdoc-ref:Array@Methods+for+Iterating].
  */
 
 static VALUE
@@ -6810,28 +7115,28 @@ rb_ary_permutation(int argc, VALUE *argv, VALUE ary)
         r = NUM2LONG(argv[0]);            /* Permutation size from argument */
 
     if (r < 0 || n < r) {
-	/* no permutations: yield nothing */
+        /* no permutations: yield nothing */
     }
     else if (r == 0) { /* exactly one permutation: the zero-length array */
-	rb_yield(rb_ary_new2(0));
+        rb_yield(rb_ary_new2(0));
     }
     else if (r == 1) { /* this is a special, easy case */
-	for (i = 0; i < RARRAY_LEN(ary); i++) {
-	    rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
-	}
+        for (i = 0; i < RARRAY_LEN(ary); i++) {
+            rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
+        }
     }
     else {             /* this is the general case */
-	volatile VALUE t0;
-	long *p = ALLOCV_N(long, t0, r+roomof(n, sizeof(long)));
-	char *used = (char*)(p + r);
-	VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
-	RBASIC_CLEAR_CLASS(ary0);
+        volatile VALUE t0;
+        long *p = ALLOCV_N(long, t0, r+roomof(n, sizeof(long)));
+        char *used = (char*)(p + r);
+        VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
+        RBASIC_CLEAR_CLASS(ary0);
 
-	MEMZERO(used, char, n); /* initialize array */
+        MEMZERO(used, char, n); /* initialize array */
 
-	permute0(n, r, p, used, ary0); /* compute and yield permutations */
-	ALLOCV_END(t0);
-	RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
+        permute0(n, r, p, used, ary0); /* compute and yield permutations */
+        ALLOCV_END(t0);
+        RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
     }
     return ary;
 }
@@ -6844,16 +7149,16 @@ combinate0(const long len, const long n, long *const stack, const VALUE values)
     MEMZERO(stack+1, long, n);
     stack[0] = -1;
     for (;;) {
-	for (lev++; lev < n; lev++) {
-	    stack[lev+1] = stack[lev]+1;
-	}
-	if (!yield_indexed_values(values, n, stack+1)) {
-	    rb_raise(rb_eRuntimeError, "combination reentered");
-	}
-	do {
-	    if (lev == 0) return;
-	    stack[lev--]++;
-	} while (stack[lev+1]+n == len+lev+1);
+        for (lev++; lev < n; lev++) {
+            stack[lev+1] = stack[lev]+1;
+        }
+        if (!yield_indexed_values(values, n, stack+1)) {
+            rb_raise(rb_eRuntimeError, "combination reentered");
+        }
+        do {
+            if (lev == 0) return;
+            stack[lev--]++;
+        } while (stack[lev+1]+n == len+lev+1);
     }
 }
 
@@ -6868,44 +7173,46 @@ rb_ary_combination_size(VALUE ary, VALUE args, VALUE eobj)
 
 /*
  *  call-seq:
- *    array.combination(n) {|element| ... } -> self
- *    array.combination(n) -> new_enumerator
+ *    combination(count) {|element| ... } -> self
+ *    combination(count) -> new_enumerator
  *
- *  Calls the block, if given, with combinations of elements of +self+;
- *  returns +self+. The order of combinations is indeterminate.
+ *  When a block and a positive
+ *  {integer-convertible object}[rdoc-ref:implicit_conversion.rdoc@Integer-Convertible+Objects]
+ *  argument +count+ (<tt>0 < count <= self.size</tt>)
+ *  are given, calls the block with each combination of +self+ of size +count+;
+ *  returns +self+:
  *
- *  When a block and an in-range positive \Integer argument +n+ (<tt>0 < n <= self.size</tt>)
- *  are given, calls the block with all +n+-tuple combinations of +self+.
+ *    a = %w[a b c]                                   # => ["a", "b", "c"]
+ *    a.combination(2) {|combination| p combination } # => ["a", "b", "c"]
  *
- *  Example:
- *    a = [0, 1, 2]
- *    a.combination(2) {|combination| p combination }
  *  Output:
- *    [0, 1]
- *    [0, 2]
- *    [1, 2]
  *
- *  Another example:
- *    a = [0, 1, 2]
- *    a.combination(3) {|combination| p combination }
- *  Output:
- *    [0, 1, 2]
+ *    ["a", "b"]
+ *    ["a", "c"]
+ *    ["b", "c"]
+ *
+ *  The order of the yielded combinations is not guaranteed.
+ *
+ *  When +count+ is zero, calls the block once with a new empty array:
+ *
+ *    a.combination(0) {|combination| p combination }
+ *    [].combination(0) {|combination| p combination }
  *
- *  When +n+ is zero, calls the block once with a new empty \Array:
- *    a = [0, 1, 2]
- *    a1 = a.combination(0) {|combination| p combination }
  *  Output:
+ *
+ *    []
  *    []
  *
- *  When +n+ is out of range (negative or larger than <tt>self.size</tt>),
+ *  When +count+ is negative or larger than +self.size+ and +self+ is non-empty,
  *  does not call the block:
- *    a = [0, 1, 2]
- *    a.combination(-1) {|combination| fail 'Cannot happen' }
- *    a.combination(4) {|combination| fail 'Cannot happen' }
  *
- *  Returns a new \Enumerator if no block given:
- *    a = [0, 1, 2]
- *    a.combination(2) # => #<Enumerator: [0, 1, 2]:combination(2)>
+ *    a.combination(-1) {|combination| fail 'Cannot happen' } # => ["a", "b", "c"]
+ *    a.combination(4)  {|combination| fail 'Cannot happen' } # => ["a", "b", "c"]
+ *
+ *  With no block given, returns a new Enumerator.
+ *
+ *  Related: Array#permutation;
+ *  see also {Methods for Iterating}[rdoc-ref:Array@Methods+for+Iterating].
  */
 
 static VALUE
@@ -6917,25 +7224,25 @@ rb_ary_combination(VALUE ary, VALUE num)
     RETURN_SIZED_ENUMERATOR(ary, 1, &num, rb_ary_combination_size);
     len = RARRAY_LEN(ary);
     if (n < 0 || len < n) {
-	/* yield nothing */
+        /* yield nothing */
     }
     else if (n == 0) {
-	rb_yield(rb_ary_new2(0));
+        rb_yield(rb_ary_new2(0));
     }
     else if (n == 1) {
-	for (i = 0; i < RARRAY_LEN(ary); i++) {
-	    rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
-	}
+        for (i = 0; i < RARRAY_LEN(ary); i++) {
+            rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
+        }
     }
     else {
-	VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
-	volatile VALUE t0;
-	long *stack = ALLOCV_N(long, t0, n+1);
+        VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
+        volatile VALUE t0;
+        long *stack = ALLOCV_N(long, t0, n+1);
 
-	RBASIC_CLEAR_CLASS(ary0);
-	combinate0(len, n, stack, ary0);
-	ALLOCV_END(t0);
-	RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
+        RBASIC_CLEAR_CLASS(ary0);
+        combinate0(len, n, stack, ary0);
+        ALLOCV_END(t0);
+        RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
     }
     return ary;
 }
@@ -6959,19 +7266,19 @@ rpermute0(const long n, const long r, long *const p, const VALUE values)
 
     p[index] = i;
     for (;;) {
-	if (++index < r-1) {
-	    p[index] = i = 0;
-	    continue;
-	}
-	for (i = 0; i < n; ++i) {
-	    p[index] = i;
-	    if (!yield_indexed_values(values, r, p)) {
-		rb_raise(rb_eRuntimeError, "repeated permute reentered");
-	    }
-	}
-	do {
-	    if (index <= 0) return;
-	} while ((i = ++p[--index]) >= n);
+        if (++index < r-1) {
+            p[index] = i = 0;
+            continue;
+        }
+        for (i = 0; i < n; ++i) {
+            p[index] = i;
+            if (!yield_indexed_values(values, r, p)) {
+                rb_raise(rb_eRuntimeError, "repeated permute reentered");
+            }
+        }
+        do {
+            if (index <= 0) return;
+        } while ((i = ++p[--index]) >= n);
     }
 }
 
@@ -6982,68 +7289,51 @@ rb_ary_repeated_permutation_size(VALUE ary, VALUE args, VALUE eobj)
     long k = NUM2LONG(RARRAY_AREF(args, 0));
 
     if (k < 0) {
-	return LONG2FIX(0);
+        return LONG2FIX(0);
     }
     if (n <= 0) {
-	return LONG2FIX(!k);
+        return LONG2FIX(!k);
     }
     return rb_int_positive_pow(n, (unsigned long)k);
 }
 
 /*
  *  call-seq:
- *    array.repeated_permutation(n) {|permutation| ... } -> self
- *    array.repeated_permutation(n) -> new_enumerator
+ *    repeated_permutation(size) {|permutation| ... } -> self
+ *    repeated_permutation(size) -> new_enumerator
  *
- *  Calls the block with each repeated permutation of length +n+ of the elements of +self+;
- *  each permutation is an \Array;
+ *  With a block given, calls the block with each repeated permutation of length +size+
+ *  of the elements of +self+;
+ *  each permutation is an array;
  *  returns +self+. The order of the permutations is indeterminate.
  *
- *  When a block and a positive \Integer argument +n+ are given, calls the block with each
- *  +n+-tuple repeated permutation of the elements of +self+.
- *  The number of permutations is <tt>self.size**n</tt>.
+ *  If a positive integer argument +size+ is given,
+ *  calls the block with each +size+-tuple repeated permutation of the elements of +self+.
+ *  The number of permutations is <tt>self.size**size</tt>.
  *
- *  +n+ = 1:
- *    a = [0, 1, 2]
- *    a.repeated_permutation(1) {|permutation| p permutation }
- *  Output:
- *    [0]
- *    [1]
- *    [2]
+ *  Examples:
  *
- *  +n+ = 2:
- *    a.repeated_permutation(2) {|permutation| p permutation }
- *  Output:
- *    [0, 0]
- *    [0, 1]
- *    [0, 2]
- *    [1, 0]
- *    [1, 1]
- *    [1, 2]
- *    [2, 0]
- *    [2, 1]
- *    [2, 2]
- *
- *  If +n+ is zero, calls the block once with an empty \Array.
- *
- *  If +n+ is negative, does not call the block:
- *    a.repeated_permutation(-1) {|permutation| fail 'Cannot happen' }
- *
- *  Returns a new \Enumerator if no block given:
- *    a = [0, 1, 2]
- *    a.repeated_permutation(2) # => #<Enumerator: [0, 1, 2]:permutation(2)>
- *
- *  Using Enumerators, it's convenient to show the permutations and counts
- *  for some values of +n+:
- *    e = a.repeated_permutation(0)
- *    e.size # => 1
- *    e.to_a # => [[]]
- *    e = a.repeated_permutation(1)
- *    e.size # => 3
- *    e.to_a # => [[0], [1], [2]]
- *    e = a.repeated_permutation(2)
- *    e.size # => 9
- *    e.to_a # => [[0, 0], [0, 1], [0, 2], [1, 0], [1, 1], [1, 2], [2, 0], [2, 1], [2, 2]]
+ *  - +size+ is 1:
+ *
+ *      p = []
+ *      [0, 1, 2].repeated_permutation(1) {|permutation| p.push(permutation) }
+ *      p # => [[0], [1], [2]]
+ *
+ *  - +size+ is 2:
+ *
+ *      p = []
+ *      [0, 1, 2].repeated_permutation(2) {|permutation| p.push(permutation) }
+ *      p # => [[0, 0], [0, 1], [0, 2], [1, 0], [1, 1], [1, 2], [2, 0], [2, 1], [2, 2]]
+ *
+ *  If +size+ is zero, calls the block once with an empty array.
+ *
+ *  If +size+ is negative, does not call the block:
+ *
+ *    [0, 1, 2].repeated_permutation(-1) {|permutation| fail 'Cannot happen' }
+ *
+ *  With no block given, returns a new Enumerator.
+ *
+ *  Related: see {Methods for Combining}[rdoc-ref:Array@Methods+for+Combining].
  */
 static VALUE
 rb_ary_repeated_permutation(VALUE ary, VALUE num)
@@ -7055,25 +7345,25 @@ rb_ary_repeated_permutation(VALUE ary, VALUE num)
     r = NUM2LONG(num);                    /* Permutation size from argument */
 
     if (r < 0) {
-	/* no permutations: yield nothing */
+        /* no permutations: yield nothing */
     }
     else if (r == 0) { /* exactly one permutation: the zero-length array */
-	rb_yield(rb_ary_new2(0));
+        rb_yield(rb_ary_new2(0));
     }
     else if (r == 1) { /* this is a special, easy case */
-	for (i = 0; i < RARRAY_LEN(ary); i++) {
-	    rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
-	}
+        for (i = 0; i < RARRAY_LEN(ary); i++) {
+            rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
+        }
     }
     else {             /* this is the general case */
-	volatile VALUE t0;
-	long *p = ALLOCV_N(long, t0, r);
-	VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
-	RBASIC_CLEAR_CLASS(ary0);
+        volatile VALUE t0;
+        long *p = ALLOCV_N(long, t0, r);
+        VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
+        RBASIC_CLEAR_CLASS(ary0);
 
-	rpermute0(n, r, p, ary0); /* compute and yield repeated permutations */
-	ALLOCV_END(t0);
-	RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
+        rpermute0(n, r, p, ary0); /* compute and yield repeated permutations */
+        ALLOCV_END(t0);
+        RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
     }
     return ary;
 }
@@ -7085,19 +7375,19 @@ rcombinate0(const long n, const long r, long *const p, const long rest, const VA
 
     p[index] = i;
     for (;;) {
-	if (++index < r-1) {
-	    p[index] = i;
-	    continue;
-	}
-	for (; i < n; ++i) {
-	    p[index] = i;
-	    if (!yield_indexed_values(values, r, p)) {
-		rb_raise(rb_eRuntimeError, "repeated combination reentered");
-	    }
-	}
-	do {
-	    if (index <= 0) return;
-	} while ((i = ++p[--index]) >= n);
+        if (++index < r-1) {
+            p[index] = i;
+            continue;
+        }
+        for (; i < n; ++i) {
+            p[index] = i;
+            if (!yield_indexed_values(values, r, p)) {
+                rb_raise(rb_eRuntimeError, "repeated combination reentered");
+            }
+        }
+        do {
+            if (index <= 0) return;
+        } while ((i = ++p[--index]) >= n);
     }
 }
 
@@ -7107,62 +7397,48 @@ rb_ary_repeated_combination_size(VALUE ary, VALUE args, VALUE eobj)
     long n = RARRAY_LEN(ary);
     long k = NUM2LONG(RARRAY_AREF(args, 0));
     if (k == 0) {
-	return LONG2FIX(1);
+        return LONG2FIX(1);
     }
     return binomial_coefficient(k, n + k - 1);
 }
 
 /*
  *  call-seq:
- *    array.repeated_combination(n) {|combination| ... } -> self
- *    array.repeated_combination(n) -> new_enumerator
+ *    repeated_combination(size) {|combination| ... } -> self
+ *    repeated_combination(size) -> new_enumerator
  *
- *  Calls the block with each repeated combination of length +n+ of the elements of +self+;
- *  each combination is an \Array;
+ *  With a block given, calls the block with each repeated combination of length +size+
+ *  of the elements of +self+;
+ *  each combination is an array;
  *  returns +self+. The order of the combinations is indeterminate.
  *
- *  When a block and a positive \Integer argument +n+ are given, calls the block with each
- *  +n+-tuple repeated combination of the elements of +self+.
- *  The number of combinations is <tt>(n+1)(n+2)/2</tt>.
+ *  If a positive integer argument +size+ is given,
+ *  calls the block with each +size+-tuple repeated combination of the elements of +self+.
+ *  The number of combinations is <tt>(size+1)(size+2)/2</tt>.
  *
- *  +n+ = 1:
- *    a = [0, 1, 2]
- *    a.repeated_combination(1) {|combination| p combination }
- *  Output:
- *    [0]
- *    [1]
- *    [2]
+ *  Examples:
  *
- *  +n+ = 2:
- *    a.repeated_combination(2) {|combination| p combination }
- *  Output:
- *    [0, 0]
- *    [0, 1]
- *    [0, 2]
- *    [1, 1]
- *    [1, 2]
- *    [2, 2]
+ *  - +size+ is 1:
  *
- *  If +n+ is zero, calls the block once with an empty \Array.
+ *      c = []
+ *      [0, 1, 2].repeated_combination(1) {|combination| c.push(combination) }
+ *      c # => [[0], [1], [2]]
  *
- *  If +n+ is negative, does not call the block:
- *    a.repeated_combination(-1) {|combination| fail 'Cannot happen' }
+ *  - +size+ is 2:
  *
- *  Returns a new \Enumerator if no block given:
- *    a = [0, 1, 2]
- *    a.repeated_combination(2) # => #<Enumerator: [0, 1, 2]:combination(2)>
- *
- *  Using Enumerators, it's convenient to show the combinations and counts
- *  for some values of +n+:
- *    e = a.repeated_combination(0)
- *    e.size # => 1
- *    e.to_a # => [[]]
- *    e = a.repeated_combination(1)
- *    e.size # => 3
- *    e.to_a # => [[0], [1], [2]]
- *    e = a.repeated_combination(2)
- *    e.size # => 6
- *    e.to_a # => [[0, 0], [0, 1], [0, 2], [1, 1], [1, 2], [2, 2]]
+ *      c = []
+ *      [0, 1, 2].repeated_combination(2) {|combination| c.push(combination) }
+ *      c # => [[0, 0], [0, 1], [0, 2], [1, 1], [1, 2], [2, 2]]
+ *
+ *  If +size+ is zero, calls the block once with an empty array.
+ *
+ *  If +size+ is negative, does not call the block:
+ *
+ *    [0, 1, 2].repeated_combination(-1) {|combination| fail 'Cannot happen' }
+ *
+ *  With no block given, returns a new Enumerator.
+ *
+ *  Related: see {Methods for Combining}[rdoc-ref:Array@Methods+for+Combining].
  */
 
 static VALUE
@@ -7174,86 +7450,90 @@ rb_ary_repeated_combination(VALUE ary, VALUE num)
     RETURN_SIZED_ENUMERATOR(ary, 1, &num, rb_ary_repeated_combination_size);   /* Return enumerator if no block */
     len = RARRAY_LEN(ary);
     if (n < 0) {
-	/* yield nothing */
+        /* yield nothing */
     }
     else if (n == 0) {
-	rb_yield(rb_ary_new2(0));
+        rb_yield(rb_ary_new2(0));
     }
     else if (n == 1) {
-	for (i = 0; i < RARRAY_LEN(ary); i++) {
-	    rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
-	}
+        for (i = 0; i < RARRAY_LEN(ary); i++) {
+            rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
+        }
     }
     else if (len == 0) {
-	/* yield nothing */
+        /* yield nothing */
     }
     else {
-	volatile VALUE t0;
-	long *p = ALLOCV_N(long, t0, n);
-	VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
-	RBASIC_CLEAR_CLASS(ary0);
+        volatile VALUE t0;
+        long *p = ALLOCV_N(long, t0, n);
+        VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
+        RBASIC_CLEAR_CLASS(ary0);
 
-	rcombinate0(len, n, p, n, ary0); /* compute and yield repeated combinations */
-	ALLOCV_END(t0);
-	RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
+        rcombinate0(len, n, p, n, ary0); /* compute and yield repeated combinations */
+        ALLOCV_END(t0);
+        RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
     }
     return ary;
 }
 
 /*
  *  call-seq:
- *    array.product(*other_arrays) -> new_array
- *    array.product(*other_arrays) {|combination| ... } -> self
+ *    product(*other_arrays) -> new_array
+ *    product(*other_arrays) {|combination| ... } -> self
+ *
+ *  Computes all combinations of elements from all the arrays,
+ *  including both +self+ and +other_arrays+:
  *
- *  Computes and returns or yields all combinations of elements from all the Arrays,
- *  including both +self+ and +other_arrays+.
  *  - The number of combinations is the product of the sizes of all the arrays,
  *    including both +self+ and +other_arrays+.
  *  - The order of the returned combinations is indeterminate.
  *
- *  When no block is given, returns the combinations as an \Array of Arrays:
- *    a = [0, 1, 2]
- *    a1 = [3, 4]
- *    a2 = [5, 6]
- *    p = a.product(a1)
- *    p.size # => 6 # a.size * a1.size
- *    p # => [[0, 3], [0, 4], [1, 3], [1, 4], [2, 3], [2, 4]]
- *    p = a.product(a1, a2)
- *    p.size # => 12 # a.size * a1.size * a2.size
- *    p # => [[0, 3, 5], [0, 3, 6], [0, 4, 5], [0, 4, 6], [1, 3, 5], [1, 3, 6], [1, 4, 5], [1, 4, 6], [2, 3, 5], [2, 3, 6], [2, 4, 5], [2, 4, 6]]
- *
- *  If any argument is an empty \Array, returns an empty \Array.
- *
- *  If no argument is given, returns an \Array of 1-element Arrays,
+ *  With no block given, returns the combinations as an array of arrays:
+ *
+ *    p = [0, 1].product([2, 3])
+ *    # => [[0, 2], [0, 3], [1, 2], [1, 3]]
+ *    p.size # => 4
+ *    p = [0, 1].product([2, 3], [4, 5])
+ *    # => [[0, 2, 4], [0, 2, 5], [0, 3, 4], [0, 3, 5], [1, 2, 4], [1, 2, 5], [1, 3, 4], [1, 3,...
+ *    p.size # => 8
+ *
+ *  If +self+ or any argument is empty, returns an empty array:
+ *
+ *    [].product([2, 3], [4, 5]) # => []
+ *    [0, 1].product([2, 3], []) # => []
+ *
+ *  If no argument is given, returns an array of 1-element arrays,
  *  each containing an element of +self+:
+ *
  *    a.product # => [[0], [1], [2]]
  *
- *  When a block is given, yields each combination as an \Array; returns +self+:
- *    a.product(a1) {|combination| p combination }
- *  Output:
- *    [0, 3]
- *    [0, 4]
- *    [1, 3]
- *    [1, 4]
- *    [2, 3]
- *    [2, 4]
- *
- *  If any argument is an empty \Array, does not call the block:
- *    a.product(a1, a2, []) {|combination| fail 'Cannot happen' }
- *
- *  If no argument is given, yields each element of +self+ as a 1-element \Array:
- *    a.product {|combination| p combination }
- *  Output:
- *    [0]
- *    [1]
- *    [2]
+ *  With a block given, calls the block with each combination; returns +self+:
+ *
+ *    p = []
+ *    [0, 1].product([2, 3]) {|combination| p.push(combination) }
+ *    p # => [[0, 2], [0, 3], [1, 2], [1, 3]]
+ *
+ *  If +self+ or any argument is empty, does not call the block:
+ *
+ *    [].product([2, 3], [4, 5]) {|combination| fail 'Cannot happen' }
+ *    # => []
+ *    [0, 1].product([2, 3], []) {|combination| fail 'Cannot happen' }
+ *    # => [0, 1]
+ *
+ *  If no argument is given, calls the block with each element of +self+ as a 1-element array:
+ *
+ *    p = []
+ *    [0, 1].product {|combination| p.push(combination) }
+ *    p # => [[0], [1]]
+ *
+ *  Related: see {Methods for Combining}[rdoc-ref:Array@Methods+for+Combining].
  */
 
 static VALUE
 rb_ary_product(int argc, VALUE *argv, VALUE ary)
 {
     int n = argc+1;    /* How many arrays we're operating on */
-    volatile VALUE t0 = tmpary(n);
+    volatile VALUE t0 = rb_ary_hidden_new(n);
     volatile VALUE t1 = Qundef;
     VALUE *arrays = RARRAY_PTR(t0); /* The arrays we're computing the product of */
     int *counters = ALLOCV_N(int, t1, n); /* The current position in each one */
@@ -7274,64 +7554,64 @@ rb_ary_product(int argc, VALUE *argv, VALUE ary)
 
     /* Otherwise, allocate and fill in an array of results */
     if (rb_block_given_p()) {
-	/* Make defensive copies of arrays; exit if any is empty */
-	for (i = 0; i < n; i++) {
-	    if (RARRAY_LEN(arrays[i]) == 0) goto done;
-	    arrays[i] = ary_make_shared_copy(arrays[i]);
-	}
+        /* Make defensive copies of arrays; exit if any is empty */
+        for (i = 0; i < n; i++) {
+            if (RARRAY_LEN(arrays[i]) == 0) goto done;
+            arrays[i] = ary_make_shared_copy(arrays[i]);
+        }
     }
     else {
-	/* Compute the length of the result array; return [] if any is empty */
-	for (i = 0; i < n; i++) {
-	    long k = RARRAY_LEN(arrays[i]);
-	    if (k == 0) {
-		result = rb_ary_new2(0);
-		goto done;
-	    }
+        /* Compute the length of the result array; return [] if any is empty */
+        for (i = 0; i < n; i++) {
+            long k = RARRAY_LEN(arrays[i]);
+            if (k == 0) {
+                result = rb_ary_new2(0);
+                goto done;
+            }
             if (MUL_OVERFLOW_LONG_P(resultlen, k))
-		rb_raise(rb_eRangeError, "too big to product");
-	    resultlen *= k;
-	}
-	result = rb_ary_new2(resultlen);
+                rb_raise(rb_eRangeError, "too big to product");
+            resultlen *= k;
+        }
+        result = rb_ary_new2(resultlen);
     }
     for (;;) {
-	int m;
-	/* fill in one subarray */
-	VALUE subarray = rb_ary_new2(n);
-	for (j = 0; j < n; j++) {
-	    rb_ary_push(subarray, rb_ary_entry(arrays[j], counters[j]));
-	}
-
-	/* put it on the result array */
-	if (NIL_P(result)) {
+        int m;
+        /* fill in one subarray */
+        VALUE subarray = rb_ary_new2(n);
+        for (j = 0; j < n; j++) {
+            rb_ary_push(subarray, rb_ary_entry(arrays[j], counters[j]));
+        }
+
+        /* put it on the result array */
+        if (NIL_P(result)) {
             FL_SET(t0, RARRAY_SHARED_ROOT_FLAG);
-	    rb_yield(subarray);
+            rb_yield(subarray);
             if (!FL_TEST(t0, RARRAY_SHARED_ROOT_FLAG)) {
-		rb_raise(rb_eRuntimeError, "product reentered");
-	    }
-	    else {
+                rb_raise(rb_eRuntimeError, "product reentered");
+            }
+            else {
                 FL_UNSET(t0, RARRAY_SHARED_ROOT_FLAG);
-	    }
-	}
-	else {
-	    rb_ary_push(result, subarray);
-	}
-
-	/*
-	 * Increment the last counter.  If it overflows, reset to 0
-	 * and increment the one before it.
-	 */
-	m = n-1;
-	counters[m]++;
-	while (counters[m] == RARRAY_LEN(arrays[m])) {
-	    counters[m] = 0;
-	    /* If the first counter overflows, we are done */
-	    if (--m < 0) goto done;
-	    counters[m]++;
-	}
+            }
+        }
+        else {
+            rb_ary_push(result, subarray);
+        }
+
+        /*
+         * Increment the last counter.  If it overflows, reset to 0
+         * and increment the one before it.
+         */
+        m = n-1;
+        counters[m]++;
+        while (counters[m] == RARRAY_LEN(arrays[m])) {
+            counters[m] = 0;
+            /* If the first counter overflows, we are done */
+            if (--m < 0) goto done;
+            counters[m]++;
+        }
     }
+
 done:
-    tmpary_discard(t0);
     ALLOCV_END(t1);
 
     return NIL_P(result) ? ary : result;
@@ -7339,18 +7619,20 @@ done:
 
 /*
  *  call-seq:
- *    array.take(n) -> new_array
+ *    take(count) -> new_array
  *
- *  Returns a new \Array containing the first +n+ element of +self+,
- *  where +n+ is a non-negative \Integer;
- *  does not modify +self+.
+ *  Returns a new array containing the first +count+ element of +self+
+ *  (as available);
+ *  +count+ must be a non-negative numeric;
+ *  does not modify +self+:
  *
- *  Examples:
- *    a = [0, 1, 2, 3, 4, 5]
- *    a.take(1) # => [0]
- *    a.take(2) # => [0, 1]
- *    a.take(50) # => [0, 1, 2, 3, 4, 5]
- *    a # => [0, 1, 2, 3, 4, 5]
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.take(2)   # => ["a", "b"]
+ *    a.take(2.1) # => ["a", "b"]
+ *    a.take(50)  # => ["a", "b", "c", "d"]
+ *    a.take(0)   # => []
+ *
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 static VALUE
@@ -7358,29 +7640,30 @@ rb_ary_take(VALUE obj, VALUE n)
 {
     long len = NUM2LONG(n);
     if (len < 0) {
-	rb_raise(rb_eArgError, "attempt to take negative size");
+        rb_raise(rb_eArgError, "attempt to take negative size");
     }
     return rb_ary_subseq(obj, 0, len);
 }
 
 /*
  *  call-seq:
- *    array.take_while {|element| ... } -> new_array
- *    array.take_while -> new_enumerator
- *
- *  Returns a new \Array containing zero or more leading elements of +self+;
- *  does not modify +self+.
+ *    take_while {|element| ... } -> new_array
+ *    take_while -> new_enumerator
  *
  *  With a block given, calls the block with each successive element of +self+;
- *  stops if the block returns +false+ or +nil+;
- *  returns a new \Array containing those elements for which the block returned a truthy value:
+ *  stops iterating if the block returns +false+ or +nil+;
+ *  returns a new array containing those elements for which the block returned a truthy value:
+ *
  *    a = [0, 1, 2, 3, 4, 5]
  *    a.take_while {|element| element < 3 } # => [0, 1, 2]
- *    a.take_while {|element| true } # => [0, 1, 2, 3, 4, 5]
- *    a # => [0, 1, 2, 3, 4, 5]
+ *    a.take_while {|element| true }        # => [0, 1, 2, 3, 4, 5]
+ *    a.take_while {|element| false }       # => []
+ *
+ *  With no block given, returns a new Enumerator.
  *
- *  With no block given, returns a new \Enumerator:
- *    [0, 1].take_while # => #<Enumerator: [0, 1]:take_while>
+ *  Does not modify +self+.
+ *
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 static VALUE
@@ -7390,24 +7673,28 @@ rb_ary_take_while(VALUE ary)
 
     RETURN_ENUMERATOR(ary, 0, 0);
     for (i = 0; i < RARRAY_LEN(ary); i++) {
-	if (!RTEST(rb_yield(RARRAY_AREF(ary, i)))) break;
+        if (!RTEST(rb_yield(RARRAY_AREF(ary, i)))) break;
     }
     return rb_ary_take(ary, LONG2FIX(i));
 }
 
 /*
  *  call-seq:
- *    array.drop(n) -> new_array
+ *    drop(count) -> new_array
  *
- *  Returns a new \Array containing all but the first +n+ element of +self+,
- *  where +n+ is a non-negative \Integer;
+ *  Returns a new array containing all but the first +count+ element of +self+,
+ *  where +count+ is a non-negative integer;
  *  does not modify +self+.
  *
  *  Examples:
+ *
  *    a = [0, 1, 2, 3, 4, 5]
  *    a.drop(0) # => [0, 1, 2, 3, 4, 5]
  *    a.drop(1) # => [1, 2, 3, 4, 5]
  *    a.drop(2) # => [2, 3, 4, 5]
+ *    a.drop(9) # => []
+ *
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 static VALUE
@@ -7416,7 +7703,7 @@ rb_ary_drop(VALUE ary, VALUE n)
     VALUE result;
     long pos = NUM2LONG(n);
     if (pos < 0) {
-	rb_raise(rb_eArgError, "attempt to drop negative size");
+        rb_raise(rb_eArgError, "attempt to drop negative size");
     }
 
     result = rb_ary_subseq(ary, pos, RARRAY_LEN(ary));
@@ -7426,20 +7713,20 @@ rb_ary_drop(VALUE ary, VALUE n)
 
 /*
  *  call-seq:
- *    array.drop_while {|element| ... } -> new_array
- *    array.drop_while -> new_enumerator
-
- *  Returns a new \Array containing zero or more trailing elements of +self+;
- *  does not modify +self+.
+ *    drop_while {|element| ... } -> new_array
+ *    drop_while -> new_enumerator
  *
  *  With a block given, calls the block with each successive element of +self+;
  *  stops if the block returns +false+ or +nil+;
- *  returns a new \Array _omitting_ those elements for which the block returned a truthy value:
+ *  returns a new array _omitting_ those elements for which the block returned a truthy value;
+ *  does not modify +self+:
+ *
  *    a = [0, 1, 2, 3, 4, 5]
  *    a.drop_while {|element| element < 3 } # => [3, 4, 5]
  *
- *  With no block given, returns a new \Enumerator:
- *    [0, 1].drop_while # => # => #<Enumerator: [0, 1]:drop_while>
+ *  With no block given, returns a new Enumerator.
+ *
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 static VALUE
@@ -7449,39 +7736,48 @@ rb_ary_drop_while(VALUE ary)
 
     RETURN_ENUMERATOR(ary, 0, 0);
     for (i = 0; i < RARRAY_LEN(ary); i++) {
-	if (!RTEST(rb_yield(RARRAY_AREF(ary, i)))) break;
+        if (!RTEST(rb_yield(RARRAY_AREF(ary, i)))) break;
     }
     return rb_ary_drop(ary, LONG2FIX(i));
 }
 
 /*
  *  call-seq:
- *    array.any? -> true or false
- *    array.any? {|element| ... } -> true or false
- *    array.any?(obj) -> true or false
+ *    any? -> true or false
+ *    any?(object) -> true or false
+ *    any? {|element| ... } -> true or false
  *
- *  Returns +true+ if any element of +self+ meets a given criterion.
+ *  Returns whether for any element of +self+, a given criterion is satisfied.
  *
- *  With no block given and no argument, returns +true+ if +self+ has any truthy element,
- *  +false+ otherwise:
- *    [nil, 0, false].any? # => true
- *    [nil, false].any? # => false
- *    [].any? # => false
+ *  With no block and no argument, returns whether any element of +self+ is truthy:
  *
- *  With a block given and no argument, calls the block with each element in +self+;
- *  returns +true+ if the block returns any truthy value, +false+ otherwise:
- *    [0, 1, 2].any? {|element| element > 1 } # => true
- *    [0, 1, 2].any? {|element| element > 2 } # => false
+ *    [nil, false, []].any? # => true  # Array object is truthy.
+ *    [nil, false, {}].any? # => true  # Hash object is truthy.
+ *    [nil, false, ''].any? # => true  # String object is truthy.
+ *    [nil, false].any?     # => false # Nil and false are not truthy.
  *
- *  If argument +obj+ is given, returns +true+ if +obj+.<tt>===</tt> any element,
- *  +false+ otherwise:
- *    ['food', 'drink'].any?(/foo/) # => true
- *    ['food', 'drink'].any?(/bar/) # => false
- *    [].any?(/foo/) # => false
- *    [0, 1, 2].any?(1) # => true
- *    [0, 1, 2].any?(3) # => false
+ *  With argument +object+ given,
+ *  returns whether <tt>object === ele</tt> for any element +ele+ in +self+:
+ *
+ *    [nil, false, 0].any?(0)          # => true
+ *    [nil, false, 1].any?(0)          # => false
+ *    [nil, false, 'food'].any?(/foo/) # => true
+ *    [nil, false, 'food'].any?(/bar/) # => false
+ *
+ *  With a block given,
+ *  calls the block with each element in +self+;
+ *  returns whether the block returns any truthy value:
+ *
+ *    [0, 1, 2].any? {|ele| ele < 1 } # => true
+ *    [0, 1, 2].any? {|ele| ele < 0 } # => false
+ *
+ *  With both a block and argument +object+ given,
+ *  ignores the block and uses +object+ as above.
  *
- *  Related: Enumerable#any?
+ *  <b>Special case</b>: returns +false+ if +self+ is empty
+ *  (regardless of any given argument or block).
+ *
+ *  Related: see {Methods for Querying}[rdoc-ref:Array@Methods+for+Querying].
  */
 
 static VALUE
@@ -7495,9 +7791,9 @@ rb_ary_any_p(int argc, VALUE *argv, VALUE ary)
         if (rb_block_given_p()) {
             rb_warn("given block not used");
         }
-	for (i = 0; i < RARRAY_LEN(ary); ++i) {
-	    if (RTEST(rb_funcall(argv[0], idEqq, 1, RARRAY_AREF(ary, i)))) return Qtrue;
-	}
+        for (i = 0; i < RARRAY_LEN(ary); ++i) {
+            if (RTEST(rb_funcall(argv[0], idEqq, 1, RARRAY_AREF(ary, i)))) return Qtrue;
+        }
     }
     else if (!rb_block_given_p()) {
         for (i = 0; i < len; ++i) {
@@ -7505,40 +7801,50 @@ rb_ary_any_p(int argc, VALUE *argv, VALUE ary)
         }
     }
     else {
-	for (i = 0; i < RARRAY_LEN(ary); ++i) {
-	    if (RTEST(rb_yield(RARRAY_AREF(ary, i)))) return Qtrue;
-	}
+        for (i = 0; i < RARRAY_LEN(ary); ++i) {
+            if (RTEST(rb_yield(RARRAY_AREF(ary, i)))) return Qtrue;
+        }
     }
     return Qfalse;
 }
 
 /*
  *  call-seq:
- *    array.all? -> true or false
- *    array.all? {|element| ... } -> true or false
- *    array.all?(obj) -> true or false
+ *    all? -> true or false
+ *    all?(object) -> true or false
+ *    all? {|element| ... } -> true or false
  *
- *  Returns +true+ if all elements of +self+ meet a given criterion.
+ *  Returns whether for every element of +self+,
+ *  a given criterion is satisfied.
  *
- *  With no block given and no argument, returns +true+ if +self+ contains only truthy elements,
- *  +false+ otherwise:
- *    [0, 1, :foo].all? # => true
- *    [0, nil, 2].all? # => false
- *    [].all? # => true
+ *  With no block and no argument,
+ *  returns whether every element of +self+ is truthy:
+ *
+ *    [[], {}, '', 0, 0.0, Object.new].all? # => true  # All truthy objects.
+ *    [[], {}, '', 0, 0.0, nil].all?        # => false # nil is not truthy.
+ *    [[], {}, '', 0, 0.0, false].all?      # => false # false is not truthy.
  *
- *  With a block given and no argument, calls the block with each element in +self+;
- *  returns +true+ if the block returns only truthy values, +false+ otherwise:
- *    [0, 1, 2].all? { |element| element < 3 } # => true
- *    [0, 1, 2].all? { |element| element < 2 } # => false
+ *  With argument +object+ given, returns whether <tt>object === ele</tt>
+ *  for every element +ele+ in +self+:
  *
- *  If argument +obj+ is given, returns +true+ if <tt>obj.===</tt> every element, +false+ otherwise:
+ *    [0, 0, 0].all?(0)                    # => true
+ *    [0, 1, 2].all?(1)                    # => false
  *    ['food', 'fool', 'foot'].all?(/foo/) # => true
- *    ['food', 'drink'].all?(/bar/) # => false
- *    [].all?(/foo/) # => true
- *    [0, 0, 0].all?(0) # => true
- *    [0, 1, 2].all?(1) # => false
+ *    ['food', 'drink'].all?(/foo/)        # => false
+ *
+ *  With a block given, calls the block with each element in +self+;
+ *  returns whether the block returns only truthy values:
+ *
+ *    [0, 1, 2].all? { |ele| ele < 3 } # => true
+ *    [0, 1, 2].all? { |ele| ele < 2 } # => false
  *
- *  Related: Enumerable#all?
+ *  With both a block and argument +object+ given,
+ *  ignores the block and uses +object+ as above.
+ *
+ *  <b>Special case</b>: returns +true+ if +self+ is empty
+ *  (regardless of any given argument or block).
+ *
+ *  Related: see {Methods for Querying}[rdoc-ref:Array@Methods+for+Querying].
  */
 
 static VALUE
@@ -7571,31 +7877,35 @@ rb_ary_all_p(int argc, VALUE *argv, VALUE ary)
 
 /*
  *  call-seq:
- *    array.none? -> true or false
- *    array.none? {|element| ... } -> true or false
- *    array.none?(obj) -> true or false
+ *    none? -> true or false
+ *    none?(object) -> true or false
+ *    none? {|element| ... } -> true or false
  *
- *  Returns +true+ if no element of +self+ meet a given criterion.
+ *  Returns +true+ if no element of +self+ meets a given criterion, +false+ otherwise.
  *
  *  With no block given and no argument, returns +true+ if +self+ has no truthy elements,
  *  +false+ otherwise:
- *    [nil, false].none? # => true
+ *
+ *    [nil, false].none?    # => true
  *    [nil, 0, false].none? # => false
- *    [].none? # => true
+ *    [].none?              # => true
  *
- *  With a block given and no argument, calls the block with each element in +self+;
- *  returns +true+ if the block returns no truthy value, +false+ otherwise:
- *    [0, 1, 2].none? {|element| element > 3 } # => true
- *    [0, 1, 2].none? {|element| element > 1 } # => false
+ *  With argument +object+ given, returns +false+ if for any element +element+,
+ *  <tt>object === element</tt>; +true+ otherwise:
  *
- *  If argument +obj+ is given, returns +true+ if <tt>obj.===</tt> no element, +false+ otherwise:
  *    ['food', 'drink'].none?(/bar/) # => true
  *    ['food', 'drink'].none?(/foo/) # => false
- *    [].none?(/foo/) # => true
- *    [0, 1, 2].none?(3) # => true
- *    [0, 1, 2].none?(1) # => false
+ *    [].none?(/foo/)                # => true
+ *    [0, 1, 2].none?(3)             # => true
+ *    [0, 1, 2].none?(1)             # => false
+ *
+ *  With a block given, calls the block with each element in +self+;
+ *  returns +true+ if the block returns no truthy value, +false+ otherwise:
+ *
+ *    [0, 1, 2].none? {|element| element > 3 } # => true
+ *    [0, 1, 2].none? {|element| element > 1 } # => false
  *
- *  Related: Enumerable#none?
+ *  Related: see {Methods for Querying}[rdoc-ref:Array@Methods+for+Querying].
  */
 
 static VALUE
@@ -7628,27 +7938,30 @@ rb_ary_none_p(int argc, VALUE *argv, VALUE ary)
 
 /*
  *  call-seq:
- *    array.one? -> true or false
- *    array.one? {|element| ... } -> true or false
- *    array.one?(obj) -> true or false
+ *    one? -> true or false
+ *    one? {|element| ... } -> true or false
+ *    one?(object) -> true or false
  *
  *  Returns +true+ if exactly one element of +self+ meets a given criterion.
  *
  *  With no block given and no argument, returns +true+ if +self+ has exactly one truthy element,
  *  +false+ otherwise:
+ *
  *    [nil, 0].one? # => true
  *    [0, 0].one? # => false
  *    [nil, nil].one? # => false
  *    [].one? # => false
  *
- *  With a block given and no argument, calls the block with each element in +self+;
+ *  With a block given, calls the block with each element in +self+;
  *  returns +true+ if the block a truthy value for exactly one element, +false+ otherwise:
+ *
  *    [0, 1, 2].one? {|element| element > 0 } # => false
  *    [0, 1, 2].one? {|element| element > 1 } # => true
  *    [0, 1, 2].one? {|element| element > 2 } # => false
  *
- *  If argument +obj+ is given, returns +true+ if <tt>obj.===</tt> exactly one element,
+ *  With argument +object+ given, returns +true+ if for exactly one element +element+, <tt>object === element</tt>;
  *  +false+ otherwise:
+ *
  *    [0, 1, 2].one?(0) # => true
  *    [0, 0, 1].one?(0) # => false
  *    [1, 1, 2].one?(0) # => false
@@ -7656,7 +7969,7 @@ rb_ary_none_p(int argc, VALUE *argv, VALUE ary)
  *    ['food', 'drink'].one?(/foo/) # => true
  *    [].one?(/foo/) # => false
  *
- *  Related: Enumerable#one?
+ *  Related: see {Methods for Querying}[rdoc-ref:Array@Methods+for+Querying].
  */
 
 static VALUE
@@ -7701,17 +8014,20 @@ rb_ary_one_p(int argc, VALUE *argv, VALUE ary)
  *  call-seq:
  *    array.dig(index, *identifiers) -> object
  *
- *  Finds and returns the object in nested objects
- *  that is specified by +index+ and +identifiers+.
- *  The nested objects may be instances of various classes.
+ *  Finds and returns the object in nested object
+ *  specified by +index+ and +identifiers+;
+ *  the nested objects may be instances of various classes.
  *  See {Dig Methods}[rdoc-ref:dig_methods.rdoc].
  *
  *  Examples:
+ *
  *    a = [:foo, [:bar, :baz, [:bat, :bam]]]
  *    a.dig(1) # => [:bar, :baz, [:bat, :bam]]
  *    a.dig(1, 2) # => [:bat, :bam]
  *    a.dig(1, 2, 0) # => :bat
  *    a.dig(1, 2, 3) # => nil
+ *
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 static VALUE
@@ -7729,7 +8045,7 @@ finish_exact_sum(long n, VALUE r, VALUE v, int z)
 {
     if (n != 0)
         v = rb_fix_plus(LONG2FIX(n), v);
-    if (r != Qundef) {
+    if (!UNDEF_P(r)) {
         v = rb_rational_plus(r, v);
     }
     else if (!n && z) {
@@ -7740,35 +8056,43 @@ finish_exact_sum(long n, VALUE r, VALUE v, int z)
 
 /*
  * call-seq:
- *   array.sum(init = 0) -> object
- *   array.sum(init = 0) {|element| ... } -> object
+ *   sum(init = 0) -> object
+ *   sum(init = 0) {|element| ... } -> object
+ *
+ *  With no block given, returns the sum of +init+ and all elements of +self+;
+ *  for array +array+ and value +init+, equivalent to:
  *
- *  When no block is given, returns the object equivalent to:
  *    sum = init
  *    array.each {|element| sum += element }
  *    sum
- *  For example, <tt>[e1, e2, e3].sum</tt> returns <tt>init + e1 + e2 + e3</tt>.
+ *
+ *  For example, <tt>[e0, e1, e2].sum</tt> returns <tt>init + e0 + e1 + e2</tt>.
  *
  *  Examples:
- *    a = [0, 1, 2, 3]
- *    a.sum # => 6
- *    a.sum(100) # => 106
  *
- *  The elements need not be numeric, but must be <tt>+</tt>-compatible
- *  with each other and with +init+:
- *    a = ['abc', 'def', 'ghi']
- *    a.sum('jkl') # => "jklabcdefghi"
+ *    [0, 1, 2, 3].sum                 # => 6
+ *    [0, 1, 2, 3].sum(100)            # => 106
+ *    ['abc', 'def', 'ghi'].sum('jkl') # => "jklabcdefghi"
+ *    [[:foo, :bar], ['foo', 'bar']].sum([2, 3])
+ *    # => [2, 3, :foo, :bar, "foo", "bar"]
+ *
+ *  The +init+ value and elements need not be numeric, but must all be <tt>+</tt>-compatible:
+ *
+ *    # Raises TypeError: Array can't be coerced into Integer.
+ *    [[:foo, :bar], ['foo', 'bar']].sum(2)
  *
- *  When a block is given, it is called with each element
- *  and the block's return value (instead of the element itself) is used as the addend:
- *    a = ['zero', 1, :two]
- *    s = a.sum('Coerced and concatenated: ') {|element| element.to_s }
- *    s # => "Coerced and concatenated: zero1two"
+ *  With a block given, calls the block with each element of +self+;
+ *  the block's return value (instead of the element itself) is used as the addend:
+ *
+ *    ['zero', 1, :two].sum('Coerced and concatenated: ') {|element| element.to_s }
+ *    # => "Coerced and concatenated: zero1two"
  *
  *  Notes:
+ *
  *  - Array#join and Array#flatten may be faster than Array#sum
- *    for an \Array of Strings or an \Array of Arrays.
+ *    for an array of strings or an array of arrays.
  *  - Array#sum method may not respect method redefinition of "+" methods such as Integer#+.
+ *
  */
 
 static VALUE
@@ -7787,6 +8111,12 @@ rb_ary_sum(int argc, VALUE *argv, VALUE ary)
 
     n = 0;
     r = Qundef;
+
+    if (!FIXNUM_P(v) && !RB_BIGNUM_TYPE_P(v) && !RB_TYPE_P(v, T_RATIONAL)) {
+        i = 0;
+        goto init_is_a_value;
+    }
+
     for (i = 0; i < RARRAY_LEN(ary); i++) {
         e = RARRAY_AREF(ary, i);
         if (block_given)
@@ -7801,7 +8131,7 @@ rb_ary_sum(int argc, VALUE *argv, VALUE ary)
         else if (RB_BIGNUM_TYPE_P(e))
             v = rb_big_plus(e, v);
         else if (RB_TYPE_P(e, T_RATIONAL)) {
-            if (r == Qundef)
+            if (UNDEF_P(r))
                 r = e;
             else
                 r = rb_rational_plus(r, e);
@@ -7871,6 +8201,7 @@ rb_ary_sum(int argc, VALUE *argv, VALUE ary)
     }
 
     goto has_some_value;
+    init_is_a_value:
     for (; i < RARRAY_LEN(ary); i++) {
         e = RARRAY_AREF(ary, i);
         if (block_given)
@@ -7881,6 +8212,7 @@ rb_ary_sum(int argc, VALUE *argv, VALUE ary)
     return v;
 }
 
+/* :nodoc: */
 static VALUE
 rb_ary_deconstruct(VALUE ary)
 {
@@ -7888,82 +8220,154 @@ rb_ary_deconstruct(VALUE ary)
 }
 
 /*
- *  An \Array is an ordered, integer-indexed collection of objects,
- *  called _elements_.  Any object may be an \Array element.
+ *  An \Array object is an ordered, integer-indexed collection of objects,
+ *  called _elements_;
+ *  the object represents
+ *  an {array data structure}[https://en.wikipedia.org/wiki/Array_(data_structure)].
+ *
+ *  An element may be any object (even another array);
+ *  elements may be any mixture of objects of different types.
+ *
+ *  Important data structures that use arrays include:
+ *
+ *  - {Coordinate vector}[https://en.wikipedia.org/wiki/Coordinate_vector].
+ *  - {Matrix}[https://en.wikipedia.org/wiki/Matrix_(mathematics)].
+ *  - {Heap}[https://en.wikipedia.org/wiki/Heap_(data_structure)].
+ *  - {Hash table}[https://en.wikipedia.org/wiki/Hash_table].
+ *  - {Deque (double-ended queue)}[https://en.wikipedia.org/wiki/Double-ended_queue].
+ *  - {Queue}[https://en.wikipedia.org/wiki/Queue_(abstract_data_type)].
+ *  - {Stack}[https://en.wikipedia.org/wiki/Stack_(abstract_data_type)].
+ *
+ *  There are also array-like data structures:
+ *
+ *  - {Associative array}[https://en.wikipedia.org/wiki/Associative_array] (see Hash).
+ *  - {Directory}[https://en.wikipedia.org/wiki/Directory_(computing)] (see Dir).
+ *  - {Environment}[https://en.wikipedia.org/wiki/Environment_variable] (see ENV).
+ *  - {Set}[https://en.wikipedia.org/wiki/Set_(abstract_data_type)] (see Set).
+ *  - {String}[https://en.wikipedia.org/wiki/String_(computer_science)] (see String).
  *
  *  == \Array Indexes
  *
  *  \Array indexing starts at 0, as in C or Java.
  *
- *  A positive index is an offset from the first element:
+ *  A non-negative index is an offset from the first element:
+ *
  *  - Index 0 indicates the first element.
  *  - Index 1 indicates the second element.
  *  - ...
  *
  *  A negative index is an offset, backwards, from the end of the array:
+ *
  *  - Index -1 indicates the last element.
  *  - Index -2 indicates the next-to-last element.
  *  - ...
  *
- *  A non-negative index is <i>in range</i> if it is smaller than
+ *
+ *  === In-Range and Out-of-Range Indexes
+ *
+ *  A non-negative index is <i>in range</i> if and only if it is smaller than
  *  the size of the array.  For a 3-element array:
+ *
  *  - Indexes 0 through 2 are in range.
  *  - Index 3 is out of range.
  *
- *  A negative index is <i>in range</i> if its absolute value is
+ *  A negative index is <i>in range</i> if and only if its absolute value is
  *  not larger than the size of the array.  For a 3-element array:
+ *
  *  - Indexes -1 through -3 are in range.
  *  - Index -4 is out of range.
  *
- *  == Creating Arrays
- *
- *  You can create an \Array object explicitly with:
- *
- *  - An {array literal}[rdoc-ref:syntax/literals.rdoc@Array+Literals].
- *
- *  You can convert certain objects to Arrays with:
- *
- *  - \Method #Array.
- *
- *  An \Array can contain different types of objects.  For
- *  example, the array below contains an Integer, a String and a Float:
+ *  === Effective Index
  *
- *     ary = [1, "two", 3.0] #=> [1, "two", 3.0]
+ *  Although the effective index into an array is always an integer,
+ *  some methods (both within class \Array and elsewhere)
+ *  accept one or more non-integer arguments that are
+ *  {integer-convertible objects}[rdoc-ref:implicit_conversion.rdoc@Integer-Convertible+Objects].
  *
- *  An array can also be created by calling Array.new with zero, one
- *  (the initial size of the \Array) or two arguments (the initial size and a
- *  default object).
- *
- *     ary = Array.new    #=> []
- *     Array.new(3)       #=> [nil, nil, nil]
- *     Array.new(3, true) #=> [true, true, true]
- *
- *  Note that the second argument populates the array with references to the
- *  same object.  Therefore, it is only recommended in cases when you need to
- *  instantiate arrays with natively immutable objects such as Symbols,
- *  numbers, true or false.
- *
- *  To create an array with separate objects a block can be passed instead.
- *  This method is safe to use with mutable objects such as hashes, strings or
- *  other arrays:
- *
- *     Array.new(4) {Hash.new}    #=> [{}, {}, {}, {}]
- *     Array.new(4) {|i| i.to_s } #=> ["0", "1", "2", "3"]
- *
- *  This is also a quick way to build up multi-dimensional arrays:
- *
- *     empty_table = Array.new(3) {Array.new(3)}
- *     #=> [[nil, nil, nil], [nil, nil, nil], [nil, nil, nil]]
+ *  == Creating Arrays
  *
- *  An array can also be created by using the Array() method, provided by
- *  Kernel, which tries to call #to_ary, then #to_a on its argument.
+ *  You can create an \Array object explicitly with:
  *
- *	Array({:a => "a", :b => "b"}) #=> [[:a, "a"], [:b, "b"]]
+ *  - An {array literal}[rdoc-ref:syntax/literals.rdoc@Array+Literals]:
+ *
+ *      [1, 'one', :one, [2, 'two', :two]]
+ *
+ *  - A {%w or %W string-array Literal}[rdoc-ref:syntax/literals.rdoc@25w+and+-25W-3A+String-Array+Literals]:
+ *
+ *      %w[foo bar baz] # => ["foo", "bar", "baz"]
+ *      %w[1 % *]       # => ["1", "%", "*"]
+ *
+ *  - A {%i or %I symbol-array Literal}[rdoc-ref:syntax/literals.rdoc@25i+and+-25I-3A+Symbol-Array+Literals]:
+ *
+ *      %i[foo bar baz] # => [:foo, :bar, :baz]
+ *      %i[1 % *]       # => [:"1", :%, :*]
+ *
+ *  - \Method Kernel#Array:
+ *
+ *      Array(["a", "b"])             # => ["a", "b"]
+ *      Array(1..5)                   # => [1, 2, 3, 4, 5]
+ *      Array(key: :value)            # => [[:key, :value]]
+ *      Array(nil)                    # => []
+ *      Array(1)                      # => [1]
+ *      Array({:a => "a", :b => "b"}) # => [[:a, "a"], [:b, "b"]]
+ *
+ *  - \Method Array.new:
+ *
+ *      Array.new               # => []
+ *      Array.new(3)            # => [nil, nil, nil]
+ *      Array.new(4) {Hash.new} # => [{}, {}, {}, {}]
+ *      Array.new(3, true)      # => [true, true, true]
+ *
+ *    Note that the last example above populates the array
+ *    with references to the same object.
+ *    This is recommended only in cases where that object is a natively immutable object
+ *    such as a symbol, a numeric, +nil+, +true+, or +false+.
+ *
+ *    Another way to create an array with various objects, using a block;
+ *    this usage is safe for mutable objects such as hashes, strings or
+ *    other arrays:
+ *
+ *      Array.new(4) {|i| i.to_s } # => ["0", "1", "2", "3"]
+ *
+ *    Here is a way to create a multi-dimensional array:
+ *
+ *      Array.new(3) {Array.new(3)}
+ *      # => [[nil, nil, nil], [nil, nil, nil], [nil, nil, nil]]
+ *
+ *  A number of Ruby methods, both in the core and in the standard library,
+ *  provide instance method +to_a+, which converts an object to an array.
+ *
+ *  - ARGF#to_a
+ *  - Array#to_a
+ *  - Enumerable#to_a
+ *  - Hash#to_a
+ *  - MatchData#to_a
+ *  - NilClass#to_a
+ *  - OptionParser#to_a
+ *  - Range#to_a
+ *  - Set#to_a
+ *  - Struct#to_a
+ *  - Time#to_a
+ *  - Benchmark::Tms#to_a
+ *  - CSV::Table#to_a
+ *  - Enumerator::Lazy#to_a
+ *  - Gem::List#to_a
+ *  - Gem::NameTuple#to_a
+ *  - Gem::Platform#to_a
+ *  - Gem::RequestSet::Lockfile::Tokenizer#to_a
+ *  - Gem::SourceList#to_a
+ *  - OpenSSL::X509::Extension#to_a
+ *  - OpenSSL::X509::Name#to_a
+ *  - Racc::ISet#to_a
+ *  - Rinda::RingFinger#to_a
+ *  - Ripper::Lexer::Elem#to_a
+ *  - RubyVM::InstructionSequence#to_a
+ *  - YAML::DBM#to_a
  *
  *  == Example Usage
  *
  *  In addition to the methods it mixes in through the Enumerable module, the
- *  \Array class has proprietary methods for accessing, searching and otherwise
+ *  +Array+ class has proprietary methods for accessing, searching and otherwise
  *  manipulating arrays.
  *
  *  Some of the more common ones are illustrated below.
@@ -8011,7 +8415,7 @@ rb_ary_deconstruct(VALUE ary)
  *
  *     arr.drop(3) #=> [4, 5, 6]
  *
- *  == Obtaining Information about an \Array
+ *  == Obtaining Information about an +Array+
  *
  *  Arrays keep track of their own length at all times.  To query an array
  *  about the number of elements it contains, use #length, #count or #size.
@@ -8049,7 +8453,7 @@ rb_ary_deconstruct(VALUE ary)
  *     arr.insert(3, 'orange', 'pear', 'grapefruit')
  *     #=> [0, 1, 2, "orange", "pear", "grapefruit", "apple", 3, 4, 5, 6]
  *
- *  == Removing Items from an \Array
+ *  == Removing Items from an +Array+
  *
  *  The method #pop removes the last element in an array and returns it:
  *
@@ -8091,9 +8495,9 @@ rb_ary_deconstruct(VALUE ary)
  *
  *  == Iterating over Arrays
  *
- *  Like all classes that include the Enumerable module, \Array has an each
+ *  Like all classes that include the Enumerable module, +Array+ has an each
  *  method, which defines what elements should be iterated over and how.  In
- *  case of Array's #each, all elements in the \Array instance are yielded to
+ *  case of Array's #each, all elements in the +Array+ instance are yielded to
  *  the supplied block in sequence.
  *
  *  Note that this operation leaves the array unchanged.
@@ -8120,7 +8524,7 @@ rb_ary_deconstruct(VALUE ary)
  *     arr                   #=> [1, 4, 9, 16, 25]
  *
  *
- *  == Selecting Items from an \Array
+ *  == Selecting Items from an +Array+
  *
  *  Elements can be selected from an array according to criteria defined in a
  *  block.  The selection can happen in a destructive or a non-destructive
@@ -8153,13 +8557,13 @@ rb_ary_deconstruct(VALUE ary)
  *
  *  == What's Here
  *
- *  First, what's elsewhere. \Class \Array:
+ *  First, what's elsewhere. \Class +Array+:
  *
  *  - Inherits from {class Object}[rdoc-ref:Object@What-27s+Here].
  *  - Includes {module Enumerable}[rdoc-ref:Enumerable@What-27s+Here],
  *    which provides dozens of additional methods.
  *
- *  Here, class \Array provides methods that are useful for:
+ *  Here, class +Array+ provides methods that are useful for:
  *
  *  - {Creating an Array}[rdoc-ref:Array@Methods+for+Creating+an+Array]
  *  - {Querying}[rdoc-ref:Array@Methods+for+Querying]
@@ -8172,154 +8576,138 @@ rb_ary_deconstruct(VALUE ary)
  *  - {Converting}[rdoc-ref:Array@Methods+for+Converting]
  *  - {And more....}[rdoc-ref:Array@Other+Methods]
  *
- *  === Methods for Creating an \Array
+ *  === Methods for Creating an +Array+
  *
  *  - ::[]: Returns a new array populated with given objects.
  *  - ::new: Returns a new array.
  *  - ::try_convert: Returns a new array created from a given object.
  *
+ *  See also {Creating Arrays}[rdoc-ref:Array@Creating+Arrays].
+ *
  *  === Methods for Querying
  *
- *  - #length, #size: Returns the count of elements.
- *  - #include?: Returns whether any element <tt>==</tt> a given object.
- *  - #empty?: Returns whether there are no elements.
  *  - #all?: Returns whether all elements meet a given criterion.
  *  - #any?: Returns whether any element meets a given criterion.
+ *  - #count: Returns the count of elements that meet a given criterion.
+ *  - #empty?: Returns whether there are no elements.
+ *  - #find_index (aliased as #index): Returns the index of the first element that meets a given criterion.
+ *  - #hash: Returns the integer hash code.
+ *  - #include?: Returns whether any element <tt>==</tt> a given object.
+ *  - #length (aliased as #size): Returns the count of elements.
  *  - #none?: Returns whether no element <tt>==</tt> a given object.
  *  - #one?: Returns whether exactly one element <tt>==</tt> a given object.
- *  - #count: Returns the count of elements that meet a given criterion.
- *  - #find_index, #index: Returns the index of the first element that meets a given criterion.
  *  - #rindex: Returns the index of the last element that meets a given criterion.
- *  - #hash: Returns the integer hash code.
  *
  *  === Methods for Comparing
  *
- *  - #<=>: Returns -1, 0, or 1 * as +self+ is less than, equal to, or
- *    greater than a given object.
- *  - #==: Returns whether each element in +self+ is <tt>==</tt> to the corresponding element
- *    in a given object.
- *  - #eql?: Returns whether each element in +self+ is <tt>eql?</tt> to the corresponding
- *    element in a given object.
+ *  - #<=>: Returns -1, 0, or 1, as +self+ is less than, equal to, or greater than a given object.
+ *  - #==: Returns whether each element in +self+ is <tt>==</tt> to the corresponding element in a given object.
+ *  - #eql?: Returns whether each element in +self+ is <tt>eql?</tt> to the corresponding element in a given object.
 
  *  === Methods for Fetching
  *
  *  These methods do not modify +self+.
  *
- *  - #[]: Returns one or more elements.
- *  - #fetch: Returns the element at a given offset.
- *  - #first: Returns one or more leading elements.
- *  - #last: Returns one or more trailing elements.
- *  - #max: Returns one or more maximum-valued elements,
- *    as determined by <tt><=></tt> or a given block.
- *  - #min: Returns one or more minimum-valued elements,
- *    as determined by <tt><=></tt> or a given block.
- *  - #minmax: Returns the minimum-valued and maximum-valued elements,
- *    as determined by <tt><=></tt> or a given block.
- *  - #assoc: Returns the first element that is an array
- *    whose first element <tt>==</tt> a given object.
- *  - #rassoc: Returns the first element that is an array
- *    whose second element <tt>==</tt> a given object.
+ *  - #[] (aliased as #slice): Returns consecutive elements as determined by a given argument.
+ *  - #assoc: Returns the first element that is an array whose first element <tt>==</tt> a given object.
  *  - #at: Returns the element at a given offset.
- *  - #values_at: Returns the elements at given offsets.
- *  - #dig: Returns the object in nested objects
- *    that is specified by a given index and additional arguments.
+ *  - #bsearch: Returns an element selected via a binary search as determined by a given block.
+ *  - #bsearch_index: Returns the index of an element selected via a binary search as determined by a given block.
+ *  - #compact: Returns an array containing all non-+nil+ elements.
+ *  - #dig: Returns the object in nested objects that is specified by a given index and additional arguments.
  *  - #drop: Returns trailing elements as determined by a given index.
- *  - #take: Returns leading elements as determined by a given index.
  *  - #drop_while: Returns trailing elements as determined by a given block.
- *  - #take_while: Returns leading elements as determined by a given block.
- *  - #slice: Returns consecutive elements as determined by a given argument.
- *  - #sort: Returns all elements in an order determined by <tt><=></tt> or a given block.
+ *  - #fetch: Returns the element at a given offset.
+ *  - #fetch_values: Returns elements at given offsets.
+ *  - #first: Returns one or more leading elements.
+ *  - #last: Returns one or more trailing elements.
+ *  - #max: Returns one or more maximum-valued elements, as determined by <tt>#<=></tt> or a given block.
+ *  - #min: Returns one or more minimum-valued elements, as determined by <tt>#<=></tt> or a given block.
+ *  - #minmax: Returns the minimum-valued and maximum-valued elements, as determined by <tt>#<=></tt> or a given block.
+ *  - #rassoc: Returns the first element that is an array whose second element <tt>==</tt> a given object.
+ *  - #reject: Returns an array containing elements not rejected by a given block.
  *  - #reverse: Returns all elements in reverse order.
- *  - #compact: Returns an array containing all non-+nil+ elements.
- *  - #select, #filter: Returns an array containing elements selected by a given block.
- *  - #uniq: Returns an array containing non-duplicate elements.
  *  - #rotate: Returns all elements with some rotated from one end to the other.
- *  - #bsearch: Returns an element selected via a binary search
- *    as determined by a given block.
- *  - #bsearch_index: Returns the index of an element selected via a binary search
- *    as determined by a given block.
  *  - #sample: Returns one or more random elements.
+ *  - #select (aliased as #filter): Returns an array containing elements selected by a given block.
  *  - #shuffle: Returns elements in a random order.
+ *  - #sort: Returns all elements in an order determined by <tt>#<=></tt> or a given block.
+ *  - #take: Returns leading elements as determined by a given index.
+ *  - #take_while: Returns leading elements as determined by a given block.
+ *  - #uniq: Returns an array containing non-duplicate elements.
+ *  - #values_at: Returns the elements at given offsets.
  *
  *  === Methods for Assigning
  *
  *  These methods add, replace, or reorder elements in +self+.
  *
+ *  - #<<: Appends an element.
  *  - #[]=: Assigns specified elements with a given object.
- *  - #push, #append, #<<: Appends trailing elements.
- *  - #unshift, #prepend: Prepends leading elements.
- *  - #insert: Inserts given objects at a given offset; does not replace elements.
  *  - #concat: Appends all elements from given arrays.
  *  - #fill: Replaces specified elements with specified objects.
- *  - #replace: Replaces the content of +self+ with the content of a given array.
+ *  - #flatten!: Replaces each nested array in +self+ with the elements from that array.
+ *  - #initialize_copy (aliased as #replace): Replaces the content of +self+ with the content of a given array.
+ *  - #insert: Inserts given objects at a given offset; does not replace elements.
+ *  - #push (aliased as #append): Appends elements.
  *  - #reverse!: Replaces +self+ with its elements reversed.
  *  - #rotate!: Replaces +self+ with its elements rotated.
  *  - #shuffle!: Replaces +self+ with its elements in random order.
- *  - #sort!: Replaces +self+ with its elements sorted,
- *    as determined by <tt><=></tt> or a given block.
+ *  - #sort!: Replaces +self+ with its elements sorted, as determined by <tt>#<=></tt> or a given block.
  *  - #sort_by!: Replaces +self+ with its elements sorted, as determined by a given block.
+ *  - #unshift (aliased as #prepend): Prepends leading elements.
  *
  *  === Methods for Deleting
  *
  *  Each of these methods removes elements from +self+:
  *
- *  - #pop: Removes and returns the last element.
- *  - #shift:  Removes and returns the first element.
- *  - #compact!: Removes all non-+nil+ elements.
+ *  - #clear: Removes all elements.
+ *  - #compact!: Removes all +nil+ elements.
  *  - #delete: Removes elements equal to a given object.
  *  - #delete_at: Removes the element at a given offset.
  *  - #delete_if: Removes elements specified by a given block.
  *  - #keep_if: Removes elements not specified by a given block.
+ *  - #pop: Removes and returns the last element.
  *  - #reject!: Removes elements specified by a given block.
- *  - #select!, #filter!: Removes elements not specified by a given block.
+ *  - #select! (aliased as #filter!): Removes elements not specified by a given block.
+ *  - #shift:  Removes and returns the first element.
  *  - #slice!: Removes and returns a sequence of elements.
  *  - #uniq!: Removes duplicates.
  *
  *  === Methods for Combining
  *
  *  - #&: Returns an array containing elements found both in +self+ and a given array.
- *  - #intersection: Returns an array containing elements found both in +self+
- *    and in each given array.
  *  - #+: Returns an array containing all elements of +self+ followed by all elements of a given array.
  *  - #-: Returns an array containing all elements of +self+ that are not found in a given array.
- *  - #|: Returns an array containing all elements of +self+ and all elements of a given array,
- *    duplicates removed.
- *  - #union: Returns an array containing all elements of +self+ and all elements of given arrays,
- *    duplicates removed.
- *  - #difference: Returns an array containing all elements of +self+ that are not found
- *    in any of the given arrays..
+ *  - #|: Returns an array containing all element of +self+ and all elements of a given array, duplicates removed.
+ *  - #difference: Returns an array containing all elements of +self+ that are not found in any of the given arrays..
+ *  - #intersection: Returns an array containing elements found both in +self+ and in each given array.
  *  - #product: Returns or yields all combinations of elements from +self+ and given arrays.
+ *  - #reverse: Returns an array containing all elements of +self+ in reverse order.
+ *  - #union: Returns an array containing all elements of +self+ and all elements of given arrays, duplicates removed.
  *
  *  === Methods for Iterating
  *
+ *  - #combination: Calls a given block with combinations of elements of +self+; a combination does not use the same element more than once.
+ *  - #cycle: Calls a given block with each element, then does so again, for a specified number of times, or forever.
  *  - #each: Passes each element to a given block.
- *  - #reverse_each:  Passes each element, in reverse order, to a given block.
  *  - #each_index: Passes each element index to a given block.
- *  - #cycle: Calls a given block with each element, then does so again,
- *    for a specified number of times, or forever.
- *  - #combination: Calls a given block with combinations of elements of +self+;
- *    a combination does not use the same element more than once.
- *  - #permutation: Calls a given block with permutations of elements of +self+;
- *    a permutation does not use the same element more than once.
- *  - #repeated_combination: Calls a given block with combinations of elements of +self+;
- *    a combination may use the same element more than once.
- *  - #repeated_permutation: Calls a given block with permutations of elements of +self+;
- *    a permutation may use the same element more than once.
+ *  - #permutation: Calls a given block with permutations of elements of +self+; a permutation does not use the same element more than once.
+ *  - #repeated_combination: Calls a given block with combinations of elements of +self+; a combination may use the same element more than once.
+ *  - #repeated_permutation: Calls a given block with permutations of elements of +self+; a permutation may use the same element more than once.
+ *  - #reverse_each:  Passes each element, in reverse order, to a given block.
  *
  *  === Methods for Converting
  *
- *  - #map, #collect: Returns an array containing the block return-value for each element.
- *  - #map!, #collect!: Replaces each element with a block return-value.
+ *  - #collect (aliased as #map): Returns an array containing the block return-value for each element.
+ *  - #collect! (aliased as #map!): Replaces each element with a block return-value.
  *  - #flatten: Returns an array that is a recursive flattening of +self+.
- *  - #flatten!: Replaces each nested array in +self+ with the elements from that array.
- *  - #inspect, #to_s: Returns a new String containing the elements.
+ *  - #inspect (aliased as #to_s): Returns a new String containing the elements.
  *  - #join: Returns a newsString containing the elements joined by the field separator.
  *  - #to_a: Returns +self+ or a new array containing all elements.
  *  - #to_ary: Returns +self+.
  *  - #to_h: Returns a new hash formed from the elements.
  *  - #transpose: Transposes +self+, which must be an array of arrays.
- *  - #zip: Returns a new array of arrays containing +self+ and given arrays;
- *    follow the link for details.
+ *  - #zip: Returns a new array of arrays containing +self+ and given arrays.
  *
  *  === Other Methods
  *
@@ -8330,7 +8718,6 @@ rb_ary_deconstruct(VALUE ary)
  *    - With string argument +field_separator+, a new string that is equivalent to
  *      <tt>join(field_separator)</tt>.
  *
- *  - #abbrev: Returns a hash of unambiguous abbreviations for elements.
  *  - #pack: Packs the elements into a binary sequence.
  *  - #sum: Returns a sum of elements according to either <tt>+</tt> or a given block.
  */
@@ -8338,6 +8725,8 @@ rb_ary_deconstruct(VALUE ary)
 void
 Init_Array(void)
 {
+    fake_ary_flags = init_fake_ary_flags();
+
     rb_cArray  = rb_define_class("Array", rb_cObject);
     rb_include_module(rb_cArray, rb_mEnumerable);
 
@@ -8362,8 +8751,6 @@ Init_Array(void)
     rb_define_method(rb_cArray, "[]=", rb_ary_aset, -1);
     rb_define_method(rb_cArray, "at", rb_ary_at, 1);
     rb_define_method(rb_cArray, "fetch", rb_ary_fetch, -1);
-    rb_define_method(rb_cArray, "first", rb_ary_first, -1);
-    rb_define_method(rb_cArray, "last", rb_ary_last, -1);
     rb_define_method(rb_cArray, "concat", rb_ary_concat_multi, -1);
     rb_define_method(rb_cArray, "union", rb_ary_union_multi, -1);
     rb_define_method(rb_cArray, "difference", rb_ary_difference_multi, -1);
@@ -8460,8 +8847,12 @@ Init_Array(void)
     rb_define_method(rb_cArray, "one?", rb_ary_one_p, -1);
     rb_define_method(rb_cArray, "dig", rb_ary_dig, -1);
     rb_define_method(rb_cArray, "sum", rb_ary_sum, -1);
+    rb_define_method(rb_cArray, "freeze", rb_ary_freeze, 0);
 
     rb_define_method(rb_cArray, "deconstruct", rb_ary_deconstruct, 0);
+
+    rb_cArray_empty_frozen = rb_ary_freeze(rb_ary_new());
+    rb_vm_register_global_object(rb_cArray_empty_frozen);
 }
 
 #include "array.rbinc"
diff --git a/array.rb b/array.rb
index b9fa9844e6..2eaec6de20 100644
--- a/array.rb
+++ b/array.rb
@@ -1,62 +1,97 @@
 class Array
   # call-seq:
-  #    array.shuffle!(random: Random) -> array
+  #   shuffle!(random: Random) -> self
   #
-  # Shuffles the elements of +self+ in place.
-  #    a = [1, 2, 3] #=> [1, 2, 3]
-  #    a.shuffle!    #=> [2, 3, 1]
-  #    a             #=> [2, 3, 1]
+  # Shuffles all elements in +self+ into a random order,
+  # as selected by the object given by the keyword argument +random+.
+  # Returns +self+:
   #
-  # The optional +random+ argument will be used as the random number generator:
-  #    a.shuffle!(random: Random.new(1))  #=> [1, 3, 2]
+  #   a =             [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+  #   a.shuffle! # => [5, 3, 8, 7, 6, 1, 9, 4, 2, 0]
+  #   a.shuffle! # => [9, 4, 0, 6, 2, 8, 1, 5, 3, 7]
+  #
+  # Duplicate elements are included:
+  #
+  #   a =             [0, 1, 0, 1, 0, 1, 0, 1, 0, 1]
+  #   a.shuffle! # => [1, 0, 0, 1, 1, 0, 1, 0, 0, 1]
+  #   a.shuffle! # => [0, 1, 0, 1, 1, 0, 1, 0, 1, 0]
+  #
+  # The object given with the keyword argument +random+ is used as the random number generator.
+  #
+  # Related: see {Methods for Assigning}[rdoc-ref:Array@Methods+for+Assigning].
   def shuffle!(random: Random)
     Primitive.rb_ary_shuffle_bang(random)
   end
 
   # call-seq:
-  #    array.shuffle(random: Random) -> new_ary
+  #   shuffle(random: Random) -> new_array
+  #
+  # Returns a new array containing all elements from +self+ in a random order,
+  # as selected by the object given by the keyword argument +random+:
+  #
+  #   a =            [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+  #   a.shuffle # => [0, 8, 1, 9, 6, 3, 4, 7, 2, 5]
+  #   a.shuffle # => [8, 9, 0, 5, 1, 2, 6, 4, 7, 3]
   #
-  # Returns a new array with elements of +self+ shuffled.
-  #    a = [1, 2, 3] #=> [1, 2, 3]
-  #    a.shuffle     #=> [2, 3, 1]
-  #    a             #=> [1, 2, 3]
+  # Duplicate elements are included:
   #
-  # The optional +random+ argument will be used as the random number generator:
-  #    a.shuffle(random: Random.new(1))  #=> [1, 3, 2]
+  #   a =            [0, 1, 0, 1, 0, 1, 0, 1, 0, 1]
+  #   a.shuffle # => [1, 0, 1, 1, 0, 0, 1, 0, 0, 1]
+  #   a.shuffle # => [1, 1, 0, 0, 0, 1, 1, 0, 0, 1]
+  #
+  # The object given with the keyword argument +random+ is used as the random number generator.
+  #
+  # Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
   def shuffle(random: Random)
     Primitive.rb_ary_shuffle(random)
   end
 
   # call-seq:
-  #    array.sample(random: Random) -> object
-  #    array.sample(n, random: Random) -> new_ary
+  #   sample(random: Random) -> object
+  #   sample(count, random: Random) -> new_ary
   #
-  # Returns random elements from +self+.
+  # Returns random elements from +self+,
+  # as selected by the object given by the keyword argument +random+.
   #
-  # When no arguments are given, returns a random element from +self+:
-  #    a = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
-  #    a.sample # => 3
-  #    a.sample # => 8
-  # If +self+ is empty, returns +nil+.
+  # With no argument +count+ given, returns one random element from +self+:
+  #
+  #   a = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+  #   a.sample # => 3
+  #   a.sample # => 8
+  #
+  # Returns +nil+ if +self+ is empty:
+  #
+  #   [].sample # => nil
+  #
+  # With a non-negative numeric argument +count+ given,
+  # returns a new array containing +count+ random elements from +self+:
+  #
+  #   a.sample(3) # => [8, 9, 2]
+  #   a.sample(6) # => [9, 6, 0, 3, 1, 4]
+  #
+  # The order of the result array is unrelated to the order of +self+.
+  #
+  # Returns a new empty +Array+ if +self+ is empty:
+  #
+  #   [].sample(4) # => []
+  #
+  # May return duplicates in +self+:
+  #
+  #   a = [1, 1, 1, 2, 2, 3]
+  #   a.sample(a.size) # => [1, 1, 3, 2, 1, 2]
   #
-  # When argument +n+ is given, returns a new \Array containing +n+ random
-  # elements from +self+:
-  #    a.sample(3) # => [8, 9, 2]
-  #    a.sample(6) # => [9, 6, 10, 3, 1, 4]
   # Returns no more than <tt>a.size</tt> elements
   # (because no new duplicates are introduced):
-  #    a.sample(a.size * 2) # => [6, 4, 1, 8, 5, 9, 10, 2, 3, 7]
-  # But +self+ may contain duplicates:
-  #    a = [1, 1, 1, 2, 2, 3]
-  #    a.sample(a.size * 2) # => [1, 1, 3, 2, 1, 2]
-  # The argument +n+ must be a non-negative numeric value.
-  # The order of the result array is unrelated to the order of +self+.
-  # Returns a new empty \Array if +self+ is empty.
   #
-  # The optional +random+ argument will be used as the random number generator:
-  #    a = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
-  #    a.sample(random: Random.new(1))     #=> 6
-  #    a.sample(4, random: Random.new(1))  #=> [6, 10, 9, 2]
+  #   a.sample(50) # => [6, 4, 1, 8, 5, 9, 0, 2, 3, 7]
+  #
+  # The object given with the keyword argument +random+ is used as the random number generator:
+  #
+  #   a = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+  #   a.sample(random: Random.new(1))     # => 6
+  #   a.sample(4, random: Random.new(1))  # => [6, 10, 9, 2]
+  #
+  # Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
   def sample(n = (ary = false), random: Random)
     if Primitive.mandatory_only?
       # Primitive.cexpr! %{ rb_ary_sample(self, rb_cRandom, Qfalse, Qfalse) }
@@ -66,4 +101,184 @@ class Array
       Primitive.ary_sample(random, n, ary)
     end
   end
+
+  # call-seq:
+  #   first -> object or nil
+  #   first(count) -> new_array
+  #
+  # Returns elements from +self+, or +nil+; does not modify +self+.
+  #
+  # With no argument given, returns the first element (if available):
+  #
+  #   a = [:foo, 'bar', 2]
+  #   a.first # => :foo
+  #   a # => [:foo, "bar", 2]
+  #
+  # If +self+ is empty, returns +nil+.
+  #
+  #   [].first # => nil
+  #
+  # With a non-negative integer argument +count+ given,
+  # returns the first +count+ elements (as available) in a new array:
+  #
+  #   a.first(0)  # => []
+  #   a.first(2)  # => [:foo, "bar"]
+  #   a.first(50) # => [:foo, "bar", 2]
+  #
+  # Related: see {Methods for Querying}[rdoc-ref:Array@Methods+for+Querying].
+  def first n = unspecified = true
+    if Primitive.mandatory_only?
+      Primitive.attr! :leaf
+      Primitive.cexpr! %q{ ary_first(self) }
+    else
+      if unspecified
+        Primitive.cexpr! %q{ ary_first(self) }
+      else
+        Primitive.cexpr! %q{  ary_take_first_or_last_n(self, NUM2LONG(n), ARY_TAKE_FIRST) }
+      end
+    end
+  end
+
+  # call-seq:
+  #  last  -> last_object or nil
+  #  last(count) -> new_array
+  #
+  # Returns elements from +self+, or +nil+; +self+ is not modified.
+  #
+  # With no argument given, returns the last element, or +nil+ if +self+ is empty:
+  #
+  #   a = [:foo, 'bar', 2]
+  #   a.last # => 2
+  #   a # => [:foo, "bar", 2]
+  #   [].last # => nil
+  #
+  #
+  # With non-negative integer argument +count+ given,
+  # returns a new array containing the trailing +count+ elements of +self+, as available:
+  #
+  #   a = [:foo, 'bar', 2]
+  #   a.last(2)  # => ["bar", 2]
+  #   a.last(50) # => [:foo, "bar", 2]
+  #   a.last(0)  # => []
+  #   [].last(3) # => []
+  #
+  # Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
+  def last n = unspecified = true
+    if Primitive.mandatory_only?
+      Primitive.attr! :leaf
+      Primitive.cexpr! %q{ ary_last(self) }
+    else
+      if unspecified
+        Primitive.cexpr! %q{ ary_last(self) }
+      else
+        Primitive.cexpr! %q{ ary_take_first_or_last_n(self, NUM2LONG(n), ARY_TAKE_LAST) }
+      end
+    end
+  end
+
+  # call-seq:
+  #   fetch_values(*indexes) -> new_array
+  #   fetch_values(*indexes) { |index| ... } -> new_array
+  #
+  # With no block given, returns a new array containing the elements of +self+
+  # at the offsets specified by +indexes+. Each of the +indexes+ must be an
+  # {integer-convertible object}[rdoc-ref:implicit_conversion.rdoc@Integer-Convertible+Objects]:
+  #
+  #    a = [:foo, :bar, :baz]
+  #    a.fetch_values(2, 0)   # => [:baz, :foo]
+  #    a.fetch_values(2.1, 0) # => [:baz, :foo]
+  #    a.fetch_values         # => []
+  #
+  # For a negative index, counts backwards from the end of the array:
+  #
+  #    a.fetch_values(-2, -1) # [:bar, :baz]
+  #
+  # When no block is given, raises an exception if any index is out of range.
+  #
+  # With a block given, for each index:
+  #
+  # - If the index is in range, uses an element of +self+ (as above).
+  # - Otherwise, calls the block with the index and uses the block's return value.
+  #
+  # Example:
+  #
+  #   a = [:foo, :bar, :baz]
+  #   a.fetch_values(1, 0, 42, 777) { |index| index.to_s }
+  #   # => [:bar, :foo, "42", "777"]
+  #
+  # Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
+  def fetch_values(*indexes, &block)
+    indexes.map! { |i| fetch(i, &block) }
+    indexes
+  end
+
+  with_yjit do
+    if Primitive.rb_builtin_basic_definition_p(:each)
+      undef :each
+
+      def each # :nodoc:
+        Primitive.attr! :inline_block, :c_trace
+
+        unless defined?(yield)
+          return Primitive.cexpr! 'SIZED_ENUMERATOR(self, 0, 0, ary_enum_length)'
+        end
+        _i = 0
+        value = nil
+        while Primitive.cexpr!(%q{ ary_fetch_next(self, LOCAL_PTR(_i), LOCAL_PTR(value)) })
+          yield value
+        end
+        self
+      end
+    end
+
+    if Primitive.rb_builtin_basic_definition_p(:map)
+      undef :map
+
+      def map # :nodoc:
+        Primitive.attr! :inline_block, :c_trace
+
+        unless defined?(yield)
+          return Primitive.cexpr! 'SIZED_ENUMERATOR(self, 0, 0, ary_enum_length)'
+        end
+
+        _i = 0
+        value = nil
+        result = Primitive.ary_sized_alloc
+        while Primitive.cexpr!(%q{ ary_fetch_next(self, LOCAL_PTR(_i), LOCAL_PTR(value)) })
+          result << yield(value)
+        end
+        result
+      end
+
+      if Primitive.rb_builtin_basic_definition_p(:collect)
+        undef :collect
+        alias collect map
+      end
+    end
+
+    if Primitive.rb_builtin_basic_definition_p(:select)
+      undef :select
+
+      def select # :nodoc:
+        Primitive.attr! :inline_block, :c_trace
+
+        unless defined?(yield)
+          return Primitive.cexpr! 'SIZED_ENUMERATOR(self, 0, 0, ary_enum_length)'
+        end
+
+        _i = 0
+        value = nil
+        result = Primitive.ary_sized_alloc
+        while Primitive.cexpr!(%q{ ary_fetch_next(self, LOCAL_PTR(_i), LOCAL_PTR(value)) })
+          result << value if yield value
+        end
+        result
+      end
+
+      if Primitive.rb_builtin_basic_definition_p(:filter)
+        undef :filter
+        alias filter select
+      end
+    end
+  end
 end
diff --git a/ast.c b/ast.c
index 42d4126a5b..a0c1801de1 100644
--- a/ast.c
+++ b/ast.c
@@ -1,6 +1,6 @@
 /* indent-tabs-mode: nil */
 #include "internal.h"
-#include "internal/parse.h"
+#include "internal/ruby_parser.h"
 #include "internal/symbol.h"
 #include "internal/warnings.h"
 #include "iseq.h"
@@ -14,9 +14,10 @@
 
 static VALUE rb_mAST;
 static VALUE rb_cNode;
+static VALUE rb_cLocation;
 
 struct ASTNodeData {
-    rb_ast_t *ast;
+    VALUE ast_value;
     const NODE *node;
 };
 
@@ -24,14 +25,16 @@ static void
 node_gc_mark(void *ptr)
 {
     struct ASTNodeData *data = (struct ASTNodeData *)ptr;
-    rb_gc_mark((VALUE)data->ast);
+    rb_gc_mark(data->ast_value);
 }
 
 static size_t
 node_memsize(const void *ptr)
 {
     struct ASTNodeData *data = (struct ASTNodeData *)ptr;
-    return rb_ast_memsize(data->ast);
+    rb_ast_t *ast = rb_ruby_ast_data_get(data->ast_value);
+
+    return sizeof(struct ASTNodeData) + rb_ast_memsize(ast);
 }
 
 static const rb_data_type_t rb_node_type = {
@@ -41,31 +44,57 @@ static const rb_data_type_t rb_node_type = {
     RUBY_TYPED_FREE_IMMEDIATELY,
 };
 
+struct ASTLocationData {
+    int first_lineno;
+    int first_column;
+    int last_lineno;
+    int last_column;
+};
+
+static void
+location_gc_mark(void *ptr)
+{
+}
+
+static size_t
+location_memsize(const void *ptr)
+{
+    return sizeof(struct ASTLocationData);
+}
+
+static const rb_data_type_t rb_location_type = {
+    "AST/location",
+    {location_gc_mark, RUBY_TYPED_DEFAULT_FREE, location_memsize,},
+    0, 0,
+    RUBY_TYPED_FREE_IMMEDIATELY,
+};
+
+
 static VALUE rb_ast_node_alloc(VALUE klass);
 
 static void
-setup_node(VALUE obj, rb_ast_t *ast, const NODE *node)
+setup_node(VALUE obj, VALUE ast_value, const NODE *node)
 {
     struct ASTNodeData *data;
 
     TypedData_Get_Struct(obj, struct ASTNodeData, &rb_node_type, data);
-    data->ast = ast;
+    data->ast_value = ast_value;
     data->node = node;
 }
 
 static VALUE
-ast_new_internal(rb_ast_t *ast, const NODE *node)
+ast_new_internal(VALUE ast_value, const NODE *node)
 {
     VALUE obj;
 
     obj = rb_ast_node_alloc(rb_cNode);
-    setup_node(obj, ast, node);
+    setup_node(obj, ast_value, node);
 
     return obj;
 }
 
-static VALUE rb_ast_parse_str(VALUE str, VALUE keep_script_lines);
-static VALUE rb_ast_parse_file(VALUE path, VALUE keep_script_lines);
+static VALUE rb_ast_parse_str(VALUE str, VALUE keep_script_lines, VALUE error_tolerant, VALUE keep_tokens);
+static VALUE rb_ast_parse_file(VALUE path, VALUE keep_script_lines, VALUE error_tolerant, VALUE keep_tokens);
 
 static VALUE
 ast_parse_new(void)
@@ -74,83 +103,77 @@ ast_parse_new(void)
 }
 
 static VALUE
-ast_parse_done(rb_ast_t *ast)
+ast_parse_done(VALUE ast_value)
 {
+    rb_ast_t *ast = rb_ruby_ast_data_get(ast_value);
+
     if (!ast->body.root) {
         rb_ast_dispose(ast);
         rb_exc_raise(GET_EC()->errinfo);
     }
 
-    return ast_new_internal(ast, (NODE *)ast->body.root);
+    return ast_new_internal(ast_value, (NODE *)ast->body.root);
 }
 
 static VALUE
-ast_s_parse(rb_execution_context_t *ec, VALUE module, VALUE str, VALUE keep_script_lines)
+ast_s_parse(rb_execution_context_t *ec, VALUE module, VALUE str, VALUE keep_script_lines, VALUE error_tolerant, VALUE keep_tokens)
 {
-    return rb_ast_parse_str(str, keep_script_lines);
+    return rb_ast_parse_str(str, keep_script_lines, error_tolerant, keep_tokens);
 }
 
 static VALUE
-rb_ast_parse_str(VALUE str, VALUE keep_script_lines)
+rb_ast_parse_str(VALUE str, VALUE keep_script_lines, VALUE error_tolerant, VALUE keep_tokens)
 {
-    rb_ast_t *ast = 0;
+    VALUE ast_value;
 
     StringValue(str);
     VALUE vparser = ast_parse_new();
-    if (RTEST(keep_script_lines)) rb_parser_keep_script_lines(vparser);
-    ast = rb_parser_compile_string_path(vparser, Qnil, str, 1);
-    return ast_parse_done(ast);
+    if (RTEST(keep_script_lines)) rb_parser_set_script_lines(vparser);
+    if (RTEST(error_tolerant)) rb_parser_error_tolerant(vparser);
+    if (RTEST(keep_tokens)) rb_parser_keep_tokens(vparser);
+    ast_value = rb_parser_compile_string_path(vparser, Qnil, str, 1);
+    return ast_parse_done(ast_value);
 }
 
 static VALUE
-ast_s_parse_file(rb_execution_context_t *ec, VALUE module, VALUE path, VALUE keep_script_lines)
+ast_s_parse_file(rb_execution_context_t *ec, VALUE module, VALUE path, VALUE keep_script_lines, VALUE error_tolerant, VALUE keep_tokens)
 {
-    return rb_ast_parse_file(path, keep_script_lines);
+    return rb_ast_parse_file(path, keep_script_lines, error_tolerant, keep_tokens);
 }
 
 static VALUE
-rb_ast_parse_file(VALUE path, VALUE keep_script_lines)
+rb_ast_parse_file(VALUE path, VALUE keep_script_lines, VALUE error_tolerant, VALUE keep_tokens)
 {
     VALUE f;
-    rb_ast_t *ast = 0;
+    VALUE ast_value = Qnil;
     rb_encoding *enc = rb_utf8_encoding();
 
-    FilePathValue(path);
     f = rb_file_open_str(path, "r");
     rb_funcall(f, rb_intern("set_encoding"), 2, rb_enc_from_encoding(enc), rb_str_new_cstr("-"));
     VALUE vparser = ast_parse_new();
-    if (RTEST(keep_script_lines)) rb_parser_keep_script_lines(vparser);
-    ast = rb_parser_compile_file_path(vparser, Qnil, f, 1);
+    if (RTEST(keep_script_lines)) rb_parser_set_script_lines(vparser);
+    if (RTEST(error_tolerant))  rb_parser_error_tolerant(vparser);
+    if (RTEST(keep_tokens))  rb_parser_keep_tokens(vparser);
+    ast_value = rb_parser_compile_file_path(vparser, Qnil, f, 1);
     rb_io_close(f);
-    return ast_parse_done(ast);
-}
-
-static VALUE
-lex_array(VALUE array, int index)
-{
-    VALUE str = rb_ary_entry(array, index);
-    if (!NIL_P(str)) {
-        StringValue(str);
-        if (!rb_enc_asciicompat(rb_enc_get(str))) {
-            rb_raise(rb_eArgError, "invalid source encoding");
-        }
-    }
-    return str;
+    return ast_parse_done(ast_value);
 }
 
 static VALUE
-rb_ast_parse_array(VALUE array, VALUE keep_script_lines)
+rb_ast_parse_array(VALUE array, VALUE keep_script_lines, VALUE error_tolerant, VALUE keep_tokens)
 {
-    rb_ast_t *ast = 0;
+    VALUE ast_value = Qnil;
 
     array = rb_check_array_type(array);
     VALUE vparser = ast_parse_new();
-    if (RTEST(keep_script_lines)) rb_parser_keep_script_lines(vparser);
-    ast = rb_parser_compile_generic(vparser, lex_array, Qnil, array, 1);
-    return ast_parse_done(ast);
+    if (RTEST(keep_script_lines)) rb_parser_set_script_lines(vparser);
+    if (RTEST(error_tolerant)) rb_parser_error_tolerant(vparser);
+    if (RTEST(keep_tokens)) rb_parser_keep_tokens(vparser);
+    ast_value = rb_parser_compile_array(vparser, Qnil, array, 1);
+    return ast_parse_done(ast_value);
 }
 
-static VALUE node_children(rb_ast_t*, const NODE*);
+static VALUE node_children(VALUE, const NODE*);
 
 static VALUE
 node_find(VALUE self, const int node_id)
@@ -162,7 +185,7 @@ node_find(VALUE self, const int node_id)
 
     if (nd_node_id(data->node) == node_id) return self;
 
-    ary = node_children(data->ast, data->node);
+    ary = node_children(data->ast_value, data->node);
 
     for (i = 0; i < RARRAY_LEN(ary); i++) {
         VALUE child = RARRAY_AREF(ary, i);
@@ -179,21 +202,24 @@ node_find(VALUE self, const int node_id)
 extern VALUE rb_e_script;
 
 static VALUE
-script_lines(VALUE path)
+node_id_for_backtrace_location(rb_execution_context_t *ec, VALUE module, VALUE location)
 {
-    VALUE hash, lines;
-    ID script_lines;
-    CONST_ID(script_lines, "SCRIPT_LINES__");
-    if (!rb_const_defined_at(rb_cObject, script_lines)) return Qnil;
-    hash = rb_const_get_at(rb_cObject, script_lines);
-    if (!RB_TYPE_P(hash, T_HASH)) return Qnil;
-    lines = rb_hash_lookup(hash, path);
-    if (!RB_TYPE_P(lines, T_ARRAY)) return Qnil;
-    return lines;
+    int node_id;
+
+    if (!rb_frame_info_p(location)) {
+        rb_raise(rb_eTypeError, "Thread::Backtrace::Location object expected");
+    }
+
+    node_id = rb_get_node_id_from_frame_info(location);
+    if (node_id == -1) {
+        return Qnil;
+    }
+
+    return INT2NUM(node_id);
 }
 
 static VALUE
-ast_s_of(rb_execution_context_t *ec, VALUE module, VALUE body, VALUE keep_script_lines)
+ast_s_of(rb_execution_context_t *ec, VALUE module, VALUE body, VALUE keep_script_lines, VALUE error_tolerant, VALUE keep_tokens)
 {
     VALUE node, lines = Qnil;
     const rb_iseq_t *iseq;
@@ -222,6 +248,11 @@ ast_s_of(rb_execution_context_t *ec, VALUE module, VALUE body, VALUE keep_script
     if (!iseq) {
         return Qnil;
     }
+
+    if (ISEQ_BODY(iseq)->prism) {
+        rb_raise(rb_eRuntimeError, "cannot get AST for ISEQ compiled by prism");
+    }
+
     lines = ISEQ_BODY(iseq)->variable.script_lines;
 
     VALUE path = rb_iseq_path(iseq);
@@ -231,14 +262,14 @@ ast_s_of(rb_execution_context_t *ec, VALUE module, VALUE body, VALUE keep_script
         rb_raise(rb_eArgError, "cannot get AST for method defined in eval");
     }
 
-    if (!NIL_P(lines) || !NIL_P(lines = script_lines(path))) {
-        node = rb_ast_parse_array(lines, keep_script_lines);
+    if (!NIL_P(lines)) {
+        node = rb_ast_parse_array(lines, keep_script_lines, error_tolerant, keep_tokens);
     }
     else if (e_option) {
-        node = rb_ast_parse_str(rb_e_script, keep_script_lines);
+        node = rb_ast_parse_str(rb_e_script, keep_script_lines, error_tolerant, keep_tokens);
     }
     else {
-        node = rb_ast_parse_file(path, keep_script_lines);
+        node = rb_ast_parse_file(path, keep_script_lines, error_tolerant, keep_tokens);
     }
 
     return node_find(node, node_id);
@@ -277,10 +308,10 @@ ast_node_node_id(rb_execution_context_t *ec, VALUE self)
     return INT2FIX(nd_node_id(data->node));
 }
 
-#define NEW_CHILD(ast, node) node ? ast_new_internal(ast, node) : Qnil
+#define NEW_CHILD(ast_value, node) (node ? ast_new_internal(ast_value, node) : Qnil)
 
 static VALUE
-rb_ary_new_from_node_args(rb_ast_t *ast, long n, ...)
+rb_ary_new_from_node_args(VALUE ast_value, long n, ...)
 {
     va_list ar;
     VALUE ary;
@@ -292,39 +323,57 @@ rb_ary_new_from_node_args(rb_ast_t *ast, long n, ...)
     for (i=0; i<n; i++) {
         NODE *node;
         node = va_arg(ar, NODE *);
-        rb_ary_push(ary, NEW_CHILD(ast, node));
+        rb_ary_push(ary, NEW_CHILD(ast_value, node));
     }
     va_end(ar);
     return ary;
 }
 
 static VALUE
-dump_block(rb_ast_t *ast, const NODE *node)
+dump_block(VALUE ast_value, const struct RNode_BLOCK *node)
 {
     VALUE ary = rb_ary_new();
     do {
-        rb_ary_push(ary, NEW_CHILD(ast, node->nd_head));
+        rb_ary_push(ary, NEW_CHILD(ast_value, node->nd_head));
     } while (node->nd_next &&
         nd_type_p(node->nd_next, NODE_BLOCK) &&
-        (node = node->nd_next, 1));
+        (node = RNODE_BLOCK(node->nd_next), 1));
     if (node->nd_next) {
-        rb_ary_push(ary, NEW_CHILD(ast, node->nd_next));
+        rb_ary_push(ary, NEW_CHILD(ast_value, node->nd_next));
     }
 
     return ary;
 }
 
 static VALUE
-dump_array(rb_ast_t *ast, const NODE *node)
+dump_array(VALUE ast_value, const struct RNode_LIST *node)
 {
     VALUE ary = rb_ary_new();
-    rb_ary_push(ary, NEW_CHILD(ast, node->nd_head));
+    rb_ary_push(ary, NEW_CHILD(ast_value, node->nd_head));
 
     while (node->nd_next && nd_type_p(node->nd_next, NODE_LIST)) {
-        node = node->nd_next;
-        rb_ary_push(ary, NEW_CHILD(ast, node->nd_head));
+        node = RNODE_LIST(node->nd_next);
+        rb_ary_push(ary, NEW_CHILD(ast_value, node->nd_head));
+    }
+    rb_ary_push(ary, NEW_CHILD(ast_value, node->nd_next));
+
+    return ary;
+}
+
+static VALUE
+dump_parser_array(VALUE ast_value, rb_parser_ary_t *p_ary)
+{
+    VALUE ary;
+
+    if (p_ary->data_type != PARSER_ARY_DATA_NODE) {
+        rb_bug("unexpected rb_parser_ary_data_type: %d", p_ary->data_type);
+    }
+
+    ary = rb_ary_new();
+
+    for (long i = 0; i < p_ary->len; i++) {
+        rb_ary_push(ary, NEW_CHILD(ast_value, p_ary->data[i]));
     }
-    rb_ary_push(ary, NEW_CHILD(ast, node->nd_next));
 
     return ary;
 }
@@ -346,305 +395,341 @@ no_name_rest(void)
 }
 
 static VALUE
-rest_arg(rb_ast_t *ast, const NODE *rest_arg)
+rest_arg(VALUE ast_value, const NODE *rest_arg)
 {
-    return NODE_NAMED_REST_P(rest_arg) ? NEW_CHILD(ast, rest_arg) : no_name_rest();
+    return NODE_NAMED_REST_P(rest_arg) ? NEW_CHILD(ast_value, rest_arg) : no_name_rest();
 }
 
 static VALUE
-node_children(rb_ast_t *ast, const NODE *node)
+node_children(VALUE ast_value, const NODE *node)
 {
-    char name[DECIMAL_SIZE_OF_BITS(sizeof(long) * CHAR_BIT) + 2]; /* including '$' */
+    char name[sizeof("$") + DECIMAL_SIZE_OF(long)];
 
     enum node_type type = nd_type(node);
     switch (type) {
       case NODE_BLOCK:
-        return dump_block(ast, node);
+        return dump_block(ast_value, RNODE_BLOCK(node));
       case NODE_IF:
-        return rb_ary_new_from_node_args(ast, 3, node->nd_cond, node->nd_body, node->nd_else);
+        return rb_ary_new_from_node_args(ast_value, 3, RNODE_IF(node)->nd_cond, RNODE_IF(node)->nd_body, RNODE_IF(node)->nd_else);
       case NODE_UNLESS:
-        return rb_ary_new_from_node_args(ast, 3, node->nd_cond, node->nd_body, node->nd_else);
+        return rb_ary_new_from_node_args(ast_value, 3, RNODE_UNLESS(node)->nd_cond, RNODE_UNLESS(node)->nd_body, RNODE_UNLESS(node)->nd_else);
       case NODE_CASE:
-        return rb_ary_new_from_node_args(ast, 2, node->nd_head, node->nd_body);
+        return rb_ary_new_from_node_args(ast_value, 2, RNODE_CASE(node)->nd_head, RNODE_CASE(node)->nd_body);
       case NODE_CASE2:
-        return rb_ary_new_from_node_args(ast, 2, node->nd_head, node->nd_body);
+        return rb_ary_new_from_node_args(ast_value, 2, RNODE_CASE2(node)->nd_head, RNODE_CASE2(node)->nd_body);
       case NODE_CASE3:
-        return rb_ary_new_from_node_args(ast, 2, node->nd_head, node->nd_body);
+        return rb_ary_new_from_node_args(ast_value, 2, RNODE_CASE3(node)->nd_head, RNODE_CASE3(node)->nd_body);
       case NODE_WHEN:
-        return rb_ary_new_from_node_args(ast, 3, node->nd_head, node->nd_body, node->nd_next);
+        return rb_ary_new_from_node_args(ast_value, 3, RNODE_WHEN(node)->nd_head, RNODE_WHEN(node)->nd_body, RNODE_WHEN(node)->nd_next);
       case NODE_IN:
-        return rb_ary_new_from_node_args(ast, 3, node->nd_head, node->nd_body, node->nd_next);
+        return rb_ary_new_from_node_args(ast_value, 3, RNODE_IN(node)->nd_head, RNODE_IN(node)->nd_body, RNODE_IN(node)->nd_next);
       case NODE_WHILE:
       case NODE_UNTIL:
-        return rb_ary_push(rb_ary_new_from_node_args(ast, 2, node->nd_cond, node->nd_body),
-                           RBOOL(node->nd_state));
+        return rb_ary_push(rb_ary_new_from_node_args(ast_value, 2, RNODE_WHILE(node)->nd_cond, RNODE_WHILE(node)->nd_body),
+                           RBOOL(RNODE_WHILE(node)->nd_state));
       case NODE_ITER:
       case NODE_FOR:
-        return rb_ary_new_from_node_args(ast, 2, node->nd_iter, node->nd_body);
+        return rb_ary_new_from_node_args(ast_value, 2, RNODE_ITER(node)->nd_iter, RNODE_ITER(node)->nd_body);
       case NODE_FOR_MASGN:
-        return rb_ary_new_from_node_args(ast, 1, node->nd_var);
+        return rb_ary_new_from_node_args(ast_value, 1, RNODE_FOR_MASGN(node)->nd_var);
       case NODE_BREAK:
+        return rb_ary_new_from_node_args(ast_value, 1, RNODE_BREAK(node)->nd_stts);
       case NODE_NEXT:
+        return rb_ary_new_from_node_args(ast_value, 1, RNODE_NEXT(node)->nd_stts);
       case NODE_RETURN:
-        return rb_ary_new_from_node_args(ast, 1, node->nd_stts);
+        return rb_ary_new_from_node_args(ast_value, 1, RNODE_RETURN(node)->nd_stts);
       case NODE_REDO:
-        return rb_ary_new_from_node_args(ast, 0);
+        return rb_ary_new_from_node_args(ast_value, 0);
       case NODE_RETRY:
-        return rb_ary_new_from_node_args(ast, 0);
+        return rb_ary_new_from_node_args(ast_value, 0);
       case NODE_BEGIN:
-        return rb_ary_new_from_node_args(ast, 1, node->nd_body);
+        return rb_ary_new_from_node_args(ast_value, 1, RNODE_BEGIN(node)->nd_body);
       case NODE_RESCUE:
-        return rb_ary_new_from_node_args(ast, 3, node->nd_head, node->nd_resq, node->nd_else);
+        return rb_ary_new_from_node_args(ast_value, 3, RNODE_RESCUE(node)->nd_head, RNODE_RESCUE(node)->nd_resq, RNODE_RESCUE(node)->nd_else);
       case NODE_RESBODY:
-        return rb_ary_new_from_node_args(ast, 3, node->nd_args, node->nd_body, node->nd_head);
+        return rb_ary_new_from_node_args(ast_value, 4, RNODE_RESBODY(node)->nd_args, RNODE_RESBODY(node)->nd_exc_var, RNODE_RESBODY(node)->nd_body, RNODE_RESBODY(node)->nd_next);
       case NODE_ENSURE:
-        return rb_ary_new_from_node_args(ast, 2, node->nd_head, node->nd_ensr);
+        return rb_ary_new_from_node_args(ast_value, 2, RNODE_ENSURE(node)->nd_head, RNODE_ENSURE(node)->nd_ensr);
       case NODE_AND:
       case NODE_OR:
         {
             VALUE ary = rb_ary_new();
 
             while (1) {
-                rb_ary_push(ary, NEW_CHILD(ast, node->nd_1st));
-                if (!node->nd_2nd || !nd_type_p(node->nd_2nd, type))
+                rb_ary_push(ary, NEW_CHILD(ast_value, RNODE_AND(node)->nd_1st));
+                if (!RNODE_AND(node)->nd_2nd || !nd_type_p(RNODE_AND(node)->nd_2nd, type))
                     break;
-                node = node->nd_2nd;
+                node = RNODE_AND(node)->nd_2nd;
             }
-            rb_ary_push(ary, NEW_CHILD(ast, node->nd_2nd));
+            rb_ary_push(ary, NEW_CHILD(ast_value, RNODE_AND(node)->nd_2nd));
             return ary;
         }
       case NODE_MASGN:
-        if (NODE_NAMED_REST_P(node->nd_args)) {
-            return rb_ary_new_from_node_args(ast, 3, node->nd_value, node->nd_head, node->nd_args);
+        if (NODE_NAMED_REST_P(RNODE_MASGN(node)->nd_args)) {
+            return rb_ary_new_from_node_args(ast_value, 3, RNODE_MASGN(node)->nd_value, RNODE_MASGN(node)->nd_head, RNODE_MASGN(node)->nd_args);
         }
         else {
-            return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_value),
-                                        NEW_CHILD(ast, node->nd_head),
+            return rb_ary_new_from_args(3, NEW_CHILD(ast_value, RNODE_MASGN(node)->nd_value),
+                                        NEW_CHILD(ast_value, RNODE_MASGN(node)->nd_head),
                                         no_name_rest());
         }
       case NODE_LASGN:
+        if (NODE_REQUIRED_KEYWORD_P(RNODE_LASGN(node)->nd_value)) {
+            return rb_ary_new_from_args(2, var_name(RNODE_LASGN(node)->nd_vid), ID2SYM(rb_intern("NODE_SPECIAL_REQUIRED_KEYWORD")));
+        }
+        return rb_ary_new_from_args(2, var_name(RNODE_LASGN(node)->nd_vid), NEW_CHILD(ast_value, RNODE_LASGN(node)->nd_value));
       case NODE_DASGN:
+        if (NODE_REQUIRED_KEYWORD_P(RNODE_DASGN(node)->nd_value)) {
+            return rb_ary_new_from_args(2, var_name(RNODE_DASGN(node)->nd_vid), ID2SYM(rb_intern("NODE_SPECIAL_REQUIRED_KEYWORD")));
+        }
+        return rb_ary_new_from_args(2, var_name(RNODE_DASGN(node)->nd_vid), NEW_CHILD(ast_value, RNODE_DASGN(node)->nd_value));
       case NODE_IASGN:
+        return rb_ary_new_from_args(2, var_name(RNODE_IASGN(node)->nd_vid), NEW_CHILD(ast_value, RNODE_IASGN(node)->nd_value));
       case NODE_CVASGN:
+        return rb_ary_new_from_args(2, var_name(RNODE_CVASGN(node)->nd_vid), NEW_CHILD(ast_value, RNODE_CVASGN(node)->nd_value));
       case NODE_GASGN:
-        if (NODE_REQUIRED_KEYWORD_P(node)) {
-            return rb_ary_new_from_args(2, var_name(node->nd_vid), ID2SYM(rb_intern("NODE_SPECIAL_REQUIRED_KEYWORD")));
-        }
-        return rb_ary_new_from_args(2, var_name(node->nd_vid), NEW_CHILD(ast, node->nd_value));
+        return rb_ary_new_from_args(2, var_name(RNODE_GASGN(node)->nd_vid), NEW_CHILD(ast_value, RNODE_GASGN(node)->nd_value));
       case NODE_CDECL:
-        if (node->nd_vid) {
-            return rb_ary_new_from_args(2, ID2SYM(node->nd_vid), NEW_CHILD(ast, node->nd_value));
+        if (RNODE_CDECL(node)->nd_vid) {
+            return rb_ary_new_from_args(2, ID2SYM(RNODE_CDECL(node)->nd_vid), NEW_CHILD(ast_value, RNODE_CDECL(node)->nd_value));
         }
-        return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_else), ID2SYM(node->nd_else->nd_mid), NEW_CHILD(ast, node->nd_value));
+        return rb_ary_new_from_args(3, NEW_CHILD(ast_value, RNODE_CDECL(node)->nd_else), ID2SYM(RNODE_COLON2(RNODE_CDECL(node)->nd_else)->nd_mid), NEW_CHILD(ast_value, RNODE_CDECL(node)->nd_value));
       case NODE_OP_ASGN1:
-        return rb_ary_new_from_args(4, NEW_CHILD(ast, node->nd_recv),
-                                    ID2SYM(node->nd_mid),
-                                    NEW_CHILD(ast, node->nd_args->nd_head),
-                                    NEW_CHILD(ast, node->nd_args->nd_body));
+        return rb_ary_new_from_args(4, NEW_CHILD(ast_value, RNODE_OP_ASGN1(node)->nd_recv),
+                                    ID2SYM(RNODE_OP_ASGN1(node)->nd_mid),
+                                    NEW_CHILD(ast_value, RNODE_OP_ASGN1(node)->nd_index),
+                                    NEW_CHILD(ast_value, RNODE_OP_ASGN1(node)->nd_rvalue));
       case NODE_OP_ASGN2:
-        return rb_ary_new_from_args(5, NEW_CHILD(ast, node->nd_recv),
-                                    RBOOL(node->nd_next->nd_aid),
-                                    ID2SYM(node->nd_next->nd_vid),
-                                    ID2SYM(node->nd_next->nd_mid),
-                                    NEW_CHILD(ast, node->nd_value));
+        return rb_ary_new_from_args(5, NEW_CHILD(ast_value, RNODE_OP_ASGN2(node)->nd_recv),
+                                    RBOOL(RNODE_OP_ASGN2(node)->nd_aid),
+                                    ID2SYM(RNODE_OP_ASGN2(node)->nd_vid),
+                                    ID2SYM(RNODE_OP_ASGN2(node)->nd_mid),
+                                    NEW_CHILD(ast_value, RNODE_OP_ASGN2(node)->nd_value));
       case NODE_OP_ASGN_AND:
-        return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_head), ID2SYM(idANDOP),
-                                    NEW_CHILD(ast, node->nd_value));
+        return rb_ary_new_from_args(3, NEW_CHILD(ast_value, RNODE_OP_ASGN_AND(node)->nd_head), ID2SYM(idANDOP),
+                                    NEW_CHILD(ast_value, RNODE_OP_ASGN_AND(node)->nd_value));
       case NODE_OP_ASGN_OR:
-        return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_head), ID2SYM(idOROP),
-                                    NEW_CHILD(ast, node->nd_value));
+        return rb_ary_new_from_args(3, NEW_CHILD(ast_value, RNODE_OP_ASGN_OR(node)->nd_head), ID2SYM(idOROP),
+                                    NEW_CHILD(ast_value, RNODE_OP_ASGN_OR(node)->nd_value));
       case NODE_OP_CDECL:
-        return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_head),
-                                    ID2SYM(node->nd_aid),
-                                    NEW_CHILD(ast, node->nd_value));
+        return rb_ary_new_from_args(3, NEW_CHILD(ast_value, RNODE_OP_CDECL(node)->nd_head),
+                                    ID2SYM(RNODE_OP_CDECL(node)->nd_aid),
+                                    NEW_CHILD(ast_value, RNODE_OP_CDECL(node)->nd_value));
       case NODE_CALL:
+        return rb_ary_new_from_args(3, NEW_CHILD(ast_value, RNODE_CALL(node)->nd_recv),
+                                    ID2SYM(RNODE_CALL(node)->nd_mid),
+                                    NEW_CHILD(ast_value, RNODE_CALL(node)->nd_args));
       case NODE_OPCALL:
+        return rb_ary_new_from_args(3, NEW_CHILD(ast_value, RNODE_OPCALL(node)->nd_recv),
+                                    ID2SYM(RNODE_OPCALL(node)->nd_mid),
+                                    NEW_CHILD(ast_value, RNODE_OPCALL(node)->nd_args));
       case NODE_QCALL:
-        return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_recv),
-                                    ID2SYM(node->nd_mid),
-                                    NEW_CHILD(ast, node->nd_args));
+        return rb_ary_new_from_args(3, NEW_CHILD(ast_value, RNODE_QCALL(node)->nd_recv),
+                                    ID2SYM(RNODE_QCALL(node)->nd_mid),
+                                    NEW_CHILD(ast_value, RNODE_QCALL(node)->nd_args));
       case NODE_FCALL:
-        return rb_ary_new_from_args(2, ID2SYM(node->nd_mid),
-                                    NEW_CHILD(ast, node->nd_args));
+        return rb_ary_new_from_args(2, ID2SYM(RNODE_FCALL(node)->nd_mid),
+                                    NEW_CHILD(ast_value, RNODE_FCALL(node)->nd_args));
       case NODE_VCALL:
-        return rb_ary_new_from_args(1, ID2SYM(node->nd_mid));
+        return rb_ary_new_from_args(1, ID2SYM(RNODE_VCALL(node)->nd_mid));
       case NODE_SUPER:
-        return rb_ary_new_from_node_args(ast, 1, node->nd_args);
+        return rb_ary_new_from_node_args(ast_value, 1, RNODE_SUPER(node)->nd_args);
       case NODE_ZSUPER:
-        return rb_ary_new_from_node_args(ast, 0);
+        return rb_ary_new_from_node_args(ast_value, 0);
       case NODE_LIST:
-      case NODE_VALUES:
-        return dump_array(ast, node);
+        return dump_array(ast_value, RNODE_LIST(node));
       case NODE_ZLIST:
-        return rb_ary_new_from_node_args(ast, 0);
+        return rb_ary_new_from_node_args(ast_value, 0);
       case NODE_HASH:
-        return rb_ary_new_from_node_args(ast, 1, node->nd_head);
+        return rb_ary_new_from_node_args(ast_value, 1, RNODE_HASH(node)->nd_head);
       case NODE_YIELD:
-        return rb_ary_new_from_node_args(ast, 1, node->nd_head);
+        return rb_ary_new_from_node_args(ast_value, 1, RNODE_YIELD(node)->nd_head);
       case NODE_LVAR:
+        return rb_ary_new_from_args(1, var_name(RNODE_LVAR(node)->nd_vid));
       case NODE_DVAR:
-        return rb_ary_new_from_args(1, var_name(node->nd_vid));
+        return rb_ary_new_from_args(1, var_name(RNODE_DVAR(node)->nd_vid));
       case NODE_IVAR:
+        return rb_ary_new_from_args(1, ID2SYM(RNODE_IVAR(node)->nd_vid));
       case NODE_CONST:
+        return rb_ary_new_from_args(1, ID2SYM(RNODE_CONST(node)->nd_vid));
       case NODE_CVAR:
+        return rb_ary_new_from_args(1, ID2SYM(RNODE_CVAR(node)->nd_vid));
       case NODE_GVAR:
-        return rb_ary_new_from_args(1, ID2SYM(node->nd_vid));
+        return rb_ary_new_from_args(1, ID2SYM(RNODE_GVAR(node)->nd_vid));
       case NODE_NTH_REF:
-        snprintf(name, sizeof(name), "$%ld", node->nd_nth);
+        snprintf(name, sizeof(name), "$%ld", RNODE_NTH_REF(node)->nd_nth);
         return rb_ary_new_from_args(1, ID2SYM(rb_intern(name)));
       case NODE_BACK_REF:
         name[0] = '$';
-        name[1] = (char)node->nd_nth;
+        name[1] = (char)RNODE_BACK_REF(node)->nd_nth;
         name[2] = '\0';
         return rb_ary_new_from_args(1, ID2SYM(rb_intern(name)));
+      case NODE_MATCH:
+        return rb_ary_new_from_args(1, rb_node_regx_string_val(node));
       case NODE_MATCH2:
-        if (node->nd_args) {
-            return rb_ary_new_from_node_args(ast, 3, node->nd_recv, node->nd_value, node->nd_args);
+        if (RNODE_MATCH2(node)->nd_args) {
+            return rb_ary_new_from_node_args(ast_value, 3, RNODE_MATCH2(node)->nd_recv, RNODE_MATCH2(node)->nd_value, RNODE_MATCH2(node)->nd_args);
         }
-        return rb_ary_new_from_node_args(ast, 2, node->nd_recv, node->nd_value);
+        return rb_ary_new_from_node_args(ast_value, 2, RNODE_MATCH2(node)->nd_recv, RNODE_MATCH2(node)->nd_value);
       case NODE_MATCH3:
-        return rb_ary_new_from_node_args(ast, 2, node->nd_recv, node->nd_value);
-      case NODE_MATCH:
-      case NODE_LIT:
+        return rb_ary_new_from_node_args(ast_value, 2, RNODE_MATCH3(node)->nd_recv, RNODE_MATCH3(node)->nd_value);
       case NODE_STR:
       case NODE_XSTR:
-        return rb_ary_new_from_args(1, node->nd_lit);
+        return rb_ary_new_from_args(1, rb_node_str_string_val(node));
+      case NODE_INTEGER:
+        return rb_ary_new_from_args(1, rb_node_integer_literal_val(node));
+      case NODE_FLOAT:
+        return rb_ary_new_from_args(1, rb_node_float_literal_val(node));
+      case NODE_RATIONAL:
+        return rb_ary_new_from_args(1, rb_node_rational_literal_val(node));
+      case NODE_IMAGINARY:
+        return rb_ary_new_from_args(1, rb_node_imaginary_literal_val(node));
+      case NODE_REGX:
+        return rb_ary_new_from_args(1, rb_node_regx_string_val(node));
       case NODE_ONCE:
-        return rb_ary_new_from_node_args(ast, 1, node->nd_body);
+        return rb_ary_new_from_node_args(ast_value, 1, RNODE_ONCE(node)->nd_body);
       case NODE_DSTR:
       case NODE_DXSTR:
       case NODE_DREGX:
       case NODE_DSYM:
         {
-            NODE *n = node->nd_next;
+            struct RNode_LIST *n = RNODE_DSTR(node)->nd_next;
             VALUE head = Qnil, next = Qnil;
             if (n) {
-                head = NEW_CHILD(ast, n->nd_head);
-                next = NEW_CHILD(ast, n->nd_next);
+                head = NEW_CHILD(ast_value, n->nd_head);
+                next = NEW_CHILD(ast_value, n->nd_next);
             }
-            return rb_ary_new_from_args(3, node->nd_lit, head, next);
+            return rb_ary_new_from_args(3, rb_node_dstr_string_val(node), head, next);
         }
+      case NODE_SYM:
+        return rb_ary_new_from_args(1, rb_node_sym_string_val(node));
       case NODE_EVSTR:
-        return rb_ary_new_from_node_args(ast, 1, node->nd_body);
+        return rb_ary_new_from_node_args(ast_value, 1, RNODE_EVSTR(node)->nd_body);
       case NODE_ARGSCAT:
-        return rb_ary_new_from_node_args(ast, 2, node->nd_head, node->nd_body);
+        return rb_ary_new_from_node_args(ast_value, 2, RNODE_ARGSCAT(node)->nd_head, RNODE_ARGSCAT(node)->nd_body);
       case NODE_ARGSPUSH:
-        return rb_ary_new_from_node_args(ast, 2, node->nd_head, node->nd_body);
+        return rb_ary_new_from_node_args(ast_value, 2, RNODE_ARGSPUSH(node)->nd_head, RNODE_ARGSPUSH(node)->nd_body);
       case NODE_SPLAT:
-        return rb_ary_new_from_node_args(ast, 1, node->nd_head);
+        return rb_ary_new_from_node_args(ast_value, 1, RNODE_SPLAT(node)->nd_head);
       case NODE_BLOCK_PASS:
-        return rb_ary_new_from_node_args(ast, 2, node->nd_head, node->nd_body);
+        return rb_ary_new_from_node_args(ast_value, 2, RNODE_BLOCK_PASS(node)->nd_head, RNODE_BLOCK_PASS(node)->nd_body);
       case NODE_DEFN:
-        return rb_ary_new_from_args(2, ID2SYM(node->nd_mid), NEW_CHILD(ast, node->nd_defn));
+        return rb_ary_new_from_args(2, ID2SYM(RNODE_DEFN(node)->nd_mid), NEW_CHILD(ast_value, RNODE_DEFN(node)->nd_defn));
       case NODE_DEFS:
-        return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_recv), ID2SYM(node->nd_mid), NEW_CHILD(ast, node->nd_defn));
+        return rb_ary_new_from_args(3, NEW_CHILD(ast_value, RNODE_DEFS(node)->nd_recv), ID2SYM(RNODE_DEFS(node)->nd_mid), NEW_CHILD(ast_value, RNODE_DEFS(node)->nd_defn));
       case NODE_ALIAS:
-        return rb_ary_new_from_node_args(ast, 2, node->nd_1st, node->nd_2nd);
+        return rb_ary_new_from_node_args(ast_value, 2, RNODE_ALIAS(node)->nd_1st, RNODE_ALIAS(node)->nd_2nd);
       case NODE_VALIAS:
-        return rb_ary_new_from_args(2, ID2SYM(node->nd_alias), ID2SYM(node->nd_orig));
+        return rb_ary_new_from_args(2, ID2SYM(RNODE_VALIAS(node)->nd_alias), ID2SYM(RNODE_VALIAS(node)->nd_orig));
       case NODE_UNDEF:
-        return rb_ary_new_from_node_args(ast, 1, node->nd_undef);
+        return rb_ary_new_from_args(1, dump_parser_array(ast_value, RNODE_UNDEF(node)->nd_undefs));
       case NODE_CLASS:
-        return rb_ary_new_from_node_args(ast, 3, node->nd_cpath, node->nd_super, node->nd_body);
+        return rb_ary_new_from_node_args(ast_value, 3, RNODE_CLASS(node)->nd_cpath, RNODE_CLASS(node)->nd_super, RNODE_CLASS(node)->nd_body);
       case NODE_MODULE:
-        return rb_ary_new_from_node_args(ast, 2, node->nd_cpath, node->nd_body);
+        return rb_ary_new_from_node_args(ast_value, 2, RNODE_MODULE(node)->nd_cpath, RNODE_MODULE(node)->nd_body);
       case NODE_SCLASS:
-        return rb_ary_new_from_node_args(ast, 2, node->nd_recv, node->nd_body);
+        return rb_ary_new_from_node_args(ast_value, 2, RNODE_SCLASS(node)->nd_recv, RNODE_SCLASS(node)->nd_body);
       case NODE_COLON2:
-        return rb_ary_new_from_args(2, NEW_CHILD(ast, node->nd_head), ID2SYM(node->nd_mid));
+        return rb_ary_new_from_args(2, NEW_CHILD(ast_value, RNODE_COLON2(node)->nd_head), ID2SYM(RNODE_COLON2(node)->nd_mid));
       case NODE_COLON3:
-        return rb_ary_new_from_args(1, ID2SYM(node->nd_mid));
+        return rb_ary_new_from_args(1, ID2SYM(RNODE_COLON3(node)->nd_mid));
       case NODE_DOT2:
       case NODE_DOT3:
       case NODE_FLIP2:
       case NODE_FLIP3:
-        return rb_ary_new_from_node_args(ast, 2, node->nd_beg, node->nd_end);
+        return rb_ary_new_from_node_args(ast_value, 2, RNODE_DOT2(node)->nd_beg, RNODE_DOT2(node)->nd_end);
       case NODE_SELF:
-        return rb_ary_new_from_node_args(ast, 0);
+        return rb_ary_new_from_node_args(ast_value, 0);
       case NODE_NIL:
-        return rb_ary_new_from_node_args(ast, 0);
+        return rb_ary_new_from_node_args(ast_value, 0);
       case NODE_TRUE:
-        return rb_ary_new_from_node_args(ast, 0);
+        return rb_ary_new_from_node_args(ast_value, 0);
       case NODE_FALSE:
-        return rb_ary_new_from_node_args(ast, 0);
+        return rb_ary_new_from_node_args(ast_value, 0);
       case NODE_ERRINFO:
-        return rb_ary_new_from_node_args(ast, 0);
+        return rb_ary_new_from_node_args(ast_value, 0);
       case NODE_DEFINED:
-        return rb_ary_new_from_node_args(ast, 1, node->nd_head);
+        return rb_ary_new_from_node_args(ast_value, 1, RNODE_DEFINED(node)->nd_head);
       case NODE_POSTEXE:
-        return rb_ary_new_from_node_args(ast, 1, node->nd_body);
+        return rb_ary_new_from_node_args(ast_value, 1, RNODE_POSTEXE(node)->nd_body);
       case NODE_ATTRASGN:
-        return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_recv), ID2SYM(node->nd_mid), NEW_CHILD(ast, node->nd_args));
+        return rb_ary_new_from_args(3, NEW_CHILD(ast_value, RNODE_ATTRASGN(node)->nd_recv), ID2SYM(RNODE_ATTRASGN(node)->nd_mid), NEW_CHILD(ast_value, RNODE_ATTRASGN(node)->nd_args));
       case NODE_LAMBDA:
-        return rb_ary_new_from_node_args(ast, 1, node->nd_body);
+        return rb_ary_new_from_node_args(ast_value, 1, RNODE_LAMBDA(node)->nd_body);
       case NODE_OPT_ARG:
-        return rb_ary_new_from_node_args(ast, 2, node->nd_body, node->nd_next);
+        return rb_ary_new_from_node_args(ast_value, 2, RNODE_OPT_ARG(node)->nd_body, RNODE_OPT_ARG(node)->nd_next);
       case NODE_KW_ARG:
-        return rb_ary_new_from_node_args(ast, 2, node->nd_body, node->nd_next);
+        return rb_ary_new_from_node_args(ast_value, 2, RNODE_KW_ARG(node)->nd_body, RNODE_KW_ARG(node)->nd_next);
       case NODE_POSTARG:
-        if (NODE_NAMED_REST_P(node->nd_1st)) {
-            return rb_ary_new_from_node_args(ast, 2, node->nd_1st, node->nd_2nd);
+        if (NODE_NAMED_REST_P(RNODE_POSTARG(node)->nd_1st)) {
+            return rb_ary_new_from_node_args(ast_value, 2, RNODE_POSTARG(node)->nd_1st, RNODE_POSTARG(node)->nd_2nd);
         }
         return rb_ary_new_from_args(2, no_name_rest(),
-                                    NEW_CHILD(ast, node->nd_2nd));
+                                    NEW_CHILD(ast_value, RNODE_POSTARG(node)->nd_2nd));
       case NODE_ARGS:
         {
-            struct rb_args_info *ainfo = node->nd_ainfo;
+            struct rb_args_info *ainfo = &RNODE_ARGS(node)->nd_ainfo;
             return rb_ary_new_from_args(10,
                                         INT2NUM(ainfo->pre_args_num),
-                                        NEW_CHILD(ast, ainfo->pre_init),
-                                        NEW_CHILD(ast, ainfo->opt_args),
+                                        NEW_CHILD(ast_value, ainfo->pre_init),
+                                        NEW_CHILD(ast_value, (NODE *)ainfo->opt_args),
                                         var_name(ainfo->first_post_arg),
                                         INT2NUM(ainfo->post_args_num),
-                                        NEW_CHILD(ast, ainfo->post_init),
+                                        NEW_CHILD(ast_value, ainfo->post_init),
                                         (ainfo->rest_arg == NODE_SPECIAL_EXCESSIVE_COMMA
                                             ? ID2SYM(rb_intern("NODE_SPECIAL_EXCESSIVE_COMMA"))
                                             : var_name(ainfo->rest_arg)),
-                                        (ainfo->no_kwarg ? Qfalse : NEW_CHILD(ast, ainfo->kw_args)),
-                                        (ainfo->no_kwarg ? Qfalse : NEW_CHILD(ast, ainfo->kw_rest_arg)),
+                                        (ainfo->no_kwarg ? Qfalse : NEW_CHILD(ast_value, (NODE *)ainfo->kw_args)),
+                                        (ainfo->no_kwarg ? Qfalse : NEW_CHILD(ast_value, ainfo->kw_rest_arg)),
                                         var_name(ainfo->block_arg));
         }
       case NODE_SCOPE:
         {
-            rb_ast_id_table_t *tbl = node->nd_tbl;
+            rb_ast_id_table_t *tbl = RNODE_SCOPE(node)->nd_tbl;
             int i, size = tbl ? tbl->size : 0;
             VALUE locals = rb_ary_new_capa(size);
             for (i = 0; i < size; i++) {
                 rb_ary_push(locals, var_name(tbl->ids[i]));
             }
-            return rb_ary_new_from_args(3, locals, NEW_CHILD(ast, node->nd_args), NEW_CHILD(ast, node->nd_body));
+            return rb_ary_new_from_args(3, locals, NEW_CHILD(ast_value, (NODE *)RNODE_SCOPE(node)->nd_args), NEW_CHILD(ast_value, RNODE_SCOPE(node)->nd_body));
         }
       case NODE_ARYPTN:
         {
-            struct rb_ary_pattern_info *apinfo = node->nd_apinfo;
-            VALUE rest = rest_arg(ast, apinfo->rest_arg);
+            VALUE rest = rest_arg(ast_value, RNODE_ARYPTN(node)->rest_arg);
             return rb_ary_new_from_args(4,
-                                        NEW_CHILD(ast, node->nd_pconst),
-                                        NEW_CHILD(ast, apinfo->pre_args),
+                                        NEW_CHILD(ast_value, RNODE_ARYPTN(node)->nd_pconst),
+                                        NEW_CHILD(ast_value, RNODE_ARYPTN(node)->pre_args),
                                         rest,
-                                        NEW_CHILD(ast, apinfo->post_args));
+                                        NEW_CHILD(ast_value, RNODE_ARYPTN(node)->post_args));
         }
       case NODE_FNDPTN:
         {
-            struct rb_fnd_pattern_info *fpinfo = node->nd_fpinfo;
-            VALUE pre_rest = rest_arg(ast, fpinfo->pre_rest_arg);
-            VALUE post_rest = rest_arg(ast, fpinfo->post_rest_arg);
+            VALUE pre_rest = rest_arg(ast_value, RNODE_FNDPTN(node)->pre_rest_arg);
+            VALUE post_rest = rest_arg(ast_value, RNODE_FNDPTN(node)->post_rest_arg);
             return rb_ary_new_from_args(4,
-                                        NEW_CHILD(ast, node->nd_pconst),
+                                        NEW_CHILD(ast_value, RNODE_FNDPTN(node)->nd_pconst),
                                         pre_rest,
-                                        NEW_CHILD(ast, fpinfo->args),
+                                        NEW_CHILD(ast_value, RNODE_FNDPTN(node)->args),
                                         post_rest);
         }
       case NODE_HSHPTN:
         {
-            VALUE kwrest = node->nd_pkwrestarg == NODE_SPECIAL_NO_REST_KEYWORD ? ID2SYM(rb_intern("NODE_SPECIAL_NO_REST_KEYWORD")) :
-                                                                                 NEW_CHILD(ast, node->nd_pkwrestarg);
+            VALUE kwrest = RNODE_HSHPTN(node)->nd_pkwrestarg == NODE_SPECIAL_NO_REST_KEYWORD ? ID2SYM(rb_intern("NODE_SPECIAL_NO_REST_KEYWORD")) :
+                                                                                 NEW_CHILD(ast_value, RNODE_HSHPTN(node)->nd_pkwrestarg);
 
             return rb_ary_new_from_args(3,
-                                        NEW_CHILD(ast, node->nd_pconst),
-                                        NEW_CHILD(ast, node->nd_pkwargs),
+                                        NEW_CHILD(ast_value, RNODE_HSHPTN(node)->nd_pconst),
+                                        NEW_CHILD(ast_value, RNODE_HSHPTN(node)->nd_pkwargs),
                                         kwrest);
         }
+      case NODE_LINE:
+        return rb_ary_new_from_args(1, rb_node_line_lineno_val(node));
+      case NODE_FILE:
+        return rb_ary_new_from_args(1, rb_node_file_path_val(node));
+      case NODE_ENCODING:
+        return rb_ary_new_from_args(1, rb_node_encoding_val(node));
+      case NODE_ERROR:
+        return rb_ary_new_from_node_args(ast_value, 0);
       case NODE_ARGS_AUX:
       case NODE_LAST:
         break;
@@ -659,7 +744,148 @@ ast_node_children(rb_execution_context_t *ec, VALUE self)
     struct ASTNodeData *data;
     TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);
 
-    return node_children(data->ast, data->node);
+    return node_children(data->ast_value, data->node);
+}
+
+static int
+null_loc_p(rb_code_location_t *loc)
+{
+    return (loc->beg_pos.lineno == 0 && loc->beg_pos.column == -1 && loc->end_pos.lineno == 0 && loc->end_pos.column == -1);
+}
+
+static VALUE
+location_new(rb_code_location_t *loc)
+{
+    VALUE obj;
+    struct ASTLocationData *data;
+
+    if (null_loc_p(loc)) return Qnil;
+
+    obj = TypedData_Make_Struct(rb_cLocation, struct ASTLocationData, &rb_location_type, data);
+    data->first_lineno = loc->beg_pos.lineno;
+    data->first_column = loc->beg_pos.column;
+    data->last_lineno = loc->end_pos.lineno;
+    data->last_column = loc->end_pos.column;
+
+    return obj;
+}
+
+static VALUE
+node_locations(VALUE ast_value, const NODE *node)
+{
+    enum node_type type = nd_type(node);
+    switch (type) {
+      case NODE_ALIAS:
+        return rb_ary_new_from_args(2,
+                                    location_new(nd_code_loc(node)),
+                                    location_new(&RNODE_ALIAS(node)->keyword_loc));
+      case NODE_AND:
+        return rb_ary_new_from_args(2,
+                                    location_new(nd_code_loc(node)),
+                                    location_new(&RNODE_AND(node)->operator_loc));
+      case NODE_BLOCK_PASS:
+        return rb_ary_new_from_args(2,
+                                    location_new(nd_code_loc(node)),
+                                    location_new(&RNODE_BLOCK_PASS(node)->operator_loc));
+
+      case NODE_BREAK:
+        return rb_ary_new_from_args(2,
+                                    location_new(nd_code_loc(node)),
+                                    location_new(&RNODE_BREAK(node)->keyword_loc));
+      case NODE_CASE:
+        return rb_ary_new_from_args(3,
+                                    location_new(nd_code_loc(node)),
+                                    location_new(&RNODE_CASE(node)->case_keyword_loc),
+                                    location_new(&RNODE_CASE(node)->end_keyword_loc));
+      case NODE_CASE2:
+        return rb_ary_new_from_args(3,
+                                    location_new(nd_code_loc(node)),
+                                    location_new(&RNODE_CASE2(node)->case_keyword_loc),
+                                    location_new(&RNODE_CASE2(node)->end_keyword_loc));
+      case NODE_CASE3:
+        return rb_ary_new_from_args(3,
+                                    location_new(nd_code_loc(node)),
+                                    location_new(&RNODE_CASE3(node)->case_keyword_loc),
+                                    location_new(&RNODE_CASE3(node)->end_keyword_loc));
+      case NODE_NEXT:
+        return rb_ary_new_from_args(2,
+                                    location_new(nd_code_loc(node)),
+                                    location_new(&RNODE_NEXT(node)->keyword_loc));
+      case NODE_OR:
+        return rb_ary_new_from_args(2,
+                                    location_new(nd_code_loc(node)),
+                                    location_new(&RNODE_OR(node)->operator_loc));
+      case NODE_OP_ASGN1:
+        return rb_ary_new_from_args(5,
+                                    location_new(nd_code_loc(node)),
+                                    location_new(&RNODE_OP_ASGN1(node)->call_operator_loc),
+                                    location_new(&RNODE_OP_ASGN1(node)->opening_loc),
+                                    location_new(&RNODE_OP_ASGN1(node)->closing_loc),
+                                    location_new(&RNODE_OP_ASGN1(node)->binary_operator_loc));
+      case NODE_OP_ASGN2:
+        return rb_ary_new_from_args(4,
+                                    location_new(nd_code_loc(node)),
+                                    location_new(&RNODE_OP_ASGN2(node)->call_operator_loc),
+                                    location_new(&RNODE_OP_ASGN2(node)->message_loc),
+                                    location_new(&RNODE_OP_ASGN2(node)->binary_operator_loc));
+      case NODE_REDO:
+        return rb_ary_new_from_args(2,
+                                    location_new(nd_code_loc(node)),
+                                    location_new(&RNODE_REDO(node)->keyword_loc));
+      case NODE_RETURN:
+        return rb_ary_new_from_args(2,
+                                    location_new(nd_code_loc(node)),
+                                    location_new(&RNODE_RETURN(node)->keyword_loc));
+      case NODE_SPLAT:
+        return rb_ary_new_from_args(2,
+                                    location_new(nd_code_loc(node)),
+                                    location_new(&RNODE_SPLAT(node)->operator_loc));
+      case NODE_UNDEF:
+        return rb_ary_new_from_args(2,
+                                    location_new(nd_code_loc(node)),
+                                    location_new(&RNODE_UNDEF(node)->keyword_loc));
+      case NODE_UNLESS:
+        return rb_ary_new_from_args(4,
+                                    location_new(nd_code_loc(node)),
+                                    location_new(&RNODE_UNLESS(node)->keyword_loc),
+                                    location_new(&RNODE_UNLESS(node)->then_keyword_loc),
+                                    location_new(&RNODE_UNLESS(node)->end_keyword_loc));
+      case NODE_VALIAS:
+        return rb_ary_new_from_args(2,
+                                    location_new(nd_code_loc(node)),
+                                    location_new(&RNODE_VALIAS(node)->keyword_loc));
+      case NODE_WHEN:
+        return rb_ary_new_from_args(3,
+                                    location_new(nd_code_loc(node)),
+                                    location_new(&RNODE_WHEN(node)->keyword_loc),
+                                    location_new(&RNODE_WHEN(node)->then_keyword_loc));
+      case NODE_WHILE:
+        return rb_ary_new_from_args(3,
+                                    location_new(nd_code_loc(node)),
+                                    location_new(&RNODE_WHILE(node)->keyword_loc),
+                                    location_new(&RNODE_WHILE(node)->closing_loc));
+      case NODE_UNTIL:
+        return rb_ary_new_from_args(3,
+                                    location_new(nd_code_loc(node)),
+                                    location_new(&RNODE_UNTIL(node)->keyword_loc),
+                                    location_new(&RNODE_UNTIL(node)->closing_loc));
+      case NODE_ARGS_AUX:
+      case NODE_LAST:
+        break;
+      default:
+        return rb_ary_new_from_args(1, location_new(nd_code_loc(node)));
+    }
+
+    rb_bug("node_locations: unknown node: %s", ruby_node_name(type));
+}
+
+static VALUE
+ast_node_locations(rb_execution_context_t *ec, VALUE self)
+{
+    struct ASTNodeData *data;
+    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);
+
+    return node_locations(data->ast_value, data->node);
 }
 
 static VALUE
@@ -699,6 +925,42 @@ ast_node_last_column(rb_execution_context_t *ec, VALUE self)
 }
 
 static VALUE
+ast_node_all_tokens(rb_execution_context_t *ec, VALUE self)
+{
+    long i;
+    struct ASTNodeData *data;
+    rb_ast_t *ast;
+    rb_parser_ary_t *parser_tokens;
+    rb_parser_ast_token_t *parser_token;
+    VALUE str, loc, token, all_tokens;
+
+    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);
+    ast = rb_ruby_ast_data_get(data->ast_value);
+
+    parser_tokens = ast->node_buffer->tokens;
+    if (parser_tokens == NULL) {
+        return Qnil;
+    }
+
+    all_tokens = rb_ary_new2(parser_tokens->len);
+    for (i = 0; i < parser_tokens->len; i++) {
+        parser_token = parser_tokens->data[i];
+        str = rb_str_new(parser_token->str->ptr, parser_token->str->len);
+        loc = rb_ary_new_from_args(4,
+            INT2FIX(parser_token->loc.beg_pos.lineno),
+            INT2FIX(parser_token->loc.beg_pos.column),
+            INT2FIX(parser_token->loc.end_pos.lineno),
+            INT2FIX(parser_token->loc.end_pos.column)
+        );
+        token = rb_ary_new_from_args(4, INT2FIX(parser_token->id), ID2SYM(rb_intern(parser_token->type_name)), str, loc);
+        rb_ary_push(all_tokens, token);
+    }
+    rb_ary_freeze(all_tokens);
+
+    return all_tokens;
+}
+
+static VALUE
 ast_node_inspect(rb_execution_context_t *ec, VALUE self)
 {
     VALUE str;
@@ -722,10 +984,66 @@ static VALUE
 ast_node_script_lines(rb_execution_context_t *ec, VALUE self)
 {
     struct ASTNodeData *data;
+    rb_ast_t *ast;
     TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);
-    VALUE ret = data->ast->body.script_lines;
-    if (!RB_TYPE_P(ret, T_ARRAY)) return Qnil;
-    return ret;
+    ast = rb_ruby_ast_data_get(data->ast_value);
+    rb_parser_ary_t *ret = ast->body.script_lines;
+    return rb_parser_build_script_lines_from(ret);
+}
+
+static VALUE
+ast_location_first_lineno(rb_execution_context_t *ec, VALUE self)
+{
+    struct ASTLocationData *data;
+    TypedData_Get_Struct(self, struct ASTLocationData, &rb_location_type, data);
+
+    return INT2NUM(data->first_lineno);
+}
+
+static VALUE
+ast_location_first_column(rb_execution_context_t *ec, VALUE self)
+{
+    struct ASTLocationData *data;
+    TypedData_Get_Struct(self, struct ASTLocationData, &rb_location_type, data);
+
+    return INT2NUM(data->first_column);
+}
+
+static VALUE
+ast_location_last_lineno(rb_execution_context_t *ec, VALUE self)
+{
+    struct ASTLocationData *data;
+    TypedData_Get_Struct(self, struct ASTLocationData, &rb_location_type, data);
+
+    return INT2NUM(data->last_lineno);
+}
+
+static VALUE
+ast_location_last_column(rb_execution_context_t *ec, VALUE self)
+{
+    struct ASTLocationData *data;
+    TypedData_Get_Struct(self, struct ASTLocationData, &rb_location_type, data);
+
+    return INT2NUM(data->last_column);
+}
+
+static VALUE
+ast_location_inspect(rb_execution_context_t *ec, VALUE self)
+{
+    VALUE str;
+    VALUE cname;
+    struct ASTLocationData *data;
+    TypedData_Get_Struct(self, struct ASTLocationData, &rb_location_type, data);
+
+    cname = rb_class_path(rb_obj_class(self));
+    str = rb_str_new2("#<");
+
+    rb_str_append(str, cname);
+    rb_str_catf(str, ":@%d:%d-%d:%d>",
+                data->first_lineno, data->first_column,
+                data->last_lineno, data->last_column);
+
+    return str;
 }
 
 #include "ast.rbinc"
@@ -735,5 +1053,7 @@ Init_ast(void)
 {
     rb_mAST = rb_define_module_under(rb_cRubyVM, "AbstractSyntaxTree");
     rb_cNode = rb_define_class_under(rb_mAST, "Node", rb_cObject);
+    rb_cLocation = rb_define_class_under(rb_mAST, "Location", rb_cObject);
     rb_undef_alloc_func(rb_cNode);
+    rb_undef_alloc_func(rb_cLocation);
 }
diff --git a/ast.rb b/ast.rb
index f866bd23e5..6380621780 100644
--- a/ast.rb
+++ b/ast.rb
@@ -13,28 +13,53 @@
 # access children nodes by name, etc.
 #
 # If you are looking for a stable API or an API working under multiple Ruby
-# implementations, consider using the _parser_ gem or Ripper. If you would
-# like to make RubyVM::AbstractSyntaxTree stable, please join the discussion
-# at https://bugs.ruby-lang.org/issues/14844.
+# implementations, consider using the _prism_ gem, which is the official
+# Ruby API to parse Ruby code.
 #
 module RubyVM::AbstractSyntaxTree
 
   #  call-seq:
-  #     RubyVM::AbstractSyntaxTree.parse(string) -> RubyVM::AbstractSyntaxTree::Node
+  #     RubyVM::AbstractSyntaxTree.parse(string, keep_script_lines: RubyVM.keep_script_lines, error_tolerant: false, keep_tokens: false) -> RubyVM::AbstractSyntaxTree::Node
   #
   #  Parses the given _string_ into an abstract syntax tree,
   #  returning the root node of that tree.
   #
-  #  SyntaxError is raised if the given _string_ is invalid syntax.
-  #
   #    RubyVM::AbstractSyntaxTree.parse("x = 1 + 2")
   #    # => #<RubyVM::AbstractSyntaxTree::Node:SCOPE@1:0-1:9>
-  def self.parse string, keep_script_lines: false
-    Primitive.ast_s_parse string, keep_script_lines
+  #
+  #  If <tt>keep_script_lines: true</tt> option is provided, the text of the parsed
+  #  source is associated with nodes and is available via Node#script_lines.
+  #
+  #  If <tt>keep_tokens: true</tt> option is provided, Node#tokens are populated.
+  #
+  #  SyntaxError is raised if the given _string_ is invalid syntax. To overwrite this
+  #  behavior, <tt>error_tolerant: true</tt> can be provided. In this case, the parser
+  #  will produce a tree where expressions with syntax errors would be represented by
+  #  Node with <tt>type=:ERROR</tt>.
+  #
+  #     root = RubyVM::AbstractSyntaxTree.parse("x = 1; p(x; y=2")
+  #     # <internal:ast>:33:in `parse': syntax error, unexpected ';', expecting ')' (SyntaxError)
+  #     # x = 1; p(x; y=2
+  #     #           ^
+  #
+  #     root = RubyVM::AbstractSyntaxTree.parse("x = 1; p(x; y=2", error_tolerant: true)
+  #     # (SCOPE@1:0-1:15
+  #     #  tbl: [:x, :y]
+  #     #  args: nil
+  #     #  body: (BLOCK@1:0-1:15 (LASGN@1:0-1:5 :x (LIT@1:4-1:5 1)) (ERROR@1:7-1:11) (LASGN@1:12-1:15 :y (LIT@1:14-1:15 2))))
+  #     root.children.last.children
+  #     # [(LASGN@1:0-1:5 :x (LIT@1:4-1:5 1)),
+  #     #  (ERROR@1:7-1:11),
+  #     #  (LASGN@1:12-1:15 :y (LIT@1:14-1:15 2))]
+  #
+  #  Note that parsing continues even after the errored expression.
+  #
+  def self.parse string, keep_script_lines: RubyVM.keep_script_lines, error_tolerant: false, keep_tokens: false
+    Primitive.ast_s_parse string, keep_script_lines, error_tolerant, keep_tokens
   end
 
   #  call-seq:
-  #     RubyVM::AbstractSyntaxTree.parse_file(pathname) -> RubyVM::AbstractSyntaxTree::Node
+  #     RubyVM::AbstractSyntaxTree.parse_file(pathname, keep_script_lines: RubyVM.keep_script_lines, error_tolerant: false, keep_tokens: false) -> RubyVM::AbstractSyntaxTree::Node
   #
   #   Reads the file from _pathname_, then parses it like ::parse,
   #   returning the root node of the abstract syntax tree.
@@ -44,13 +69,15 @@ module RubyVM::AbstractSyntaxTree
   #
   #     RubyVM::AbstractSyntaxTree.parse_file("my-app/app.rb")
   #     # => #<RubyVM::AbstractSyntaxTree::Node:SCOPE@1:0-31:3>
-  def self.parse_file pathname, keep_script_lines: false
-    Primitive.ast_s_parse_file pathname, keep_script_lines
+  #
+  #   See ::parse for explanation of keyword argument meaning and usage.
+  def self.parse_file pathname, keep_script_lines: RubyVM.keep_script_lines, error_tolerant: false, keep_tokens: false
+    Primitive.ast_s_parse_file pathname, keep_script_lines, error_tolerant, keep_tokens
   end
 
   #  call-seq:
-  #     RubyVM::AbstractSyntaxTree.of(proc)   -> RubyVM::AbstractSyntaxTree::Node
-  #     RubyVM::AbstractSyntaxTree.of(method) -> RubyVM::AbstractSyntaxTree::Node
+  #     RubyVM::AbstractSyntaxTree.of(proc, keep_script_lines: RubyVM.keep_script_lines, error_tolerant: false, keep_tokens: false)   -> RubyVM::AbstractSyntaxTree::Node
+  #     RubyVM::AbstractSyntaxTree.of(method, keep_script_lines: RubyVM.keep_script_lines, error_tolerant: false, keep_tokens: false) -> RubyVM::AbstractSyntaxTree::Node
   #
   #   Returns AST nodes of the given _proc_ or _method_.
   #
@@ -63,8 +90,25 @@ module RubyVM::AbstractSyntaxTree
   #
   #     RubyVM::AbstractSyntaxTree.of(method(:hello))
   #     # => #<RubyVM::AbstractSyntaxTree::Node:SCOPE@1:0-3:3>
-  def self.of body, keep_script_lines: false
-    Primitive.ast_s_of body, keep_script_lines
+  #
+  #   See ::parse for explanation of keyword argument meaning and usage.
+  def self.of body, keep_script_lines: RubyVM.keep_script_lines, error_tolerant: false, keep_tokens: false
+    Primitive.ast_s_of body, keep_script_lines, error_tolerant, keep_tokens
+  end
+
+  #  call-seq:
+  #     RubyVM::AbstractSyntaxTree.node_id_for_backtrace_location(backtrace_location)   -> integer
+  #
+  #   Returns the node id for the given backtrace location.
+  #
+  #     begin
+  #       raise
+  #     rescue =>  e
+  #       loc = e.backtrace_locations.first
+  #       RubyVM::AbstractSyntaxTree.node_id_for_backtrace_location(loc)
+  #     end # => 0
+  def self.node_id_for_backtrace_location backtrace_location
+    Primitive.node_id_for_backtrace_location backtrace_location
   end
 
   # RubyVM::AbstractSyntaxTree::Node instances are created by parse methods in
@@ -122,6 +166,47 @@ module RubyVM::AbstractSyntaxTree
     end
 
     #  call-seq:
+    #     node.tokens -> array
+    #
+    #  Returns tokens corresponding to the location of the node.
+    #  Returns +nil+ if +keep_tokens+ is not enabled when #parse method is called.
+    #
+    #    root = RubyVM::AbstractSyntaxTree.parse("x = 1 + 2", keep_tokens: true)
+    #    root.tokens # => [[0, :tIDENTIFIER, "x", [1, 0, 1, 1]], [1, :tSP, " ", [1, 1, 1, 2]], ...]
+    #    root.tokens.map{_1[2]}.join # => "x = 1 + 2"
+    #
+    #  Token is an array of:
+    #
+    #  - id
+    #  - token type
+    #  - source code text
+    #  - location [ first_lineno, first_column, last_lineno, last_column ]
+    def tokens
+      return nil unless all_tokens
+
+      all_tokens.each_with_object([]) do |token, a|
+        loc = token.last
+        if ([first_lineno, first_column] <=> [loc[0], loc[1]]) <= 0 &&
+           ([last_lineno, last_column]   <=> [loc[2], loc[3]]) >= 0
+           a << token
+        end
+      end
+    end
+
+    #  call-seq:
+    #     node.all_tokens -> array
+    #
+    #  Returns all tokens for the input script regardless the receiver node.
+    #  Returns +nil+ if +keep_tokens+ is not enabled when #parse method is called.
+    #
+    #    root = RubyVM::AbstractSyntaxTree.parse("x = 1 + 2", keep_tokens: true)
+    #    root.all_tokens # => [[0, :tIDENTIFIER, "x", [1, 0, 1, 1]], [1, :tSP, " ", [1, 1, 1, 2]], ...]
+    #    root.children[-1].all_tokens # => [[0, :tIDENTIFIER, "x", [1, 0, 1, 1]], [1, :tSP, " ", [1, 1, 1, 2]], ...]
+    def all_tokens
+      Primitive.ast_node_all_tokens
+    end
+
+    #  call-seq:
     #     node.children -> array
     #
     #  Returns AST nodes under this one.  Each kind of node
@@ -179,12 +264,69 @@ module RubyVM::AbstractSyntaxTree
       lines = script_lines
       if lines
         lines = lines[first_lineno - 1 .. last_lineno - 1]
-        lines[-1] = lines[-1][0...last_column]
-        lines[0] = lines[0][first_column..-1]
+        lines[-1] = lines[-1].byteslice(0...last_column)
+        lines[0] = lines[0].byteslice(first_column..-1)
         lines.join
       else
         nil
       end
     end
+
+    #  call-seq:
+    #     node.locations -> array
+    #
+    #  Returns location objects associated with the AST node.
+    #  The returned array contains RubyVM::AbstractSyntaxTree::Location.
+    def locations
+      Primitive.ast_node_locations
+    end
+  end
+
+  # RubyVM::AbstractSyntaxTree::Location instances are created by
+  # RubyVM::AbstractSyntaxTree::Node#locations.
+  #
+  # This class is MRI specific.
+  #
+  class Location
+
+    #  call-seq:
+    #     location.first_lineno -> integer
+    #
+    #  The line number in the source code where this AST's text began.
+    def first_lineno
+      Primitive.ast_location_first_lineno
+    end
+
+    #  call-seq:
+    #     location.first_column -> integer
+    #
+    #  The column number in the source code where this AST's text began.
+    def first_column
+      Primitive.ast_location_first_column
+    end
+
+    #  call-seq:
+    #     location.last_lineno -> integer
+    #
+    #  The line number in the source code where this AST's text ended.
+    def last_lineno
+      Primitive.ast_location_last_lineno
+    end
+
+    #  call-seq:
+    #     location.last_column -> integer
+    #
+    #  The column number in the source code where this AST's text ended.
+    def last_column
+      Primitive.ast_location_last_column
+    end
+
+    #  call-seq:
+    #     location.inspect -> string
+    #
+    #  Returns debugging information about this location as a string.
+    def inspect
+      Primitive.ast_location_inspect
+    end
   end
 end
diff --git a/basictest/test.rb b/basictest/test.rb
index 95875b52a6..711e4f4ab3 100755
--- a/basictest/test.rb
+++ b/basictest/test.rb
@@ -879,7 +879,7 @@ $x.sort!{|a,b| b-a}		# reverse sort
 test_ok($x == [7,5,3,2,1])
 
 # split test
-$x = "The Book of Mormon"
+$x = +"The Book of Mormon"
 test_ok($x.split(//).reverse!.join == $x.reverse)
 test_ok($x.reverse == $x.reverse!)
 test_ok("1 byte string".split(//).reverse.join(":") == "g:n:i:r:t:s: :e:t:y:b: :1")
@@ -1643,7 +1643,7 @@ test_ok(/^(?:ab+)+/ =~ "ababb" && $& == "ababb")
 test_ok(/(\s+\d+){2}/ =~ " 1 2" && $& == " 1 2")
 test_ok(/(?:\s+\d+){2}/ =~ " 1 2" && $& == " 1 2")
 
-$x = <<END;
+$x = +<<END;
 ABCD
 ABCD
 END
@@ -1682,12 +1682,12 @@ test_ok(?a == ?a)
 test_ok(?\C-a == "\1")
 test_ok(?\M-a == "\341")
 test_ok(?\M-\C-a == "\201")
-test_ok("a".upcase![0] == ?A)
-test_ok("A".downcase![0] == ?a)
-test_ok("abc".tr!("a-z", "A-Z") == "ABC")
-test_ok("aabbcccc".tr_s!("a-z", "A-Z") == "ABC")
-test_ok("abcc".squeeze!("a-z") == "abc")
-test_ok("abcd".delete!("bc") == "ad")
+test_ok("a".dup.upcase![0] == ?A)
+test_ok("A".dup.downcase![0] == ?a)
+test_ok("abc".dup.tr!("a-z", "A-Z") == "ABC")
+test_ok("aabbcccc".dup.tr_s!("a-z", "A-Z") == "ABC")
+test_ok("abcc".dup.squeeze!("a-z") == "abc")
+test_ok("abcd".dup.delete!("bc") == "ad")
 
 $x = "abcdef"
 $y = [ ?a, ?b, ?c, ?d, ?e, ?f ]
@@ -1700,7 +1700,7 @@ $x.each_byte {|i|
 }
 test_ok(!$bad)
 
-s = "a string"
+s = +"a string"
 s[0..s.size]="another string"
 test_ok(s == "another string")
 
diff --git a/benchmark/README.md b/benchmark/README.md
index c222164be3..c5c29d0daf 100644
--- a/benchmark/README.md
+++ b/benchmark/README.md
@@ -27,17 +27,20 @@ benchmark-driver benchmark/*.yml
 See also:
 
 ```console
+benchmark-driver --help
 Usage: benchmark-driver [options] RUBY|YAML...
-    -r, --runner TYPE                Specify runner type: ips, time, memory, once (default: ips)
-    -o, --output TYPE                Specify output type: compare, simple, markdown, record (default: compare)
+    -r, --runner TYPE                Specify runner type: ips, time, memory, once, block (default: ips)
+    -o, --output TYPE                Specify output type: compare, simple, markdown, record, all (default: compare)
     -e, --executables EXECS          Ruby executables (e1::path1 arg1; e2::path2 arg2;...)
         --rbenv VERSIONS             Ruby executables in rbenv (x.x.x arg1;y.y.y arg2;...)
         --repeat-count NUM           Try benchmark NUM times and use the fastest result or the worst memory usage
         --repeat-result TYPE         Yield "best", "average" or "worst" result with --repeat-count (default: best)
+        --alternate                  Alternate executables instead of running the same executable in a row with --repeat-count
         --bundler                    Install and use gems specified in Gemfile
         --filter REGEXP              Filter out benchmarks with given regexp
         --run-duration SECONDS       Warmup estimates loop_count to run for this duration (default: 3)
-    -v, --verbose                    Verbose mode. Multiple -v options increase visibility (max: 2)
+        --timeout SECONDS            Timeout ruby command execution with timeout(1)
+    -v, --verbose                    Verbose mode. Multiple -v options increase visilibity (max: 2)
 ```
 
 ## make benchmark
diff --git a/benchmark/app_aobench.rb b/benchmark/app_aobench.rb
index 16296af12b..c1546e08ab 100644
--- a/benchmark/app_aobench.rb
+++ b/benchmark/app_aobench.rb
@@ -151,7 +151,7 @@ def clamp(f)
   i.to_i
 end
 
-def otherBasis(basis, n)
+def orthoBasis(basis, n)
   basis[2] = Vec.new(n.x, n.y, n.z)
   basis[1] = Vec.new(0.0, 0.0, 0.0)
 
@@ -183,7 +183,7 @@ class Scene
 
   def ambient_occlusion(isect)
     basis = Array.new
-    otherBasis(basis, isect.n)
+    orthoBasis(basis, isect.n)
 
     ntheta    = NAO_SAMPLES
     nphi      = NAO_SAMPLES
diff --git a/benchmark/array_large_literal.yml b/benchmark/array_large_literal.yml
new file mode 100644
index 0000000000..423d68391f
--- /dev/null
+++ b/benchmark/array_large_literal.yml
@@ -0,0 +1,19 @@
+prelude: |
+  def def_array(size)
+    Object.class_eval(<<-END)
+      def array_#{size}
+        x = 1
+        [#{(['x'] * size).join(',')}]
+      end
+    END
+  end
+  def_array(100)
+  def_array(1000)
+  def_array(10000)
+  def_array(100000)
+benchmark:
+  array_100: array_100
+  array_1000: array_1000
+  array_10000: array_10000
+  array_100000: array_100000
+
diff --git a/benchmark/array_sort_int.yml b/benchmark/array_sort_int.yml
new file mode 100644
index 0000000000..7b9027ebf7
--- /dev/null
+++ b/benchmark/array_sort_int.yml
@@ -0,0 +1,15 @@
+prelude: |
+  ary2 = 2.times.to_a.shuffle
+  ary10 = 10.times.to_a.shuffle
+  ary100 = 100.times.to_a.shuffle
+  ary1000 = 1000.times.to_a.shuffle
+  ary10000 = 10000.times.to_a.shuffle
+
+benchmark:
+  ary2.sort: ary2.sort
+  ary10.sort: ary10.sort
+  ary100.sort: ary100.sort
+  ary1000.sort: ary1000.sort
+  ary10000.sort: ary10000.sort
+
+loop_count: 10000
diff --git a/benchmark/buffer_each.yml b/benchmark/buffer_each.yml
new file mode 100644
index 0000000000..417941104e
--- /dev/null
+++ b/benchmark/buffer_each.yml
@@ -0,0 +1,27 @@
+prelude: |
+  # frozen_string_literal: true
+  Warning[:experimental] = false
+  string = "The quick brown fox jumped over the lazy dog."
+  array = string.bytes
+  buffer = IO::Buffer.for(string)
+benchmark:
+  string.each_byte: |
+    upcased = String.new
+    string.each_byte do |byte|
+      upcased << (byte ^ 32)
+    end
+  array.each: |
+    upcased = String.new
+    array.each do |byte|
+      upcased << (byte ^ 32)
+    end
+  buffer.each: |
+    upcased = String.new
+    buffer.each(:U8) do |offset, byte|
+      upcased << (byte ^ 32)
+    end
+  buffer.each_byte: |
+    upcased = String.new
+    buffer.each_byte do |byte|
+      upcased << (byte ^ 32)
+    end
diff --git a/benchmark/buffer_get.yml b/benchmark/buffer_get.yml
index e375dcf85d..9e1f99d64e 100644
--- a/benchmark/buffer_get.yml
+++ b/benchmark/buffer_get.yml
@@ -1,9 +1,25 @@
+prelude: |
+  # frozen_string_literal: true
+  Warning[:experimental] = false
+  string = "The quick brown fox jumped over the lazy dog."
+  buffer = IO::Buffer.for(string)
+  format = [:U32, :U32, :U32, :U32]
 benchmark:
-  - name: buffer.get
-    prelude: buffer = IO::Buffer.new(32, IO::Buffer::MAPPED)
-    script: buffer.get(:U32, 0)
-    loop_count: 20000000
-  - name: string.unpack
-    prelude: string = "\0" * 32
-    script: string.unpack("C")
-    loop_count: 20000000
+  string.unpack1: |
+    [
+      string.unpack1("N"),
+      string.unpack1("N", offset: 4),
+      string.unpack1("N", offset: 8),
+      string.unpack1("N", offset: 12),
+    ]
+  buffer.get_value: |
+    [
+      buffer.get_value(:U32, 0),
+      buffer.get_value(:U32, 4),
+      buffer.get_value(:U32, 8),
+      buffer.get_value(:U32, 12),
+    ]
+  buffer.get_values: |
+    buffer.get_values(format, 0)
+  string.unpack: |
+    string.unpack("NNNN")
diff --git a/benchmark/cgi_escape_html.yml b/benchmark/cgi_escape_html.yml
index af6abd08ac..655be9d7d8 100644
--- a/benchmark/cgi_escape_html.yml
+++ b/benchmark/cgi_escape_html.yml
@@ -1,32 +1,23 @@
-prelude: require 'cgi/escape'
+prelude: |
+  # frozen_string_literal: true
+  require 'cgi/escape'
 benchmark:
-  - name: escape_html_blank
-    prelude: str = ""
-    script: CGI.escapeHTML(str)
+  - script: CGI.escapeHTML("")
     loop_count: 20000000
-  - name: escape_html_short_none
-    prelude: str = "abcde"
-    script: CGI.escapeHTML(str)
+  - script: CGI.escapeHTML("abcde")
     loop_count: 20000000
-  - name: escape_html_short_one
-    prelude: str = "abcd<"
-    script: CGI.escapeHTML(str)
+  - script: CGI.escapeHTML("abcd<")
     loop_count: 20000000
-  - name: escape_html_short_all
-    prelude: str = "'&\"<>"
-    script: CGI.escapeHTML(str)
+  - script: CGI.escapeHTML("'&\"<>")
     loop_count: 5000000
-  - name: escape_html_long_none
-    prelude: str = "abcde" * 300
-    script: CGI.escapeHTML(str)
+  - prelude: long_no_escape = "abcde" * 300
+    script: CGI.escapeHTML(long_no_escape)
     loop_count: 1000000
-  - name: escape_html_long_all
-    prelude: str = "'&\"<>" * 10
-    script: CGI.escapeHTML(str)
+  - prelude: long_all_escape = "'&\"<>" * 10
+    script: CGI.escapeHTML(long_all_escape)
     loop_count: 1000000
-  - name: escape_html_real
-    prelude: | # http://example.com/
-      str = <<~HTML
+  - prelude: | # http://example.com/
+      example_html = <<~HTML
         <body>
         <div>
             <h1>Example Domain</h1>
@@ -36,5 +27,5 @@ benchmark:
         </div>
         </body>
       HTML
-    script: CGI.escapeHTML(str)
+    script: CGI.escapeHTML(example_html)
     loop_count: 1000000
diff --git a/benchmark/enum_minmax.yml b/benchmark/enum_minmax.yml
new file mode 100644
index 0000000000..9d01731abb
--- /dev/null
+++ b/benchmark/enum_minmax.yml
@@ -0,0 +1,25 @@
+prelude: |
+  set2 = 2.times.to_a.shuffle.to_set
+  set10 = 10.times.to_a.shuffle.to_set
+  set100 = 100.times.to_a.shuffle.to_set
+  set1000 = 1000.times.to_a.shuffle.to_set
+  set10000 = 10000.times.to_a.shuffle.to_set
+
+benchmark:
+  set2.min: set2.min
+  set10.min: set10.min
+  set100.min: set100.min
+  set1000.min: set1000.min
+  set10000.min: set10000.min
+  set2.max: set2.max
+  set10.max: set10.max
+  set100.max: set100.max
+  set1000.max: set1000.max
+  set10000.max: set10000.max
+  set2.minmax: set2.minmax
+  set10.minmax: set10.minmax
+  set100.minmax: set100.minmax
+  set1000.minmax: set1000.minmax
+  set10000.minmax: set10000.minmax
+
+loop_count: 10000
diff --git a/benchmark/enum_sort.yml b/benchmark/enum_sort.yml
new file mode 100644
index 0000000000..6f26e748c6
--- /dev/null
+++ b/benchmark/enum_sort.yml
@@ -0,0 +1,15 @@
+prelude: |
+  set2 = 2.times.to_a.shuffle.to_set
+  set10 = 10.times.to_a.shuffle.to_set
+  set100 = 100.times.to_a.shuffle.to_set
+  set1000 = 1000.times.to_a.shuffle.to_set
+  set10000 = 10000.times.to_a.shuffle.to_set
+
+benchmark:
+  set2.sort_by: set2.sort_by { 0 }
+  set10.sort_by: set10.sort_by { 0 }
+  set100.sort_by: set100.sort_by { 0 }
+  set1000.sort_by: set1000.sort_by { 0 }
+  set10000.sort_by: set10000.sort_by { 0 }
+
+loop_count: 10000
diff --git a/benchmark/enum_sort_by.yml b/benchmark/enum_sort_by.yml
new file mode 100644
index 0000000000..d386353888
--- /dev/null
+++ b/benchmark/enum_sort_by.yml
@@ -0,0 +1,53 @@
+prelude: |
+  array_length = 2
+  fixnum_array2 = array_length.times.to_a.map {rand(10000)}
+  float_array2 = array_length.times.to_a.map {rand(10000.0).to_f}
+  string_array2 = array_length.times.to_a.map {"r" * rand(1..10000)}
+  mix_array2 = array_length.times.to_a.map {if rand(1..100) <= 50 then rand(1..10000).to_f else rand(1..10000) end}
+  all_zero_array2 =array_length.times.to_a.map {0}
+
+  array_length = 10
+  fixnum_array10 = array_length.times.to_a.map {rand(10000)}
+  float_array10 = array_length.times.to_a.map {rand(10000.0).to_f}
+  string_array10 = array_length.times.to_a.map {"r" * rand(1..10000)}
+  mix_array10 = array_length.times.to_a.map {if rand(1..100) <= 50 then rand(1..10000).to_f else rand(1..10000) end}
+  all_zero_array10 =array_length.times.to_a.map {0}
+
+  array_length = 1000
+  fixnum_array1000 = array_length.times.to_a.map {rand(10000)}
+  float_array1000 = array_length.times.to_a.map {rand(10000.0).to_f}
+  string_array1000 = array_length.times.to_a.map {"r" * rand(1..10000)}
+  mix_array1000 = array_length.times.to_a.map {if rand(1..100) <= 50 then rand(1..10000).to_f else rand(1..10000) end}
+  all_zero_array1000 =array_length.times.to_a.map {0}
+
+  array_length = 100000
+  fixnum_array100000 = array_length.times.to_a.map {rand(10000)}
+  float_array100000 = array_length.times.to_a.map {rand(10000.0).to_f}
+  string_array100000 = array_length.times.to_a.map {"r" * rand(1..10000)}
+  mix_array100000 = array_length.times.to_a.map {if rand(1..100) <= 50 then rand(1..10000).to_f else rand(1..10000) end}
+  all_zero_array100000 =array_length.times.to_a.map {0}
+
+benchmark:
+  fixnum_array2.sort_by: fixnum_array2.sort_by {|a| a}
+  float_array2.sort_by:  float_array2.sort_by {|a| a}
+  string_length2.sort_by: string_array2.sort_by {|a| a.length}
+  mix_array2.sort_by:  mix_array2.sort_by {|a| a}
+  all_zero2.sort_by: all_zero_array2.sort_by{|a| a}
+
+  fixnum_array10.sort_by: fixnum_array10.sort_by {|a| a}
+  float_array10.sort_by:  float_array10.sort_by {|a| a}
+  string_length10.sort_by: string_array10.sort_by {|a| a.length}
+  mix_array10.sort_by:  mix_array10.sort_by {|a| a}
+  all_zero10.sort_by: all_zero_array10.sort_by{|a| a}
+
+  fixnum_array1000.sort_by: fixnum_array1000.sort_by {|a| a}
+  float_array1000.sort_by:  float_array1000.sort_by {|a| a}
+  string_length1000.sort_by: string_array1000.sort_by {|a| a.length}
+  mix_array1000.sort_by:  mix_array1000.sort_by {|a| a}
+  all_zero1000.sort_by: all_zero_array1000.sort_by{|a| a}
+
+  fixnum_array100000.sort_by: fixnum_array100000.sort_by {|a| a}
+  float_array100000.sort_by:  float_array100000.sort_by {|a| a}
+  string_length100000.sort_by: string_array100000.sort_by {|a| a.length}
+  mix_array100000.sort_by:  mix_array100000.sort_by {|a| a}
+  all_zero100000.sort_by: all_zero_array100000.sort_by{|a| a}
diff --git a/benchmark/erb_escape_html.yml b/benchmark/erb_escape_html.yml
new file mode 100644
index 0000000000..ca28d756e7
--- /dev/null
+++ b/benchmark/erb_escape_html.yml
@@ -0,0 +1,31 @@
+prelude: |
+  # frozen_string_literal: true
+  require 'erb'
+benchmark:
+  - script: ERB::Util.html_escape("")
+    loop_count: 20000000
+  - script: ERB::Util.html_escape("abcde")
+    loop_count: 20000000
+  - script: ERB::Util.html_escape("abcd<")
+    loop_count: 20000000
+  - script: ERB::Util.html_escape("'&\"<>")
+    loop_count: 5000000
+  - prelude: long_no_escape = "abcde" * 300
+    script: ERB::Util.html_escape(long_no_escape)
+    loop_count: 1000000
+  - prelude: long_all_escape = "'&\"<>" * 10
+    script: ERB::Util.html_escape(long_all_escape)
+    loop_count: 1000000
+  - prelude: | # http://example.com/
+      example_html = <<~HTML
+        <body>
+        <div>
+            <h1>Example Domain</h1>
+            <p>This domain is established to be used for illustrative examples in documents. You may use this
+            domain in examples without prior coordination or asking for permission.</p>
+            <p><a href="http://www.iana.org/domains/example">More information...</a></p>
+        </div>
+        </body>
+      HTML
+    script: ERB::Util.html_escape(example_html)
+    loop_count: 1000000
diff --git a/benchmark/hash_aref_str_lit.yml b/benchmark/hash_aref_str_lit.yml
new file mode 100644
index 0000000000..ed8142bcf1
--- /dev/null
+++ b/benchmark/hash_aref_str_lit.yml
@@ -0,0 +1,20 @@
+prelude: |
+  # frozen_string_literal: true
+  hash = 10.times.to_h do |i|
+    [i, i]
+  end
+  dyn_sym = "dynamic_symbol".to_sym
+  binary = RubyVM::InstructionSequence.compile("# frozen_string_literal: true\n'iseq_load'").to_binary
+  iseq_literal_string = RubyVM::InstructionSequence.load_from_binary(binary).eval
+
+  hash[:some_symbol] = 1
+  hash[dyn_sym] = 2
+  hash["small"] = 3
+  hash["frozen_string_literal"] = 4
+  hash[iseq_literal_string] = 5
+benchmark:
+  symbol: hash[:some_symbol]
+  dyn_symbol: hash[dyn_sym]
+  small_lit: hash["small"]
+  frozen_lit: hash["frozen_string_literal"]
+  iseq_lit: hash[iseq_literal_string]
diff --git a/benchmark/hash_key.yml b/benchmark/hash_key.yml
new file mode 100644
index 0000000000..cab4cf9ca4
--- /dev/null
+++ b/benchmark/hash_key.yml
@@ -0,0 +1,5 @@
+prelude: |
+  obj = Object.new
+  hash = { obj => true }
+benchmark: hash.key?(obj)
+loop_count: 30000000
diff --git a/benchmark/hash_new.yml b/benchmark/hash_new.yml
new file mode 100644
index 0000000000..9d8e34187f
--- /dev/null
+++ b/benchmark/hash_new.yml
@@ -0,0 +1,16 @@
+prelude: |
+  has_hash_with_capa = Hash.instance_method(:initialize).parameters.include?([:key, :capacity])
+  strings_1k = 1_000.times.map { |i| -i.to_s.freeze }
+  strings_100k = 100_000.times.map { |i| -i.to_s.freeze }
+benchmark:
+  new: Hash.new
+  new_with_capa_1k: |
+    h = has_hash_with_capa ? Hash.new(capacity: strings_1k.size) : {}
+    strings_1k.each do |x|
+      h[x] = true
+    end
+  new_with_capa_100k: |
+    h = has_hash_with_capa ? Hash.new(capacity: strings_100k.size) : {}
+    strings_100k.each do |x|
+      h[x] = true
+    end
diff --git a/benchmark/io_write.rb b/benchmark/io_write.rb
new file mode 100644
index 0000000000..cdb409948b
--- /dev/null
+++ b/benchmark/io_write.rb
@@ -0,0 +1,22 @@
+#!/usr/bin/env ruby
+
+require 'benchmark'
+
+i, o = IO.pipe
+o.sync = true
+
+DOT = ".".freeze
+
+chunks = 100_000.times.collect{DOT}
+
+thread = Thread.new do
+  while i.read(1024)
+  end
+end
+
+100.times do
+  o.write(*chunks)
+end
+
+o.close
+thread.join
diff --git a/benchmark/lib/benchmark_driver/runner/mjit.rb b/benchmark/lib/benchmark_driver/runner/mjit.rb
deleted file mode 100644
index 1d4693e8be..0000000000
--- a/benchmark/lib/benchmark_driver/runner/mjit.rb
+++ /dev/null
@@ -1,34 +0,0 @@
-require 'benchmark_driver/struct'
-require 'benchmark_driver/metric'
-require 'erb'
-
-# A runner to measure after-JIT performance easily
-class BenchmarkDriver::Runner::Mjit < BenchmarkDriver::Runner::Ips
-  # JobParser returns this, `BenchmarkDriver::Runner.runner_for` searches "*::Job"
-  Job = Class.new(BenchmarkDriver::DefaultJob)
-
-  # Dynamically fetched and used by `BenchmarkDriver::JobParser.parse`
-  JobParser = BenchmarkDriver::DefaultJobParser.for(klass: Job, metrics: [METRIC]).extend(Module.new{
-    def parse(**)
-      jobs = super
-      jobs.map do |job|
-        job = job.dup
-        job.prelude = "#{job.prelude}\n#{<<~EOS}"
-          if defined?(RubyVM::MJIT) && RubyVM::MJIT.enabled?
-            __bmdv_ruby_i = 0
-            while __bmdv_ruby_i < 10000 # jit_min_calls
-              #{job.script}
-              __bmdv_ruby_i += 1
-            end
-            RubyVM::MJIT.pause # compile
-            #{job.script}
-            RubyVM::MJIT.resume; RubyVM::MJIT.pause # recompile
-            #{job.script}
-            RubyVM::MJIT.resume; RubyVM::MJIT.pause # recompile 2
-          end
-        EOS
-        job
-      end
-    end
-  })
-end
diff --git a/benchmark/lib/benchmark_driver/runner/mjit_exec.rb b/benchmark/lib/benchmark_driver/runner/mjit_exec.rb
deleted file mode 100644
index eac3dfba84..0000000000
--- a/benchmark/lib/benchmark_driver/runner/mjit_exec.rb
+++ /dev/null
@@ -1,237 +0,0 @@
-require 'benchmark_driver/struct'
-require 'benchmark_driver/metric'
-require 'erb'
-
-# A special runner dedicated for measuring mjit_exec overhead.
-class BenchmarkDriver::Runner::MjitExec
-  METRIC = BenchmarkDriver::Metric.new(name: 'Iteration per second', unit: 'i/s')
-
-  # JobParser returns this, `BenchmarkDriver::Runner.runner_for` searches "*::Job"
-  Job = ::BenchmarkDriver::Struct.new(
-    :name,        # @param [String] name - This is mandatory for all runner
-    :metrics,     # @param [Array<BenchmarkDriver::Metric>]
-    :num_methods, # @param [Integer] num_methods - The number of methods to be defined
-    :loop_count,  # @param [Integer] loop_count
-    :from_jit,    # @param [TrueClass,FalseClass] from_jit - Whether the mjit_exec() is from JIT or not
-    :to_jit,      # @param [TrueClass,FalseClass] to_jit - Whether the mjit_exec() is to JIT or not
-  )
-  # Dynamically fetched and used by `BenchmarkDriver::JobParser.parse`
-  class << JobParser = Module.new
-    # @param [Array,String] num_methods
-    # @param [Integer] loop_count
-    # @param [TrueClass,FalseClass] from_jit
-    # @param [TrueClass,FalseClass] to_jit
-    def parse(num_methods:, loop_count:, from_jit:, to_jit:)
-      if num_methods.is_a?(String)
-        num_methods = eval(num_methods)
-      end
-
-      num_methods.map do |num|
-        if num_methods.size > 1
-          suffix = "[#{'%4d' % num}]"
-        else
-          suffix = "_#{num}"
-        end
-        Job.new(
-          name: "mjit_exec_#{from_jit ? 'JT' : 'VM'}2#{to_jit ? 'JT' : 'VM'}#{suffix}",
-          metrics: [METRIC],
-          num_methods: num,
-          loop_count: loop_count,
-          from_jit: from_jit,
-          to_jit: to_jit,
-        )
-      end
-    end
-  end
-
-  # @param [BenchmarkDriver::Config::RunnerConfig] config
-  # @param [BenchmarkDriver::Output] output
-  # @param [BenchmarkDriver::Context] contexts
-  def initialize(config:, output:, contexts:)
-    @config = config
-    @output = output
-    @contexts = contexts
-  end
-
-  # This method is dynamically called by `BenchmarkDriver::JobRunner.run`
-  # @param [Array<BenchmarkDriver::Runner::Peak::Job>] jobs
-  def run(jobs)
-    @output.with_benchmark do
-      jobs.each do |job|
-        @output.with_job(name: job.name) do
-          @contexts.each do |context|
-            result = BenchmarkDriver::Repeater.with_repeat(config: @config, larger_better: true, rest_on_average: :average) do
-              run_benchmark(job, context: context)
-            end
-            value, duration = result.value
-            @output.with_context(name: context.name, executable: context.executable, gems: context.gems, prelude: context.prelude) do
-              @output.report(values: { METRIC => value }, duration: duration, loop_count: job.loop_count)
-            end
-          end
-        end
-      end
-    end
-  end
-
-  private
-
-  # @param [BenchmarkDriver::Runner::Ips::Job] job - loop_count is not nil
-  # @param [BenchmarkDriver::Context] context
-  # @return [BenchmarkDriver::Metrics]
-  def run_benchmark(job, context:)
-    if job.from_jit
-      if job.to_jit
-        benchmark = BenchmarkJT2JT.new(num_methods: job.num_methods, loop_count: job.loop_count)
-      else
-        raise NotImplementedError, "JT2VM is not implemented yet"
-      end
-    else
-      if job.to_jit
-        benchmark = BenchmarkVM2JT.new(num_methods: job.num_methods, loop_count: job.loop_count)
-      else
-        benchmark = BenchmarkVM2VM.new(num_methods: job.num_methods, loop_count: job.loop_count)
-      end
-    end
-
-    duration = Tempfile.open(['benchmark_driver-result', '.txt']) do |f|
-      with_script(benchmark.render(result: f.path)) do |path|
-        opt = []
-        if context.executable.command.any? { |c| c.start_with?('--jit') }
-          opt << '--jit-min-calls=2'
-        end
-        IO.popen([*context.executable.command, '--disable-gems', *opt, path], &:read)
-        if $?.success?
-          Float(f.read)
-        else
-          BenchmarkDriver::Result::ERROR
-        end
-      end
-    end
-
-    [job.loop_count.to_f / duration, duration]
-  end
-
-  def with_script(script)
-    if @config.verbose >= 2
-      sep = '-' * 30
-      $stdout.puts "\n\n#{sep}[Script begin]#{sep}\n#{script}#{sep}[Script end]#{sep}\n\n"
-    end
-
-    Tempfile.open(['benchmark_driver-', '.rb']) do |f|
-      f.puts script
-      f.close
-      return yield(f.path)
-    end
-  end
-
-  # @param [Integer] num_methods
-  # @param [Integer] loop_count
-  BenchmarkVM2VM = ::BenchmarkDriver::Struct.new(:num_methods, :loop_count) do
-    # @param [String] result - A file to write result
-    def render(result:)
-      ERB.new(<<~EOS, trim_mode: '%').result(binding)
-        % num_methods.times do |i|
-        def a<%= i %>
-          nil
-        end
-        % end
-        RubyVM::MJIT.pause if defined?(RubyVM::MJIT) && RubyVM::MJIT.enabled?
-
-        def vm
-          t = Process.clock_gettime(Process::CLOCK_MONOTONIC)
-          i = 0
-          while i < <%= loop_count / 1000 %>
-        % 1000.times do |i|
-            a<%= i % num_methods %>
-        % end
-            i += 1
-          end
-        % (loop_count % 1000).times do |i|
-          a<%= i % num_methods %>
-        % end
-          Process.clock_gettime(Process::CLOCK_MONOTONIC) - t
-        end
-
-        vm # warmup call cache
-        File.write(<%= result.dump %>, vm)
-      EOS
-    end
-  end
-  private_constant :BenchmarkVM2VM
-
-  # @param [Integer] num_methods
-  # @param [Integer] loop_count
-  BenchmarkVM2JT = ::BenchmarkDriver::Struct.new(:num_methods, :loop_count) do
-    # @param [String] result - A file to write result
-    def render(result:)
-      ERB.new(<<~EOS, trim_mode: '%').result(binding)
-        % num_methods.times do |i|
-        def a<%= i %>
-          nil
-        end
-        a<%= i %>
-        a<%= i %> # --jit-min-calls=2
-        % end
-        RubyVM::MJIT.pause if defined?(RubyVM::MJIT) && RubyVM::MJIT.enabled?
-
-        def vm
-          t = Process.clock_gettime(Process::CLOCK_MONOTONIC)
-          i = 0
-          while i < <%= loop_count / 1000 %>
-        % 1000.times do |i|
-            a<%= i % num_methods %>
-        % end
-            i += 1
-          end
-        % (loop_count % 1000).times do |i|
-          a<%= i % num_methods %>
-        % end
-          Process.clock_gettime(Process::CLOCK_MONOTONIC) - t
-        end
-
-        vm # warmup call cache
-        File.write(<%= result.dump %>, vm)
-      EOS
-    end
-  end
-  private_constant :BenchmarkVM2JT
-
-  # @param [Integer] num_methods
-  # @param [Integer] loop_count
-  BenchmarkJT2JT = ::BenchmarkDriver::Struct.new(:num_methods, :loop_count) do
-    # @param [String] result - A file to write result
-    def render(result:)
-      ERB.new(<<~EOS, trim_mode: '%').result(binding)
-        % num_methods.times do |i|
-        def a<%= i %>
-          nil
-        end
-        % end
-
-        # You may need to:
-        #   * Increase `JIT_ISEQ_SIZE_THRESHOLD` to 10000000 in mjit.h
-        #   * Always return false in `inlinable_iseq_p()` of mjit_compile.c
-        def jit
-          t = Process.clock_gettime(Process::CLOCK_MONOTONIC)
-          i = 0
-          while i < <%= loop_count / 1000 %>
-        % 1000.times do |i|
-            a<%= i % num_methods %>
-        % end
-            i += 1
-          end
-        % (loop_count % 1000).times do |i|
-          a<%= i % num_methods %>
-        % end
-          Process.clock_gettime(Process::CLOCK_MONOTONIC) - t
-        end
-
-        jit
-        jit
-        RubyVM::MJIT.pause if defined?(RubyVM::MJIT) && RubyVM::MJIT.enabled?
-        File.write(<%= result.dump %>, jit)
-      EOS
-    end
-  end
-  private_constant :BenchmarkJT2JT
-end
diff --git a/benchmark/loop_each.yml b/benchmark/loop_each.yml
new file mode 100644
index 0000000000..1c757185a8
--- /dev/null
+++ b/benchmark/loop_each.yml
@@ -0,0 +1,4 @@
+prelude: |
+  arr = [nil] * 30_000_000
+benchmark:
+  loop_each: arr.each{|e|}
diff --git a/benchmark/loop_generator.rb b/benchmark/loop_generator.rb
index d3375c744c..6a3194b670 100644
--- a/benchmark/loop_generator.rb
+++ b/benchmark/loop_generator.rb
@@ -1,4 +1,4 @@
-max = 600000
+max = 6000000
 
 if defined? Fiber
   gen = (1..max).each
diff --git a/benchmark/loop_times_megamorphic.yml b/benchmark/loop_times_megamorphic.yml
new file mode 100644
index 0000000000..f9343ba897
--- /dev/null
+++ b/benchmark/loop_times_megamorphic.yml
@@ -0,0 +1,7 @@
+prelude: |
+  eval(<<~EOS)
+    def loop_times_megamorphic
+      #{"1.times {|i|};" * 1000}
+    end
+  EOS
+benchmark: loop_times_megamorphic
diff --git a/benchmark/marshal_dump_load_integer.yml b/benchmark/marshal_dump_load_integer.yml
new file mode 100644
index 0000000000..78ebf823d2
--- /dev/null
+++ b/benchmark/marshal_dump_load_integer.yml
@@ -0,0 +1,22 @@
+prelude: |
+  smallint_array = 1000.times.map { |x| x }
+  bigint32_array = 1000.times.map { |x| x + 2**32 }
+  bigint64_array = 1000.times.map { |x| x + 2**64 }
+
+  smallint_dump = Marshal.dump(smallint_array)
+  bigint32_dump = Marshal.dump(bigint32_array)
+  bigint64_dump = Marshal.dump(bigint64_array)
+benchmark:
+  marshal_dump_integer_small: |
+    Marshal.dump(smallint_array)
+  marshal_dump_integer_over_32_bit: |
+    Marshal.dump(bigint32_array)
+  marshal_dump_integer_over_64_bit: |
+    Marshal.dump(bigint64_array)
+  marshal_load_integer_small: |
+    Marshal.load(smallint_dump)
+  marshal_load_integer_over_32_bit: |
+    Marshal.load(bigint32_dump)
+  marshal_load_integer_over_64_bit: |
+    Marshal.load(bigint64_dump)
+loop_count: 4000
diff --git a/benchmark/masgn.yml b/benchmark/masgn.yml
index 4be9333e23..31cb8ee4a3 100644
--- a/benchmark/masgn.yml
+++ b/benchmark/masgn.yml
@@ -1,7 +1,7 @@
 prelude: |
   a = [nil] * 3
   b = Class.new{attr_writer :a, :b, :c}.new
-  c, d, e, f = nil, nil, nil, nil
+  c = d = e = f = g = h = i = nil
 benchmark:
   array2_2: "c = (a[0], a[1] = 1, 2)"
   array2_3: "c = (a[0], a[1] = 1, 2, 3)"
@@ -27,3 +27,27 @@ benchmark:
   lvar2_3p: "(d, e = 1, 2, 3; nil)"
   lvar3_2p: "(d, e, f = 1, 2; nil)"
   lvar3_3p: "(d, e, f = 1, 2, 3; nil)"
+  array2_2lv: "c = (a[0], a[1] = g, h)"
+  array2_ilv: "c = (a[0], a[1] = g, h, i)"
+  arrayi_2lv: "c = (a[0], a[1], a[2] = g, h)"
+  arrayi_ilv: "c = (a[0], a[1], a[2] = g, h, i)"
+  attr2_2lv: "c = (b.a, b.b = g, h)"
+  attr2_ilv: "c = (b.a, b.b = g, h, i)"
+  attri_2lv: "c = (b.a, b.b, b.c = g, h)"
+  attri_ilv: "c = (b.a, b.b, b.c = g, h, i)"
+  lvar2_2lv: "c = (d, e = g, h)"
+  lvar2_ilv: "c = (d, e = g, h, i)"
+  lvari_2lv: "c = (d, e, f = g, h)"
+  lvari_ilv: "c = (d, e, f = g, h, i)"
+  array2_2plv: "(a[0], a[1] = g, h; nil)"
+  array2_iplv: "(a[0], a[1] = g, h, i; nil)"
+  arrayi_2plv: "(a[0], a[1], a[2] = g, h; nil)"
+  arrayi_iplv: "(a[0], a[1], a[2] = g, h, i; nil)"
+  attr2_2plv: "(b.a, b.b = g, h; nil)"
+  attr2_iplv: "(b.a, b.b = g, h, i; nil)"
+  attri_2plv: "(b.a, b.b, b.c = g, h; nil)"
+  attri_iplv: "(b.a, b.b, b.c = g, h, i; nil)"
+  lvar2_2plv: "(d, e = g, h; nil)"
+  lvar2_iplv: "(d, e = g, h, i; nil)"
+  lvari_2plv: "(d, e, f = g, h; nil)"
+  lvari_iplv: "(d, e, f = g, h, i; nil)"
diff --git a/benchmark/mjit_exec_jt2jt.yml b/benchmark/mjit_exec_jt2jt.yml
deleted file mode 100644
index 6c303c7a44..0000000000
--- a/benchmark/mjit_exec_jt2jt.yml
+++ /dev/null
@@ -1,6 +0,0 @@
-type: lib/benchmark_driver/runner/mjit_exec
-num_methods: [1]
-#num_methods: (1..100).to_a + [200, 300, 400, 500, 600, 700, 800, 900, 1000]
-loop_count: 50000000
-from_jit: true
-to_jit: true
diff --git a/benchmark/mjit_exec_vm2jt.yml b/benchmark/mjit_exec_vm2jt.yml
deleted file mode 100644
index 764883f070..0000000000
--- a/benchmark/mjit_exec_vm2jt.yml
+++ /dev/null
@@ -1,6 +0,0 @@
-type: lib/benchmark_driver/runner/mjit_exec
-num_methods: [1]
-#num_methods: (1..100).to_a + [200, 300, 400, 500, 600, 700, 800, 900, 1000]
-loop_count: 50000000
-from_jit: false
-to_jit: true
diff --git a/benchmark/mjit_exec_vm2vm.yml b/benchmark/mjit_exec_vm2vm.yml
deleted file mode 100644
index 030aa76c1c..0000000000
--- a/benchmark/mjit_exec_vm2vm.yml
+++ /dev/null
@@ -1,6 +0,0 @@
-type: lib/benchmark_driver/runner/mjit_exec
-num_methods: [1]
-#num_methods: (1..100).to_a + [200, 300, 400, 500, 600, 700, 800, 900, 1000]
-loop_count: 50000000
-from_jit: false
-to_jit: false
diff --git a/benchmark/mjit_exivar.yml b/benchmark/mjit_exivar.yml
deleted file mode 100644
index 2584fa6410..0000000000
--- a/benchmark/mjit_exivar.yml
+++ /dev/null
@@ -1,18 +0,0 @@
-type: lib/benchmark_driver/runner/mjit
-prelude: |
-  class Bench < Hash
-    def initialize
-      @exivar = nil
-    end
-
-    def exivar
-      @exivar
-    end
-  end
-
-  bench = Bench.new
-
-benchmark:
-  mjit_exivar: bench.exivar
-
-loop_count: 200000000
diff --git a/benchmark/mjit_integer.yml b/benchmark/mjit_integer.yml
deleted file mode 100644
index a6b5c9ee16..0000000000
--- a/benchmark/mjit_integer.yml
+++ /dev/null
@@ -1,32 +0,0 @@
-type: lib/benchmark_driver/runner/mjit
-prelude: |
-  def mjit_abs(int)        int.abs        end
-  def mjit_bit_length(int) int.bit_length end
-  def mjit_comp(int)       ~int           end
-  def mjit_even?(int)      int.even?      end
-  def mjit_integer?(int)   int.integer?   end
-  def mjit_magnitude(int)  int.magnitude  end
-  def mjit_odd?(int)       int.odd?       end
-  def mjit_ord(int)        int.ord        end
-  def mjit_size(int)       int.size       end
-  def mjit_to_i(int)       int.to_i       end
-  def mjit_to_int(int)     int.to_int     end
-  def mjit_uminus(int)     -int           end
-  def mjit_zero?(int)      int.zero?      end
-
-benchmark:
-  - mjit_abs(-1)
-  - mjit_bit_length(100)
-  - mjit_comp(1)
-  - mjit_even?(2)
-  - mjit_integer?(0)
-  - mjit_magnitude(-1)
-  - mjit_odd?(1)
-  - mjit_ord(1)
-  - mjit_size(1)
-  - mjit_to_i(1)
-  - mjit_to_int(1)
-  - mjit_uminus(1)
-  - mjit_zero?(0)
-
-loop_count: 40000000
diff --git a/benchmark/mjit_kernel.yml b/benchmark/mjit_kernel.yml
deleted file mode 100644
index 7720e65c2c..0000000000
--- a/benchmark/mjit_kernel.yml
+++ /dev/null
@@ -1,20 +0,0 @@
-type: lib/benchmark_driver/runner/mjit
-prelude: |
-  def mjit_class(obj)
-    obj.class
-  end
-
-  def mjit_frozen?(obj)
-    obj.frozen?
-  end
-
-  str = ""
-  fstr = "".freeze
-
-benchmark:
-  - mjit_class(self)
-  - mjit_class(1)
-  - mjit_frozen?(str)
-  - mjit_frozen?(fstr)
-
-loop_count: 40000000
diff --git a/benchmark/mjit_leave.yml b/benchmark/mjit_leave.yml
deleted file mode 100644
index 9ac68b164b..0000000000
--- a/benchmark/mjit_leave.yml
+++ /dev/null
@@ -1,8 +0,0 @@
-type: lib/benchmark_driver/runner/mjit
-prelude: |
-  def leave
-    nil
-  end
-benchmark:
-  mjit_leave: leave
-loop_count: 200000000
diff --git a/benchmark/mjit_opt_cc_insns.yml b/benchmark/mjit_opt_cc_insns.yml
deleted file mode 100644
index fed6d34bd5..0000000000
--- a/benchmark/mjit_opt_cc_insns.yml
+++ /dev/null
@@ -1,27 +0,0 @@
-# opt_* insns using vm_method_cfunc_is with send-compatible operands:
-#   * opt_nil_p
-#   * opt_not
-#   * opt_eq
-type: lib/benchmark_driver/runner/mjit
-prelude: |
-  def mjit_nil?(obj)
-    obj.nil?
-  end
-
-  def mjit_not(obj)
-    !obj
-  end
-
-  def mjit_eq(a, b)
-    a == b
-  end
-
-benchmark:
-  - script: mjit_nil?(1)
-    loop_count: 40000000
-  - script: mjit_not(1)
-    loop_count: 40000000
-  - script: mjit_eq(1, nil)
-    loop_count: 8000000
-  - script: mjit_eq(nil, 1)
-    loop_count: 8000000
diff --git a/benchmark/mjit_struct_aref.yml b/benchmark/mjit_struct_aref.yml
deleted file mode 100644
index bfba1323f2..0000000000
--- a/benchmark/mjit_struct_aref.yml
+++ /dev/null
@@ -1,10 +0,0 @@
-type: lib/benchmark_driver/runner/mjit
-prelude: |
-  def mjit_struct_aref(struct)
-    struct.aa
-  end
-  struct = Struct.new(:a0, :a1, :a2, :a3, :a4, :a5, :a6, :a7, :a8, :a9, :aa).new
-
-benchmark: mjit_struct_aref(struct)
-
-loop_count: 40000000
diff --git a/benchmark/numeric_methods.yml b/benchmark/numeric_methods.yml
index 433c2268a3..1384902935 100644
--- a/benchmark/numeric_methods.yml
+++ b/benchmark/numeric_methods.yml
@@ -10,4 +10,20 @@ benchmark:
     int.finite?
   infinite?: |
     int.infinite?
+  integer_real: |
+    int.real
+  float_real: |
+    flo.real
+  integr_imag: |
+    int.imag
+  float_imag: |
+    flo.imag
+  integer_conj: |
+    int.conj
+  float_conj: |
+    flo.conj
+  integer_numerator: |
+    int.numerator
+  integer_denominator: |
+    int.denominator
 loop_count: 20000000
diff --git a/benchmark/object_allocate.yml b/benchmark/object_allocate.yml
index 93ff463e41..bdbd4536db 100644
--- a/benchmark/object_allocate.yml
+++ b/benchmark/object_allocate.yml
@@ -11,6 +11,26 @@ prelude: |
   class OneTwentyEight
     128.times { include(Module.new) }
   end
+  class OnePositional
+    def initialize a; end
+  end
+  class TwoPositional
+    def initialize a, b; end
+  end
+  class ThreePositional
+    def initialize a, b, c; end
+  end
+  class FourPositional
+    def initialize a, b, c, d; end
+  end
+  class KWArg
+    def initialize a:, b:, c:, d:
+    end
+  end
+  class Mixed
+    def initialize a, b, c:, d:
+    end
+  end
   # Disable GC to see raw throughput:
   GC.disable
 benchmark:
@@ -18,4 +38,11 @@ benchmark:
   allocate_32_deep: ThirtyTwo.new
   allocate_64_deep: SixtyFour.new
   allocate_128_deep: OneTwentyEight.new
+  allocate_1_positional_params: OnePositional.new(1)
+  allocate_2_positional_params: TwoPositional.new(1, 2)
+  allocate_3_positional_params: ThreePositional.new(1, 2, 3)
+  allocate_4_positional_params: FourPositional.new(1, 2, 3, 4)
+  allocate_kwarg_params: "KWArg.new(a: 1, b: 2, c: 3, d: 4)"
+  allocate_mixed_params: "Mixed.new(1, 2, c: 3, d: 4)"
+  allocate_no_params: "Object.new"
 loop_count: 100000
diff --git a/benchmark/range_bsearch_bignum.yml b/benchmark/range_bsearch_bignum.yml
new file mode 100644
index 0000000000..5730c93fcf
--- /dev/null
+++ b/benchmark/range_bsearch_bignum.yml
@@ -0,0 +1,10 @@
+prelude: |
+  first = 2**100
+  last = 2**1000
+  mid = (first + last) / 2
+  r = first..last
+
+benchmark:
+  first: r.bsearch { |x| x >= first }
+  mid: r.bsearch { |x| x >= mid }
+  last: r.bsearch { |x| x >= last }
diff --git a/benchmark/range_bsearch_endpointless.yml b/benchmark/range_bsearch_endpointless.yml
new file mode 100644
index 0000000000..8d7bedb662
--- /dev/null
+++ b/benchmark/range_bsearch_endpointless.yml
@@ -0,0 +1,21 @@
+prelude: |
+  re = (1..)
+  rb = (..0)
+
+benchmark:
+  'endless 10**0': re.bsearch { |x| x >= 1 }
+  'endless 10**1': re.bsearch { |x| x >= 10 }
+  'endless 10**2': re.bsearch { |x| x >= 100 }
+  'endless 10**3': re.bsearch { |x| x >= 1000 }
+  'endless 10**4': re.bsearch { |x| x >= 10000 }
+  'endless 10**5': re.bsearch { |x| x >= 100000 }
+  'endless 10**10': re.bsearch { |x| x >= 10000000000 }
+  'endless 10**100': re.bsearch { |x| x >= 10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 }
+  'beginless -10**0': rb.bsearch { |x| x >= -1 }
+  'beginless -10**1': rb.bsearch { |x| x >= -10 }
+  'beginless -10**2': rb.bsearch { |x| x >= -100 }
+  'beginless -10**3': rb.bsearch { |x| x >= -1000 }
+  'beginless -10**4': rb.bsearch { |x| x >= -10000 }
+  'beginless -10**5': rb.bsearch { |x| x >= -100000 }
+  'beginless -10**10': rb.bsearch { |x| x >= -10000000000 }
+  'beginless -10**100': rb.bsearch { |x| x >= -10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 }
diff --git a/benchmark/range_bsearch_fixnum.yml b/benchmark/range_bsearch_fixnum.yml
new file mode 100644
index 0000000000..59416531b9
--- /dev/null
+++ b/benchmark/range_bsearch_fixnum.yml
@@ -0,0 +1,10 @@
+prelude: |
+  first = 1
+  last = 10000
+  mid = (first + last) / 2
+  r = first..last
+
+benchmark:
+  first: r.bsearch { |x| x >= first }
+  mid: r.bsearch { |x| x >= mid }
+  last: r.bsearch { |x| x >= last }
diff --git a/benchmark/range_count.yml b/benchmark/range_count.yml
new file mode 100644
index 0000000000..58f53a0236
--- /dev/null
+++ b/benchmark/range_count.yml
@@ -0,0 +1,11 @@
+prelude: |
+  r_1 = 1..1
+  r_1k = 1..1000
+  r_1m = 1..1000000
+  r_str = 'a'..'z'
+
+benchmark:
+  'int 1': r_1.count
+  'int 1K': r_1k.count
+  'int 1M': r_1m.count
+  string: r_str.count
diff --git a/benchmark/range_min.yml b/benchmark/range_min.yml
new file mode 100644
index 0000000000..9e60dd7308
--- /dev/null
+++ b/benchmark/range_min.yml
@@ -0,0 +1,2 @@
+benchmark:
+  - (1..10).min
diff --git a/benchmark/range_overlap.yml b/benchmark/range_overlap.yml
new file mode 100644
index 0000000000..700a00053c
--- /dev/null
+++ b/benchmark/range_overlap.yml
@@ -0,0 +1,19 @@
+prelude: |
+  class Range
+    unless method_defined?(:overlap?)
+      def overlap?(other)
+        other.begin == self.begin || cover?(other.begin) || other.cover?(self.begin)
+      end
+    end
+  end
+
+benchmark:
+  - (2..3).overlap?(1..1)
+  - (2..3).overlap?(2..4)
+  - (2..3).overlap?(4..5)
+  - (2..3).overlap?(2..1)
+  - (2..3).overlap?(0..1)
+  - (2..3).overlap?(...1)
+  - (2...3).overlap?(..2)
+  - (2...3).overlap?(3...)
+  - (2..3).overlap?('a'..'d')
diff --git a/benchmark/range_reverse_each.yml b/benchmark/range_reverse_each.yml
new file mode 100644
index 0000000000..a32efeccc6
--- /dev/null
+++ b/benchmark/range_reverse_each.yml
@@ -0,0 +1,16 @@
+prelude: |
+  rf_1 = 0..1
+  rf_1k = 0..1000
+  rf_1m = 0..1000000
+  big = 2**1000
+  rb_1 = big..big+1
+  rb_1k = big..big+1000
+  rb_1m = big..big+1000000
+
+benchmark:
+  "Fixnum 1": rf_1.reverse_each { _1 }
+  "Fixnum 1K": rf_1k.reverse_each { _1 }
+  "Fixnum 1M": rf_1m.reverse_each { _1 }
+  "Bignum 1": rb_1.reverse_each { _1 }
+  "Bignum 1K": rb_1k.reverse_each { _1 }
+  "Bignum 1M": rb_1m.reverse_each { _1 }
diff --git a/benchmark/realpath.yml b/benchmark/realpath.yml
index 90a029d5b9..6b6a4836b0 100644
--- a/benchmark/realpath.yml
+++ b/benchmark/realpath.yml
@@ -12,6 +12,9 @@ prelude: |
   relative_dir = 'b/c'
   absolute_dir = File.join(pwd, relative_dir)
   file_dir = 'c'
+teardown: |
+  require 'fileutils'
+  FileUtils.rm_rf('b')
 benchmark:
   relative_nil: "f.realpath(relative, nil)"
   absolute_nil: "f.realpath(absolute, nil)"
diff --git a/benchmark/regexp_dup.yml b/benchmark/regexp_dup.yml
new file mode 100644
index 0000000000..52f89991cd
--- /dev/null
+++ b/benchmark/regexp_dup.yml
@@ -0,0 +1,6 @@
+prelude: |
+  str = "a" * 1000
+  re = Regexp.new(str)
+
+benchmark:
+  dup: re.dup
diff --git a/benchmark/regexp_new.yml b/benchmark/regexp_new.yml
new file mode 100644
index 0000000000..bc9ab3ca21
--- /dev/null
+++ b/benchmark/regexp_new.yml
@@ -0,0 +1,7 @@
+prelude: |
+  str = "a" * 1000
+  re = Regexp.new(str)
+
+benchmark:
+  string: Regexp.new(str)
+  regexp: Regexp.new(re)
diff --git a/benchmark/scan.yaml b/benchmark/scan.yaml
new file mode 100644
index 0000000000..62ad1d6862
--- /dev/null
+++ b/benchmark/scan.yaml
@@ -0,0 +1,16 @@
+prelude: |
+  $LOAD_PATH.unshift(File.expand_path("lib"))
+  require "strscan"
+  str = "test string"
+  scanner = StringScanner.new(str)
+  str = "test"
+  reg = /test/
+benchmark:
+  check(reg): |
+    scanner.check(reg)
+  check(str): |
+    scanner.check(str)
+  match?(reg): |
+    scanner.match?(reg)
+  match?(str): |
+    scanner.match?(str)
diff --git a/benchmark/search.yaml b/benchmark/search.yaml
new file mode 100644
index 0000000000..42a50c90e6
--- /dev/null
+++ b/benchmark/search.yaml
@@ -0,0 +1,16 @@
+prelude: |
+  $LOAD_PATH.unshift(File.expand_path("lib"))
+  require "strscan"
+  str = "test string"
+  scanner = StringScanner.new(str)
+  str = "string"
+  reg = /string/
+benchmark:
+  check_until(reg): |
+    scanner.check_until(reg)
+  check_until(str): |
+    scanner.check_until(str)
+  exist?(reg): |
+    scanner.exist?(reg)
+  exist?(str): |
+    scanner.exist?(str)
diff --git a/benchmark/so_count_words.yml b/benchmark/so_count_words.yml
index 99683505f9..f7322a8541 100644
--- a/benchmark/so_count_words.yml
+++ b/benchmark/so_count_words.yml
@@ -15,13 +15,13 @@ prelude: |
   Newsgroups:   rec.games.roguelike.nethack
   X-Mailer:     Mozilla 1.1N (Macintosh; I; 68K)
 
-  Hello there, Izchak Miller was my father.  When I was younger I spent 
-  many a night, hunched over the keyboard with a cup of tea, playing 
-  nethack with him and my brother.  my dad was a philosopher with a strong 
-  weakness for fantasy/sci fi.  I remember when he started to get involved 
-  with the Nethack team- my brother's Dungeons and Dragons monster book 
-  found a regular place beside my dad's desk. it's nice to see him living 
-  on in the game he loved so much :-).  
+  Hello there,  Izchak Miller was my  father.  When I was  younger I spent
+  many  a night,  hunched over  the keyboard  with a  cup of  tea, playing
+  nethack with him and my brother.  my dad was a philosopher with a strong
+  weakness for fantasy/sci fi.  I remember when he started to get involved
+  with the  Nethack team- my  brother's Dungeons and Dragons  monster book
+  found a regular place beside my dad's  desk. it's nice to see him living
+  on in the game he loved so much :-).
                                                                     Tamar Miller
 
   The following is a really long word of 5000 characters:
@@ -38,8 +38,9 @@ prelude: |
       13.times{
         data << data
       }
-      open(wcinput, 'w'){|f| f.write data}
+      File.write(wcinput, data)
     end
+    at_exit {File.unlink(wcinput) rescue nil}
   end
 
   prepare_wc_input(wc_input_base)
@@ -49,16 +50,16 @@ benchmark:
     # $Id: wc-ruby.code,v 1.4 2004/11/13 07:43:32 bfulgham Exp $
     # http://www.bagley.org/~doug/shootout/
     # with help from Paul Brannan
-    input = open(File.join(File.dirname($0), 'wc.input'), 'rb')
 
     nl = nw = nc = 0
-    while true
-      tmp = input.read(4096) or break
-      data = tmp << (input.gets || "")
-      nc += data.length
-      nl += data.count("\n")
-      ((data.strip! || data).tr!("\n", " ") || data).squeeze!
-      nw += data.count(" ") + 1
+    File.open(File.join(File.dirname($0), 'wc.input'), 'rb') do |input|
+      while tmp = input.read(4096)
+        data = tmp << (input.gets || "")
+        nc += data.length
+        nl += data.count("\n")
+        ((data.strip! || data).tr!("\n", " ") || data).squeeze!
+        nw += data.count(" ") + 1
+      end
     end
     # STDERR.puts "#{nl} #{nw} #{nc}"
 
diff --git a/benchmark/so_meteor_contest.rb b/benchmark/so_meteor_contest.rb
index 8c136baa6c..d8c8e3ab9c 100644
--- a/benchmark/so_meteor_contest.rb
+++ b/benchmark/so_meteor_contest.rb
@@ -447,7 +447,7 @@ end
 #   as an inverse.  The inverse will ALWAYS be 3 one of the piece configurations that is exactly 3 rotations away
 #   (an odd number).  Checking even vs odd then produces a higher probability of finding more pieces earlier
 #   in the cycle.  We still need to keep checking all the permutations, but our probability of finding one will
-#   diminsh over time.  Since we are TOLD how many to search for this lets us exit before checking all pieces
+#   diminish over time.  Since we are TOLD how many to search for this lets us exit before checking all pieces
 #   this bennifit is very great when seeking small numbers of solutions and is 0 when looking for more than the
 #   maximum number
 def find_top( rotation_skip)
diff --git a/benchmark/so_nbody.rb b/benchmark/so_nbody.rb
index d6c5bb9e61..9884fc4edc 100644
--- a/benchmark/so_nbody.rb
+++ b/benchmark/so_nbody.rb
@@ -12,38 +12,38 @@ def _puts *args
 end
 
 class Planet
- attr_accessor :x, :y, :z, :vx, :vy, :vz, :mass
+  attr_accessor :x, :y, :z, :vx, :vy, :vz, :mass
 
- def initialize(x, y, z, vx, vy, vz, mass)
-  @x, @y, @z = x, y, z
-  @vx, @vy, @vz = vx * DAYS_PER_YEAR, vy * DAYS_PER_YEAR, vz * DAYS_PER_YEAR
-  @mass = mass * SOLAR_MASS
- end
-
- def move_from_i(bodies, nbodies, dt, i)
-  while i < nbodies
-   b2 = bodies[i]
-   dx = @x - b2.x
-   dy = @y - b2.y
-   dz = @z - b2.z
-
-   distance = Math.sqrt(dx * dx + dy * dy + dz * dz)
-   mag = dt / (distance * distance * distance)
-   b_mass_mag, b2_mass_mag = @mass * mag, b2.mass * mag
-
-   @vx -= dx * b2_mass_mag
-   @vy -= dy * b2_mass_mag
-   @vz -= dz * b2_mass_mag
-   b2.vx += dx * b_mass_mag
-   b2.vy += dy * b_mass_mag
-   b2.vz += dz * b_mass_mag
-   i += 1
+  def initialize(x, y, z, vx, vy, vz, mass)
+    @x, @y, @z = x, y, z
+    @vx, @vy, @vz = vx * DAYS_PER_YEAR, vy * DAYS_PER_YEAR, vz * DAYS_PER_YEAR
+    @mass = mass * SOLAR_MASS
   end
 
-  @x += dt * @vx
-  @y += dt * @vy
-  @z += dt * @vz
- end
+  def move_from_i(bodies, nbodies, dt, i)
+    while i < nbodies
+      b2 = bodies[i]
+      dx = @x - b2.x
+      dy = @y - b2.y
+      dz = @z - b2.z
+
+      distance = Math.sqrt(dx * dx + dy * dy + dz * dz)
+      mag = dt / (distance * distance * distance)
+      b_mass_mag, b2_mass_mag = @mass * mag, b2.mass * mag
+
+      @vx -= dx * b2_mass_mag
+      @vy -= dy * b2_mass_mag
+      @vz -= dz * b2_mass_mag
+      b2.vx += dx * b_mass_mag
+      b2.vy += dy * b_mass_mag
+      b2.vz += dz * b_mass_mag
+      i += 1
+    end
+
+    @x += dt * @vx
+    @y += dt * @vy
+    @z += dt * @vz
+  end
 end
 
 def energy(bodies)
diff --git a/benchmark/string_concat.yml b/benchmark/string_concat.yml
new file mode 100644
index 0000000000..f11f95ee9a
--- /dev/null
+++ b/benchmark/string_concat.yml
@@ -0,0 +1,51 @@
+prelude: |
+  CHUNK = "a" * 64
+  UCHUNK = "é" * 32
+  SHORT = "a" * (GC::INTERNAL_CONSTANTS[:BASE_SLOT_SIZE] / 2)
+  LONG = "a" * (GC::INTERNAL_CONSTANTS[:BASE_SLOT_SIZE] * 2)
+  GC.disable # GC causes a lot of variance
+benchmark:
+  binary_concat_7bit: |
+    buffer = String.new(capacity: 4096, encoding: Encoding::BINARY)
+    buffer << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK
+    buffer << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK
+    buffer << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK
+    buffer << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK
+    buffer << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK
+    buffer << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK
+    buffer << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK
+    buffer << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK
+  utf8_concat_7bit: |
+    buffer = String.new(capacity: 4096, encoding: Encoding::UTF_8)
+    buffer << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK
+    buffer << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK
+    buffer << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK
+    buffer << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK
+    buffer << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK
+    buffer << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK
+    buffer << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK
+    buffer << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK << CHUNK
+  utf8_concat_UTF8: |
+    buffer = String.new(capacity: 4096, encoding: Encoding::UTF_8)
+    buffer << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK
+    buffer << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK
+    buffer << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK
+    buffer << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK
+    buffer << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK
+    buffer << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK
+    buffer << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK
+    buffer << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK << UCHUNK
+  interpolation: |
+    buffer = "#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}" \
+      "#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}" \
+      "#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}" \
+      "#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}" \
+      "#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}" \
+      "#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}" \
+      "#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}" \
+      "#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}" \
+      "#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}#{CHUNK}"
+  interpolation_same_heap: |
+    buffer = "#{SHORT}#{SHORT}"
+  interpolation_switching_heaps: |
+    buffer = "#{SHORT}#{LONG}"
diff --git a/benchmark/string_dup.yml b/benchmark/string_dup.yml
new file mode 100644
index 0000000000..90793f9f2a
--- /dev/null
+++ b/benchmark/string_dup.yml
@@ -0,0 +1,7 @@
+prelude: |
+  # frozen_string_literal: true
+benchmark:
+  uplus: |
+    +"A"
+  dup: |
+    "A".dup
diff --git a/benchmark/string_rpartition.yml b/benchmark/string_rpartition.yml
new file mode 100644
index 0000000000..37e9d1b071
--- /dev/null
+++ b/benchmark/string_rpartition.yml
@@ -0,0 +1,18 @@
+prelude: |
+  str1 = [*"a".."z",*"0".."9"].join("")
+  str10 = str1 * 10 + ":"
+  str100 = str1 * 100 + ":"
+  str1000 = str1 * 1000 + ":"
+  nonascii1 = [*"\u{e0}".."\u{ff}"].join("")
+  nonascii10 = nonascii1 * 10 + ":"
+  nonascii100 = nonascii1 * 100 + ":"
+  nonascii1000 = nonascii1 * 1000 + ":"
+benchmark:
+  rpartition-1: str1.rpartition(":")
+  rpartition-10: str10.rpartition(":")
+  rpartition-100: str100.rpartition(":")
+  rpartition-1000: str1000.rpartition(":")
+  rpartition-nonascii1: nonascii1.rpartition(":")
+  rpartition-nonascii10: nonascii10.rpartition(":")
+  rpartition-nonascii100: nonascii100.rpartition(":")
+  rpartition-nonascii1000: nonascii1000.rpartition(":")
diff --git a/benchmark/struct_accessor.yml b/benchmark/struct_accessor.yml
new file mode 100644
index 0000000000..61176cfdd4
--- /dev/null
+++ b/benchmark/struct_accessor.yml
@@ -0,0 +1,25 @@
+prelude: |
+  C = Struct.new(:x) do
+    class_eval <<-END
+      def r
+        #{'x;'*256}
+      end
+      def w
+        #{'self.x = nil;'*256}
+      end
+      def rm
+        m = method(:x)
+        #{'m.call;'*256}
+      end
+      def wm
+        m = method(:x=)
+        #{'m.call(nil);'*256}
+      end
+    END
+  end
+  obj = C.new(nil)
+benchmark:
+  member_reader: "obj.r"
+  member_writer: "obj.w"
+  member_reader_method: "obj.rm"
+  member_writer_method: "obj.wm"
diff --git a/benchmark/time_parse.yml b/benchmark/time_parse.yml
index a6d6948b9c..6060b58bc6 100644
--- a/benchmark/time_parse.yml
+++ b/benchmark/time_parse.yml
@@ -6,3 +6,5 @@ benchmark:
   - Time.iso8601(iso8601)
   - Time.parse(iso8601)
   - Time.parse(inspect)
+  - Time.new(iso8601) rescue Time.iso8601(iso8601)
+  - Time.new(inspect) rescue Time.parse(inspect)
diff --git a/benchmark/time_strftime.yml b/benchmark/time_strftime.yml
new file mode 100644
index 0000000000..28f62aec87
--- /dev/null
+++ b/benchmark/time_strftime.yml
@@ -0,0 +1,7 @@
+prelude: |
+  # frozen_string_literal: true
+  time = Time.now
+benchmark:
+  - time.strftime("%FT%T")     # 19B
+  - time.strftime("%FT%T.%3N") # 23B
+  - time.strftime("%FT%T.%6N") # 26B
diff --git a/benchmark/time_xmlschema.yml b/benchmark/time_xmlschema.yml
new file mode 100644
index 0000000000..654e5cfcbc
--- /dev/null
+++ b/benchmark/time_xmlschema.yml
@@ -0,0 +1,27 @@
+prelude: |
+  # frozen_string_literal
+  unless Time.method_defined?(:xmlschema)
+    class Time
+      def xmlschema(fraction_digits=0)
+        fraction_digits = fraction_digits.to_i
+        s = strftime("%FT%T")
+        if fraction_digits > 0
+          s << strftime(".%#{fraction_digits}N")
+        end
+        s << (utc? ? 'Z' : strftime("%:z"))
+      end
+    end
+  end
+  time = Time.now
+  utc_time = Time.now.utc
+  fraction_sec = Time.at(123456789.quo(9999999999)).getlocal("+09:00")
+  future_time = Time.utc(10000)
+benchmark:
+  - time.xmlschema
+  - utc_time.xmlschema
+  - time.xmlschema(6)
+  - utc_time.xmlschema(6)
+  - time.xmlschema(9)
+  - utc_time.xmlschema(9)
+  - fraction_sec.xmlschema(10)
+  - future_time.xmlschema
diff --git a/benchmark/vm_call_bmethod.yml b/benchmark/vm_call_bmethod.yml
new file mode 100644
index 0000000000..40136e5aa4
--- /dev/null
+++ b/benchmark/vm_call_bmethod.yml
@@ -0,0 +1,37 @@
+prelude: |
+  define_method(:a0){}
+  define_method(:a1){|a| a}
+  define_method(:s){|*a| a}
+  define_method(:b){|kw: 1| kw}
+
+  t0 = 0.times.to_a
+  t1 = 1.times.to_a
+  t10 = 10.times.to_a
+  t100 = 100.times.to_a
+  kw = {kw: 2}
+benchmark:
+  bmethod_simple_0: |
+    a0
+  bmethod_simple_1: |
+    a1(1)
+  bmethod_simple_0_splat: |
+    a0(*t0)
+  bmethod_simple_1_splat: |
+    a1(*t1)
+  bmethod_no_splat: |
+    s
+  bmethod_0_splat: |
+    s(*t0)
+  bmethod_1_splat: |
+    s(*t1)
+  bmethod_10_splat: |
+    s(*t10)
+  bmethod_100_splat: |
+    s(*t100)
+  bmethod_kw: |
+    b(kw: 1)
+  bmethod_no_kw: |
+    b
+  bmethod_kw_splat: |
+    b(**kw)
+loop_count: 6000000
diff --git a/benchmark/vm_call_kw_and_kw_splat.yml b/benchmark/vm_call_kw_and_kw_splat.yml
new file mode 100644
index 0000000000..aa6e549e0c
--- /dev/null
+++ b/benchmark/vm_call_kw_and_kw_splat.yml
@@ -0,0 +1,25 @@
+prelude: |
+  h1, h10, h100, h1000 = [1, 10, 100, 1000].map do |n|
+    h = {kw: 1}
+    n.times{|i| h[i.to_s.to_sym] = i}
+    h
+  end
+  eh = {}
+  def kw(kw: nil, **kws) end
+benchmark:
+  1: |
+    kw(**h1)
+  1_mutable: |
+    kw(**eh, **h1)
+  10: |
+    kw(**h10)
+  10_mutable: |
+    kw(**eh, **h10)
+  100: |
+    kw(**h100)
+  100_mutable: |
+    kw(**eh, **h100)
+  1000: |
+    kw(**h1000)
+  1000_mutable: |
+    kw(**eh, **h1000)
diff --git a/benchmark/vm_call_method_missing.yml b/benchmark/vm_call_method_missing.yml
new file mode 100644
index 0000000000..f890796f11
--- /dev/null
+++ b/benchmark/vm_call_method_missing.yml
@@ -0,0 +1,62 @@
+prelude: |
+  class A0
+    def method_missing(m); m end
+  end
+  class A1
+    def method_missing(m, a) a; end
+  end
+  class S
+    def method_missing(m, *a) a; end
+  end
+  class B
+    def method_missing(m, kw: 1) kw end
+  end
+  class SB
+    def method_missing(m, *a, kw: 1) kw end
+  end
+
+  t0 = 0.times.to_a
+  t1 = 1.times.to_a
+  t10 = 10.times.to_a
+  t200 = 200.times.to_a
+  kw = {kw: 2}
+
+  a0 = A0.new
+  a1 = A1.new
+  s = S.new
+  b = B.new
+  sb = SB.new
+benchmark:
+  method_missing_simple_0: |
+    a0.()
+  method_missing_simple_1: |
+    a1.x(1)
+  method_missing_simple_0_splat: |
+    a0.(*t0)
+  method_missing_simple_1_splat: |
+    a1.(*t1)
+  method_missing_no_splat: |
+    s.()
+  method_missing_0_splat: |
+    s.(*t0)
+  method_missing_1_splat: |
+    s.(*t1)
+  method_missing_10_splat: |
+    s.(*t10)
+  method_missing_200_splat: |
+    s.(*t200)
+  method_missing_kw: |
+    b.(kw: 1)
+  method_missing_no_kw: |
+    b.()
+  method_missing_kw_splat: |
+    b.(**kw)
+  method_missing_0_splat_kw: |
+    sb.(*t0, **kw)
+  method_missing_1_splat_kw: |
+    sb.(*t1, **kw)
+  method_missing_10_splat_kw: |
+    sb.(*t10, **kw)
+  method_missing_200_splat_kw: |
+    sb.(*t200, **kw)
+loop_count: 1000000
diff --git a/benchmark/vm_call_send_iseq.yml b/benchmark/vm_call_send_iseq.yml
new file mode 100644
index 0000000000..60ff23c475
--- /dev/null
+++ b/benchmark/vm_call_send_iseq.yml
@@ -0,0 +1,77 @@
+prelude: |
+  def a0; end
+  def a1(a) a; end
+  def s(*a) a; end
+  def b(kw: 1) kw end
+  def sb(*a, kw: 1) kw end
+
+  t0 = 0.times.to_a
+  t1 = 1.times.to_a
+  t10 = 10.times.to_a
+  t200 = 200.times.to_a
+
+  a0_t0 = [:a0, *t0]
+  a1_t1 = [:a1, *t1]
+  s_t0 = [:s, *t0]
+  s_t1 = [:s, *t1]
+  s_t10 = [:s, *t10]
+  s_t200 = [:s, *t200]
+  sb_t0 = [:sb, *t0]
+  sb_t1 = [:sb, *t1]
+  sb_t10 = [:sb, *t10]
+  sb_t200 = [:sb, *t200]
+  kw = {kw: 2}
+benchmark:
+  send_simple_0: |
+    send(:a0)
+  send_simple_1: |
+    send(:a1, 1)
+  send_simple_0_splat: |
+    send(:a0, *t0)
+  send_simple_1_splat: |
+    send(:a1, *t1)
+  send_simple_0_splat_comb: |
+    send(*a0_t0)
+  send_simple_1_splat_comb: |
+    send(*a1_t1)
+  send_no_splat: |
+    send(:s)
+  send_0_splat: |
+    send(:s, *t0)
+  send_1_splat: |
+    send(:s, *t1)
+  send_10_splat: |
+    send(:s, *t10)
+  send_200_splat: |
+    send(:s, *t200)
+  send_0_splat_comb: |
+    send(*s_t0)
+  send_1_splat_comb: |
+    send(*s_t1)
+  send_10_splat_comb: |
+    send(*s_t10)
+  send_200_splat_comb: |
+    send(*s_t200)
+  send_kw: |
+    send(:b, kw: 1)
+  send_no_kw: |
+    send(:b)
+  send_kw_splat: |
+    send(:b, **kw)
+  send_0_splat_kw: |
+    send(:sb, *t0, **kw)
+  send_1_splat_kw: |
+    send(:sb, *t1, **kw)
+  send_10_splat_kw: |
+    send(:sb, *t10, **kw)
+  send_200_splat_kw: |
+    send(:sb, *t200, **kw)
+  send_0_splat_comb_kw: |
+    send(*sb_t0, **kw)
+  send_1_splat_comb_kw: |
+    send(*sb_t1, **kw)
+  send_10_splat_comb_kw: |
+    send(*sb_t10, **kw)
+  send_200_splat_comb_kw: |
+    send(*sb_t200, **kw)
+loop_count: 3000000
diff --git a/benchmark/vm_call_symproc.yml b/benchmark/vm_call_symproc.yml
new file mode 100644
index 0000000000..16e0ac579e
--- /dev/null
+++ b/benchmark/vm_call_symproc.yml
@@ -0,0 +1,83 @@
+prelude: |
+  def self.a0; end
+  def self.a1(a) a; end
+  def self.s(*a) a; end
+  def self.b(kw: 1) kw end
+  def self.sb(*a, kw: 1) kw end
+
+  t0 = 0.times.to_a
+  t1 = 1.times.to_a
+  t10 = 10.times.to_a
+  t200 = 200.times.to_a
+
+  a0_t0 = [self, *t0]
+  a1_t1 = [self, *t1]
+  s_t0 = [self, *t0]
+  s_t1 = [self, *t1]
+  s_t10 = [self, *t10]
+  s_t200 = [self, *t200]
+  sb_t0 = [self, *t0]
+  sb_t1 = [self, *t1]
+  sb_t10 = [self, *t10]
+  sb_t200 = [self, *t200]
+  kw = {kw: 2}
+
+  a0 = :a0.to_proc
+  a1 = :a1.to_proc
+  s = :s.to_proc
+  b = :b.to_proc
+  sb = :sb.to_proc
+benchmark:
+  symproc_simple_0: |
+    a0.(self)
+  symproc_simple_1: |
+    a1.(self, 1)
+  symproc_simple_0_splat: |
+    a0.(self, *t0)
+  symproc_simple_1_splat: |
+    a1.(self, *t1)
+  symproc_simple_0_splat_comb: |
+    a0.(*a0_t0)
+  symproc_simple_1_splat_comb: |
+    a1.(*a1_t1)
+  symproc_no_splat: |
+    s.(self)
+  symproc_0_splat: |
+    s.(self, *t0)
+  symproc_1_splat: |
+    s.(self, *t1)
+  symproc_10_splat: |
+    s.(self, *t10)
+  symproc_200_splat: |
+    s.(self, *t200)
+  symproc_0_splat_comb: |
+    s.(*s_t0)
+  symproc_1_splat_comb: |
+    s.(*s_t1)
+  symproc_10_splat_comb: |
+    s.(*s_t10)
+  symproc_200_splat_comb: |
+    s.(*s_t200)
+  symproc_kw: |
+    b.(self, kw: 1)
+  symproc_no_kw: |
+    b.(self)
+  symproc_kw_splat: |
+    b.(self, **kw)
+  symproc_0_splat_kw: |
+    sb.(self, *t0, **kw)
+  symproc_1_splat_kw: |
+    sb.(self, *t1, **kw)
+  symproc_10_splat_kw: |
+    sb.(self, *t10, **kw)
+  symproc_200_splat_kw: |
+    sb.(self, *t200, **kw)
+  symproc_0_splat_comb_kw: |
+    sb.(*sb_t0, **kw)
+  symproc_1_splat_comb_kw: |
+    sb.(*sb_t1, **kw)
+  symproc_10_splat_comb_kw: |
+    sb.(*sb_t10, **kw)
+  symproc_200_splat_comb_kw: |
+    sb.(*sb_t200, **kw)
+loop_count: 1000000
diff --git a/benchmark/vm_const.yml b/benchmark/vm_const.yml
index 6064d4eed0..8939ca0cd3 100644
--- a/benchmark/vm_const.yml
+++ b/benchmark/vm_const.yml
@@ -1,7 +1,13 @@
 prelude: |
   Const = 1
+  A = B = C = D = E = F = G = H = I = J = K = L = M = N = O = P = Q = R = S = T = U = V = W = X = Y = Z = 1
+  def foo
+    A; B; C; D; E; F; G; H; I; J; K; L; M; N; O; P; Q; R; S; T; U; V; W; X; Y; Z
+  end
 benchmark:
   vm_const: |
     j = Const
     k = Const
+  vm_const_many: |
+    foo
 loop_count: 30000000
diff --git a/benchmark/vm_freezeobj.yml b/benchmark/vm_freezeobj.yml
new file mode 100644
index 0000000000..69a795a354
--- /dev/null
+++ b/benchmark/vm_freezeobj.yml
@@ -0,0 +1,6 @@
+prelude: |
+ objs = 100000.times.map { Object.new }
+benchmark:
+  vm_freeze_obj: |
+    objs.map(&:freeze)
+loop_count: 600
diff --git a/benchmark/vm_ivar_embedded_obj_init.yml b/benchmark/vm_ivar_embedded_obj_init.yml
new file mode 100644
index 0000000000..74fe20a630
--- /dev/null
+++ b/benchmark/vm_ivar_embedded_obj_init.yml
@@ -0,0 +1,14 @@
+prelude: |
+  class C
+    def set_ivars
+      @a = nil
+      @b = nil
+      @c = nil
+    end
+  end
+
+  c = C.new
+benchmark:
+  vm_ivar_embedded_obj_init: |
+    c.set_ivars
+loop_count: 30000000
diff --git a/benchmark/vm_ivar_extended_obj_init.yml b/benchmark/vm_ivar_extended_obj_init.yml
new file mode 100644
index 0000000000..f054bab282
--- /dev/null
+++ b/benchmark/vm_ivar_extended_obj_init.yml
@@ -0,0 +1,16 @@
+prelude: |
+  class C
+    def set_ivars
+      @a = nil
+      @b = nil
+      @c = nil
+      @d = nil
+      @e = nil
+    end
+  end
+
+  c = C.new
+benchmark:
+  vm_ivar_extended_obj_init: |
+    c.set_ivars
+loop_count: 30000000
diff --git a/benchmark/vm_ivar_generic_get.yml b/benchmark/vm_ivar_generic_get.yml
new file mode 100644
index 0000000000..dae2d37671
--- /dev/null
+++ b/benchmark/vm_ivar_generic_get.yml
@@ -0,0 +1,17 @@
+prelude: |
+  class C < Array
+    attr_reader :a, :b, :c
+    def initialize
+      @a = nil
+      @b = nil
+      @c = nil
+    end
+  end
+
+  c = C.new
+benchmark:
+  vm_ivar_generic_get: |
+    c.a
+    c.b
+    c.c
+loop_count: 30000000
diff --git a/benchmark/vm_ivar_generic_set.yml b/benchmark/vm_ivar_generic_set.yml
new file mode 100644
index 0000000000..102a6577fb
--- /dev/null
+++ b/benchmark/vm_ivar_generic_set.yml
@@ -0,0 +1,14 @@
+prelude: |
+  class C < Array
+    def set_ivars
+      @a = nil
+      @b = nil
+      @c = nil
+    end
+  end
+
+  c = C.new
+benchmark:
+  vm_ivar_generic_set: |
+    c.set_ivars
+loop_count: 30000000
diff --git a/benchmark/vm_ivar_get.yml b/benchmark/vm_ivar_get.yml
new file mode 100644
index 0000000000..9174af6965
--- /dev/null
+++ b/benchmark/vm_ivar_get.yml
@@ -0,0 +1,37 @@
+prelude: |
+  class Example
+    def initialize
+      @v0 = 1
+      @v1 = 2
+      @v3 = 3
+      @levar = 1
+    end
+
+    def get_value_loop
+      sum = 0
+
+      i = 0
+      while i < 1000000
+        # 10 times to de-emphasize loop overhead
+        sum += @levar
+        sum += @levar
+        sum += @levar
+        sum += @levar
+        sum += @levar
+        sum += @levar
+        sum += @levar
+        sum += @levar
+        sum += @levar
+        sum += @levar
+        i += 1
+      end
+
+      return sum
+    end
+  end
+
+  obj = Example.new
+benchmark:
+  vm_ivar_get: |
+    obj.get_value_loop
+loop_count: 100
diff --git a/benchmark/vm_ivar_get_unintialized.yml b/benchmark/vm_ivar_get_unintialized.yml
new file mode 100644
index 0000000000..a1ccfb06ce
--- /dev/null
+++ b/benchmark/vm_ivar_get_unintialized.yml
@@ -0,0 +1,12 @@
+prelude: |
+  class Example
+    def read
+      @uninitialized
+    end
+  end
+
+  obj = Example.new
+benchmark:
+  vm_ivar_get_uninitialized: |
+    obj.read
+loop_count: 30000000
diff --git a/benchmark/vm_ivar_ic_miss.yml b/benchmark/vm_ivar_ic_miss.yml
new file mode 100644
index 0000000000..944fb1a9e6
--- /dev/null
+++ b/benchmark/vm_ivar_ic_miss.yml
@@ -0,0 +1,20 @@
+prelude: |
+  class Foo
+    def initialize diverge
+      if diverge
+        @a = 1
+      end
+
+      @a0 = @a1 = @a2 = @a3 = @a4 = @a5 = @a6 = @a7 = @a8 = @a9 = @a10 = @a11 = @a12 = @a13 = @a14 = @a15 = @a16 = @a17 = @a18 = @a19 = @a20 = @a21 = @a22 = @a23 = @a24 = @a25 = @a26 = @a27 = @a28 = @a29 = @a30 = @a31 = @a32 = @a33 = @a34 = @a35 = @a36 = @a37 = @a38 = @a39 = @a40 = @a41 = @a42 = @a43 = @a44 = @a45 = @a46 = @a47 = @a48 = @a49 = @a50 = @a51 = @a52 = @a53 = @a54 = @a55 = @a56 = @a57 = @a58 = @a59 = @a60 = @a61 = @a62 = @a63 = @a64 = @a65 = @a66 = @a67 = @a68 = @a69 = @a70 = @a71 = @a72 = @a73 = @a74 = @b = 1
+    end
+
+    def b; @b; end
+  end
+
+  a = Foo.new false
+  b = Foo.new true
+benchmark:
+  vm_ivar_ic_miss: |
+    a.b
+    b.b
+loop_count: 30000000
diff --git a/benchmark/vm_ivar_init.yml b/benchmark/vm_ivar_init.yml
deleted file mode 100644
index c6f1633907..0000000000
--- a/benchmark/vm_ivar_init.yml
+++ /dev/null
@@ -1,14 +0,0 @@
-prelude: |
-  class C
-    def initialize
-      @a = nil
-      @b = nil
-      @c = nil
-      @d = nil
-      @e = nil
-    end
-  end
-benchmark:
-  vm_ivar_init: |
-    C.new
-loop_count: 30000000
diff --git a/benchmark/vm_ivar_lazy_set.yml b/benchmark/vm_ivar_lazy_set.yml
new file mode 100644
index 0000000000..7372ffcfbc
--- /dev/null
+++ b/benchmark/vm_ivar_lazy_set.yml
@@ -0,0 +1,12 @@
+prelude: |
+  class Example
+    def lazy_set
+      @uninitialized ||= 123
+    end
+  end
+
+  objs = 10000000.times.map { Example.new }
+benchmark:
+  vm_ivar_lazy_set: |
+    objs.each(&:lazy_set)
+loop_count: 1
diff --git a/benchmark/vm_ivar_memoize.yml b/benchmark/vm_ivar_memoize.yml
new file mode 100644
index 0000000000..90f6b07f05
--- /dev/null
+++ b/benchmark/vm_ivar_memoize.yml
@@ -0,0 +1,85 @@
+prelude: |
+  IVARS = 60
+  class Record
+    def initialize(offset = false)
+      @offset = 1 if offset
+      @first = 0
+      IVARS.times do |i|
+        instance_variable_set("@ivar_#{i}", i)
+      end
+    end
+
+    def first
+      @first
+    end
+
+    def lazy_set
+      @lazy_set ||= 123
+    end
+
+    def undef
+      @undef
+    end
+  end
+
+  Record.new # Need one alloc to right size
+
+  BASE = Record.new
+  LAZY = Record.new
+  LAZY.lazy_set
+
+  class Miss < Record
+    @first = 0
+    IVARS.times do |i|
+      instance_variable_set("@i_#{i}", i)
+    end
+  end
+
+  Miss.new # Need one alloc to right size
+  MISS = Miss.new
+
+  DIVERGENT = Record.new(true)
+
+benchmark:
+  vm_ivar_stable_shape: |
+    BASE.first
+    BASE.first
+    BASE.first
+    BASE.first
+    BASE.first
+    BASE.first
+  vm_ivar_memoize_unstable_shape: |
+    BASE.first
+    LAZY.first
+    BASE.first
+    LAZY.first
+    BASE.first
+    LAZY.first
+  vm_ivar_memoize_unstable_shape_miss: |
+    BASE.first
+    MISS.first
+    BASE.first
+    MISS.first
+    BASE.first
+    MISS.first
+  vm_ivar_unstable_undef: |
+    BASE.undef
+    LAZY.undef
+    BASE.undef
+    LAZY.undef
+    BASE.undef
+    LAZY.undef
+  vm_ivar_divergent_shape: |
+    BASE.first
+    DIVERGENT.first
+    BASE.first
+    DIVERGENT.first
+    BASE.first
+    DIVERGENT.first
+  vm_ivar_divergent_shape_imbalanced: |
+    BASE.first
+    DIVERGENT.first
+    DIVERGENT.first
+    DIVERGENT.first
+    DIVERGENT.first
+    DIVERGENT.first
diff --git a/benchmark/vm_ivar_set_on_instance.yml b/benchmark/vm_ivar_set_on_instance.yml
new file mode 100644
index 0000000000..91857b7742
--- /dev/null
+++ b/benchmark/vm_ivar_set_on_instance.yml
@@ -0,0 +1,35 @@
+prelude: |
+  class TheClass
+    def initialize
+      @v0 = 1
+      @v1 = 2
+      @v3 = 3
+      @levar = 1
+    end
+
+    def set_value_loop
+      # 1M
+      i = 0
+      while i < 1000000
+        # 10 times to de-emphasize loop overhead
+        @levar = i
+        @levar = i
+        @levar = i
+        @levar = i
+        @levar = i
+        @levar = i
+        @levar = i
+        @levar = i
+        @levar = i
+        @levar = i
+        i += 1
+      end
+    end
+  end
+
+  obj = TheClass.new
+
+benchmark:
+  vm_ivar_set_on_instance: |
+    obj.set_value_loop
+loop_count: 100
diff --git a/benchmark/vm_ivar_set_subclass.yml b/benchmark/vm_ivar_set_subclass.yml
index 2653d36ded..bc8bf5bf6b 100644
--- a/benchmark/vm_ivar_set_subclass.yml
+++ b/benchmark/vm_ivar_set_subclass.yml
@@ -1,6 +1,6 @@
 prelude: |
   class A
-    def initialize
+    def set_ivars
       @a = nil
       @b = nil
       @c = nil
@@ -10,8 +10,11 @@ prelude: |
   end
   class B < A; end
   class C < A; end
+
+  b = B.new
+  c = C.new
 benchmark:
   vm_ivar_init_subclass: |
-    B.new
-    C.new
+    b.set_ivars
+    c.set_ivars
 loop_count: 3000000
diff --git a/benchmark/vm_lvar_cond_set.yml b/benchmark/vm_lvar_cond_set.yml
new file mode 100644
index 0000000000..1845f9d12e
--- /dev/null
+++ b/benchmark/vm_lvar_cond_set.yml
@@ -0,0 +1,8 @@
+benchmark:
+  vm_lvar_cond_set: |
+    a ||= 1
+    b ||= 1
+    c ||= 1
+    d ||= 1
+    nil
+loop_count: 30000000
diff --git a/benchmark/vm_method_splat_calls.yml b/benchmark/vm_method_splat_calls.yml
new file mode 100644
index 0000000000..f2f366e99c
--- /dev/null
+++ b/benchmark/vm_method_splat_calls.yml
@@ -0,0 +1,13 @@
+prelude: |
+  def f(x=0, y: 0) end
+  a = [1]
+  ea = []
+  kw = {y: 1}
+  b = lambda{}
+benchmark:
+  arg_splat: "f(1, *ea)"
+  arg_splat_block: "f(1, *ea, &b)"
+  splat_kw_splat: "f(*a, **kw)"
+  splat_kw_splat_block: "f(*a, **kw, &b)"
+  splat_kw: "f(*a, y: 1)"
+  splat_kw_block: "f(*a, y: 1, &b)"
diff --git a/benchmark/vm_method_splat_calls2.yml b/benchmark/vm_method_splat_calls2.yml
new file mode 100644
index 0000000000..d33dcd7e8b
--- /dev/null
+++ b/benchmark/vm_method_splat_calls2.yml
@@ -0,0 +1,27 @@
+prelude: |
+  def named_arg_splat(*a) end
+  def named_arg_kw_splat(*a, **kw) end
+  def anon_arg_splat(*) end
+  def anon_kw_splat(**) end
+  def anon_arg_kw_splat(*, **) end
+  def anon_fw_to_named(*, **) named_arg_kw_splat(*, **) end
+  def fw_to_named(...) named_arg_kw_splat(...) end
+  def fw_to_anon_to_named(...) anon_fw_to_named(...) end
+  def fw_no_kw(...) named_arg_splat(...) end
+  a = [1]
+  kw = {y: 1}
+benchmark:
+  named_multi_arg_splat: "named_arg_splat(*a, *a)"
+  named_post_splat: "named_arg_splat(*a, a)"
+  anon_arg_splat: "anon_arg_splat(*a)"
+  anon_arg_kw_splat: "anon_arg_kw_splat(*a, **kw)"
+  anon_multi_arg_splat: "anon_arg_splat(*a, *a)"
+  anon_post_splat: "anon_arg_splat(*a, a)"
+  anon_kw_splat: "anon_kw_splat(**kw)"
+  anon_fw_to_named_splat: "anon_fw_to_named(*a, **kw)"
+  anon_fw_to_named_no_splat: "anon_fw_to_named(1, y: 1)"
+  fw_to_named_splat: "fw_to_named(*a, **kw)"
+  fw_to_named_no_splat: "fw_to_named(1, y: 1)"
+  fw_to_anon_to_named_splat: "fw_to_anon_to_named(*a, **kw)"
+  fw_to_anon_to_named_no_splat: "fw_to_anon_to_named(1, y: 1)"
+  fw_no_kw: "fw_no_kw(1, 2)"
diff --git a/benchmark/vm_send_cfunc.yml b/benchmark/vm_send_cfunc.yml
index b114ac317d..6f12b65176 100644
--- a/benchmark/vm_send_cfunc.yml
+++ b/benchmark/vm_send_cfunc.yml
@@ -1,3 +1,14 @@
+prelude: |
+  ary = []
+  kw = {a: 1}
+  empty_kw = {}
+  kw_ary = [Hash.ruby2_keywords_hash(a: 1)]
+  empty_kw_ary = [Hash.ruby2_keywords_hash({})]
 benchmark:
-  vm_send_cfunc: self.class
-loop_count: 100000000
+  vm_send_cfunc: itself
+  vm_send_cfunc_splat: itself(*ary)
+  vm_send_cfunc_splat_kw_hash: equal?(*kw_ary)
+  vm_send_cfunc_splat_empty_kw_hash: itself(*empty_kw_ary)
+  vm_send_cfunc_splat_kw: equal?(*ary, **kw)
+  vm_send_cfunc_splat_empty_kw: itself(*ary, **empty_kw)
+loop_count: 20000000
diff --git a/benchmark/vm_super_splat_calls.yml b/benchmark/vm_super_splat_calls.yml
new file mode 100644
index 0000000000..795e44e4da
--- /dev/null
+++ b/benchmark/vm_super_splat_calls.yml
@@ -0,0 +1,25 @@
+prelude: |
+  @a = [1].freeze
+  @ea = [].freeze
+  @kw = {y: 1}.freeze
+  @b = lambda{}
+  extend(Module.new{def arg_splat(x=0, y: 0) end})
+  extend(Module.new{def arg_splat_block(x=0, y: 0) end})
+  extend(Module.new{def splat_kw_splat(x=0, y: 0) end})
+  extend(Module.new{def splat_kw_splat_block(x=0, y: 0) end})
+  extend(Module.new{def splat_kw(x=0, y: 0) end})
+  extend(Module.new{def splat_kw_block(x=0, y: 0) end})
+
+  extend(Module.new{def arg_splat; super(1, *@ea) end})
+  extend(Module.new{def arg_splat_block; super(1, *@ea, &@b) end})
+  extend(Module.new{def splat_kw_splat; super(*@a, **@kw) end})
+  extend(Module.new{def splat_kw_splat_block; super(*@a, **@kw, &@b) end})
+  extend(Module.new{def splat_kw; super(*@a, y: 1) end})
+  extend(Module.new{def splat_kw_block; super(*@a, y: 1, &@b) end})
+benchmark:
+  arg_splat: "arg_splat"
+  arg_splat_block: "arg_splat_block"
+  splat_kw_splat: "splat_kw_splat"
+  splat_kw_splat_block: "splat_kw_splat_block"
+  splat_kw: "splat_kw"
+  splat_kw_block: "splat_kw_block"
diff --git a/benchmark/vm_zsuper_splat_calls.yml b/benchmark/vm_zsuper_splat_calls.yml
new file mode 100644
index 0000000000..82dc22349d
--- /dev/null
+++ b/benchmark/vm_zsuper_splat_calls.yml
@@ -0,0 +1,28 @@
+prelude: |
+  a = [1].freeze
+  ea = [].freeze
+  kw = {y: 1}.freeze
+  b = lambda{}
+  extend(Module.new{def arg_splat(x=0, y: 0) end})
+  extend(Module.new{def arg_splat_block(x=0, y: 0) end})
+  extend(Module.new{def arg_splat_post(x=0, y: 0) end})
+  extend(Module.new{def splat_kw_splat(x=0, y: 0) end})
+  extend(Module.new{def splat_kw_splat_block(x=0, y: 0) end})
+  extend(Module.new{def splat_kw(x=0, y: 0) end})
+  extend(Module.new{def splat_kw_block(x=0, y: 0) end})
+
+  extend(Module.new{def arg_splat(x, *a) super end})
+  extend(Module.new{def arg_splat_block(x, *a, &b) super end})
+  extend(Module.new{def arg_splat_post(*a, x) super end})
+  extend(Module.new{def splat_kw_splat(*a, **kw) super end})
+  extend(Module.new{def splat_kw_splat_block(*a, **kw, &b) super end})
+  extend(Module.new{def splat_kw(*a, y: 1) super end})
+  extend(Module.new{def splat_kw_block(*a, y: 1, &b) super end})
+benchmark:
+  arg_splat: "arg_splat(1, *ea)"
+  arg_splat_block: "arg_splat_block(1, *ea, &b)"
+  arg_splat_post: "arg_splat_post(1, *ea, &b)"
+  splat_kw_splat: "splat_kw_splat(*a, **kw)"
+  splat_kw_splat_block: "splat_kw_splat_block(*a, **kw, &b)"
+  splat_kw: "splat_kw(*a, y: 1)"
+  splat_kw_block: "splat_kw_block(*a, y: 1, &b)"
diff --git a/bignum.c b/bignum.c
index 4ab117b557..fb4714307e 100644
--- a/bignum.c
+++ b/bignum.c
@@ -23,9 +23,12 @@
 # include <ieeefp.h>
 #endif
 
+#if !defined(USE_GMP)
 #if defined(HAVE_LIBGMP) && defined(HAVE_GMP_H)
-# define USE_GMP
-# include <gmp.h>
+# define USE_GMP 1
+#else
+# define USE_GMP 0
+#endif
 #endif
 
 #include "id.h"
@@ -42,6 +45,23 @@
 #include "ruby/util.h"
 #include "ruby_assert.h"
 
+#if USE_GMP
+RBIMPL_WARNING_PUSH()
+# ifdef _MSC_VER
+RBIMPL_WARNING_IGNORED(4146) /* for mpn_neg() */
+# endif
+# include <gmp.h>
+RBIMPL_WARNING_POP()
+#endif
+
+static const bool debug_integer_pack = (
+#ifdef DEBUG_INTEGER_PACK
+    DEBUG_INTEGER_PACK+0
+#else
+    RUBY_DEBUG
+#endif
+    ) != 0;
+
 const char ruby_digitmap[] = "0123456789abcdefghijklmnopqrstuvwxyz";
 
 #ifndef SIZEOF_BDIGIT_DBL
@@ -99,8 +119,8 @@ STATIC_ASSERT(sizeof_long_and_sizeof_bdigit, SIZEOF_BDIGIT % SIZEOF_LONG == 0);
 #endif
 
 #define BIGZEROP(x) (BIGNUM_LEN(x) == 0 || \
-		     (BDIGITS(x)[0] == 0 && \
-		      (BIGNUM_LEN(x) == 1 || bigzero_p(x))))
+                     (BDIGITS(x)[0] == 0 && \
+                      (BIGNUM_LEN(x) == 1 || bigzero_p(x))))
 #define BIGSIZE(x) (BIGNUM_LEN(x) == 0 ? (size_t)0 : \
     BDIGITS(x)[BIGNUM_LEN(x)-1] ? \
         (size_t)(BIGNUM_LEN(x)*SIZEOF_BDIGIT - nlz(BDIGITS(x)[BIGNUM_LEN(x)-1])/CHAR_BIT) : \
@@ -145,7 +165,7 @@ STATIC_ASSERT(sizeof_long_and_sizeof_bdigit, SIZEOF_BDIGIT % SIZEOF_LONG == 0);
 #define GMP_DIV_DIGITS 20
 #define GMP_BIG2STR_DIGITS 20
 #define GMP_STR2BIG_DIGITS 20
-#ifdef USE_GMP
+#if USE_GMP
 # define NAIVE_MUL_DIGITS GMP_MUL_DIGITS
 #else
 # define NAIVE_MUL_DIGITS KARATSUBA_MUL_DIGITS
@@ -335,7 +355,7 @@ maxpow_in_bdigit_dbl(int base, int *exp_ret)
     BDIGIT_DBL maxpow;
     int exponent;
 
-    assert(2 <= base && base <= 36);
+    RUBY_ASSERT(2 <= base && base <= 36);
 
     {
 #if SIZEOF_BDIGIT_DBL == 2
@@ -367,7 +387,7 @@ maxpow_in_bdigit_dbl(int base, int *exp_ret)
 static inline BDIGIT_DBL
 bary2bdigitdbl(const BDIGIT *ds, size_t n)
 {
-    assert(n <= 2);
+    RUBY_ASSERT(n <= 2);
 
     if (n == 2)
         return ds[0] | BIGUP(ds[1]);
@@ -379,7 +399,7 @@ bary2bdigitdbl(const BDIGIT *ds, size_t n)
 static inline void
 bdigitdbl2bary(BDIGIT *ds, size_t n, BDIGIT_DBL num)
 {
-    assert(n == 2);
+    RUBY_ASSERT(n == 2);
 
     ds[0] = BIGLO(num);
     ds[1] = (BDIGIT)BIGDN(num);
@@ -410,12 +430,12 @@ bary_small_lshift(BDIGIT *zds, const BDIGIT *xds, size_t n, int shift)
 {
     size_t i;
     BDIGIT_DBL num = 0;
-    assert(0 <= shift && shift < BITSPERDIG);
+    RUBY_ASSERT(0 <= shift && shift < BITSPERDIG);
 
     for (i=0; i<n; i++) {
-	num = num | (BDIGIT_DBL)*xds++ << shift;
-	*zds++ = BIGLO(num);
-	num = BIGDN(num);
+        num = num | (BDIGIT_DBL)*xds++ << shift;
+        *zds++ = BIGLO(num);
+        num = BIGDN(num);
     }
     return BIGLO(num);
 }
@@ -426,14 +446,14 @@ bary_small_rshift(BDIGIT *zds, const BDIGIT *xds, size_t n, int shift, BDIGIT hi
     size_t i;
     BDIGIT_DBL num = 0;
 
-    assert(0 <= shift && shift < BITSPERDIG);
+    RUBY_ASSERT(0 <= shift && shift < BITSPERDIG);
 
     num = BIGUP(higher_bdigit);
     for (i = 0; i < n; i++) {
         BDIGIT x = xds[n - i - 1];
-	num = (num | x) >> shift;
+        num = (num | x) >> shift;
         zds[n - i - 1] = BIGLO(num);
-	num = BIGUP(x);
+        num = BIGUP(x);
     }
 }
 
@@ -443,7 +463,7 @@ bary_zero_p(const BDIGIT *xds, size_t xn)
     if (xn == 0)
         return 1;
     do {
-	if (xds[--xn]) return 0;
+        if (xds[--xn]) return 0;
     } while (xn);
     return 1;
 }
@@ -971,7 +991,7 @@ integer_unpack_num_bdigits_small(size_t numwords, size_t wordsize, size_t nails,
 {
     /* nlp_bits stands for number of leading padding bits */
     size_t num_bits = (wordsize * CHAR_BIT - nails) * numwords;
-    size_t num_bdigits = (num_bits + BITSPERDIG - 1) / BITSPERDIG;
+    size_t num_bdigits = roomof(num_bits, BITSPERDIG);
     *nlp_bits_ret = (int)(num_bdigits * BITSPERDIG - num_bits);
     return num_bdigits;
 }
@@ -981,7 +1001,7 @@ integer_unpack_num_bdigits_generic(size_t numwords, size_t wordsize, size_t nail
 {
     /* BITSPERDIG = SIZEOF_BDIGIT * CHAR_BIT */
     /* num_bits = (wordsize * CHAR_BIT - nails) * numwords */
-    /* num_bdigits = (num_bits + BITSPERDIG - 1) / BITSPERDIG */
+    /* num_bdigits = roomof(num_bits, BITSPERDIG) */
 
     /* num_bits = CHAR_BIT * (wordsize * numwords) - nails * numwords = CHAR_BIT * num_bytes1 - nails * numwords */
     size_t num_bytes1 = wordsize * numwords;
@@ -1043,15 +1063,13 @@ integer_unpack_num_bdigits(size_t numwords, size_t wordsize, size_t nails, int *
 
     if (numwords <= (SIZE_MAX - (BITSPERDIG-1)) / CHAR_BIT / wordsize) {
         num_bdigits = integer_unpack_num_bdigits_small(numwords, wordsize, nails, nlp_bits_ret);
-#ifdef DEBUG_INTEGER_PACK
-        {
+        if (debug_integer_pack) {
             int nlp_bits1;
             size_t num_bdigits1 = integer_unpack_num_bdigits_generic(numwords, wordsize, nails, &nlp_bits1);
-            assert(num_bdigits == num_bdigits1);
-            assert(*nlp_bits_ret == nlp_bits1);
+            RUBY_ASSERT(num_bdigits == num_bdigits1);
+            RUBY_ASSERT(*nlp_bits_ret == nlp_bits1);
             (void)num_bdigits1;
         }
-#endif
     }
     else {
         num_bdigits = integer_unpack_num_bdigits_generic(numwords, wordsize, nails, nlp_bits_ret);
@@ -1259,7 +1277,7 @@ bary_unpack_internal(BDIGIT *bdigits, size_t num_bdigits, const void *words, siz
         }
         if (dd)
             *dp++ = (BDIGIT)dd;
-        assert(dp <= de);
+        RUBY_ASSERT(dp <= de);
         while (dp < de)
             *dp++ = 0;
 #undef PUSH_BITS
@@ -1318,7 +1336,7 @@ bary_unpack(BDIGIT *bdigits, size_t num_bdigits, const void *words, size_t numwo
 
     num_bdigits0 = integer_unpack_num_bdigits(numwords, wordsize, nails, &nlp_bits);
 
-    assert(num_bdigits0 <= num_bdigits);
+    RUBY_ASSERT(num_bdigits0 <= num_bdigits);
 
     sign = bary_unpack_internal(bdigits, num_bdigits0, words, numwords, wordsize, nails, flags, nlp_bits);
 
@@ -1337,16 +1355,16 @@ bary_subb(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t xn, const BDIGIT *yd
     size_t i;
     size_t sn;
 
-    assert(xn <= zn);
-    assert(yn <= zn);
+    RUBY_ASSERT(xn <= zn);
+    RUBY_ASSERT(yn <= zn);
 
     sn = xn < yn ? xn : yn;
 
     num = borrow ? -1 : 0;
     for (i = 0; i < sn; i++) {
-	num += (BDIGIT_DBL_SIGNED)xds[i] - yds[i];
-	zds[i] = BIGLO(num);
-	num = BIGDN(num);
+        num += (BDIGIT_DBL_SIGNED)xds[i] - yds[i];
+        zds[i] = BIGLO(num);
+        num = BIGDN(num);
     }
     if (yn <= xn) {
         for (; i < xn; i++) {
@@ -1365,7 +1383,7 @@ bary_subb(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t xn, const BDIGIT *yd
     }
     if (num == 0) goto num_is_zero;
     for (; i < zn; i++) {
-	zds[i] = BDIGMAX;
+        zds[i] = BDIGMAX;
     }
     return 1;
 
@@ -1373,10 +1391,10 @@ bary_subb(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t xn, const BDIGIT *yd
     if (xds == zds && xn == zn)
         return 0;
     for (; i < xn; i++) {
-	zds[i] = xds[i];
+        zds[i] = xds[i];
     }
     for (; i < zn; i++) {
-	zds[i] = 0;
+        zds[i] = 0;
     }
     return 0;
 }
@@ -1399,31 +1417,31 @@ bary_addc(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t xn, const BDIGIT *yd
     BDIGIT_DBL num;
     size_t i;
 
-    assert(xn <= zn);
-    assert(yn <= zn);
+    RUBY_ASSERT(xn <= zn);
+    RUBY_ASSERT(yn <= zn);
 
     if (xn > yn) {
-	const BDIGIT *tds;
-	tds = xds; xds = yds; yds = tds;
-	i = xn; xn = yn; yn = i;
+        const BDIGIT *tds;
+        tds = xds; xds = yds; yds = tds;
+        i = xn; xn = yn; yn = i;
     }
 
     num = carry ? 1 : 0;
     for (i = 0; i < xn; i++) {
-	num += (BDIGIT_DBL)xds[i] + yds[i];
-	zds[i] = BIGLO(num);
-	num = BIGDN(num);
+        num += (BDIGIT_DBL)xds[i] + yds[i];
+        zds[i] = BIGLO(num);
+        num = BIGDN(num);
     }
     for (; i < yn; i++) {
         if (num == 0) goto num_is_zero;
-	num += yds[i];
-	zds[i] = BIGLO(num);
-	num = BIGDN(num);
+        num += yds[i];
+        zds[i] = BIGLO(num);
+        num = BIGDN(num);
     }
     for (; i < zn; i++) {
         if (num == 0) goto num_is_zero;
-	zds[i] = BIGLO(num);
-	num = BIGDN(num);
+        zds[i] = BIGLO(num);
+        num = BIGDN(num);
     }
     return num != 0;
 
@@ -1431,10 +1449,10 @@ bary_addc(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t xn, const BDIGIT *yd
     if (yds == zds && yn == zn)
         return 0;
     for (; i < yn; i++) {
-	zds[i] = yds[i];
+        zds[i] = yds[i];
     }
     for (; i < zn; i++) {
-	zds[i] = 0;
+        zds[i] = 0;
     }
     return 0;
 }
@@ -1464,7 +1482,7 @@ bary_mul_single(BDIGIT *zds, size_t zn, BDIGIT x, BDIGIT y)
 {
     BDIGIT_DBL n;
 
-    assert(2 <= zn);
+    RUBY_ASSERT(2 <= zn);
 
     n = (BDIGIT_DBL)x * y;
     bdigitdbl2bary(zds, 2, n);
@@ -1478,7 +1496,7 @@ bary_muladd_1xN(BDIGIT *zds, size_t zn, BDIGIT x, const BDIGIT *yds, size_t yn)
     BDIGIT_DBL dd;
     size_t j;
 
-    assert(zn > yn);
+    RUBY_ASSERT(zn > yn);
 
     if (x == 0)
         return 0;
@@ -1513,7 +1531,7 @@ bigdivrem_mulsub(BDIGIT *zds, size_t zn, BDIGIT x, const BDIGIT *yds, size_t yn)
     BDIGIT_DBL t2;
     BDIGIT_DBL_SIGNED num;
 
-    assert(zn == yn + 1);
+    RUBY_ASSERT(zn == yn + 1);
 
     num = 0;
     t2 = 0;
@@ -1538,7 +1556,7 @@ bary_mulsub_1xN(BDIGIT *zds, size_t zn, BDIGIT x, const BDIGIT *yds, size_t yn)
 {
     BDIGIT_DBL_SIGNED num;
 
-    assert(zn == yn + 1);
+    RUBY_ASSERT(zn == yn + 1);
 
     num = bigdivrem_mulsub(zds, zn, x, yds, yn);
     zds[yn] = BIGLO(num);
@@ -1552,7 +1570,7 @@ bary_mul_normal(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t xn, const BDIG
 {
     size_t i;
 
-    assert(xn + yn <= zn);
+    RUBY_ASSERT(xn + yn <= zn);
 
     BDIGITS_ZERO(zds, zn);
     for (i = 0; i < xn; i++) {
@@ -1573,7 +1591,7 @@ rb_big_mul_normal(VALUE x, VALUE y)
 
 /* efficient squaring (2 times faster than normal multiplication)
  * ref: Handbook of Applied Cryptography, Algorithm 14.16
- *      http://www.cacr.math.uwaterloo.ca/hac/about/chap14.pdf
+ *      https://www.cacr.math.uwaterloo.ca/hac/about/chap14.pdf
  */
 static void
 bary_sq_fast(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t xn)
@@ -1583,7 +1601,7 @@ bary_sq_fast(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t xn)
     BDIGIT vl;
     int vh;
 
-    assert(xn * 2 <= zn);
+    RUBY_ASSERT(xn * 2 <= zn);
 
     BDIGITS_ZERO(zds, zn);
 
@@ -1591,30 +1609,30 @@ bary_sq_fast(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t xn)
         return;
 
     for (i = 0; i < xn-1; i++) {
-	v = (BDIGIT_DBL)xds[i];
-	if (!v)
+        v = (BDIGIT_DBL)xds[i];
+        if (!v)
             continue;
-	c = (BDIGIT_DBL)zds[i + i] + v * v;
-	zds[i + i] = BIGLO(c);
-	c = BIGDN(c);
-	v *= 2;
+        c = (BDIGIT_DBL)zds[i + i] + v * v;
+        zds[i + i] = BIGLO(c);
+        c = BIGDN(c);
+        v *= 2;
         vl = BIGLO(v);
         vh = (int)BIGDN(v);
-	for (j = i + 1; j < xn; j++) {
-	    w = (BDIGIT_DBL)xds[j];
-	    c += (BDIGIT_DBL)zds[i + j] + vl * w;
-	    zds[i + j] = BIGLO(c);
-	    c = BIGDN(c);
-	    if (vh)
+        for (j = i + 1; j < xn; j++) {
+            w = (BDIGIT_DBL)xds[j];
+            c += (BDIGIT_DBL)zds[i + j] + vl * w;
+            zds[i + j] = BIGLO(c);
+            c = BIGDN(c);
+            if (vh)
                 c += w;
-	}
-	if (c) {
-	    c += (BDIGIT_DBL)zds[i + xn];
-	    zds[i + xn] = BIGLO(c);
-	    c = BIGDN(c);
+        }
+        if (c) {
+            c += (BDIGIT_DBL)zds[i + xn];
+            zds[i + xn] = BIGLO(c);
+            c = BIGDN(c);
             if (c)
                 zds[i + xn + 1] += (BDIGIT)c;
-	}
+        }
     }
 
     /* i == xn-1 */
@@ -1639,6 +1657,12 @@ rb_big_sq_fast(VALUE x)
     return z;
 }
 
+static inline size_t
+max_size(size_t a, size_t b)
+{
+    return (a > b ? a : b);
+}
+
 /* balancing multiplication by slicing larger argument */
 static void
 bary_mul_balance_with_mulfunc(BDIGIT *const zds, const size_t zn,
@@ -1649,15 +1673,21 @@ bary_mul_balance_with_mulfunc(BDIGIT *const zds, const size_t zn,
     VALUE work = 0;
     size_t n;
 
-    assert(xn + yn <= zn);
-    assert(xn <= yn);
-    assert(!KARATSUBA_BALANCED(xn, yn) || !TOOM3_BALANCED(xn, yn));
+    RUBY_ASSERT(xn + yn <= zn);
+    RUBY_ASSERT(xn <= yn);
+    RUBY_ASSERT(!KARATSUBA_BALANCED(xn, yn) || !TOOM3_BALANCED(xn, yn));
 
     BDIGITS_ZERO(zds, xn);
 
     if (wn < xn) {
-        const size_t r = (yn % xn) ? (yn % xn) : xn;
-        if ((2 * xn + yn + r) > zn) {
+        /* The condition when a new buffer is needed:
+         * 1. (2(xn+r) > zn-(yn-r)) => (2xn+r > zn-yn), at the last
+         *    iteration (or r == 0)
+         * 2. (2(xn+xn) > zn-(yn-r-xn)) => (3xn-r > zn-yn), at the
+         *    previous iteration.
+         */
+        const size_t r = yn % xn;
+        if (2*xn + yn + max_size(xn-r, r) > zn) {
             wn = xn;
             wds = ALLOCV_N(BDIGIT, work, wn);
         }
@@ -1692,7 +1722,7 @@ bary_mul_balance_with_mulfunc(BDIGIT *const zds, const size_t zn,
                      zds + n, tn,
                      wds, xn);
         }
-	n += r;
+        n += r;
     }
     BDIGITS_ZERO(zds+xn+yn, zn - (xn+yn));
 
@@ -1727,9 +1757,9 @@ bary_mul_karatsuba(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t xn, const B
     const BDIGIT *xds0, *xds1, *yds0, *yds1;
     BDIGIT *zds0, *zds1, *zds2, *zds3;
 
-    assert(xn + yn <= zn);
-    assert(xn <= yn);
-    assert(yn < 2 * xn);
+    RUBY_ASSERT(xn + yn <= zn);
+    RUBY_ASSERT(xn <= yn);
+    RUBY_ASSERT(yn < 2 * xn);
 
     sq = xds == yds && xn == yn;
 
@@ -1744,7 +1774,7 @@ bary_mul_karatsuba(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t xn, const B
 
     n = yn / 2;
 
-    assert(n < xn);
+    RUBY_ASSERT(n < xn);
 
     if (wn < n) {
         /* This function itself needs only n BDIGITs for work area.
@@ -1865,7 +1895,7 @@ bary_mul_karatsuba(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t xn, const B
         for (x = 0, i = xn-1; 0 <= i; i--) { x <<= SIZEOF_BDIGIT*CHAR_BIT; x |= xds[i]; }
         for (y = 0, i = yn-1; 0 <= i; i--) { y <<= SIZEOF_BDIGIT*CHAR_BIT; y |= yds[i]; }
         for (z = 0, i = zn-1; 0 <= i; i--) { z <<= SIZEOF_BDIGIT*CHAR_BIT; z |= zds[i]; }
-        assert(z == x * y);
+        RUBY_ASSERT(z == x * y);
     }
     */
 
@@ -1933,11 +1963,11 @@ bary_mul_toom3(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t xn, const BDIGI
 
     int sq = xds == yds && xn == yn;
 
-    assert(xn <= yn);  /* assume y >= x */
-    assert(xn + yn <= zn);
+    RUBY_ASSERT(xn <= yn);  /* assume y >= x */
+    RUBY_ASSERT(xn + yn <= zn);
 
     n = (yn + 2) / 3;
-    assert(2*n < xn);
+    RUBY_ASSERT(2*n < xn);
 
     wnc = 0;
 
@@ -2084,21 +2114,21 @@ bary_mul_toom3(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t xn, const BDIGI
         v3n = u3n; v3ds = u3ds; v3p = u3p;
     }
     else {
-	/* v1 <- y0 + y2 */
+        /* v1 <- y0 + y2 */
         bary_add(v1ds, v1n, y0ds, y0n, y2ds, y2n);
         v1p = 1;
 
-	/* y(-1) : v2 <- v1 - y1 = y0 - y1 + y2 */
+        /* y(-1) : v2 <- v1 - y1 = y0 - y1 + y2 */
         v2p = 1;
         if (bary_sub(v2ds, v2n, v1ds, v1n, y1ds, y1n)) {
             bary_2comp(v2ds, v2n);
             v2p = 0;
         }
 
-	/* y(1) : v1 <- v1 + y1 = y0 + y1 + y2 */
+        /* y(1) : v1 <- v1 + y1 = y0 + y1 + y2 */
         bary_add(v1ds, v1n, v1ds, v1n, y1ds, y1n);
 
-	/* y(-2) : v3 <- 2 * (v2 + y2) - y0 = y0 - 2 * (y1 - 2 * y2) */
+        /* y(-2) : v3 <- 2 * (v2 + y2) - y0 = y0 - 2 * (y1 - 2 * y2) */
         v3p = 1;
         if (v2p) {
             bary_add(v3ds, v3n, v2ds, v2n, y2ds, y2n);
@@ -2124,19 +2154,19 @@ bary_mul_toom3(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t xn, const BDIGI
     /* z(1) : t1 <- u1 * v1 */
     bary_mul_toom3_start(t1ds, t1n, u1ds, u1n, v1ds, v1n, wds, wn);
     t1p = u1p == v1p;
-    assert(t1ds[t1n-1] == 0);
+    RUBY_ASSERT(t1ds[t1n-1] == 0);
     t1n--;
 
     /* z(-1) : t2 <- u2 * v2 */
     bary_mul_toom3_start(t2ds, t2n, u2ds, u2n, v2ds, v2n, wds, wn);
     t2p = u2p == v2p;
-    assert(t2ds[t2n-1] == 0);
+    RUBY_ASSERT(t2ds[t2n-1] == 0);
     t2n--;
 
     /* z(-2) : t3 <- u3 * v3 */
     bary_mul_toom3_start(t3ds, t3n, u3ds, u3n, v3ds, v3n, wds, wn);
     t3p = u3p == v3p;
-    assert(t3ds[t3n-1] == 0);
+    RUBY_ASSERT(t3ds[t3n-1] == 0);
     t3n--;
 
     /* z(inf) : t4 <- x2 * y2 */
@@ -2291,7 +2321,7 @@ rb_big_mul_toom3(VALUE x, VALUE y)
     return z;
 }
 
-#ifdef USE_GMP
+#if USE_GMP
 static inline void
 bdigits_to_mpz(mpz_t mp, const BDIGIT *digits, size_t len)
 {
@@ -2312,7 +2342,7 @@ bary_mul_gmp(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t xn, const BDIGIT
     mpz_t x, y, z;
     size_t count;
 
-    assert(xn + yn <= zn);
+    RUBY_ASSERT(xn + yn <= zn);
 
     mpz_init(x);
     mpz_init(y);
@@ -2347,7 +2377,7 @@ rb_big_mul_gmp(VALUE x, VALUE y)
 static void
 bary_short_mul(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t xn, const BDIGIT *yds, size_t yn)
 {
-    assert(xn + yn <= zn);
+    RUBY_ASSERT(xn + yn <= zn);
 
     if (xn == 1 && yn == 1) {
         bary_mul_single(zds, zn, xds[0], yds[0]);
@@ -2383,7 +2413,7 @@ bary_mul_precheck(BDIGIT **zdsp, size_t *znp, const BDIGIT **xdsp, size_t *xnp,
     const BDIGIT *yds = *ydsp;
     size_t yn = *ynp;
 
-    assert(xn + yn <= zn);
+    RUBY_ASSERT(xn + yn <= zn);
 
     nlsz = 0;
 
@@ -2429,10 +2459,10 @@ bary_mul_precheck(BDIGIT **zdsp, size_t *znp, const BDIGIT **xdsp, size_t *xnp,
     if (xn > yn) {
         const BDIGIT *tds;
         size_t tn;
-	tds = xds; xds = yds; yds = tds;
-	tn = xn; xn = yn; yn = tn;
+        tds = xds; xds = yds; yds = tds;
+        tn = xn; xn = yn; yn = tn;
     }
-    assert(xn <= yn);
+    RUBY_ASSERT(xn <= yn);
 
     if (xn <= 1) {
         if (xn == 0) {
@@ -2556,7 +2586,7 @@ bary_mul(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t xn, const BDIGIT *yds
         }
     }
 
-#ifdef USE_GMP
+#if USE_GMP
     bary_mul_gmp(zds, zn, xds, xn, yds, yn);
 #else
     bary_mul_toom3_start(zds, zn, xds, xn, yds, yn, NULL, 0);
@@ -2580,26 +2610,26 @@ bigdivrem1(void *ptr)
     BDIGIT q;
 
     do {
-	if (bds->stop) {
-	    bds->zn = zn;
-	    return 0;
+        if (bds->stop) {
+            bds->zn = zn;
+            return 0;
         }
-	if (zds[zn-1] == yds[yn-1]) q = BDIGMAX;
-	else q = (BDIGIT)((BIGUP(zds[zn-1]) + zds[zn-2])/yds[yn-1]);
-	if (q) {
+        if (zds[zn-1] == yds[yn-1]) q = BDIGMAX;
+        else q = (BDIGIT)((BIGUP(zds[zn-1]) + zds[zn-2])/yds[yn-1]);
+        if (q) {
             num = bigdivrem_mulsub(zds+zn-(yn+1), yn+1,
                                    q,
                                    yds, yn);
-	    while (num) { /* "add back" required */
-		q--;
+            while (num) { /* "add back" required */
+                q--;
                 num = bary_add(zds+zn-(yn+1), yn,
                                zds+zn-(yn+1), yn,
                                yds, yn);
                 num--;
-	    }
-	}
+            }
+        }
         zn--;
-	zds[zn] = q;
+        zds[zn] = q;
     } while (zn > yn);
     return 0;
 }
@@ -2615,8 +2645,8 @@ rb_big_stop(void *ptr)
 static BDIGIT
 bigdivrem_single1(BDIGIT *qds, const BDIGIT *xds, size_t xn, BDIGIT x_higher_bdigit, BDIGIT y)
 {
-    assert(0 < xn);
-    assert(x_higher_bdigit < y);
+    RUBY_ASSERT(0 < xn);
+    RUBY_ASSERT(x_higher_bdigit < y);
     if (POW2_P(y)) {
         BDIGIT r;
         r = xds[0] & (y-1);
@@ -2648,9 +2678,9 @@ bigdivrem_restoring(BDIGIT *zds, size_t zn, BDIGIT *yds, size_t yn)
     struct big_div_struct bds;
     size_t ynzero;
 
-    assert(yn < zn);
-    assert(BDIGIT_MSB(yds[yn-1]));
-    assert(zds[zn-1] < yds[yn-1]);
+    RUBY_ASSERT(yn < zn);
+    RUBY_ASSERT(BDIGIT_MSB(yds[yn-1]));
+    RUBY_ASSERT(zds[zn-1] < yds[yn-1]);
 
     for (ynzero = 0; !yds[ynzero]; ynzero++);
 
@@ -2668,16 +2698,16 @@ bigdivrem_restoring(BDIGIT *zds, size_t zn, BDIGIT *yds, size_t yn)
     bds.zn = zn - ynzero;
     if (bds.zn > 10000 || bds.yn > 10000) {
       retry:
-	bds.stop = Qfalse;
-        rb_nogvl(bigdivrem1, &bds, rb_big_stop, &bds, RB_NOGVL_UBF_ASYNC_SAFE);
+        bds.stop = Qfalse;
+        rb_nogvl(bigdivrem1, &bds, rb_big_stop, &bds, RB_NOGVL_UBF_ASYNC_SAFE | RB_NOGVL_OFFLOAD_SAFE);
 
-	if (bds.stop == Qtrue) {
-	    /* execute trap handler, but exception was not raised. */
-	    goto retry;
-	}
+        if (bds.stop == Qtrue) {
+            /* execute trap handler, but exception was not raised. */
+            goto retry;
+        }
     }
     else {
-	bigdivrem1(&bds);
+        bigdivrem1(&bds);
     }
 }
 
@@ -2689,9 +2719,9 @@ bary_divmod_normal(BDIGIT *qds, size_t qn, BDIGIT *rds, size_t rn, const BDIGIT
     size_t zn;
     VALUE tmpyz = 0;
 
-    assert(yn < xn || (xn == yn && yds[yn - 1] <= xds[xn - 1]));
-    assert(qds ? (xn - yn + 1) <= qn : 1);
-    assert(rds ? yn <= rn : 1);
+    RUBY_ASSERT(yn < xn || (xn == yn && yds[yn - 1] <= xds[xn - 1]));
+    RUBY_ASSERT(qds ? (xn - yn + 1) <= qn : 1);
+    RUBY_ASSERT(rds ? yn <= rn : 1);
 
     zn = xn + BIGDIVREM_EXTRA_WORDS;
 
@@ -2776,17 +2806,17 @@ rb_big_divrem_normal(VALUE x, VALUE y)
     return rb_assoc_new(q, r);
 }
 
-#ifdef USE_GMP
+#if USE_GMP
 static void
 bary_divmod_gmp(BDIGIT *qds, size_t qn, BDIGIT *rds, size_t rn, const BDIGIT *xds, size_t xn, const BDIGIT *yds, size_t yn)
 {
     mpz_t x, y, q, r;
     size_t count;
 
-    assert(yn < xn || (xn == yn && yds[yn - 1] <= xds[xn - 1]));
-    assert(qds ? (xn - yn + 1) <= qn : 1);
-    assert(rds ? yn <= rn : 1);
-    assert(qds || rds);
+    RUBY_ASSERT(yn < xn || (xn == yn && yds[yn - 1] <= xds[xn - 1]));
+    RUBY_ASSERT(qds ? (xn - yn + 1) <= qn : 1);
+    RUBY_ASSERT(rds ? yn <= rn : 1);
+    RUBY_ASSERT(qds || rds);
 
     mpz_init(x);
     mpz_init(y);
@@ -2860,7 +2890,7 @@ rb_big_divrem_gmp(VALUE x, VALUE y)
 static void
 bary_divmod_branch(BDIGIT *qds, size_t qn, BDIGIT *rds, size_t rn, const BDIGIT *xds, size_t xn, const BDIGIT *yds, size_t yn)
 {
-#ifdef USE_GMP
+#if USE_GMP
     if (GMP_DIV_DIGITS < xn) {
         bary_divmod_gmp(qds, qn, rds, rn, xds, xn, yds, yn);
         return;
@@ -2872,8 +2902,8 @@ bary_divmod_branch(BDIGIT *qds, size_t qn, BDIGIT *rds, size_t rn, const BDIGIT
 static void
 bary_divmod(BDIGIT *qds, size_t qn, BDIGIT *rds, size_t rn, const BDIGIT *xds, size_t xn, const BDIGIT *yds, size_t yn)
 {
-    assert(xn <= qn);
-    assert(yn <= rn);
+    RUBY_ASSERT(xn <= qn);
+    RUBY_ASSERT(yn <= rn);
 
     BARY_TRUNC(yds, yn);
     if (yn == 0)
@@ -2935,7 +2965,7 @@ int
 rb_cmpint(VALUE val, VALUE a, VALUE b)
 {
     if (NIL_P(val)) {
-	rb_cmperr(a, b);
+        rb_cmperr(a, b);
     }
     if (FIXNUM_P(val)) {
         long l = FIX2LONG(val);
@@ -2944,9 +2974,9 @@ rb_cmpint(VALUE val, VALUE a, VALUE b)
         return 0;
     }
     if (RB_BIGNUM_TYPE_P(val)) {
-	if (BIGZEROP(val)) return 0;
-	if (BIGNUM_SIGN(val)) return 1;
-	return -1;
+        if (BIGZEROP(val)) return 0;
+        if (BIGNUM_SIGN(val)) return 1;
+        return -1;
     }
     if (RTEST(rb_funcall(val, '>', 1, INT2FIX(0)))) return 1;
     if (RTEST(rb_funcall(val, '<', 1, INT2FIX(0)))) return -1;
@@ -2956,8 +2986,8 @@ rb_cmpint(VALUE val, VALUE a, VALUE b)
 #define BIGNUM_SET_LEN(b,l) \
     (BIGNUM_EMBED_P(b) ? \
      (void)(RBASIC(b)->flags = \
-	    (RBASIC(b)->flags & ~BIGNUM_EMBED_LEN_MASK) | \
-	    ((l) << BIGNUM_EMBED_LEN_SHIFT)) : \
+            (RBASIC(b)->flags & ~BIGNUM_EMBED_LEN_MASK) | \
+            ((l) << BIGNUM_EMBED_LEN_SHIFT)) : \
      (void)(RBIGNUM(b)->as.heap.len = (l)))
 
 static void
@@ -2965,33 +2995,33 @@ rb_big_realloc(VALUE big, size_t len)
 {
     BDIGIT *ds;
     if (BIGNUM_EMBED_P(big)) {
-	if (BIGNUM_EMBED_LEN_MAX < len) {
-	    ds = ALLOC_N(BDIGIT, len);
-	    MEMCPY(ds, RBIGNUM(big)->as.ary, BDIGIT, BIGNUM_EMBED_LEN_MAX);
-	    RBIGNUM(big)->as.heap.len = BIGNUM_LEN(big);
-	    RBIGNUM(big)->as.heap.digits = ds;
+        if (BIGNUM_EMBED_LEN_MAX < len) {
+            ds = ALLOC_N(BDIGIT, len);
+            MEMCPY(ds, RBIGNUM(big)->as.ary, BDIGIT, BIGNUM_EMBED_LEN_MAX);
+            RBIGNUM(big)->as.heap.len = BIGNUM_LEN(big);
+            RBIGNUM(big)->as.heap.digits = ds;
             FL_UNSET_RAW(big, BIGNUM_EMBED_FLAG);
-	}
+        }
     }
     else {
-	if (len <= BIGNUM_EMBED_LEN_MAX) {
-	    ds = RBIGNUM(big)->as.heap.digits;
+        if (len <= BIGNUM_EMBED_LEN_MAX) {
+            ds = RBIGNUM(big)->as.heap.digits;
             FL_SET_RAW(big, BIGNUM_EMBED_FLAG);
-	    BIGNUM_SET_LEN(big, len);
+            BIGNUM_SET_LEN(big, len);
             (void)VALGRIND_MAKE_MEM_UNDEFINED((void*)RBIGNUM(big)->as.ary, sizeof(RBIGNUM(big)->as.ary));
-	    if (ds) {
-		MEMCPY(RBIGNUM(big)->as.ary, ds, BDIGIT, len);
-		xfree(ds);
-	    }
-	}
-	else {
-	    if (BIGNUM_LEN(big) == 0) {
-		RBIGNUM(big)->as.heap.digits = ALLOC_N(BDIGIT, len);
-	    }
-	    else {
-		REALLOC_N(RBIGNUM(big)->as.heap.digits, BDIGIT, len);
-	    }
-	}
+            if (ds) {
+                MEMCPY(RBIGNUM(big)->as.ary, ds, BDIGIT, len);
+                xfree(ds);
+            }
+        }
+        else {
+            if (BIGNUM_LEN(big) == 0) {
+                RBIGNUM(big)->as.heap.digits = ALLOC_N(BDIGIT, len);
+            }
+            else {
+                REALLOC_N(RBIGNUM(big)->as.heap.digits, BDIGIT, len);
+            }
+        }
     }
 }
 
@@ -3005,7 +3035,8 @@ rb_big_resize(VALUE big, size_t len)
 static VALUE
 bignew_1(VALUE klass, size_t len, int sign)
 {
-    NEWOBJ_OF(big, struct RBignum, klass, T_BIGNUM | (RGENGC_WB_PROTECTED_BIGNUM ? FL_WB_PROTECTED : 0));
+    NEWOBJ_OF(big, struct RBignum, klass,
+            T_BIGNUM | (RGENGC_WB_PROTECTED_BIGNUM ? FL_WB_PROTECTED : 0), sizeof(struct RBignum), 0);
     VALUE bigv = (VALUE)big;
     BIGNUM_SET_SIGN(bigv, sign);
     if (len <= BIGNUM_EMBED_LEN_MAX) {
@@ -3077,7 +3108,7 @@ abs2twocomp(VALUE *xp, long *n_ret)
         MEMCPY(BDIGITS(z), ds, BDIGIT, n);
         bary_2comp(BDIGITS(z), n);
         hibits = BDIGMAX;
-	*xp = z;
+        *xp = z;
     }
     *n_ret = n;
     return hibits;
@@ -3101,7 +3132,7 @@ bigtrunc(VALUE x)
     if (len == 0) return x;
     while (--len && !ds[len]);
     if (BIGNUM_LEN(x) > len+1) {
-	rb_big_resize(x, len+1);
+        rb_big_resize(x, len+1);
     }
     return x;
 }
@@ -3154,7 +3185,7 @@ static VALUE
 bignorm(VALUE x)
 {
     if (RB_BIGNUM_TYPE_P(x)) {
-	x = bigfixize(x);
+        x = bigfixize(x);
     }
     return x;
 }
@@ -3176,8 +3207,8 @@ rb_uint2big(uintptr_t n)
     digits[0] = n;
 #else
     for (i = 0; i < bdigit_roomof(SIZEOF_VALUE); i++) {
-	digits[i] = BIGLO(n);
-	n = BIGDN(n);
+        digits[i] = BIGLO(n);
+        n = BIGDN(n);
     }
 #endif
 
@@ -3196,14 +3227,14 @@ rb_int2big(intptr_t n)
 
     if (n < 0) {
         u = 1 + (VALUE)(-(n + 1)); /* u = -n avoiding overflow */
-	neg = 1;
+        neg = 1;
     }
     else {
         u = n;
     }
     big = rb_uint2big(u);
     if (neg) {
-	BIGNUM_SET_NEGATIVE_SIGN(big);
+        BIGNUM_SET_NEGATIVE_SIGN(big);
     }
     return big;
 }
@@ -3362,7 +3393,7 @@ absint_numwords_generic(size_t numbytes, int nlz_bits_in_msbyte, size_t word_num
 
     if (sign == 2) {
 #if defined __GNUC__ && (__GNUC__ == 4 && __GNUC_MINOR__ == 4)
-	*nlz_bits_ret = 0;
+        *nlz_bits_ret = 0;
 #endif
         return (size_t)-1;
     }
@@ -3404,15 +3435,13 @@ rb_absint_numwords(VALUE val, size_t word_numbits, size_t *nlz_bits_ret)
 
     if (numbytes <= SIZE_MAX / CHAR_BIT) {
         numwords = absint_numwords_small(numbytes, nlz_bits_in_msbyte, word_numbits, &nlz_bits);
-#ifdef DEBUG_INTEGER_PACK
-        {
+        if (debug_integer_pack) {
             size_t numwords0, nlz_bits0;
             numwords0 = absint_numwords_generic(numbytes, nlz_bits_in_msbyte, word_numbits, &nlz_bits0);
-            assert(numwords0 == numwords);
-            assert(nlz_bits0 == nlz_bits);
+            RUBY_ASSERT(numwords0 == numwords);
+            RUBY_ASSERT(nlz_bits0 == nlz_bits);
             (void)numwords0;
         }
-#endif
     }
     else {
         numwords = absint_numwords_generic(numbytes, nlz_bits_in_msbyte, word_numbits, &nlz_bits);
@@ -3682,7 +3711,7 @@ rb_integer_unpack(const void *words, size_t numwords, size_t wordsize, size_t na
         }
         else if (num_bdigits == numberof(fixbuf)) {
             val = bignew((long)num_bdigits+1, 0);
-	    MEMCPY(BDIGITS(val), fixbuf, BDIGIT, num_bdigits);
+            MEMCPY(BDIGITS(val), fixbuf, BDIGIT, num_bdigits);
             BDIGITS(val)[num_bdigits++] = 1;
         }
         else {
@@ -3694,9 +3723,9 @@ rb_integer_unpack(const void *words, size_t numwords, size_t wordsize, size_t na
         BDIGIT_DBL u = fixbuf[0] + BIGUP(fixbuf[1]);
         if (u == 0)
             return LONG2FIX(0);
-	if (0 < sign && POSFIXABLE(u))
+        if (0 < sign && POSFIXABLE(u))
             return LONG2FIX((long)u);
-	if (sign < 0 && BDIGIT_MSB(fixbuf[1]) == 0 &&
+        if (sign < 0 && BDIGIT_MSB(fixbuf[1]) == 0 &&
                 NEGFIXABLE(-(BDIGIT_DBL_SIGNED)u))
             return LONG2FIX((long)-(BDIGIT_DBL_SIGNED)u);
         val = bignew((long)num_bdigits, 0 <= sign);
@@ -3748,41 +3777,41 @@ str2big_scan_digits(const char *s, const char *str, int base, int badcheck, size
     int c;
 
     if (!len) {
-	*num_digits_p = 0;
-	*len_p = 0;
-	return TRUE;
+        *num_digits_p = 0;
+        *len_p = 0;
+        return TRUE;
     }
 
     if (badcheck && *str == '_') return FALSE;
 
     while ((c = *str++) != 0) {
-	if (c == '_') {
-	    if (nondigit) {
+        if (c == '_') {
+            if (nondigit) {
                 if (badcheck) return FALSE;
-		break;
-	    }
-	    nondigit = (char) c;
-	}
-	else if ((c = conv_digit(c)) < 0 || c >= base) {
-	    break;
-	}
-	else {
-	    nondigit = 0;
-	    num_digits++;
-	    digits_end = str;
-	}
-	if (len > 0 && !--len) break;
+                break;
+            }
+            nondigit = (char) c;
+        }
+        else if ((c = conv_digit(c)) < 0 || c >= base) {
+            break;
+        }
+        else {
+            nondigit = 0;
+            num_digits++;
+            digits_end = str;
+        }
+        if (len > 0 && !--len) break;
     }
     if (badcheck && nondigit) return FALSE;
     if (badcheck && len) {
-	str--;
-	while (*str && ISSPACE(*str)) {
-	    str++;
-	    if (len > 0 && !--len) break;
-	}
-	if (len && *str) {
-	    return FALSE;
-	}
+        str--;
+        while (*str && ISSPACE(*str)) {
+            str++;
+            if (len > 0 && !--len) break;
+        }
+        if (len && *str) {
+            return FALSE;
+        }
     }
     *num_digits_p = num_digits;
     *len_p = digits_end - digits_start;
@@ -3825,7 +3854,7 @@ str2big_poweroftwo(
     if (numbits) {
         *dp++ = BIGLO(dd);
     }
-    assert((size_t)(dp - BDIGITS(z)) == num_bdigits);
+    RUBY_ASSERT((size_t)(dp - BDIGITS(z)) == num_bdigits);
 
     return z;
 }
@@ -3868,7 +3897,7 @@ str2big_normal(
             }
             break;
         }
-        assert(blen <= num_bdigits);
+        RUBY_ASSERT(blen <= num_bdigits);
     }
 
     return z;
@@ -3926,7 +3955,7 @@ str2big_karatsuba(
             current_base = 1;
         }
     }
-    assert(i == num_bdigits);
+    RUBY_ASSERT(i == num_bdigits);
     for (unit = 2; unit < num_bdigits; unit *= 2) {
         for (i = 0; i < num_bdigits; i += unit*2) {
             if (2*unit <= num_bdigits - i) {
@@ -3957,7 +3986,7 @@ str2big_karatsuba(
     return z;
 }
 
-#ifdef USE_GMP
+#if USE_GMP
 static VALUE
 str2big_gmp(
     int sign,
@@ -4024,8 +4053,8 @@ rb_cstr_to_inum(const char *str, int base, int badcheck)
     char *end;
     VALUE ret = rb_cstr_parse_inum(str, -1, (badcheck ? NULL : &end), base);
     if (NIL_P(ret)) {
-	if (badcheck) rb_invalid_str(str, "Integer()");
-	ret = INT2FIX(0);
+        if (badcheck) rb_invalid_str(str, "Integer()");
+        ret = INT2FIX(0);
     }
     return ret;
 }
@@ -4049,7 +4078,7 @@ rb_cstr_to_inum(const char *str, int base, int badcheck)
 
 VALUE
 rb_int_parse_cstr(const char *str, ssize_t len, char **endp, size_t *ndigits,
-		  int base, int flags)
+                  int base, int flags)
 {
     const char *const s = str;
     char sign = 1;
@@ -4066,82 +4095,82 @@ rb_int_parse_cstr(const char *str, ssize_t len, char **endp, size_t *ndigits,
     const int badcheck = !endp;
 
 #define ADV(n) do {\
-	if (len > 0 && len <= (n)) goto bad; \
-	str += (n); \
-	len -= (n); \
+        if (len > 0 && len <= (n)) goto bad; \
+        str += (n); \
+        len -= (n); \
     } while (0)
 #define ASSERT_LEN() do {\
-	assert(len != 0); \
-	if (len0 >= 0) assert(s + len0 == str + len); \
+        RUBY_ASSERT(len != 0); \
+        if (len0 >= 0) RUBY_ASSERT(s + len0 == str + len); \
     } while (0)
 
     if (!str) {
         goto bad;
     }
     if (len && (flags & RB_INT_PARSE_SIGN)) {
-	while (ISSPACE(*str)) ADV(1);
+        while (ISSPACE(*str)) ADV(1);
 
-	if (str[0] == '+') {
-	    ADV(1);
-	}
-	else if (str[0] == '-') {
-	    ADV(1);
-	    sign = 0;
-	}
-	ASSERT_LEN();
+        if (str[0] == '+') {
+            ADV(1);
+        }
+        else if (str[0] == '-') {
+            ADV(1);
+            sign = 0;
+        }
+        ASSERT_LEN();
     }
     if (base <= 0) {
-	if (str[0] == '0' && len > 1) {
-	    switch (str[1]) {
-	      case 'x': case 'X':
-		base = 16;
-		ADV(2);
-		break;
-	      case 'b': case 'B':
-		base = 2;
-		ADV(2);
-		break;
-	      case 'o': case 'O':
-		base = 8;
-		ADV(2);
-		break;
-	      case 'd': case 'D':
-		base = 10;
-		ADV(2);
-		break;
-	      default:
-		base = 8;
-	    }
-	}
-	else if (base < -1) {
-	    base = -base;
-	}
-	else {
-	    base = 10;
-	}
+        if (str[0] == '0' && len > 1) {
+            switch (str[1]) {
+              case 'x': case 'X':
+                base = 16;
+                ADV(2);
+                break;
+              case 'b': case 'B':
+                base = 2;
+                ADV(2);
+                break;
+              case 'o': case 'O':
+                base = 8;
+                ADV(2);
+                break;
+              case 'd': case 'D':
+                base = 10;
+                ADV(2);
+                break;
+              default:
+                base = 8;
+            }
+        }
+        else if (base < -1) {
+            base = -base;
+        }
+        else {
+            base = 10;
+        }
     }
     else if (len == 1 || !(flags & RB_INT_PARSE_PREFIX)) {
-	/* no prefix */
+        /* no prefix */
     }
     else if (base == 2) {
-	if (str[0] == '0' && (str[1] == 'b'||str[1] == 'B')) {
-	    ADV(2);
-	}
+        if (str[0] == '0' && (str[1] == 'b'||str[1] == 'B')) {
+            ADV(2);
+        }
     }
     else if (base == 8) {
-	if (str[0] == '0' && (str[1] == 'o'||str[1] == 'O')) {
-	    ADV(2);
-	}
+        if (str[0] == '0' && (str[1] == 'o'||str[1] == 'O')) {
+            ADV(2);
+        }
     }
     else if (base == 10) {
-	if (str[0] == '0' && (str[1] == 'd'||str[1] == 'D')) {
-	    ADV(2);
-	}
+        if (str[0] == '0' && (str[1] == 'd'||str[1] == 'D')) {
+            ADV(2);
+        }
     }
     else if (base == 16) {
-	if (str[0] == '0' && (str[1] == 'x'||str[1] == 'X')) {
-	    ADV(2);
-	}
+        if (str[0] == '0' && (str[1] == 'x'||str[1] == 'X')) {
+            ADV(2);
+        }
     }
     if (!valid_radix_p(base)) {
         invalid_radix(base);
@@ -4149,80 +4178,79 @@ rb_int_parse_cstr(const char *str, ssize_t len, char **endp, size_t *ndigits,
     if (!len) goto bad;
     num_digits = str - s;
     if (*str == '0' && len != 1) { /* squeeze preceding 0s */
-	int us = 0;
-	const char *end = len < 0 ? NULL : str + len;
-	++num_digits;
-	while ((c = *++str) == '0' ||
-	       ((flags & RB_INT_PARSE_UNDERSCORE) && c == '_')) {
-	    if (c == '_') {
-		if (++us >= 2)
-		    break;
-	    }
-	    else {
-		++num_digits;
-		us = 0;
-	    }
-	    if (str == end) break;
-	}
-	if (!c || ISSPACE(c)) --str;
-	if (end) len = end - str;
-	ASSERT_LEN();
+        int us = 0;
+        const char *end = len < 0 ? NULL : str + len;
+        ++num_digits;
+        while ((c = *++str) == '0' ||
+               ((flags & RB_INT_PARSE_UNDERSCORE) && c == '_')) {
+            if (c == '_') {
+                if (++us >= 2)
+                    break;
+            }
+            else {
+                ++num_digits;
+                us = 0;
+            }
+            if (str == end) break;
+        }
+        if (!c || ISSPACE(c)) --str;
+        if (end) len = end - str;
     }
     c = *str;
     c = conv_digit(c);
     if (c < 0 || c >= base) {
-	if (!badcheck && num_digits) z = INT2FIX(0);
-	goto bad;
+        if (!badcheck && num_digits) z = INT2FIX(0);
+        goto bad;
     }
 
     if (ndigits) *ndigits = num_digits;
     val = ruby_scan_digits(str, len, base, &num_digits, &ov);
     if (!ov) {
-	const char *end = &str[num_digits];
-	if (num_digits > 0 && *end == '_' && (flags & RB_INT_PARSE_UNDERSCORE))
-	    goto bigparse;
-	if (endp) *endp = (char *)end;
-	if (ndigits) *ndigits += num_digits;
-	if (badcheck) {
-	    if (num_digits == 0) return Qnil; /* no number */
-	    while (len < 0 ? *end : end < str + len) {
-		if (!ISSPACE(*end)) return Qnil; /* trailing garbage */
-		end++;
-	    }
-	}
-
-	if (POSFIXABLE(val)) {
-	    if (sign) return LONG2FIX(val);
-	    else {
-		long result = -(long)val;
-		return LONG2FIX(result);
-	    }
-	}
-	else {
-	    VALUE big = rb_uint2big(val);
-	    BIGNUM_SET_SIGN(big, sign);
-	    return bignorm(big);
-	}
+        const char *end = &str[num_digits];
+        if (num_digits > 0 && *end == '_' && (flags & RB_INT_PARSE_UNDERSCORE))
+            goto bigparse;
+        if (endp) *endp = (char *)end;
+        if (ndigits) *ndigits += num_digits;
+        if (badcheck) {
+            if (num_digits == 0) return Qnil; /* no number */
+            while (len < 0 ? *end : end < str + len) {
+                if (!ISSPACE(*end)) return Qnil; /* trailing garbage */
+                end++;
+            }
+        }
+
+        if (POSFIXABLE(val)) {
+            if (sign) return LONG2FIX(val);
+            else {
+                long result = -(long)val;
+                return LONG2FIX(result);
+            }
+        }
+        else {
+            VALUE big = rb_uint2big(val);
+            BIGNUM_SET_SIGN(big, sign);
+            return bignorm(big);
+        }
     }
 
   bigparse:
     digits_start = str;
     if (!str2big_scan_digits(s, str, base, badcheck, &num_digits, &len))
-	goto bad;
+        goto bad;
     if (endp) *endp = (char *)(str + len);
     if (ndigits) *ndigits += num_digits;
     digits_end = digits_start + len;
 
     if (POW2_P(base)) {
         z = str2big_poweroftwo(sign, digits_start, digits_end, num_digits,
-			       bit_length(base-1));
+                               bit_length(base-1));
     }
     else {
         int digits_per_bdigits_dbl;
         maxpow_in_bdigit_dbl(base, &digits_per_bdigits_dbl);
         num_bdigits = roomof(num_digits, digits_per_bdigits_dbl)*2;
 
-#ifdef USE_GMP
+#if USE_GMP
         if (GMP_STR2BIG_DIGITS < num_bdigits) {
             z = str2big_gmp(sign, digits_start, digits_end, num_digits,
                     num_bdigits, base);
@@ -4251,7 +4279,7 @@ static VALUE
 rb_cstr_parse_inum(const char *str, ssize_t len, char **endp, int base)
 {
     return rb_int_parse_cstr(str, len, endp, NULL, base,
-			     RB_INT_PARSE_DEFAULT);
+                             RB_INT_PARSE_DEFAULT);
 }
 
 VALUE
@@ -4300,14 +4328,14 @@ rb_str2big_poweroftwo(VALUE arg, int base, int badcheck)
     s = str = StringValueCStr(arg);
     len = RSTRING_LEN(arg);
     if (*str == '-') {
-	len--;
+        len--;
         str++;
         positive_p = 0;
     }
 
     digits_start = str;
     if (!str2big_scan_digits(s, str, base, badcheck, &num_digits, &len))
-	invalid_integer(arg);
+        invalid_integer(arg);
     digits_end = digits_start + len;
 
     z = str2big_poweroftwo(positive_p, digits_start, digits_end, num_digits,
@@ -4339,14 +4367,14 @@ rb_str2big_normal(VALUE arg, int base, int badcheck)
     s = str = StringValuePtr(arg);
     len = RSTRING_LEN(arg);
     if (len > 0 && *str == '-') {
-	len--;
+        len--;
         str++;
         positive_p = 0;
     }
 
     digits_start = str;
     if (!str2big_scan_digits(s, str, base, badcheck, &num_digits, &len))
-	invalid_integer(arg);
+        invalid_integer(arg);
     digits_end = digits_start + len;
 
     maxpow_in_bdigit_dbl(base, &digits_per_bdigits_dbl);
@@ -4381,14 +4409,14 @@ rb_str2big_karatsuba(VALUE arg, int base, int badcheck)
     s = str = StringValuePtr(arg);
     len = RSTRING_LEN(arg);
     if (len > 0 && *str == '-') {
-	len--;
+        len--;
         str++;
         positive_p = 0;
     }
 
     digits_start = str;
     if (!str2big_scan_digits(s, str, base, badcheck, &num_digits, &len))
-	invalid_integer(arg);
+        invalid_integer(arg);
     digits_end = digits_start + len;
 
     maxpow_in_bdigit_dbl(base, &digits_per_bdigits_dbl);
@@ -4402,7 +4430,7 @@ rb_str2big_karatsuba(VALUE arg, int base, int badcheck)
     return bignorm(z);
 }
 
-#ifdef USE_GMP
+#if USE_GMP
 VALUE
 rb_str2big_gmp(VALUE arg, int base, int badcheck)
 {
@@ -4424,14 +4452,14 @@ rb_str2big_gmp(VALUE arg, int base, int badcheck)
     s = str = StringValuePtr(arg);
     len = RSTRING_LEN(arg);
     if (len > 0 && *str == '-') {
-	len--;
+        len--;
         str++;
         positive_p = 0;
     }
 
     digits_start = str;
     if (!str2big_scan_digits(s, str, base, badcheck, &num_digits, &len))
-	invalid_integer(arg);
+        invalid_integer(arg);
     digits_end = digits_start + len;
 
     maxpow_in_bdigit_dbl(base, &digits_per_bdigits_dbl);
@@ -4458,8 +4486,8 @@ rb_ull2big(unsigned LONG_LONG n)
     digits[0] = n;
 #else
     for (i = 0; i < bdigit_roomof(SIZEOF_LONG_LONG); i++) {
-	digits[i] = BIGLO(n);
-	n = BIGDN(n);
+        digits[i] = BIGLO(n);
+        n = BIGDN(n);
     }
 #endif
 
@@ -4478,14 +4506,14 @@ rb_ll2big(LONG_LONG n)
 
     if (n < 0) {
         u = 1 + (unsigned LONG_LONG)(-(n + 1)); /* u = -n avoiding overflow */
-	neg = 1;
+        neg = 1;
     }
     else {
         u = n;
     }
     big = rb_ull2big(u);
     if (neg) {
-	BIGNUM_SET_NEGATIVE_SIGN(big);
+        BIGNUM_SET_NEGATIVE_SIGN(big);
     }
     return big;
 }
@@ -4515,7 +4543,7 @@ rb_uint128t2big(uint128_t n)
     BDIGIT *digits = BDIGITS(big);
 
     for (i = 0; i < bdigit_roomof(SIZEOF_INT128_T); i++) {
-	digits[i] = BIGLO(RSHIFT(n ,BITSPERDIG*i));
+        digits[i] = BIGLO(RSHIFT(n ,BITSPERDIG*i));
     }
 
     i = bdigit_roomof(SIZEOF_INT128_T);
@@ -4524,7 +4552,7 @@ rb_uint128t2big(uint128_t n)
     return big;
 }
 
-MJIT_FUNC_EXPORTED VALUE
+VALUE
 rb_int128t2big(int128_t n)
 {
     int neg = 0;
@@ -4533,14 +4561,14 @@ rb_int128t2big(int128_t n)
 
     if (n < 0) {
         u = 1 + (uint128_t)(-(n + 1)); /* u = -n avoiding overflow */
-	neg = 1;
+        neg = 1;
     }
     else {
         u = n;
     }
     big = rb_uint128t2big(u);
     if (neg) {
-	BIGNUM_SET_NEGATIVE_SIGN(big);
+        BIGNUM_SET_NEGATIVE_SIGN(big);
     }
     return big;
 }
@@ -4569,11 +4597,14 @@ big_shift3(VALUE x, int lshift_p, size_t shift_numdigits, int shift_numbits)
 
     if (lshift_p) {
         if (LONG_MAX < shift_numdigits) {
-            rb_raise(rb_eArgError, "too big number");
+          too_big:
+            rb_raise(rb_eRangeError, "shift width too big");
         }
         s1 = shift_numdigits;
         s2 = shift_numbits;
+        if ((size_t)s1 != shift_numdigits) goto too_big;
         xn = BIGNUM_LEN(x);
+        if (LONG_MAX/SIZEOF_BDIGIT <= xn+s1) goto too_big;
         z = bignew(xn+s1+1, BIGNUM_SIGN(x));
         zds = BDIGITS(z);
         BDIGITS_ZERO(zds, s1);
@@ -4615,8 +4646,8 @@ big_shift2(VALUE x, int lshift_p, VALUE y)
     size_t shift_numdigits;
     int shift_numbits;
 
-    assert(POW2_P(CHAR_BIT));
-    assert(POW2_P(BITSPERDIG));
+    RUBY_ASSERT(POW2_P(CHAR_BIT));
+    RUBY_ASSERT(POW2_P(BITSPERDIG));
 
     if (BIGZEROP(x))
         return INT2FIX(0);
@@ -4703,7 +4734,7 @@ power_cache_get_power(int base, int power_level, size_t *numdigits_ret)
         rb_obj_hide(power);
         base36_power_cache[base - 2][power_level] = power;
         base36_numdigits_cache[base - 2][power_level] = numdigits;
-	rb_gc_register_mark_object(power);
+        rb_vm_register_global_object(power);
     }
     if (numdigits_ret)
         *numdigits_ret = base36_numdigits_cache[base - 2][power_level];
@@ -4739,7 +4770,7 @@ big2str_2bdigits(struct big2str_struct *b2s, BDIGIT *xds, size_t xn, size_t tail
     int beginning = !b2s->ptr;
     size_t len = 0;
 
-    assert(xn <= 2);
+    RUBY_ASSERT(xn <= 2);
     num = bary2bdigitdbl(xds, xn);
 
     if (beginning) {
@@ -4754,7 +4785,7 @@ big2str_2bdigits(struct big2str_struct *b2s, BDIGIT *xds, size_t xn, size_t tail
         } while (num);
         len = sizeof(buf) - j;
         big2str_alloc(b2s, len + taillen);
-	MEMCPY(b2s->ptr, buf + j, char, len);
+        MEMCPY(b2s->ptr, buf + j, char, len);
     }
     else {
         p = b2s->ptr;
@@ -4771,7 +4802,7 @@ big2str_2bdigits(struct big2str_struct *b2s, BDIGIT *xds, size_t xn, size_t tail
 
 static void
 big2str_karatsuba(struct big2str_struct *b2s, BDIGIT *xds, size_t xn, size_t wn,
-		  int power_level, size_t taillen)
+                  int power_level, size_t taillen)
 {
     VALUE b;
     size_t half_numdigits, lower_numdigits;
@@ -4801,17 +4832,17 @@ big2str_karatsuba(struct big2str_struct *b2s, BDIGIT *xds, size_t xn, size_t wn,
      */
 
     if (xn == 0 || bary_zero_p(xds, xn)) {
-	if (b2s->ptr) {
+        if (b2s->ptr) {
             /* When x is zero, power_cache_get_power(base, power_level) should be cached already. */
             power_cache_get_power(b2s->base, power_level, &len);
-	    memset(b2s->ptr, '0', len);
+            memset(b2s->ptr, '0', len);
             b2s->ptr += len;
-	}
+        }
         return;
     }
 
     if (power_level == 0) {
-	big2str_2bdigits(b2s, xds, xn, taillen);
+        big2str_2bdigits(b2s, xds, xn, taillen);
         return;
     }
 
@@ -4839,7 +4870,7 @@ big2str_karatsuba(struct big2str_struct *b2s, BDIGIT *xds, size_t xn, size_t wn,
             memset(b2s->ptr, '0', len);
             b2s->ptr += len;
         }
-	big2str_2bdigits(b2s, xds, xn, taillen);
+        big2str_2bdigits(b2s, xds, xn, taillen);
     }
     else {
         BDIGIT *qds, *rds;
@@ -4867,7 +4898,7 @@ big2str_karatsuba(struct big2str_struct *b2s, BDIGIT *xds, size_t xn, size_t wn,
             /* bigdivrem_restoring will modify y.
              * So use temporary buffer.  */
             tds = xds + qn;
-            assert(qn + bn <= xn + wn);
+            RUBY_ASSERT(qn + bn <= xn + wn);
             bary_small_lshift(tds, bds, bn, shift);
             xds[xn] = bary_small_lshift(xds, xds, xn, shift);
         }
@@ -4885,7 +4916,7 @@ big2str_karatsuba(struct big2str_struct *b2s, BDIGIT *xds, size_t xn, size_t wn,
         }
 
         BARY_TRUNC(qds, qn);
-        assert(qn <= bn);
+        RUBY_ASSERT(qn <= bn);
         big2str_karatsuba(b2s, qds, qn, xn+wn - (rn+qn), lower_power_level, lower_numdigits+taillen);
         BARY_TRUNC(rds, rn);
         big2str_karatsuba(b2s, rds, rn, xn+wn - rn, lower_power_level, taillen);
@@ -4943,14 +4974,14 @@ big2str_generic(VALUE x, int base)
     BARY_TRUNC(xds, xn);
 
     if (xn == 0) {
-	return rb_usascii_str_new2("0");
+        return rb_usascii_str_new2("0");
     }
 
     if (!valid_radix_p(base))
-	invalid_radix(base);
+        invalid_radix(base);
 
     if (xn >= LONG_MAX/BITSPERDIG) {
-        rb_raise(rb_eRangeError, "bignum too big to convert into `string'");
+        rb_raise(rb_eRangeError, "bignum too big to convert into 'string'");
     }
 
     power_level = 0;
@@ -4960,7 +4991,7 @@ big2str_generic(VALUE x, int base)
         power_level++;
         power = power_cache_get_power(base, power_level, NULL);
     }
-    assert(power_level != MAX_BASE36_POWER_TABLE_ENTRIES);
+    RUBY_ASSERT(power_level != MAX_BASE36_POWER_TABLE_ENTRIES);
 
     if ((size_t)BIGNUM_LEN(power) <= xn) {
         /*
@@ -4984,7 +5015,7 @@ big2str_generic(VALUE x, int base)
     b2s_data.ptr = NULL;
 
     if (power_level == 0) {
-	big2str_2bdigits(&b2s_data, xds, xn, 0);
+        big2str_2bdigits(&b2s_data, xds, xn, 0);
     }
     else {
         VALUE tmpw = 0;
@@ -4993,7 +5024,7 @@ big2str_generic(VALUE x, int base)
         wn = power_level * BIGDIVREM_EXTRA_WORDS + BIGNUM_LEN(power);
         wds = ALLOCV_N(BDIGIT, tmpw, xn + wn);
         MEMCPY(wds, xds, BDIGIT, xn);
-	big2str_karatsuba(&b2s_data, wds, xn, wn, power_level, 0);
+        big2str_karatsuba(&b2s_data, wds, xn, wn, power_level, 0);
         if (tmpw)
             ALLOCV_END(tmpw);
     }
@@ -5012,7 +5043,7 @@ rb_big2str_generic(VALUE x, int base)
     return big2str_generic(x, base);
 }
 
-#ifdef USE_GMP
+#if USE_GMP
 static VALUE
 big2str_gmp(VALUE x, int base)
 {
@@ -5059,7 +5090,7 @@ rb_big2str1(VALUE x, int base)
     size_t xn;
 
     if (FIXNUM_P(x)) {
-	return rb_fix2str(x, base);
+        return rb_fix2str(x, base);
     }
 
     bigtrunc(x);
@@ -5068,14 +5099,14 @@ rb_big2str1(VALUE x, int base)
     BARY_TRUNC(xds, xn);
 
     if (xn == 0) {
-	return rb_usascii_str_new2("0");
+        return rb_usascii_str_new2("0");
     }
 
     if (!valid_radix_p(base))
-	invalid_radix(base);
+        invalid_radix(base);
 
     if (xn >= LONG_MAX/BITSPERDIG) {
-        rb_raise(rb_eRangeError, "bignum too big to convert into `string'");
+        rb_raise(rb_eRangeError, "bignum too big to convert into 'string'");
     }
 
     if (POW2_P(base)) {
@@ -5083,7 +5114,7 @@ rb_big2str1(VALUE x, int base)
         return big2str_base_poweroftwo(x, base);
     }
 
-#ifdef USE_GMP
+#if USE_GMP
     if (GMP_BIG2STR_DIGITS < xn) {
         return big2str_gmp(x, base);
     }
@@ -5111,7 +5142,7 @@ big2ulong(VALUE x, const char *type)
     if (len == 0)
         return 0;
     if (BIGSIZE(x) > sizeof(long)) {
-        rb_raise(rb_eRangeError, "bignum too big to convert into `%s'", type);
+        rb_raise(rb_eRangeError, "bignum too big to convert into '%s'", type);
     }
     ds = BDIGITS(x);
 #if SIZEOF_LONG <= SIZEOF_BDIGIT
@@ -5119,7 +5150,7 @@ big2ulong(VALUE x, const char *type)
 #else
     num = 0;
     for (i = 0; i < len; i++) {
-	num <<= BITSPERDIG;
+        num <<= BITSPERDIG;
         num += (unsigned long)ds[len - i - 1]; /* overflow is already checked */
     }
 #endif
@@ -5154,7 +5185,7 @@ rb_big2long(VALUE x)
         if (num <= 1+(unsigned long)(-(LONG_MIN+1)))
             return -(long)(num-1)-1;
     }
-    rb_raise(rb_eRangeError, "bignum too big to convert into `long'");
+    rb_raise(rb_eRangeError, "bignum too big to convert into 'long'");
 }
 
 #if HAVE_LONG_LONG
@@ -5172,13 +5203,13 @@ big2ull(VALUE x, const char *type)
     if (len == 0)
         return 0;
     if (BIGSIZE(x) > SIZEOF_LONG_LONG)
-	rb_raise(rb_eRangeError, "bignum too big to convert into `%s'", type);
+        rb_raise(rb_eRangeError, "bignum too big to convert into '%s'", type);
 #if SIZEOF_LONG_LONG <= SIZEOF_BDIGIT
     num = (unsigned LONG_LONG)ds[0];
 #else
     num = 0;
     for (i = 0; i < len; i++) {
-	num = BIGUP(num);
+        num = BIGUP(num);
         num += ds[len - i - 1];
     }
 #endif
@@ -5213,7 +5244,7 @@ rb_big2ll(VALUE x)
         if (num <= 1+(unsigned LONG_LONG)(-(LLONG_MIN+1)))
             return -(LONG_LONG)(num-1)-1;
     }
-    rb_raise(rb_eRangeError, "bignum too big to convert into `long long'");
+    rb_raise(rb_eRangeError, "bignum too big to convert into 'long long'");
 }
 
 #endif  /* HAVE_LONG_LONG */
@@ -5228,23 +5259,23 @@ dbl2big(double d)
     double u = (d < 0)?-d:d;
 
     if (isinf(d)) {
-	rb_raise(rb_eFloatDomainError, d < 0 ? "-Infinity" : "Infinity");
+        rb_raise(rb_eFloatDomainError, d < 0 ? "-Infinity" : "Infinity");
     }
     if (isnan(d)) {
-	rb_raise(rb_eFloatDomainError, "NaN");
+        rb_raise(rb_eFloatDomainError, "NaN");
     }
 
     while (1.0 <= u) {
-	u /= (double)(BIGRAD);
-	i++;
+        u /= (double)(BIGRAD);
+        i++;
     }
     z = bignew(i, d>=0);
     digits = BDIGITS(z);
     while (i--) {
-	u *= BIGRAD;
-	c = (BDIGIT)u;
-	u -= c;
-	digits[i] = c;
+        u *= BIGRAD;
+        c = (BDIGIT)u;
+        u -= c;
+        digits[i] = c;
     }
 
     return z;
@@ -5264,28 +5295,28 @@ big2dbl(VALUE x)
     BDIGIT *ds = BDIGITS(x), dl;
 
     if (i) {
-	bits = i * BITSPERDIG - nlz(ds[i-1]);
-	if (bits > DBL_MANT_DIG+DBL_MAX_EXP) {
-	    d = HUGE_VAL;
-	}
-	else {
-	    if (bits > DBL_MANT_DIG+1)
-		lo = (bits -= DBL_MANT_DIG+1) / BITSPERDIG;
-	    else
-		bits = 0;
-	    while (--i > lo) {
-		d = ds[i] + BIGRAD*d;
-	    }
-	    dl = ds[i];
-	    if (bits && (dl & ((BDIGIT)1 << (bits %= BITSPERDIG)))) {
-		int carry = (dl & ~(BDIGMAX << bits)) != 0;
-		if (!carry) {
-		    while (i-- > 0) {
-			carry = ds[i] != 0;
-			if (carry) break;
-		    }
-		}
-		if (carry) {
+        bits = i * BITSPERDIG - nlz(ds[i-1]);
+        if (bits > DBL_MANT_DIG+DBL_MAX_EXP) {
+            d = HUGE_VAL;
+        }
+        else {
+            if (bits > DBL_MANT_DIG+1)
+                lo = (bits -= DBL_MANT_DIG+1) / BITSPERDIG;
+            else
+                bits = 0;
+            while (--i > lo) {
+                d = ds[i] + BIGRAD*d;
+            }
+            dl = ds[i];
+            if (bits && (dl & ((BDIGIT)1 << (bits %= BITSPERDIG)))) {
+                int carry = (dl & ~(BDIGMAX << bits)) != 0;
+                if (!carry) {
+                    while (i-- > 0) {
+                        carry = ds[i] != 0;
+                        if (carry) break;
+                    }
+                }
+                if (carry) {
                     BDIGIT mask = BDIGMAX;
                     BDIGIT bit = 1;
                     mask <<= bits;
@@ -5293,19 +5324,19 @@ big2dbl(VALUE x)
                     dl &= mask;
                     dl += bit;
                     dl = BIGLO(dl);
-		    if (!dl) d += 1;
-		}
-	    }
-	    d = dl + BIGRAD*d;
-	    if (lo) {
-		if (lo > INT_MAX / BITSPERDIG)
-		    d = HUGE_VAL;
-		else if (lo < INT_MIN / BITSPERDIG)
-		    d = 0.0;
-		else
-		    d = ldexp(d, (int)(lo * BITSPERDIG));
-	    }
-	}
+                    if (!dl) d += 1;
+                }
+            }
+            d = dl + BIGRAD*d;
+            if (lo) {
+                if (lo > INT_MAX / BITSPERDIG)
+                    d = HUGE_VAL;
+                else if (lo < INT_MIN / BITSPERDIG)
+                    d = 0.0;
+                else
+                    d = ldexp(d, (int)(lo * BITSPERDIG));
+            }
+        }
     }
     if (BIGNUM_NEGATIVE_P(x)) d = -d;
     return d;
@@ -5317,11 +5348,11 @@ rb_big2dbl(VALUE x)
     double d = big2dbl(x);
 
     if (isinf(d)) {
-	rb_warning("Integer out of Float range");
-	if (d < 0.0)
-	    d = -HUGE_VAL;
-	else
-	    d = HUGE_VAL;
+        rb_warning("Integer out of Float range");
+        if (d < 0.0)
+            d = -HUGE_VAL;
+        else
+            d = HUGE_VAL;
     }
     return d;
 }
@@ -5418,26 +5449,26 @@ VALUE
 rb_big_cmp(VALUE x, VALUE y)
 {
     if (FIXNUM_P(y)) {
-	x = bigfixize(x);
+        x = bigfixize(x);
         if (FIXNUM_P(x)) {
-	    /* SIGNED_VALUE and Fixnum have same sign-bits, same
-	     * order */
-	    SIGNED_VALUE sx = (SIGNED_VALUE)x, sy = (SIGNED_VALUE)y;
-	    if (sx < sy) return INT2FIX(-1);
-	    return INT2FIX(sx > sy);
+            /* SIGNED_VALUE and Fixnum have same sign-bits, same
+             * order */
+            SIGNED_VALUE sx = (SIGNED_VALUE)x, sy = (SIGNED_VALUE)y;
+            if (sx < sy) return INT2FIX(-1);
+            return INT2FIX(sx > sy);
         }
     }
     else if (RB_BIGNUM_TYPE_P(y)) {
-	if (BIGNUM_SIGN(x) == BIGNUM_SIGN(y)) {
-	    int cmp = bary_cmp(BDIGITS(x), BIGNUM_LEN(x), BDIGITS(y), BIGNUM_LEN(y));
-	    return INT2FIX(BIGNUM_SIGN(x) ? cmp : -cmp);
-	}
+        if (BIGNUM_SIGN(x) == BIGNUM_SIGN(y)) {
+            int cmp = bary_cmp(BDIGITS(x), BIGNUM_LEN(x), BDIGITS(y), BIGNUM_LEN(y));
+            return INT2FIX(BIGNUM_SIGN(x) ? cmp : -cmp);
+        }
     }
     else if (RB_FLOAT_TYPE_P(y)) {
         return rb_integer_float_cmp(x, y);
     }
     else {
-	return rb_num_coerce_cmp(x, y, idCmp);
+        return rb_num_coerce_cmp(x, y, idCmp);
     }
     return INT2FIX(BIGNUM_SIGN(x) ? 1 : -1);
 }
@@ -5456,30 +5487,30 @@ big_op(VALUE x, VALUE y, enum big_op_t op)
     int n;
 
     if (RB_INTEGER_TYPE_P(y)) {
-	rel = rb_big_cmp(x, y);
+        rel = rb_big_cmp(x, y);
     }
     else if (RB_FLOAT_TYPE_P(y)) {
         rel = rb_integer_float_cmp(x, y);
     }
     else {
-	ID id = 0;
-	switch (op) {
-	  case big_op_gt: id = '>'; break;
-	  case big_op_ge: id = idGE; break;
-	  case big_op_lt: id = '<'; break;
-	  case big_op_le: id = idLE; break;
-	}
-	return rb_num_coerce_relop(x, y, id);
+        ID id = 0;
+        switch (op) {
+          case big_op_gt: id = '>'; break;
+          case big_op_ge: id = idGE; break;
+          case big_op_lt: id = '<'; break;
+          case big_op_le: id = idLE; break;
+        }
+        return rb_num_coerce_relop(x, y, id);
     }
 
     if (NIL_P(rel)) return Qfalse;
     n = FIX2INT(rel);
 
     switch (op) {
-	case big_op_gt: return RBOOL(n >  0);
-	case big_op_ge: return RBOOL(n >= 0);
-	case big_op_lt: return RBOOL(n <  0);
-	case big_op_le: return RBOOL(n <= 0);
+      case big_op_gt: return RBOOL(n >  0);
+      case big_op_ge: return RBOOL(n >= 0);
+      case big_op_lt: return RBOOL(n <  0);
+      case big_op_le: return RBOOL(n <= 0);
     }
     return Qundef;
 }
@@ -5523,7 +5554,7 @@ VALUE
 rb_big_eq(VALUE x, VALUE y)
 {
     if (FIXNUM_P(y)) {
-	return RBOOL(bignorm(x) == y);
+        return RBOOL(bignorm(x) == y);
     }
     else if (RB_BIGNUM_TYPE_P(y)) {
     }
@@ -5531,7 +5562,7 @@ rb_big_eq(VALUE x, VALUE y)
         return rb_integer_float_eq(x, y);
     }
     else {
-	return rb_equal(y, x);
+        return rb_equal(y, x);
     }
     if (BIGNUM_SIGN(x) != BIGNUM_SIGN(y)) return Qfalse;
     if (BIGNUM_LEN(x) != BIGNUM_LEN(y)) return Qfalse;
@@ -5635,13 +5666,13 @@ bigsub_int(VALUE x, long y0)
     zds = BDIGITS(z);
 
 #if SIZEOF_BDIGIT >= SIZEOF_LONG
-    assert(xn == zn);
+    RUBY_ASSERT(xn == zn);
     num = (BDIGIT_DBL_SIGNED)xds[0] - y;
     if (xn == 1 && num < 0) {
-	BIGNUM_NEGATE(z);
-	zds[0] = (BDIGIT)-num;
-	RB_GC_GUARD(x);
-	return bignorm(z);
+        BIGNUM_NEGATE(z);
+        zds[0] = (BDIGIT)-num;
+        RB_GC_GUARD(x);
+        return bignorm(z);
     }
     zds[0] = BIGLO(num);
     num = BIGDN(num);
@@ -5653,10 +5684,10 @@ bigsub_int(VALUE x, long y0)
     num = 0;
     for (i=0; i < xn; i++) {
         if (y == 0) goto y_is_zero_x;
-	num += (BDIGIT_DBL_SIGNED)xds[i] - BIGLO(y);
-	zds[i] = BIGLO(num);
-	num = BIGDN(num);
-	y = BIGDN(y);
+        num += (BDIGIT_DBL_SIGNED)xds[i] - BIGLO(y);
+        zds[i] = BIGLO(num);
+        num = BIGDN(num);
+        y = BIGDN(y);
     }
     for (; i < zn; i++) {
         if (y == 0) goto y_is_zero_z;
@@ -5671,9 +5702,9 @@ bigsub_int(VALUE x, long y0)
     for (; i < xn; i++) {
       y_is_zero_x:
         if (num == 0) goto num_is_zero_x;
-	num += xds[i];
-	zds[i] = BIGLO(num);
-	num = BIGDN(num);
+        num += xds[i];
+        zds[i] = BIGLO(num);
+        num = BIGDN(num);
     }
 #if SIZEOF_BDIGIT < SIZEOF_LONG
     for (; i < zn; i++) {
@@ -5687,7 +5718,7 @@ bigsub_int(VALUE x, long y0)
 
     for (; i < xn; i++) {
       num_is_zero_x:
-	zds[i] = xds[i];
+        zds[i] = xds[i];
     }
 #if SIZEOF_BDIGIT < SIZEOF_LONG
     for (; i < zn; i++) {
@@ -5698,10 +5729,10 @@ bigsub_int(VALUE x, long y0)
     goto finish;
 
   finish:
-    assert(num == 0 || num == -1);
+    RUBY_ASSERT(num == 0 || num == -1);
     if (num < 0) {
         get2comp(z);
-	BIGNUM_NEGATE(z);
+        BIGNUM_NEGATE(z);
     }
     RB_GC_GUARD(x);
     return bignorm(z);
@@ -5744,17 +5775,17 @@ bigadd_int(VALUE x, long y)
     num = 0;
     for (i=0; i < xn; i++) {
         if (y == 0) goto y_is_zero_x;
-	num += (BDIGIT_DBL)xds[i] + BIGLO(y);
-	zds[i] = BIGLO(num);
-	num = BIGDN(num);
-	y = BIGDN(y);
+        num += (BDIGIT_DBL)xds[i] + BIGLO(y);
+        zds[i] = BIGLO(num);
+        num = BIGDN(num);
+        y = BIGDN(y);
     }
     for (; i < zn; i++) {
         if (y == 0) goto y_is_zero_z;
-	num += BIGLO(y);
-	zds[i] = BIGLO(num);
-	num = BIGDN(num);
-	y = BIGDN(y);
+        num += BIGLO(y);
+        zds[i] = BIGLO(num);
+        num = BIGDN(num);
+        y = BIGDN(y);
     }
     goto finish;
 
@@ -5763,25 +5794,25 @@ bigadd_int(VALUE x, long y)
     for (;i < xn; i++) {
       y_is_zero_x:
         if (num == 0) goto num_is_zero_x;
-	num += (BDIGIT_DBL)xds[i];
-	zds[i] = BIGLO(num);
-	num = BIGDN(num);
+        num += (BDIGIT_DBL)xds[i];
+        zds[i] = BIGLO(num);
+        num = BIGDN(num);
     }
     for (; i < zn; i++) {
       y_is_zero_z:
         if (num == 0) goto num_is_zero_z;
-	zds[i] = BIGLO(num);
-	num = BIGDN(num);
+        zds[i] = BIGLO(num);
+        num = BIGDN(num);
     }
     goto finish;
 
     for (;i < xn; i++) {
       num_is_zero_x:
-	zds[i] = xds[i];
+        zds[i] = xds[i];
     }
     for (; i < zn; i++) {
       num_is_zero_z:
-	zds[i] = 0;
+        zds[i] = 0;
     }
     goto finish;
 
@@ -5798,15 +5829,15 @@ bigadd(VALUE x, VALUE y, int sign)
 
     sign = (sign == BIGNUM_SIGN(y));
     if (BIGNUM_SIGN(x) != sign) {
-	if (sign) return bigsub(y, x);
-	return bigsub(x, y);
+        if (sign) return bigsub(y, x);
+        return bigsub(x, y);
     }
 
     if (BIGNUM_LEN(x) > BIGNUM_LEN(y)) {
-	len = BIGNUM_LEN(x) + 1;
+        len = BIGNUM_LEN(x) + 1;
     }
     else {
-	len = BIGNUM_LEN(y) + 1;
+        len = BIGNUM_LEN(y) + 1;
     }
     z = bignew(len, sign);
 
@@ -5823,26 +5854,26 @@ rb_big_plus(VALUE x, VALUE y)
     long n;
 
     if (FIXNUM_P(y)) {
-	n = FIX2LONG(y);
-	if ((n > 0) != BIGNUM_SIGN(x)) {
-	    if (n < 0) {
-		n = -n;
-	    }
-	    return bigsub_int(x, n);
-	}
-	if (n < 0) {
-	    n = -n;
-	}
-	return bigadd_int(x, n);
+        n = FIX2LONG(y);
+        if ((n > 0) != BIGNUM_SIGN(x)) {
+            if (n < 0) {
+                n = -n;
+            }
+            return bigsub_int(x, n);
+        }
+        if (n < 0) {
+            n = -n;
+        }
+        return bigadd_int(x, n);
     }
     else if (RB_BIGNUM_TYPE_P(y)) {
-	return bignorm(bigadd(x, y, 1));
+        return bignorm(bigadd(x, y, 1));
     }
     else if (RB_FLOAT_TYPE_P(y)) {
-	return DBL2NUM(rb_big2dbl(x) + RFLOAT_VALUE(y));
+        return DBL2NUM(rb_big2dbl(x) + RFLOAT_VALUE(y));
     }
     else {
-	return rb_num_coerce_bin(x, y, '+');
+        return rb_num_coerce_bin(x, y, '+');
     }
 }
 
@@ -5852,26 +5883,26 @@ rb_big_minus(VALUE x, VALUE y)
     long n;
 
     if (FIXNUM_P(y)) {
-	n = FIX2LONG(y);
-	if ((n > 0) != BIGNUM_SIGN(x)) {
-	    if (n < 0) {
-		n = -n;
-	    }
-	    return bigadd_int(x, n);
-	}
-	if (n < 0) {
-	    n = -n;
-	}
-	return bigsub_int(x, n);
+        n = FIX2LONG(y);
+        if ((n > 0) != BIGNUM_SIGN(x)) {
+            if (n < 0) {
+                n = -n;
+            }
+            return bigadd_int(x, n);
+        }
+        if (n < 0) {
+            n = -n;
+        }
+        return bigsub_int(x, n);
     }
     else if (RB_BIGNUM_TYPE_P(y)) {
-	return bignorm(bigadd(x, y, 0));
+        return bignorm(bigadd(x, y, 0));
     }
     else if (RB_FLOAT_TYPE_P(y)) {
-	return DBL2NUM(rb_big2dbl(x) - RFLOAT_VALUE(y));
+        return DBL2NUM(rb_big2dbl(x) - RFLOAT_VALUE(y));
     }
     else {
-	return rb_num_coerce_bin(x, y, '-');
+        return rb_num_coerce_bin(x, y, '-');
     }
 }
 
@@ -5883,6 +5914,8 @@ bigsq(VALUE x)
     BDIGIT *xds, *zds;
 
     xn = BIGNUM_LEN(x);
+    if (MUL_OVERFLOW_LONG_P(2, xn))
+        rb_raise(rb_eArgError, "square overflow");
     zn = 2 * xn;
 
     z = bignew(zn, 1);
@@ -5911,6 +5944,8 @@ bigmul0(VALUE x, VALUE y)
 
     xn = BIGNUM_LEN(x);
     yn = BIGNUM_LEN(y);
+    if (ADD_OVERFLOW_LONG_P(xn, yn))
+        rb_raise(rb_eArgError, "multiplication overflow");
     zn = xn + yn;
 
     z = bignew(zn, BIGNUM_SIGN(x)==BIGNUM_SIGN(y));
@@ -5930,15 +5965,15 @@ VALUE
 rb_big_mul(VALUE x, VALUE y)
 {
     if (FIXNUM_P(y)) {
-	y = rb_int2big(FIX2LONG(y));
+        y = rb_int2big(FIX2LONG(y));
     }
     else if (RB_BIGNUM_TYPE_P(y)) {
     }
     else if (RB_FLOAT_TYPE_P(y)) {
-	return DBL2NUM(rb_big2dbl(x) * RFLOAT_VALUE(y));
+        return DBL2NUM(rb_big2dbl(x) * RFLOAT_VALUE(y));
     }
     else {
-	return rb_num_coerce_bin(x, y, '*');
+        return rb_num_coerce_bin(x, y, '*');
     }
 
     return bignorm(bigmul0(x, y));
@@ -5965,21 +6000,21 @@ bigdivrem(VALUE x, VALUE y, volatile VALUE *divp, volatile VALUE *modp)
     BARY_TRUNC(xds, xn);
 
     if (xn < yn || (xn == yn && xds[xn - 1] < yds[yn - 1])) {
-	if (divp) *divp = rb_int2big(0);
-	if (modp) *modp = x;
-	return Qnil;
+        if (divp) *divp = rb_int2big(0);
+        if (modp) *modp = x;
+        return Qnil;
     }
     if (yn == 1) {
-	dd = yds[0];
-	z = bignew(xn, BIGNUM_SIGN(x)==BIGNUM_SIGN(y));
-	zds = BDIGITS(z);
+        dd = yds[0];
+        z = bignew(xn, BIGNUM_SIGN(x)==BIGNUM_SIGN(y));
+        zds = BDIGITS(z);
         dd = bigdivrem_single(zds, xds, xn, dd);
-	if (modp) {
-	    *modp = rb_uint2big((uintptr_t)dd);
-	    BIGNUM_SET_SIGN(*modp, BIGNUM_SIGN(x));
-	}
-	if (divp) *divp = z;
-	return Qnil;
+        if (modp) {
+            *modp = rb_uint2big((uintptr_t)dd);
+            BIGNUM_SET_SIGN(*modp, BIGNUM_SIGN(x));
+        }
+        if (divp) *divp = z;
+        return Qnil;
     }
     if (xn == 2 && yn == 2) {
         BDIGIT_DBL x0 = bary2bdigitdbl(xds, 2);
@@ -6044,11 +6079,11 @@ bigdivmod(VALUE x, VALUE y, volatile VALUE *divp, volatile VALUE *modp)
 
     bigdivrem(x, y, divp, &mod);
     if (BIGNUM_SIGN(x) != BIGNUM_SIGN(y) && !BIGZEROP(mod)) {
-	if (divp) *divp = bigadd(*divp, rb_int2big(1), 0);
-	if (modp) *modp = bigadd(mod, y, 1);
+        if (divp) *divp = bigadd(*divp, rb_int2big(1), 0);
+        if (modp) *modp = bigadd(mod, y, 1);
     }
     else if (modp) {
-	*modp = mod;
+        *modp = mod;
     }
 }
 
@@ -6059,25 +6094,25 @@ rb_big_divide(VALUE x, VALUE y, ID op)
     VALUE z;
 
     if (FIXNUM_P(y)) {
-	y = rb_int2big(FIX2LONG(y));
+        y = rb_int2big(FIX2LONG(y));
     }
     else if (RB_BIGNUM_TYPE_P(y)) {
     }
     else if (RB_FLOAT_TYPE_P(y)) {
-	if (op == '/') {
+        if (op == '/') {
             double dx = rb_big2dbl(x);
             return rb_flo_div_flo(DBL2NUM(dx), y);
-	}
-	else {
+        }
+        else {
             VALUE v;
-	    double dy = RFLOAT_VALUE(y);
-	    if (dy == 0.0) rb_num_zerodiv();
+            double dy = RFLOAT_VALUE(y);
+            if (dy == 0.0) rb_num_zerodiv();
             v = rb_big_divide(x, y, '/');
             return rb_dbl2big(RFLOAT_VALUE(v));
-	}
+        }
     }
     else {
-	return rb_num_coerce_bin(x, y, op);
+        return rb_num_coerce_bin(x, y, op);
     }
     bigdivmod(x, y, &z, 0);
 
@@ -6102,10 +6137,10 @@ rb_big_modulo(VALUE x, VALUE y)
     VALUE z;
 
     if (FIXNUM_P(y)) {
-	y = rb_int2big(FIX2LONG(y));
+        y = rb_int2big(FIX2LONG(y));
     }
     else if (!RB_BIGNUM_TYPE_P(y)) {
-	return rb_num_coerce_bin(x, y, '%');
+        return rb_num_coerce_bin(x, y, '%');
     }
     bigdivmod(x, y, 0, &z);
 
@@ -6118,10 +6153,10 @@ rb_big_remainder(VALUE x, VALUE y)
     VALUE z;
 
     if (FIXNUM_P(y)) {
-	y = rb_int2big(FIX2LONG(y));
+        y = rb_int2big(FIX2LONG(y));
     }
     else if (!RB_BIGNUM_TYPE_P(y)) {
-	return rb_num_coerce_bin(x, y, rb_intern("remainder"));
+        return rb_num_coerce_bin(x, y, rb_intern("remainder"));
     }
     bigdivrem(x, y, 0, &z);
 
@@ -6134,7 +6169,7 @@ rb_big_divmod(VALUE x, VALUE y)
     VALUE div, mod;
 
     if (FIXNUM_P(y)) {
-	y = rb_int2big(FIX2LONG(y));
+        y = rb_int2big(FIX2LONG(y));
     }
     else if (!RB_BIGNUM_TYPE_P(y)) {
         return rb_num_coerce_bin(x, y, idDivmod);
@@ -6148,9 +6183,9 @@ static VALUE
 big_shift(VALUE x, long n)
 {
     if (n < 0)
-	return big_lshift(x, 1+(unsigned long)(-(n+1)));
+        return big_lshift(x, 1+(unsigned long)(-(n+1)));
     else if (n > 0)
-	return big_rshift(x, (unsigned long)n);
+        return big_rshift(x, (unsigned long)n);
     return x;
 }
 
@@ -6174,9 +6209,9 @@ big_fdiv(VALUE x, VALUE y, long ey)
     l = ex - ey;
 #if SIZEOF_LONG > SIZEOF_INT
     {
-	/* Visual C++ can't be here */
-	if (l > INT_MAX) return HUGE_VAL;
-	if (l < INT_MIN) return 0.0;
+        /* Visual C++ can't be here */
+        if (l > INT_MAX) return HUGE_VAL;
+        if (l < INT_MIN) return 0.0;
     }
 #endif
     return ldexp(big2dbl(z), (int)l);
@@ -6210,19 +6245,19 @@ rb_big_fdiv_double(VALUE x, VALUE y)
 
     dx = big2dbl(x);
     if (FIXNUM_P(y)) {
-	dy = (double)FIX2LONG(y);
-	if (isinf(dx))
-	    return big_fdiv_int(x, rb_int2big(FIX2LONG(y)));
+        dy = (double)FIX2LONG(y);
+        if (isinf(dx))
+            return big_fdiv_int(x, rb_int2big(FIX2LONG(y)));
     }
     else if (RB_BIGNUM_TYPE_P(y)) {
-	return big_fdiv_int(x, y);
+        return big_fdiv_int(x, y);
     }
     else if (RB_FLOAT_TYPE_P(y)) {
-	dy = RFLOAT_VALUE(y);
-	if (isnan(dy))
-	    return dy;
-	if (isinf(dx))
-	    return big_fdiv_float(x, y);
+        dy = RFLOAT_VALUE(y);
+        if (isnan(dy))
+            return dy;
+        if (isinf(dx))
+            return big_fdiv_float(x, y);
     }
     else {
         return NUM2DBL(rb_num_coerce_bin(x, y, idFdiv));
@@ -6247,20 +6282,19 @@ rb_big_pow(VALUE x, VALUE y)
     if (y == INT2FIX(0)) return INT2FIX(1);
     if (y == INT2FIX(1)) return x;
     if (RB_FLOAT_TYPE_P(y)) {
-	d = RFLOAT_VALUE(y);
-	if ((BIGNUM_NEGATIVE_P(x) && !BIGZEROP(x))) {
+        d = RFLOAT_VALUE(y);
+        if ((BIGNUM_NEGATIVE_P(x) && !BIGZEROP(x))) {
             return rb_dbl_complex_new_polar_pi(pow(-rb_big2dbl(x), d), d);
-	}
+        }
     }
     else if (RB_BIGNUM_TYPE_P(y)) {
-	y = bignorm(y);
-	if (FIXNUM_P(y))
-	    goto again;
-	rb_warn("in a**b, b may be too big");
-	d = rb_big2dbl(y);
+        y = bignorm(y);
+        if (FIXNUM_P(y))
+            goto again;
+        rb_raise(rb_eArgError, "exponent is too large");
     }
     else if (FIXNUM_P(y)) {
-	yy = FIX2LONG(y);
+        yy = FIX2LONG(y);
 
         if (yy < 0) {
             x = rb_big_pow(x, LONG2NUM(-yy));
@@ -6269,31 +6303,35 @@ rb_big_pow(VALUE x, VALUE y)
             else
                 return DBL2NUM(1.0 / NUM2DBL(x));
         }
-	else {
-	    VALUE z = 0;
-	    SIGNED_VALUE mask;
+        else {
+            VALUE z = 0;
+            SIGNED_VALUE mask;
             const size_t xbits = rb_absint_numwords(x, 1, NULL);
-	    const size_t BIGLEN_LIMIT = 32*1024*1024;
+#if SIZEOF_SIZE_T == 4
+            const size_t BIGLEN_LIMIT = 1ULL << 31; // 2 GB
+#else // SIZEOF_SIZE_T == 8
+            const size_t BIGLEN_LIMIT = 1ULL << 34; // 16 GB
+#endif
 
-	    if (xbits == (size_t)-1 ||
+            if (xbits == (size_t)-1 ||
                 (xbits > BIGLEN_LIMIT) ||
+                MUL_OVERFLOW_LONG_P(yy, xbits) ||
                 (xbits * yy > BIGLEN_LIMIT)) {
-		rb_warn("in a**b, b may be too big");
-		d = (double)yy;
-	    }
-	    else {
-		for (mask = FIXNUM_MAX + 1; mask; mask >>= 1) {
-		    if (z) z = bigsq(z);
-		    if (yy & mask) {
-			z = z ? bigtrunc(bigmul0(z, x)) : x;
-		    }
-		}
-		return bignorm(z);
-	    }
-	}
+                rb_raise(rb_eArgError, "exponent is too large");
+            }
+            else {
+                for (mask = FIXNUM_MAX + 1; mask; mask >>= 1) {
+                    if (z) z = bigsq(z);
+                    if (yy & mask) {
+                        z = z ? bigtrunc(bigmul0(z, x)) : x;
+                    }
+                }
+                return bignorm(z);
+            }
+        }
     }
     else {
-	return rb_num_coerce_bin(x, y, idPow);
+        return rb_num_coerce_bin(x, y, idPow);
     }
     return DBL2NUM(pow(rb_big2dbl(x), d));
 }
@@ -6313,8 +6351,8 @@ bigand_int(VALUE x, long xn, BDIGIT hibitsx, long y)
     xds = BDIGITS(x);
 #if SIZEOF_BDIGIT >= SIZEOF_LONG
     if (!hibitsy) {
-	y &= xds[0];
-	return LONG2NUM(y);
+        y &= xds[0];
+        return LONG2NUM(y);
     }
 #endif
 
@@ -6343,10 +6381,10 @@ bigand_int(VALUE x, long xn, BDIGIT hibitsx, long y)
     }
 #endif
     for (;i < xn; i++) {
-	zds[i] = xds[i] & hibitsy;
+        zds[i] = xds[i] & hibitsy;
     }
     for (;i < zn; i++) {
-	zds[i] = hibitsx & hibitsy;
+        zds[i] = hibitsx & hibitsy;
     }
     twocomp2abs_bang(z, hibitsx && hibitsy);
     RB_GC_GUARD(x);
@@ -6366,12 +6404,12 @@ rb_big_and(VALUE x, VALUE y)
     long tmpn;
 
     if (!RB_INTEGER_TYPE_P(y)) {
-	return rb_num_coerce_bit(x, y, '&');
+        return rb_num_coerce_bit(x, y, '&');
     }
 
     hibitsx = abs2twocomp(&x, &xn);
     if (FIXNUM_P(y)) {
-	return bigand_int(x, xn, hibitsx, FIX2LONG(y));
+        return bigand_int(x, xn, hibitsx, FIX2LONG(y));
     }
     hibitsy = abs2twocomp(&y, &yn);
     if (xn > yn) {
@@ -6393,10 +6431,10 @@ rb_big_and(VALUE x, VALUE y)
     zds = BDIGITS(z);
 
     for (i=0; i<n1; i++) {
-	zds[i] = ds1[i] & ds2[i];
+        zds[i] = ds1[i] & ds2[i];
     }
     for (; i<n2; i++) {
-	zds[i] = hibits1 & ds2[i];
+        zds[i] = hibits1 & ds2[i];
     }
     twocomp2abs_bang(z, hibits1 && hibits2);
     RB_GC_GUARD(x);
@@ -6485,12 +6523,12 @@ rb_big_or(VALUE x, VALUE y)
     long tmpn;
 
     if (!RB_INTEGER_TYPE_P(y)) {
-	return rb_num_coerce_bit(x, y, '|');
+        return rb_num_coerce_bit(x, y, '|');
     }
 
     hibitsx = abs2twocomp(&x, &xn);
     if (FIXNUM_P(y)) {
-	return bigor_int(x, xn, hibitsx, FIX2LONG(y));
+        return bigor_int(x, xn, hibitsx, FIX2LONG(y));
     }
     hibitsy = abs2twocomp(&y, &yn);
     if (xn > yn) {
@@ -6512,10 +6550,10 @@ rb_big_or(VALUE x, VALUE y)
     zds = BDIGITS(z);
 
     for (i=0; i<n1; i++) {
-	zds[i] = ds1[i] | ds2[i];
+        zds[i] = ds1[i] | ds2[i];
     }
     for (; i<n2; i++) {
-	zds[i] = hibits1 | ds2[i];
+        zds[i] = hibits1 | ds2[i];
     }
     twocomp2abs_bang(z, hibits1 || hibits2);
     RB_GC_GUARD(x);
@@ -6579,12 +6617,12 @@ rb_big_xor(VALUE x, VALUE y)
     long tmpn;
 
     if (!RB_INTEGER_TYPE_P(y)) {
-	return rb_num_coerce_bit(x, y, '^');
+        return rb_num_coerce_bit(x, y, '^');
     }
 
     hibitsx = abs2twocomp(&x, &xn);
     if (FIXNUM_P(y)) {
-	return bigxor_int(x, xn, hibitsx, FIX2LONG(y));
+        return bigxor_int(x, xn, hibitsx, FIX2LONG(y));
     }
     hibitsy = abs2twocomp(&y, &yn);
     if (xn > yn) {
@@ -6603,10 +6641,10 @@ rb_big_xor(VALUE x, VALUE y)
     zds = BDIGITS(z);
 
     for (i=0; i<n1; i++) {
-	zds[i] = ds1[i] ^ ds2[i];
+        zds[i] = ds1[i] ^ ds2[i];
     }
     for (; i<n2; i++) {
-	zds[i] = hibitsx ^ ds2[i];
+        zds[i] = hibitsx ^ ds2[i];
     }
     twocomp2abs_bang(z, (hibits1 ^ hibits2) != 0);
     RB_GC_GUARD(x);
@@ -6622,25 +6660,25 @@ rb_big_lshift(VALUE x, VALUE y)
     int shift_numbits;
 
     for (;;) {
-	if (FIXNUM_P(y)) {
-	    long l = FIX2LONG(y);
+        if (FIXNUM_P(y)) {
+            long l = FIX2LONG(y);
             unsigned long shift;
-	    if (0 <= l) {
-		lshift_p = 1;
+            if (0 <= l) {
+                lshift_p = 1;
                 shift = l;
             }
             else {
-		lshift_p = 0;
-		shift = 1+(unsigned long)(-(l+1));
-	    }
+                lshift_p = 0;
+                shift = 1+(unsigned long)(-(l+1));
+            }
             shift_numbits = (int)(shift & (BITSPERDIG-1));
             shift_numdigits = shift >> bit_length(BITSPERDIG-1);
             return bignorm(big_shift3(x, lshift_p, shift_numdigits, shift_numbits));
-	}
-	else if (RB_BIGNUM_TYPE_P(y)) {
+        }
+        else if (RB_BIGNUM_TYPE_P(y)) {
             return bignorm(big_shift2(x, 1, y));
-	}
-	y = rb_to_int(y);
+        }
+        y = rb_to_int(y);
     }
 }
 
@@ -6652,8 +6690,8 @@ rb_big_rshift(VALUE x, VALUE y)
     int shift_numbits;
 
     for (;;) {
-	if (FIXNUM_P(y)) {
-	    long l = FIX2LONG(y);
+        if (FIXNUM_P(y)) {
+            long l = FIX2LONG(y);
             unsigned long shift;
             if (0 <= l) {
                 lshift_p = 0;
@@ -6661,16 +6699,16 @@ rb_big_rshift(VALUE x, VALUE y)
             }
             else {
                 lshift_p = 1;
-		shift = 1+(unsigned long)(-(l+1));
-	    }
+                shift = 1+(unsigned long)(-(l+1));
+            }
             shift_numbits = (int)(shift & (BITSPERDIG-1));
             shift_numdigits = shift >> bit_length(BITSPERDIG-1);
             return bignorm(big_shift3(x, lshift_p, shift_numdigits, shift_numbits));
-	}
-	else if (RB_BIGNUM_TYPE_P(y)) {
+        }
+        else if (RB_BIGNUM_TYPE_P(y)) {
             return bignorm(big_shift2(x, 0, y));
-	}
-	y = rb_to_int(y);
+        }
+        y = rb_to_int(y);
     }
 }
 
@@ -6684,22 +6722,22 @@ rb_big_aref(VALUE x, VALUE y)
     BDIGIT bit;
 
     if (RB_BIGNUM_TYPE_P(y)) {
-	if (BIGNUM_NEGATIVE_P(y))
-	    return INT2FIX(0);
-	bigtrunc(y);
-	if (BIGSIZE(y) > sizeof(size_t)) {
-	    return BIGNUM_SIGN(x) ? INT2FIX(0) : INT2FIX(1);
-	}
+        if (BIGNUM_NEGATIVE_P(y))
+            return INT2FIX(0);
+        bigtrunc(y);
+        if (BIGSIZE(y) > sizeof(size_t)) {
+            return BIGNUM_SIGN(x) ? INT2FIX(0) : INT2FIX(1);
+        }
 #if SIZEOF_SIZE_T <= SIZEOF_LONG
-	shift = big2ulong(y, "long");
+        shift = big2ulong(y, "long");
 #else
-	shift = big2ull(y, "long long");
+        shift = big2ull(y, "long long");
 #endif
     }
     else {
-	l = NUM2LONG(y);
-	if (l < 0) return INT2FIX(0);
-	shift = (size_t)l;
+        l = NUM2LONG(y);
+        if (l < 0) return INT2FIX(0);
+        shift = (size_t)l;
     }
     s1 = shift/BITSPERDIG;
     s2 = shift%BITSPERDIG;
@@ -6760,8 +6798,8 @@ VALUE
 rb_big_abs(VALUE x)
 {
     if (BIGNUM_NEGATIVE_P(x)) {
-	x = rb_big_clone(x);
-	BIGNUM_SET_POSITIVE_SIGN(x);
+        x = rb_big_clone(x);
+        BIGNUM_SET_POSITIVE_SIGN(x);
     }
     return x;
 }
@@ -6835,7 +6873,7 @@ VALUE
 rb_big_even_p(VALUE num)
 {
     if (BIGNUM_LEN(num) != 0 && BDIGITS(num)[0] & 1) {
-	return Qfalse;
+        return Qfalse;
     }
     return Qtrue;
 }
@@ -6853,94 +6891,36 @@ BDIGIT rb_bdigit_dbl_isqrt(BDIGIT_DBL);
 # define BDIGIT_DBL_TO_DOUBLE(n) (double)(n)
 #endif
 
-static BDIGIT *
-estimate_initial_sqrt(VALUE *xp, const size_t xn, const BDIGIT *nds, size_t len)
-{
-    enum {dbl_per_bdig = roomof(DBL_MANT_DIG,BITSPERDIG)};
-    const int zbits = nlz(nds[len-1]);
-    VALUE x = *xp = bignew_1(0, xn, 1); /* division may release the GVL */
-    BDIGIT *xds = BDIGITS(x);
-    BDIGIT_DBL d = bary2bdigitdbl(nds+len-dbl_per_bdig, dbl_per_bdig);
-    BDIGIT lowbits = 1;
-    int rshift = (int)((BITSPERDIG*2-zbits+(len&BITSPERDIG&1) - DBL_MANT_DIG + 1) & ~1);
-    double f;
-
-    if (rshift > 0) {
-	lowbits = (BDIGIT)d & ~(~(BDIGIT)1U << rshift);
-	d >>= rshift;
-    }
-    else if (rshift < 0) {
-	d <<= -rshift;
-	d |= nds[len-dbl_per_bdig-1] >> (BITSPERDIG+rshift);
-    }
-    f = sqrt(BDIGIT_DBL_TO_DOUBLE(d));
-    d = (BDIGIT_DBL)ceil(f);
-    if (BDIGIT_DBL_TO_DOUBLE(d) == f) {
-	if (lowbits || (lowbits = !bary_zero_p(nds, len-dbl_per_bdig)))
-	    ++d;
-    }
-    else {
-	lowbits = 1;
-    }
-    rshift /= 2;
-    rshift += (2-(len&1))*BITSPERDIG/2;
-    if (rshift >= 0) {
-        if (nlz((BDIGIT)d) + rshift >= BITSPERDIG) {
-            /* (d << rshift) does cause overflow.
-             * example: Integer.sqrt(0xffff_ffff_ffff_ffff ** 2)
-             */
-            d = ~(BDIGIT_DBL)0;
-        }
-        else {
-            d <<= rshift;
-        }
-    }
-    BDIGITS_ZERO(xds, xn-2);
-    bdigitdbl2bary(&xds[xn-2], 2, d);
-
-    if (!lowbits) return NULL; /* special case, exact result */
-    return xds;
-}
-
 VALUE
 rb_big_isqrt(VALUE n)
 {
     BDIGIT *nds = BDIGITS(n);
     size_t len = BIGNUM_LEN(n);
-    size_t xn = (len+1) / 2;
-    VALUE x;
-    BDIGIT *xds;
 
     if (len <= 2) {
-	BDIGIT sq = rb_bdigit_dbl_isqrt(bary2bdigitdbl(nds, len));
+        BDIGIT sq = rb_bdigit_dbl_isqrt(bary2bdigitdbl(nds, len));
 #if SIZEOF_BDIGIT > SIZEOF_LONG
-	return ULL2NUM(sq);
+        return ULL2NUM(sq);
 #else
-	return ULONG2NUM(sq);
+        return ULONG2NUM(sq);
 #endif
     }
-    else if ((xds = estimate_initial_sqrt(&x, xn, nds, len)) != 0) {
-	size_t tn = xn + BIGDIVREM_EXTRA_WORDS;
-	VALUE t = bignew_1(0, tn, 1);
-	BDIGIT *tds = BDIGITS(t);
-	tn = BIGNUM_LEN(t);
-
-	/* t = n/x */
-	while (bary_divmod_branch(tds, tn, NULL, 0, nds, len, xds, xn),
-	       bary_cmp(tds, tn, xds, xn) < 0) {
-	    int carry;
-	    BARY_TRUNC(tds, tn);
-	    /* x = (x+t)/2 */
-	    carry = bary_add(xds, xn, xds, xn, tds, tn);
-	    bary_small_rshift(xds, xds, xn, 1, carry);
-	    tn = BIGNUM_LEN(t);
-	}
-    }
-    RBASIC_SET_CLASS_RAW(x, rb_cInteger);
-    return x;
+    else {
+        size_t shift = FIX2LONG(rb_big_bit_length(n)) / 4;
+        VALUE n2 = rb_int_rshift(n, SIZET2NUM(2 * shift));
+        VALUE x = FIXNUM_P(n2) ? LONG2FIX(rb_ulong_isqrt(FIX2ULONG(n2))) : rb_big_isqrt(n2);
+        /* x = (x+n/x)/2 */
+        x = rb_int_plus(rb_int_lshift(x, SIZET2NUM(shift - 1)), rb_int_idiv(rb_int_rshift(n, SIZET2NUM(shift + 1)), x));
+        VALUE xx = rb_int_mul(x, x);
+        while (rb_int_gt(xx, n)) {
+            xx = rb_int_minus(xx, rb_int_minus(rb_int_plus(x, x), INT2FIX(1)));
+            x = rb_int_minus(x, INT2FIX(1));
+        }
+        return x;
+    }
 }
 
-#ifdef USE_GMP
+#if USE_GMP
 static void
 bary_powm_gmp(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t xn, const BDIGIT *yds, size_t yn, const BDIGIT *mds, size_t mn)
 {
@@ -6966,7 +6946,7 @@ bary_powm_gmp(BDIGIT *zds, size_t zn, const BDIGIT *xds, size_t xn, const BDIGIT
 static VALUE
 int_pow_tmp3(VALUE x, VALUE y, VALUE m, int nega_flg)
 {
-#ifdef USE_GMP
+#if USE_GMP
     VALUE z;
     size_t xn, yn, mn, zn;
 
@@ -6976,7 +6956,7 @@ int_pow_tmp3(VALUE x, VALUE y, VALUE m, int nega_flg)
     if (FIXNUM_P(y)) {
        y = rb_int2big(FIX2LONG(y));
     }
-    assert(RB_BIGNUM_TYPE_P(m));
+    RUBY_ASSERT(RB_BIGNUM_TYPE_P(m));
     xn = BIGNUM_LEN(x);
     yn = BIGNUM_LEN(y);
     mn = BIGNUM_LEN(m);
@@ -7142,7 +7122,7 @@ rb_int_powm(int const argc, VALUE * const argv, VALUE const num)
         }
         else {
             if (rb_bigzero_p(m)) rb_num_zerodiv();
-	    if (bignorm(m) == INT2FIX(1)) return INT2FIX(0);
+            if (bignorm(m) == INT2FIX(1)) return INT2FIX(0);
             return int_pow_tmp3(rb_int_modulo(a, m), b, m, nega_flg);
         }
     }
@@ -7172,7 +7152,7 @@ Init_Bignum(void)
 {
     rb_define_method(rb_cInteger, "coerce", rb_int_coerce, 1);
 
-#ifdef USE_GMP
+#if USE_GMP
     /* The version of loaded GMP. */
     rb_define_const(rb_cInteger, "GMP_VERSION", rb_sprintf("GMP %s", gmp_version));
 #endif
diff --git a/bin/gem b/bin/gem
index a4ec754abb..3ac1d9e623 100755
--- a/bin/gem
+++ b/bin/gem
@@ -1,25 +1,12 @@
 #!/usr/bin/env ruby
+# frozen_string_literal: true
+
 #--
 # Copyright 2006 by Chad Fowler, Rich Kilmer, Jim Weirich and others.
 # All rights reserved.
 # See LICENSE.txt for permissions.
 #++
 
-require 'rubygems'
-require 'rubygems/gem_runner'
-require 'rubygems/exceptions'
-
-required_version = Gem::Requirement.new ">= 1.8.7"
-
-unless required_version.satisfied_by? Gem.ruby_version then
-  abort "Expected Ruby Version #{required_version}, is #{Gem.ruby_version}"
-end
-
-args = ARGV.clone
-
-begin
-  Gem::GemRunner.new.run args
-rescue Gem::SystemExitException => e
-  exit e.exit_code
-end
+require "rubygems/gem_runner"
 
+Gem::GemRunner.new.run ARGV.clone
diff --git a/bootstraptest/runner.rb b/bootstraptest/runner.rb
index 3d42390254..3f905a9f02 100755
--- a/bootstraptest/runner.rb
+++ b/bootstraptest/runner.rb
@@ -6,7 +6,6 @@
 # Never use optparse in this file.
 # Never use test/unit in this file.
 # Never use Ruby extensions in this file.
-# Maintain Ruby 1.8 compatibility for now
 
 $start_time = Time.now
 
@@ -61,7 +60,7 @@ if !Dir.respond_to?(:mktmpdir)
 end
 
 # Configuration
-BT = Struct.new(:ruby,
+bt = Struct.new(:ruby,
                 :verbose,
                 :color,
                 :tty,
@@ -73,9 +72,85 @@ BT = Struct.new(:ruby,
                 :failed,
                 :reset,
                 :columns,
+                :window_width,
                 :width,
+                :indent,
                 :platform,
-                ).new
+                :timeout,
+                :timeout_scale,
+                :launchable_test_reports
+                )
+BT = Class.new(bt) do
+  def indent=(n)
+    super
+    if (self.columns ||= 0) < n
+      $stderr.print(' ' * (n - self.columns))
+    end
+    self.columns = indent
+  end
+
+  def putc(c)
+    unless self.quiet
+      if self.window_width == nil
+        unless w = ENV["COLUMNS"] and (w = w.to_i) > 0
+          w = 80
+        end
+        w -= 1
+        self.window_width = w
+      end
+      if self.window_width and self.columns >= self.window_width
+        $stderr.print "\n", " " * (self.indent ||= 0)
+        self.columns = indent
+      end
+      $stderr.print c
+      $stderr.flush
+      self.columns += 1
+    end
+  end
+
+  def wn=(wn)
+    unless wn == 1
+      if /(?:\A|\s)--jobserver-(?:auth|fds)=(?:(\d+),(\d+)|fifo:((?:\\.|\S)+))/ =~ ENV.delete("MAKEFLAGS")
+        begin
+          if fifo = $3
+            fifo.gsub!(/\\(?=.)/, '')
+            r = File.open(fifo, IO::RDONLY|IO::NONBLOCK|IO::BINARY)
+            w = File.open(fifo, IO::WRONLY|IO::NONBLOCK|IO::BINARY)
+          else
+            r = IO.for_fd($1.to_i(10), "rb", autoclose: false)
+            w = IO.for_fd($2.to_i(10), "wb", autoclose: false)
+          end
+        rescue
+          r.close if r
+        else
+          r.close_on_exec = true
+          w.close_on_exec = true
+          tokens = r.read_nonblock(wn > 0 ? wn : 1024, exception: false)
+          r.close
+          if String === tokens
+            tokens.freeze
+            auth = w
+            w = nil
+            at_exit {auth << tokens; auth.close}
+            wn = tokens.size + 1
+          else
+            w.close
+            wn = 1
+          end
+        end
+      end
+      if wn <= 0
+        require 'etc'
+        wn = [Etc.nprocessors / 2, 1].max
+      end
+    end
+    super wn
+  end
+
+  def apply_timeout_scale(timeout)
+    timeout&.*(timeout_scale)
+  end
+end.new
 
 BT_STATE = Struct.new(:count, :error).new
 
@@ -87,7 +162,13 @@ def main
   BT.color = nil
   BT.tty = nil
   BT.quiet = false
-  BT.wn = 1
+  BT.timeout = 180
+  BT.timeout_scale = (defined?(RubyVM::RJIT) && RubyVM::RJIT.enabled? ? 3 : 1) # for --jit-wait
+  if (ts = (ENV["RUBY_TEST_TIMEOUT_SCALE"] || ENV["RUBY_TEST_SUBPROCESS_TIMEOUT_SCALE"]).to_i) > 1
+    BT.timeout_scale *= ts
+  end
+
+  # BT.wn = 1
   dir = nil
   quiet = false
   tests = nil
@@ -117,19 +198,18 @@ def main
       warn "unknown --tty argument: #$3" if $3
       BT.tty = !$1 || !$2
       true
-    when /\A(-q|--q(uiet))\z/
+    when /\A(-q|--q(uiet)?)\z/
       quiet = true
       BT.quiet = true
       true
     when /\A-j(\d+)?/
-      wn = $1.to_i
-      if wn <= 0
-        require 'etc'
-        wn = [Etc.nprocessors / 2, 1].max
-      end
-      BT.wn = wn
+      BT.wn = $1.to_i
       true
-    when /\A(-v|--v(erbose))\z/
+    when /\A--timeout=(\d+(?:_\d+)*(?:\.\d+(?:_\d+)*)?)(?::(\d+(?:_\d+)*(?:\.\d+(?:_\d+)*)?))?/
+      BT.timeout = $1.to_f
+      BT.timeout_scale = $2.to_f if defined?($2)
+      true
+    when /\A(-v|--v(erbose)?)\z/
       BT.verbose = true
       BT.quiet = false
       true
@@ -141,6 +221,7 @@ Usage: #{File.basename($0, '.*')} --ruby=PATH [--sets=NAME,NAME,...]
                                     default: /tmp/bootstraptestXXXXX.tmpwd
         --color[=WHEN]              Colorize the output.  WHEN defaults to 'always'
                                     or can be 'never' or 'auto'.
+        --timeout=TIMEOUT           Default timeout in seconds.
     -s, --stress                    stress test.
     -v, --verbose                   Output test name before exec.
     -q, --quiet                     Don\'t print header message.
@@ -149,21 +230,46 @@ End
       exit true
     when /\A-j/
       true
+    when /--launchable-test-reports=(.*)/
+      if File.exist?($1)
+        # To protect files from overwritten, do nothing when the file exists.
+        return true
+      end
+
+      begin
+        require_relative '../tool/lib/launchable'
+      rescue LoadError
+        # The following error sometimes happens, so we're going to skip writing Launchable report files in this case.
+        #
+        # ```
+        # /tmp/tmp.bISss9CtXZ/.ext/common/json/ext.rb:15:in 'Kernel#require':
+        #   /tmp/tmp.bISss9CtXZ/.ext/x86_64-linux/json/ext/parser.so:
+        #     undefined symbol: ruby_abi_version - ruby_abi_version (LoadError)
+        # ```
+        #
+        return true
+      end
+      BT.launchable_test_reports = writer = Launchable::JsonStreamWriter.new($1)
+      writer.write_array('testCases')
+      at_exit {
+        writer.close
+      }
+      true
     else
       false
     end
   }
   if tests and not ARGV.empty?
-    $stderr.puts "--tests and arguments are exclusive"
-    exit false
+    abort "--sets and arguments are exclusive"
   end
   tests ||= ARGV
   tests = Dir.glob("#{File.dirname($0)}/test_*.rb").sort if tests.empty?
-  pathes = tests.map {|path| File.expand_path(path) }
+  paths = tests.map {|path| File.expand_path(path) }
 
   BT.progress = %w[- \\ | /]
   BT.progress_bs = "\b" * BT.progress[0].size
   BT.tty = $stderr.tty? if BT.tty.nil?
+  BT.wn ||= /-j(\d+)?/ =~ (ENV["MAKEFLAGS"] || ENV["MFLAGS"]) ? $1.to_i : 1
 
   case BT.color
   when nil
@@ -202,7 +308,7 @@ End
   end
 
   in_temporary_working_directory(dir) do
-    exec_test pathes
+    exec_test paths
   end
 end
 
@@ -214,8 +320,8 @@ def erase(e = true)
   end
 end
 
-def load_test pathes
-  pathes.each do |path|
+def load_test paths
+  paths.each do |path|
     load File.expand_path(path)
   end
 end
@@ -241,19 +347,20 @@ def concurrent_exec_test
     end
   end
 
-  $stderr.print ' ' unless BT.quiet
+  BT.indent = 1
   aq.close
   i = 1
   term_wn = 0
   begin
     while BT.wn != term_wn
       if r = rq.pop
+        BT_STATE.count += 1
         case
         when BT.quiet
         when BT.tty
           $stderr.print "#{BT.progress_bs}#{BT.progress[(i+=1) % BT.progress.size]}"
         else
-          $stderr.print '.'
+          BT.putc '.'
         end
       else
         term_wn += 1
@@ -265,17 +372,70 @@ def concurrent_exec_test
   end
 end
 
-def exec_test(pathes)
+##
+# Module for writing a test file for uploading test results into Launchable.
+# In bootstraptest, we aggregate the test results based on file level.
+module Launchable
+  @@last_test_name = nil
+  @@failure_log = ''
+  @@duration = 0
+
+  def show_progress(message = '')
+    faildesc, t = super
+
+    if writer = BT.launchable_test_reports
+      if faildesc
+        @@failure_log += faildesc
+      end
+      repo_path = File.expand_path("#{__dir__}/../")
+      relative_path = File.join(__dir__, self.path).delete_prefix("#{repo_path}/")
+      if @@last_test_name != nil && @@last_test_name != relative_path
+        # The test path is a URL-encoded representation.
+        # https://github.com/launchableinc/cli/blob/v1.81.0/launchable/testpath.py#L18
+        test_path = "#{encode_test_path_component("file")}=#{encode_test_path_component(@@last_test_name)}"
+        if @@failure_log.size > 0
+          status = 'TEST_FAILED'
+        else
+          status = 'TEST_PASSED'
+        end
+        writer.write_object(
+          {
+            testPath: test_path,
+            status: status,
+            duration: t,
+            createdAt: Time.now.to_s,
+            stderr: @@failure_log,
+            stdout: nil,
+            data: {
+              lineNumber: self.lineno
+            }
+          }
+        )
+        @@duration = 0
+        @@failure_log.clear
+      end
+      @@last_test_name = relative_path
+      @@duration += t
+    end
+  end
+
+  private
+  def encode_test_path_component component
+    component.to_s.gsub('%', '%25').gsub('=', '%3D').gsub('#', '%23').gsub('&', '%26')
+  end
+end
+
+def exec_test(paths)
   # setup
-  load_test pathes
+  load_test paths
   BT_STATE.count = 0
   BT_STATE.error = 0
   BT.columns = 0
-  BT.width = pathes.map {|path| File.basename(path).size}.max + 2
+  BT.width = paths.map {|path| File.basename(path).size}.max + 2
 
   # execute tests
   if BT.wn > 1
-    concurrent_exec_test if BT.wn > 1
+    concurrent_exec_test
   else
     prev_basename = nil
     Assertion.all.each do |basename, assertions|
@@ -341,6 +501,7 @@ def target_platform
 end
 
 class Assertion < Struct.new(:src, :path, :lineno, :proc)
+  prepend Launchable
   @count = 0
   @all = Hash.new{|h, k| h[k] = []}
   @errbuf = []
@@ -364,7 +525,7 @@ class Assertion < Struct.new(:src, :path, :lineno, :proc)
   def initialize(*args)
     super
     self.class.add self
-    @category = self.path.match(/test_(.+)\.rb/)[1]
+    @category = self.path[/\Atest_(.+)\.rb\z/, 1]
   end
 
   def call
@@ -415,9 +576,9 @@ class Assertion < Struct.new(:src, :path, :lineno, :proc)
       $stderr.print "#{BT.progress_bs}#{BT.progress[BT_STATE.count % BT.progress.size]}"
     end
 
-    t = Time.now if BT.verbose
+    t = Time.now if BT.verbose || BT.launchable_test_reports
     faildesc, errout = with_stderr {yield}
-    t = Time.now - t if BT.verbose
+    t = Time.now - t if BT.verbose || BT.launchable_test_reports
 
     if !faildesc
       # success
@@ -428,7 +589,7 @@ class Assertion < Struct.new(:src, :path, :lineno, :proc)
       elsif BT.verbose
         $stderr.printf(". %.3f\n", t)
       else
-        $stderr.print '.'
+        BT.putc '.'
       end
     else
       $stderr.print "#{BT.failed}F"
@@ -444,6 +605,8 @@ class Assertion < Struct.new(:src, :path, :lineno, :proc)
         $stderr.printf("%-*s%s", BT.width, path, BT.progress[BT_STATE.count % BT.progress.size])
       end
     end
+
+    [faildesc, t]
   rescue Interrupt
     $stderr.puts "\##{@id} #{path}:#{lineno}"
     raise
@@ -462,14 +625,16 @@ class Assertion < Struct.new(:src, :path, :lineno, :proc)
     end
   end
 
-  def get_result_string(opt = '', **argh)
+  def get_result_string(opt = '', timeout: BT.timeout, **argh)
     if BT.ruby
+      timeout = BT.apply_timeout_scale(timeout)
       filename = make_srcfile(**argh)
       begin
         kw = self.err ? {err: self.err} : {}
         out = IO.popen("#{BT.ruby} -W0 #{opt} #{filename}", **kw)
         pid = out.pid
-        out.read.tap{ Process.waitpid(pid); out.close }
+        th = Thread.new {out.read.tap {Process.waitpid(pid); out.close}}
+        th.value if th.join(timeout)
       ensure
         raise Interrupt if $? and $?.signaled? && $?.termsig == Signal.list["INT"]
 
@@ -487,9 +652,14 @@ class Assertion < Struct.new(:src, :path, :lineno, :proc)
   def make_srcfile(frozen_string_literal: nil)
     filename = "bootstraptest.#{self.path}_#{self.lineno}_#{self.id}.rb"
     File.open(filename, 'w') {|f|
-      f.puts "#frozen_string_literal:true" if frozen_string_literal
-      f.puts "GC.stress = true" if $stress
-      f.puts "print(begin; #{self.src}; end)"
+      f.puts "#frozen_string_literal:#{frozen_string_literal}" unless frozen_string_literal.nil?
+      if $stress
+        f.puts "GC.stress = true" if $stress
+      else
+        f.puts ""
+      end
+      f.puts "class BT_Skip < Exception; end; def skip(msg) = raise(BT_Skip, msg.to_s)"
+      f.puts "print(begin; #{self.src}; rescue BT_Skip; $!.message; end)"
     }
     filename
   end
@@ -503,9 +673,9 @@ def add_assertion src, pr
   Assertion.new(src, path, lineno, pr)
 end
 
-def assert_equal(expected, testsrc, message = '', opt = '', **argh)
+def assert_equal(expected, testsrc, message = '', opt = '', **kwargs)
   add_assertion testsrc, -> as do
-    as.assert_check(message, opt, **argh) {|result|
+    as.assert_check(message, opt, **kwargs) {|result|
       if expected == result
         nil
       else
@@ -516,9 +686,9 @@ def assert_equal(expected, testsrc, message = '', opt = '', **argh)
   end
 end
 
-def assert_match(expected_pattern, testsrc, message = '')
+def assert_match(expected_pattern, testsrc, message = '', **argh)
   add_assertion testsrc, -> as do
-    as.assert_check(message) {|result|
+    as.assert_check(message, **argh) {|result|
       if expected_pattern =~ result
         nil
       else
@@ -550,8 +720,9 @@ def assert_valid_syntax(testsrc, message = '')
   end
 end
 
-def assert_normal_exit(testsrc, *rest, timeout: nil, **opt)
+def assert_normal_exit(testsrc, *rest, timeout: BT.timeout, **opt)
   add_assertion testsrc, -> as do
+    timeout = BT.apply_timeout_scale(timeout)
     message, ignore_signals = rest
     message ||= ''
     as.show_progress(message) {
@@ -560,23 +731,19 @@ def assert_normal_exit(testsrc, *rest, timeout: nil, **opt)
       timeout_signaled = false
       logfile = "assert_normal_exit.#{as.path}.#{as.lineno}.log"
 
-      begin
-        err = open(logfile, "w")
-        io = IO.popen("#{BT.ruby} -W0 #{filename}", err: err)
-        pid = io.pid
-        th = Thread.new {
-          io.read
-          io.close
-          $?
-        }
-        if !th.join(timeout)
-          Process.kill :KILL, pid
-          timeout_signaled = true
-        end
-        status = th.value
-      ensure
-        err.close
+      io = IO.popen("#{BT.ruby} -W0 #{filename}", err: logfile)
+      pid = io.pid
+      th = Thread.new {
+        io.read
+        io.close
+        $?
+      }
+      if !th.join(timeout)
+        Process.kill :KILL, pid
+        timeout_signaled = true
       end
+      status = th.value
+
       if status && status.signaled?
         signo = status.termsig
         signame = Signal.list.invert[signo]
@@ -605,9 +772,7 @@ end
 
 def assert_finish(timeout_seconds, testsrc, message = '')
   add_assertion testsrc, -> as do
-    if defined?(RubyVM::MJIT) && RubyVM::MJIT.enabled? # for --jit-wait
-      timeout_seconds *= 3
-    end
+    timeout_seconds = BT.apply_timeout_scale(timeout_seconds)
 
     as.show_progress(message) {
       faildesc = nil
@@ -663,6 +828,8 @@ end
 
 def pretty(src, desc, result)
   src = src.sub(/\A\s*\n/, '')
+  lines = src.lines
+  src = lines[0..20].join + "(...snip)\n" if lines.size > 20
   (/\n/ =~ src ? "\n#{adjust_indent(src)}" : src) + "  #=> #{desc}"
 end
 
@@ -720,4 +887,13 @@ def check_coredump
   end
 end
 
+def yjit_enabled?
+  ENV.key?('RUBY_YJIT_ENABLE') || ENV.fetch('RUN_OPTS', '').include?('yjit') || BT.ruby.include?('yjit')
+end
+
+def rjit_enabled?
+  # Don't check `RubyVM::RJIT.enabled?`. On btest-bruby, target Ruby != runner Ruby.
+  ENV.fetch('RUN_OPTS', '').include?('rjit')
+end
+
 exit main
diff --git a/bootstraptest/test_attr.rb b/bootstraptest/test_attr.rb
index 721a847145..3cb9d3eb39 100644
--- a/bootstraptest/test_attr.rb
+++ b/bootstraptest/test_attr.rb
@@ -34,3 +34,19 @@ assert_equal %{ok}, %{
     print "ok"
   end
 }, '[ruby-core:15120]'
+
+assert_equal %{ok}, %{
+  class Big
+    attr_reader :foo
+    def initialize
+      @foo = "ok"
+    end
+  end
+
+  obj = Big.new
+  100.times do |i|
+    obj.instance_variable_set(:"@ivar_\#{i}", i)
+  end
+
+  Big.new.foo
+}
diff --git a/bootstraptest/test_autoload.rb b/bootstraptest/test_autoload.rb
index 9e0850bc52..de66f1f3ee 100644
--- a/bootstraptest/test_autoload.rb
+++ b/bootstraptest/test_autoload.rb
@@ -11,7 +11,7 @@ assert_equal 'ok', %q{
 }, '[ruby-dev:43816]'
 
 assert_equal 'ok', %q{
-  open('zzz2.rb', 'w') {|f| f.puts '' }
+  File.write('zzz2.rb', '')
   instance_eval do
     autoload :ZZZ, './zzz2.rb'
     begin
@@ -23,7 +23,7 @@ assert_equal 'ok', %q{
 }, '[ruby-dev:43816]'
 
 assert_equal 'ok', %q{
-  open('zzz3.rb', 'w') {|f| f.puts 'class ZZZ; def self.ok;:ok;end;end'}
+  File.write('zzz3.rb', "class ZZZ; def self.ok;:ok;end;end\n")
   instance_eval do
     autoload :ZZZ, './zzz3.rb'
     ZZZ.ok
@@ -31,20 +31,20 @@ assert_equal 'ok', %q{
 }, '[ruby-dev:43816]'
 
 assert_equal 'ok', %q{
-  open("zzz4.rb", "w") {|f| f.puts "class ZZZ; def self.ok;:ok;end;end"}
+  File.write("zzz4.rb", "class ZZZ; def self.ok;:ok;end;end\n")
   autoload :ZZZ, "./zzz4.rb"
   ZZZ.ok
 }
 
 assert_equal 'ok', %q{
-  open("zzz5.rb", "w") {|f| f.puts "class ZZZ; def self.ok;:ok;end;end"}
+  File.write("zzz5.rb", "class ZZZ; def self.ok;:ok;end;end\n")
   autoload :ZZZ, "./zzz5.rb"
   require "./zzz5.rb"
   ZZZ.ok
 }
 
 assert_equal 'okok', %q{
-  open("zzz6.rb", "w") {|f| f.puts "class ZZZ; def self.ok;:ok;end;end"}
+  File.write("zzz6.rb", "class ZZZ; def self.ok;:ok;end;end\n")
   autoload :ZZZ, "./zzz6.rb"
   t1 = Thread.new {ZZZ.ok}
   t2 = Thread.new {ZZZ.ok}
@@ -60,7 +60,7 @@ assert_finish 5, %q{
 }, '[ruby-core:21696]'
 
 assert_equal 'A::C', %q{
-  open("zzz7.rb", "w") {}
+  File.write("zzz7.rb", "")
   class A
     autoload :C, "./zzz7"
     class C
diff --git a/bootstraptest/test_eval.rb b/bootstraptest/test_eval.rb
index a9f389c673..20bd9615f4 100644
--- a/bootstraptest/test_eval.rb
+++ b/bootstraptest/test_eval.rb
@@ -217,7 +217,7 @@ assert_equal %q{[10, main]}, %q{
 }
 
 %w[break next redo].each do |keyword|
-  assert_match %r"Can't escape from eval with #{keyword}\b", %{
+  assert_match %r"Invalid #{keyword}\b", %{
     $stderr = STDOUT
     begin
       eval "0 rescue #{keyword}"
@@ -227,6 +227,16 @@ assert_equal %q{[10, main]}, %q{
   }, '[ruby-dev:31372]'
 end
 
+assert_normal_exit %{
+  $stderr = STDOUT
+  5000.times do
+    begin
+      eval "0 rescue break"
+    rescue SyntaxError
+    end
+  end
+}
+
 assert_normal_exit %q{
   $stderr = STDOUT
   class Foo
@@ -354,3 +364,34 @@ assert_normal_exit %q{
   end
 }, 'check escaping the internal value th->base_block'
 
+assert_equal "false", <<~RUBY, "literal strings are mutable", "--disable-frozen-string-literal"
+  eval("'test'").frozen?
+RUBY
+
+assert_equal "false", <<~RUBY, "literal strings are mutable", "--disable-frozen-string-literal", frozen_string_literal: true
+  eval("'test'").frozen?
+RUBY
+
+assert_equal "true", <<~RUBY, "literal strings are frozen", "--enable-frozen-string-literal"
+  eval("'test'").frozen?
+RUBY
+
+assert_equal "true", <<~RUBY, "literal strings are frozen", "--enable-frozen-string-literal", frozen_string_literal: false
+  eval("'test'").frozen?
+RUBY
+
+assert_equal "false", <<~RUBY, "__FILE__ is mutable", "--disable-frozen-string-literal"
+  eval("__FILE__").frozen?
+RUBY
+
+assert_equal "false", <<~RUBY, "__FILE__ is mutable", "--disable-frozen-string-literal", frozen_string_literal: true
+  eval("__FILE__").frozen?
+RUBY
+
+assert_equal "true", <<~RUBY, "__FILE__ is frozen", "--enable-frozen-string-literal"
+  eval("__FILE__").frozen?
+RUBY
+
+assert_equal "true", <<~RUBY, "__FILE__ is frozen", "--enable-frozen-string-literal", frozen_string_literal: false
+  eval("__FILE__").frozen?
+RUBY
diff --git a/bootstraptest/test_exception.rb b/bootstraptest/test_exception.rb
index 0fb6f552b8..decfdc08a3 100644
--- a/bootstraptest/test_exception.rb
+++ b/bootstraptest/test_exception.rb
@@ -370,7 +370,7 @@ assert_equal %q{}, %q{
 }
 
 ##
-assert_match /undefined method `foo\'/, %q{#`
+assert_match /undefined method 'foo\'/, %q{#`
   STDERR.reopen(STDOUT)
   class C
     def inspect
diff --git a/bootstraptest/test_finalizer.rb b/bootstraptest/test_finalizer.rb
index 22a16b1220..ccfa0b55d6 100644
--- a/bootstraptest/test_finalizer.rb
+++ b/bootstraptest/test_finalizer.rb
@@ -6,3 +6,11 @@ ObjectSpace.define_finalizer(b1,proc{b1.inspect})
 ObjectSpace.define_finalizer(a2,proc{a1.inspect})
 ObjectSpace.define_finalizer(a1,proc{})
 }, '[ruby-dev:35778]'
+
+assert_equal 'true', %q{
+  obj = Object.new
+  id = obj.object_id
+
+  ObjectSpace.define_finalizer(obj, proc { |i| print(id == i) })
+  nil
+}
diff --git a/bootstraptest/test_flow.rb b/bootstraptest/test_flow.rb
index 35f19db588..15528a4213 100644
--- a/bootstraptest/test_flow.rb
+++ b/bootstraptest/test_flow.rb
@@ -363,7 +363,7 @@ assert_equal %q{[1, 2, 3, 5, 2, 3, 5, 7, 8]}, %q{$a = []; begin;  ; $a << 1
 ; $a << 8
 ; rescue Exception; $a << 99; end; $a}
 assert_equal %q{[1, 2, 6, 3, 5, 7, 8]}, %q{$a = []; begin;  ; $a << 1
-  o = "test"; $a << 2
+  o = "test".dup; $a << 2
   def o.test(a); $a << 3
     return a; $a << 4
   ensure; $a << 5
diff --git a/bootstraptest/test_fork.rb b/bootstraptest/test_fork.rb
index 83923dad97..a54316dbca 100644
--- a/bootstraptest/test_fork.rb
+++ b/bootstraptest/test_fork.rb
@@ -75,3 +75,25 @@ assert_equal '[1, 2]', %q{
   end
 }, '[ruby-dev:44005] [Ruby 1.9 - Bug #4950]'
 
+assert_equal 'ok', %q{
+  def now = Process.clock_gettime(Process::CLOCK_MONOTONIC)
+
+  Thread.new do
+    loop { sleep 0.0001 }
+  end
+
+  10.times do
+    pid = fork{ exit!(0) }
+    deadline = now + 10
+    until Process.waitpid(pid, Process::WNOHANG)
+      if now > deadline
+        Process.kill(:KILL, pid)
+        raise "failed"
+      end
+      sleep 0.001
+    end
+  rescue NotImplementedError
+  end
+  :ok
+}, '[Bug #20670]'
+
diff --git a/bootstraptest/test_gc.rb b/bootstraptest/test_gc.rb
index eb68c9845e..17bc497822 100644
--- a/bootstraptest/test_gc.rb
+++ b/bootstraptest/test_gc.rb
@@ -14,7 +14,7 @@ ms = "a".."k"
     o.send(meth)
   end
 end
-}, '[ruby-dev:39453]'
+}, '[ruby-dev:39453]' unless rjit_enabled? # speed up RJIT CI
 
 assert_normal_exit %q{
 a = []
diff --git a/bootstraptest/test_insns.rb b/bootstraptest/test_insns.rb
index 91fba9b011..8a6efae089 100644
--- a/bootstraptest/test_insns.rb
+++ b/bootstraptest/test_insns.rb
@@ -92,7 +92,7 @@ tests = [
   [ 'intern',                   %q{ :"#{true}" }, ],
 
   [ 'newarray',    %q{ ["true"][0] }, ],
-  [ 'newarraykwsplat', %q{ [**{x:'true'}][0][:x] }, ],
+  [ 'pushtoarraykwsplat', %q{ [**{x:'true'}][0][:x] }, ],
   [ 'duparray',    %q{ [ true ][0] }, ],
   [ 'expandarray', %q{ y = [ true, false, nil ]; x, = y; x }, ],
   [ 'expandarray', %q{ y = [ true, false, nil ]; x, *z = y; x }, ],
@@ -214,9 +214,24 @@ tests = [
     'true'.freeze
   },
 
-  [ 'opt_newarray_max', %q{ [ ].max.nil? }, ],
-  [ 'opt_newarray_max', %q{ [1, x = 2, 3].max == 3 }, ],
-  [ 'opt_newarray_max', <<-'},', ], # {
+  [ 'opt_duparray_send', %q{ x = :a; [:a, :b].include?(x) }, ],
+  [ 'opt_duparray_send', <<-'},', ], # {
+    class Array
+      def include?(i)
+        i == 1
+      end
+    end
+    x = 1
+    [:a, :b].include?(x)
+  },
+
+  [ 'opt_newarray_send', %q{ ![ ].hash.nil? }, ],
+
+  [ 'opt_newarray_send', %q{ v=2; [1, Object.new, 2].include?(v) }, ],
+
+  [ 'opt_newarray_send', %q{ [ ].max.nil? }, ],
+  [ 'opt_newarray_send', %q{ [1, x = 2, 3].max == 3 }, ],
+  [ 'opt_newarray_send', <<-'},', ], # {
     class Array
       def max
         true
@@ -224,9 +239,9 @@ tests = [
     end
     [1, x = 2, 3].max
   },
-  [ 'opt_newarray_min', %q{ [ ].min.nil? }, ],
-  [ 'opt_newarray_min', %q{ [3, x = 2, 1].min == 1 }, ],
-  [ 'opt_newarray_min', <<-'},', ], # {
+  [ 'opt_newarray_send', %q{ [ ].min.nil? }, ],
+  [ 'opt_newarray_send', %q{ [3, x = 2, 1].min == 1 }, ],
+  [ 'opt_newarray_send', <<-'},', ], # {
     class Array
       def min
         true
@@ -234,6 +249,48 @@ tests = [
     end
     [3, x = 2, 1].min
   },
+  [ 'opt_newarray_send', %q{ v = 1.23; [v, v*2].pack("E*").unpack("E*") == [v, v*2] }, ],
+  [ 'opt_newarray_send', %q{ v = 4.56; b = +"x"; [v, v*2].pack("E*", buffer: b); b[1..].unpack("E*") == [v, v*2] }, ],
+  [ 'opt_newarray_send', <<-'},', ], # {
+    v = 7.89;
+    b = +"x";
+    class Array
+      alias _pack pack
+      def pack(s, buffer: nil, prefix: "y")
+        buffer ||= +"b"
+        buffer << prefix
+        _pack(s, buffer: buffer)
+      end
+    end
+    tests = []
+
+    ret = [v].pack("E*", prefix: "z")
+    tests << (ret[0..1] == "bz")
+    tests << (ret[2..].unpack("E*") == [v])
+
+    ret = [v].pack("E*")
+    tests << (ret[0..1] == "by")
+    tests << (ret[2..].unpack("E*") == [v])
+
+    [v, v*2, v*3].pack("E*", buffer: b)
+    tests << (b[0..1] == "xy")
+    tests << (b[2..].unpack("E*") == [v, v*2, v*3])
+
+    class Array
+      def pack(_fmt, buffer:) = buffer
+    end
+
+    b = nil
+    tests << [v].pack("E*", buffer: b).nil?
+
+    class Array
+      def pack(_fmt, **kw) = kw.empty?
+    end
+
+    tests << [v].pack("E*") == true
+
+    tests.all? or puts tests
+  },
 
   [ 'throw',        %q{ false.tap { break true } }, ],
   [ 'branchif',     %q{ x = nil;  x ||= true }, ],
@@ -352,7 +409,7 @@ tests = [
   [ 'opt_ge', %q{ +0.0.next_float >= 0.0 }, ],
   [ 'opt_ge', %q{              ?z >= ?a }, ],
 
-  [ 'opt_ltlt', %q{  '' << 'true' }, ],
+  [ 'opt_ltlt', %q{  +'' << 'true' }, ],
   [ 'opt_ltlt', %q{ ([] << 'true').join }, ],
   [ 'opt_ltlt', %q{ (1 << 31) == 2147483648 }, ],
 
@@ -361,7 +418,7 @@ tests = [
   [ 'opt_aref', %q{ 'true'[0] == ?t }, ],
   [ 'opt_aset', %q{ [][0] = true }, ],
   [ 'opt_aset', %q{ {}[0] = true }, ],
-  [ 'opt_aset', %q{ x = 'frue'; x[0] = 't'; x }, ],
+  [ 'opt_aset', %q{ x = +'frue'; x[0] = 't'; x }, ],
   [ 'opt_aset', <<-'},', ], # {
     # opt_aref / opt_aset mixup situation
     class X; def x; {}; end; end
diff --git a/bootstraptest/test_io.rb b/bootstraptest/test_io.rb
index 73deca8383..4e5d6d59c9 100644
--- a/bootstraptest/test_io.rb
+++ b/bootstraptest/test_io.rb
@@ -1,3 +1,4 @@
+/freebsd/ =~ RUBY_PLATFORM or
 assert_finish 5, %q{
   r, w = IO.pipe
   t1 = Thread.new { r.sysread(1) }
@@ -30,6 +31,7 @@ assert_finish 10, %q{
   end
 }, '[ruby-dev:32566]'
 
+/freebsd/ =~ RUBY_PLATFORM or
 assert_finish 5, %q{
   r, w = IO.pipe
   Thread.new {
@@ -83,12 +85,13 @@ assert_normal_exit %q{
   ARGF.set_encoding "foo"
 }
 
+/freebsd/ =~ RUBY_PLATFORM or
 10.times do
   assert_normal_exit %q{
     at_exit { p :foo }
 
     megacontent = "abc" * 12345678
-    #File.open("megasrc", "w") {|f| f << megacontent }
+    #File.write("megasrc", megacontent)
 
     t0 = Thread.main
     Thread.new { sleep 0.001 until t0.stop?; Process.kill(:INT, $$) }
diff --git a/bootstraptest/test_jump.rb b/bootstraptest/test_jump.rb
index d07c47a56d..8751343b1f 100644
--- a/bootstraptest/test_jump.rb
+++ b/bootstraptest/test_jump.rb
@@ -292,7 +292,7 @@ assert_equal "true", %q{
       end
     end
   end
-  s = "foo"
+  s = +"foo"
   s.return_eigenclass == class << s; self; end
 }, '[ruby-core:21379]'
 
diff --git a/bootstraptest/test_literal.rb b/bootstraptest/test_literal.rb
index a0d4ee08c6..7295f7a148 100644
--- a/bootstraptest/test_literal.rb
+++ b/bootstraptest/test_literal.rb
@@ -70,6 +70,7 @@ if /wasi/ !~ target_platform
   assert_equal "foo\n",           %q(`echo foo`)
   assert_equal "foo\n",           %q(s = "foo"; `echo #{s}`)
 end
+assert_equal "ECHO FOO",        %q(def `(s) s.upcase; end; `echo foo`)
 
 # regexp
 assert_equal '',                '//.source'
@@ -118,14 +119,14 @@ assert_equal '5',               'a = [1,2,3]; a[1] = 5; a[1]'
 assert_equal 'bar',             '[*:foo];:bar'
 assert_equal '[1, 2]',          'def nil.to_a; [2]; end; [1, *nil]'
 assert_equal '[1, 2]',          'def nil.to_a; [1, 2]; end; [*nil]'
-assert_equal '[0, 1, {2=>3}]',  '[0, *[1], 2=>3]', "[ruby-dev:31592]"
+assert_equal '[0, 1, {2 => 3}]', '[0, *[1], 2=>3]', "[ruby-dev:31592]"
 
 
 # hash
 assert_equal 'Hash',            '{}.class'
 assert_equal '{}',              '{}.inspect'
 assert_equal 'Hash',            '{1=>2}.class'
-assert_equal '{1=>2}',          '{1=>2}.inspect'
+assert_equal '{1 => 2}',        '{1=>2}.inspect'
 assert_equal '2',               'h = {1 => 2}; h[1]'
 assert_equal '0',               'h = {1 => 2}; h.delete(1); h.size'
 assert_equal '',                'h = {1 => 2}; h.delete(1); h[1]'
diff --git a/bootstraptest/test_literal_suffix.rb b/bootstraptest/test_literal_suffix.rb
index c36fa7078f..7a4d67d0fa 100644
--- a/bootstraptest/test_literal_suffix.rb
+++ b/bootstraptest/test_literal_suffix.rb
@@ -46,9 +46,9 @@ assert_equal '1',               '1rescue nil'
 assert_equal '10000000000000000001/10000000000000000000',
              '1.0000000000000000001r'
 
-assert_equal 'syntax error, unexpected local variable or method, expecting end-of-input',
-             %q{begin eval('1ir', nil, '', 0); rescue SyntaxError => e; e.message[/\A:(?:\d+:)? (.*)/, 1] end}
-assert_equal 'syntax error, unexpected local variable or method, expecting end-of-input',
-             %q{begin eval('1.2ir', nil, '', 0); rescue SyntaxError => e; e.message[/\A:(?:\d+:)? (.*)/, 1] end}
-assert_equal 'syntax error, unexpected local variable or method, expecting end-of-input',
-             %q{begin eval('1e1r', nil, '', 0); rescue SyntaxError => e; e.message[/\A:(?:\d+:)? (.*)/, 1] end}
+assert_equal 'unexpected local variable or method, expecting end-of-input',
+             %q{begin eval('1ir', nil, '', 0); rescue SyntaxError => e; e.message[/(?:\^~*|\A:(?:\d+:)? syntax error,) (.*)/, 1]; end}
+assert_equal 'unexpected local variable or method, expecting end-of-input',
+             %q{begin eval('1.2ir', nil, '', 0); rescue SyntaxError => e; e.message[/(?:\^~*|\A:(?:\d+:)? syntax error,) (.*)/, 1]; end}
+assert_equal 'unexpected local variable or method, expecting end-of-input',
+             %q{begin eval('1e1r', nil, '', 0); rescue SyntaxError => e; e.message[/(?:\^~*|\A:(?:\d+:)? syntax error,) (.*)/, 1]; end}
diff --git a/bootstraptest/test_load.rb b/bootstraptest/test_load.rb
index e63c93a8f4..5046d4fcea 100644
--- a/bootstraptest/test_load.rb
+++ b/bootstraptest/test_load.rb
@@ -1,9 +1,9 @@
 assert_equal 'ok', %q{
-  open("require-lock-test.rb", "w") {|f|
-    f.puts "sleep 0.1"
-    f.puts "module M"
-    f.puts "end"
-  }
+  File.write("require-lock-test.rb", <<-END)
+    sleep 0.1
+    module M
+    end
+  END
   $:.unshift Dir.pwd
   vs = (1..2).map {|i|
     Thread.start {
@@ -12,11 +12,11 @@ assert_equal 'ok', %q{
     }
   }.map {|t| t.value }
   vs[0] == M && vs[1] == M ? :ok : :ng
-}, '[ruby-dev:32048]'
+}, '[ruby-dev:32048]' unless ENV.fetch('RUN_OPTS', '').include?('rjit') # Thread seems to be switching during JIT. To be fixed later.
 
 assert_equal 'ok', %q{
   %w[a a/foo b].each {|d| Dir.mkdir(d)}
-  open("b/foo", "w") {|f| f.puts "$ok = :ok"}
+  File.write("b/foo", "$ok = :ok\n")
   $:.replace(%w[a b])
   begin
     load "foo"
diff --git a/bootstraptest/test_method.rb b/bootstraptest/test_method.rb
index 04c9eb2d11..f6f04541d6 100644
--- a/bootstraptest/test_method.rb
+++ b/bootstraptest/test_method.rb
@@ -340,24 +340,6 @@ assert_equal '1',       %q( class C; def m() 7 end; private :m end
 assert_equal '1',       %q( class C; def m() 1 end; private :m end
                             C.new.send(:m) )
 
-# with block
-assert_equal '[[:ok1, :foo], [:ok2, :foo, :bar]]',
-%q{
-  class C
-    def [](a)
-      $ary << [yield, a]
-    end
-    def []=(a, b)
-      $ary << [yield, a, b]
-    end
-  end
-
-  $ary = []
-  C.new[:foo, &lambda{:ok1}]
-  C.new[:foo, &lambda{:ok2}] = :bar
-  $ary
-}
-
 # with
 assert_equal '[:ok1, [:ok2, 11]]', %q{
   class C
@@ -404,7 +386,6 @@ $result
 
 # aset and splat
 assert_equal '4', %q{class Foo;def []=(a,b,c,d);end;end;Foo.new[1,*a=[2,3]]=4}
-assert_equal '4', %q{class Foo;def []=(a,b,c,d);end;end;def m(&blk)Foo.new[1,*a=[2,3],&blk]=4;end;m{}}
 
 # post test
 assert_equal %q{[1, 2, :o1, :o2, [], 3, 4, NilClass, nil, nil]}, %q{
@@ -1107,10 +1088,6 @@ assert_equal 'ok', %q{
     'ok'
   end
 }
-assert_equal 'ok', %q{
-  [0][0, &proc{}] += 21
-  'ok'
-}, '[ruby-core:30534]'
 
 # should not cache when splat
 assert_equal 'ok', %q{
@@ -1190,3 +1167,231 @@ assert_equal 'DC', %q{
   test2 o1, [], block
   $result.join
 }
+
+assert_equal 'ok', %q{
+  def foo
+    binding
+    ["ok"].first
+  end
+  foo
+  foo
+}, '[Bug #20178]'
+
+assert_equal 'ok', %q{
+  def bar(x); x; end
+  def foo(...); bar(...); end
+  foo('ok')
+}
+
+assert_equal 'ok', %q{
+  def bar(x); x; end
+  def foo(z, ...); bar(...); end
+  foo(1, 'ok')
+}
+
+assert_equal 'ok', %q{
+  def bar(x, y); x; end
+  def foo(...); bar("ok", ...); end
+  foo(1)
+}
+
+assert_equal 'ok', %q{
+  def bar(x); x; end
+  def foo(...); 1.times { return bar(...) }; end
+  foo("ok")
+}
+
+assert_equal 'ok', %q{
+  def bar(x); x; end
+  def foo(...); x = nil; 1.times { x = bar(...) }; x; end
+  foo("ok")
+}
+
+assert_equal 'ok', %q{
+  def bar(x); yield; end
+  def foo(...); bar(...); end
+  foo(1) { "ok" }
+}
+
+assert_equal 'ok', %q{
+  def baz(x); x; end
+  def bar(...); baz(...); end
+  def foo(...); bar(...); end
+  foo("ok")
+}
+
+assert_equal '[1, 2, 3, 4]', %q{
+  def baz(a, b, c, d); [a, b, c, d]; end
+  def bar(...); baz(1, ...); end
+  def foo(...); bar(2, ...); end
+  foo(3, 4)
+}
+
+assert_equal 'ok', %q{
+  class Foo; def self.foo(x); x; end; end
+  class Bar < Foo; def self.foo(...); super; end; end
+  Bar.foo('ok')
+}
+
+assert_equal 'ok', %q{
+  class Foo; def self.foo(x); x; end; end
+  class Bar < Foo; def self.foo(...); super(...); end; end
+  Bar.foo('ok')
+}
+
+assert_equal 'ok', %q{
+  class Foo; def self.foo(x, y); x + y; end; end
+  class Bar < Foo; def self.foo(...); super("o", ...); end; end
+  Bar.foo('k')
+}
+
+assert_equal 'ok', %q{
+  def bar(a); a; end
+  def foo(...); lambda { bar(...) }; end
+  foo("ok").call
+}
+
+assert_equal 'ok', %q{
+  class Foo; def self.foo(x, y); x + y; end; end
+  class Bar < Foo; def self.y(&b); b; end; def self.foo(...); y { super("o", ...) }; end; end
+  Bar.foo('k').call
+}
+
+assert_equal 'ok', %q{
+  def baz(n); n; end
+  def foo(...); bar = baz(...); lambda { lambda { bar } }; end
+  foo("ok").call.call
+}
+
+assert_equal 'ok', %q{
+  class A; def self.foo(...); new(...); end; attr_reader :b; def initialize(a, b:"ng"); @a = a; @b = b; end end
+  A.foo(1).b
+  A.foo(1, b: "ok").b
+}
+
+assert_equal 'ok', %q{
+  class A; def initialize; @a = ["ok"]; end; def first(...); @a.first(...); end; end
+  def call x; x.first; end
+  def call1 x; x.first(1); end
+  call(A.new)
+  call1(A.new).first
+}
+
+assert_equal 'ok', %q{
+  class A; def foo; yield("o"); end; end
+  class B < A; def foo(...); super { |x| yield(x + "k") }; end; end
+  B.new.foo { |x| x }
+}
+
+assert_equal "[1, 2, 3, 4]", %q{
+  def foo(*b) = b
+
+  def forward(...)
+    splat = [1,2,3]
+    foo(*splat, ...)
+  end
+
+  forward(4)
+}
+
+assert_equal "[1, 2, 3, 4]", %q{
+class A
+  def foo(*b) = b
+end
+
+class B < A
+  def foo(...)
+    splat = [1,2,3]
+    super(*splat, ...)
+  end
+end
+
+B.new.foo(4)
+}
+
+assert_equal 'ok', %q{
+  class A; attr_reader :iv; def initialize(...) = @iv = "ok"; end
+  A.new("foo", bar: []).iv
+}
+
+assert_equal 'ok', %q{
+  def foo(a, b) = a + b
+  def bar(...) = foo(...)
+  bar(1, 2)
+  bar(1, 2)
+  begin
+    bar(1, 2, 3)
+    "ng"
+  rescue ArgumentError
+    "ok"
+  end
+}
+
+assert_equal 'ok', %q{
+  class C
+    def foo(...) = :ok
+    def bar(...) = __send__(:foo, ...)
+  end
+
+  C.new.bar
+}
+
+assert_equal 'ok', %q{
+  class C
+    def method_missing(...) = :ok
+    def foo(...) = xyzzy(...)
+  end
+
+  C.new.foo
+}
+
+assert_equal 'ok', %q{
+  class C
+    def initialize(a)
+    end
+  end
+
+  def foo(...)
+    C.new(...)
+    :ok
+  end
+
+  foo(*["bar"])
+  foo("baz")
+}
+
+assert_equal 'ok', %q{
+  class C
+    def foo(b:)
+      b
+    end
+  end
+
+  def foo(...)
+    C.new.send(...)
+  end
+
+  foo(:foo, b: :ok)
+  foo(*["foo"], b: :ok)
+}
+
+assert_equal 'ok', %q{
+  Thing = Struct.new(:value)
+
+  Obj = Thing.new("ok")
+
+  def delegate(...)
+    Obj.value(...)
+  end
+
+  def no_args
+    delegate
+  end
+
+  def splat_args(*args)
+    delegate(*args)
+  end
+
+  no_args
+  splat_args
+}
diff --git a/bootstraptest/test_ractor.rb b/bootstraptest/test_ractor.rb
index b29db7ab0e..b3ab7f607c 100644
--- a/bootstraptest/test_ractor.rb
+++ b/bootstraptest/test_ractor.rb
@@ -211,22 +211,12 @@ assert_equal '[:a, :b, :c, :d, :e, :f, :g]', %q{
   Ractor.make_shareable(closure).call
 }
 
-# Now autoload in non-main Ractor is not supported
-assert_equal 'ok', %q{
-  autoload :Foo, 'foo.rb'
-  r = Ractor.new do
-    p Foo
-  rescue Ractor::UnsafeError
-    :ok
-  end
-  r.take
-}
-
 ###
 ###
 # Ractor still has several memory corruption so skip huge number of tests
 if ENV['GITHUB_WORKFLOW'] &&
-   ENV['GITHUB_WORKFLOW'] == 'Compilations'
+   (ENV['GITHUB_WORKFLOW'] == 'Compilations' ||
+   ENV['GITHUB_WORKFLOW'] == 'ModGC')
    # ignore the follow
 else
 
@@ -283,8 +273,7 @@ assert_equal 30.times.map { 'ok' }.to_s, %q{
   30.times.map{|i|
     test i
   }
-} unless ENV['RUN_OPTS'] =~ /--jit-min-calls=5/ || # This always fails with --jit-wait --jit-min-calls=5
-  (ENV.key?('TRAVIS') && ENV['TRAVIS_CPU_ARCH'] == 'arm64') # https://bugs.ruby-lang.org/issues/17878
+} unless (ENV.key?('TRAVIS') && ENV['TRAVIS_CPU_ARCH'] == 'arm64') # https://bugs.ruby-lang.org/issues/17878
 
 # Exception for empty select
 assert_match /specify at least one ractor/, %q{
@@ -501,7 +490,7 @@ assert_equal '[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]', %q{
     rs.delete r
     n
   }.sort
-}
+} unless /mswin/ =~ RUBY_PLATFORM # randomly hangs on mswin https://github.com/ruby/ruby/actions/runs/3753871445/jobs/6377551069#step:20:131
 
 # Ractor.select also support multiple take, receive and yield
 assert_equal '[true, true, true]', %q{
@@ -515,9 +504,9 @@ assert_equal '[true, true, true]', %q{
     end
   }
   received = []
-  take = []
+  taken = []
   yielded = []
-  until rs.empty?
+  until received.size == RN && taken.size == RN && yielded.size == RN
     r, v = Ractor.select(CR, *rs, yield_value: 'yield')
     case r
     when :receive
@@ -525,11 +514,17 @@ assert_equal '[true, true, true]', %q{
     when :yield
       yielded << v
     else
-      take << v
+      taken << v
       rs.delete r
     end
   end
-  [received.all?('sendyield'), yielded.all?(nil), take.all?('take')]
+  r = [received == ['sendyield'] * RN,
+       yielded  == [nil] * RN,
+       taken    == ['take'] * RN,
+  ]
+
+  STDERR.puts [received, yielded, taken].inspect
+  r
 }
 
 # multiple Ractors can send to one Ractor
@@ -566,7 +561,7 @@ assert_equal '[RuntimeError, "ok", true]', %q{
 }
 
 # threads in a ractor will killed
-assert_equal '{:ok=>3}', %q{
+assert_equal '{ok: 3}', %q{
   Ractor.new Ractor.current do |main|
     q = Thread::Queue.new
     Thread.new do
@@ -596,7 +591,7 @@ assert_equal '{:ok=>3}', %q{
   end
 
   3.times.map{Ractor.receive}.tally
-}
+} unless yjit_enabled? # `[BUG] Bus Error at 0x000000010b7002d0` in jit_exec()
 
 # unshareable object are copied
 assert_equal 'false', %q{
@@ -623,7 +618,7 @@ assert_equal "allocator undefined for Thread", %q{
 }
 
 # send shareable and unshareable objects
-assert_equal "ok", %q{
+assert_equal "ok", <<~'RUBY', frozen_string_literal: false
   echo_ractor = Ractor.new do
     loop do
       v = Ractor.receive
@@ -690,10 +685,10 @@ assert_equal "ok", %q{
   else
     results.inspect
   end
-}
+RUBY
 
 # frozen Objects are shareable
-assert_equal [false, true, false].inspect, %q{
+assert_equal [false, true, false].inspect, <<~'RUBY', frozen_string_literal: false
   class C
     def initialize freeze
       @a = 1
@@ -716,11 +711,11 @@ assert_equal [false, true, false].inspect, %q{
   results << check(C.new(true))         # false
   results << check(C.new(true).freeze)  # true
   results << check(C.new(false).freeze) # false
-}
+RUBY
 
 # move example2: String
 # touching moved object causes an error
-assert_equal 'hello world', %q{
+assert_equal 'hello world', <<~'RUBY', frozen_string_literal: false
   # move
   r = Ractor.new do
     obj = Ractor.receive
@@ -738,7 +733,7 @@ assert_equal 'hello world', %q{
   else
     raise 'unreachable'
   end
-}
+RUBY
 
 # move example2: Array
 assert_equal '[0, 1]', %q{
@@ -757,6 +752,17 @@ assert_equal '[0, 1]', %q{
   end
 }
 
+# unshareable frozen objects should still be frozen in new ractor after move
+assert_equal 'true', %q{
+r = Ractor.new do
+  obj = receive
+  { frozen: obj.frozen? }
+end
+obj = [Object.new].freeze
+r.send(obj, move: true)
+r.take[:frozen]
+}
+
 # move with yield
 assert_equal 'hello', %q{
   r = Ractor.new do
@@ -941,7 +947,7 @@ assert_equal 'ArgumentError', %q{
 }
 
 # ivar in shareable-objects are not allowed to access from non-main Ractor
-assert_equal "can not get unshareable values from instance variables of classes/modules from non-main Ractors", %q{
+assert_equal "can not get unshareable values from instance variables of classes/modules from non-main Ractors", <<~'RUBY', frozen_string_literal: false
   class C
     @iv = 'str'
   end
@@ -952,13 +958,12 @@ assert_equal "can not get unshareable values from instance variables of classes/
     end
   end
 
-
   begin
     r.take
   rescue Ractor::RemoteError => e
     e.cause.message
   end
-}
+RUBY
 
 # ivar in shareable-objects are not allowed to access from non-main Ractor
 assert_equal 'can not access instance variables of shareable objects from non-main Ractors', %q{
@@ -1082,6 +1087,41 @@ assert_equal '333', %q{
   a + b + c + d + e + f
 }
 
+assert_equal '["instance-variable", "instance-variable", nil]', %q{
+  class C
+    @iv1 = ""
+    @iv2 = 42
+    def self.iv1 = defined?(@iv1) # "instance-variable"
+    def self.iv2 = defined?(@iv2) # "instance-variable"
+    def self.iv3 = defined?(@iv3) # nil
+  end
+
+  Ractor.new{
+    [C.iv1, C.iv2, C.iv3]
+  }.take
+}
+
+# moved objects have their shape properly set to original object's shape
+assert_equal '1234', %q{
+class Obj
+  attr_accessor :a, :b, :c, :d
+  def initialize
+    @a = 1
+    @b = 2
+    @c = 3
+  end
+end
+r = Ractor.new do
+  obj = receive
+  obj.d = 4
+  [obj.a, obj.b, obj.c, obj.d]
+end
+obj = Obj.new
+r.send(obj, move: true)
+values = r.take
+values.join
+}
+
 # cvar in shareable-objects are not allowed to access from non-main Ractor
 assert_equal 'can not access class variables from non-main Ractors', %q{
   class C
@@ -1124,7 +1164,7 @@ assert_equal 'can not access class variables from non-main Ractors', %q{
 }
 
 # Getting non-shareable objects via constants by other Ractors is not allowed
-assert_equal 'can not access non-shareable objects in constant C::CONST by non-main Ractor.', %q{
+assert_equal 'can not access non-shareable objects in constant C::CONST by non-main Ractor.', <<~'RUBY', frozen_string_literal: false
   class C
     CONST = 'str'
   end
@@ -1136,10 +1176,10 @@ assert_equal 'can not access non-shareable objects in constant C::CONST by non-m
   rescue Ractor::RemoteError => e
     e.cause.message
   end
-}
+  RUBY
 
 # Constant cache should care about non-sharable constants
-assert_equal "can not access non-shareable objects in constant Object::STR by non-main Ractor.", %q{
+assert_equal "can not access non-shareable objects in constant Object::STR by non-main Ractor.", <<~'RUBY', frozen_string_literal: false
   STR = "hello"
   def str; STR; end
   s = str() # fill const cache
@@ -1148,10 +1188,10 @@ assert_equal "can not access non-shareable objects in constant Object::STR by no
   rescue Ractor::RemoteError => e
     e.cause.message
   end
-}
+RUBY
 
 # Setting non-shareable objects into constants by other Ractors is not allowed
-assert_equal 'can not set constants with non-shareable objects by non-main Ractors', %q{
+assert_equal 'can not set constants with non-shareable objects by non-main Ractors', <<~'RUBY', frozen_string_literal: false
   class C
   end
   r = Ractor.new do
@@ -1162,7 +1202,7 @@ assert_equal 'can not set constants with non-shareable objects by non-main Racto
   rescue Ractor::RemoteError => e
     e.cause.message
   end
-}
+RUBY
 
 # define_method is not allowed
 assert_equal "defined with an un-shareable Proc in a different Ractor", %q{
@@ -1215,7 +1255,7 @@ assert_equal '0', %q{
 }
 
 # ObjectSpace._id2ref can not handle unshareable objects with Ractors
-assert_equal 'ok', %q{
+assert_equal 'ok', <<~'RUBY', frozen_string_literal: false
   s = 'hello'
 
   Ractor.new s.object_id do |id ;s|
@@ -1225,10 +1265,10 @@ assert_equal 'ok', %q{
       :ok
     end
   end.take
-}
+RUBY
 
 # Ractor.make_shareable(obj)
-assert_equal 'true', %q{
+assert_equal 'true', <<~'RUBY', frozen_string_literal: false
   class C
     def initialize
       @a = 'foo'
@@ -1299,7 +1339,7 @@ assert_equal 'true', %q{
   }
 
   Ractor.shareable?(a)
-}
+RUBY
 
 # Ractor.make_shareable(obj) doesn't freeze shareable objects
 assert_equal 'true', %q{
@@ -1396,14 +1436,14 @@ assert_equal '[false, false, true, true]', %q{
 }
 
 # TracePoint with normal Proc should be Ractor local
-assert_equal '[4, 8]', %q{
+assert_equal '[6, 10]', %q{
   rs = []
   TracePoint.new(:line){|tp| rs << tp.lineno if tp.path == __FILE__}.enable do
-    Ractor.new{ # line 4
+    Ractor.new{ # line 5
       a = 1
       b = 2
     }.take
-    c = 3       # line 8
+    c = 3       # line 9
   end
   rs
 }
@@ -1441,6 +1481,25 @@ assert_equal '[:ok, :ok]', %q{
   end
 }
 
+# Ractor.select is interruptible
+assert_normal_exit %q{
+  trap(:INT) do
+    exit
+  end
+
+  r = Ractor.new do
+    loop do
+      sleep 1
+    end
+  end
+
+  Thread.new do
+    sleep 0.5
+    Process.kill(:INT, Process.pid)
+  end
+  Ractor.select(r)
+}
+
 # Ractor-local storage
 assert_equal '[nil, "b", "a"]', %q{
   ans = []
@@ -1455,6 +1514,21 @@ assert_equal '[nil, "b", "a"]', %q{
   ans << Ractor.current[:key]
 }
 
+assert_equal '1', %q{
+  N = 1_000
+  Ractor.new{
+    a = []
+    1_000.times.map{|i|
+      Thread.new(i){|i|
+        Thread.pass if i < N
+        a << Ractor.store_if_absent(:i){ i }
+        a << Ractor.current[:i]
+      }
+    }.each(&:join)
+    a.uniq.size
+  }.take
+}
+
 ###
 ### Synchronization tests
 ###
@@ -1471,28 +1545,13 @@ assert_equal "#{N}#{N}", %Q{
   }.map{|r| r.take}.join
 }
 
-# enc_table
-assert_equal "#{N/10}", %Q{
-  Ractor.new do
-    loop do
-      Encoding.find("test-enc-#{rand(5_000)}").inspect
-    rescue ArgumentError => e
-    end
-  end
-
-  src = Encoding.find("UTF-8")
-  #{N/10}.times{|i|
-    src.replicate("test-enc-\#{i}")
-  }
-}
-
 # Generic ivtbl
 n = N/2
 assert_equal "#{n}#{n}", %Q{
   2.times.map{
     Ractor.new do
       #{n}.times do
-        obj = ''
+        obj = +''
         obj.instance_variable_set("@a", 1)
         obj.instance_variable_set("@b", 1)
         obj.instance_variable_set("@c", 1)
@@ -1504,8 +1563,9 @@ assert_equal "#{n}#{n}", %Q{
 
 # NameError
 assert_equal "ok", %q{
+  obj = "".freeze # NameError refers the receiver indirectly
   begin
-    bar
+    obj.bar
   rescue => err
   end
   begin
@@ -1541,7 +1601,7 @@ assert_equal "ok", %q{
 
   1_000.times { idle_worker, tmp_reporter = Ractor.select(*workers) }
   "ok"
-}
+} unless yjit_enabled? || rjit_enabled? # flaky
 
 assert_equal "ok", %q{
   def foo(*); ->{ super }; end
@@ -1579,4 +1639,303 @@ assert_equal "ok", %q{
   end
 }
 
+# check method cache invalidation
+assert_equal "ok", %q{
+  module M
+    def foo
+      @foo
+    end
+  end
+
+  class A
+    include M
+
+    def initialize
+      100.times { |i| instance_variable_set(:"@var_#{i}", "bad: #{i}") }
+      @foo = 2
+    end
+  end
+
+  class B
+    include M
+
+    def initialize
+      @foo = 1
+    end
+  end
+
+  Ractor.new do
+    b = B.new
+    100_000.times do
+      raise unless b.foo == 1
+    end
+  end
+
+  a = A.new
+  100_000.times do
+    raise unless a.foo == 2
+  end
+
+  "ok"
+}
+
+# check method cache invalidation
+assert_equal 'true', %q{
+  class C1; def self.foo = 1; end
+  class C2; def self.foo = 2; end
+  class C3; def self.foo = 3; end
+  class C4; def self.foo = 5; end
+  class C5; def self.foo = 7; end
+  class C6; def self.foo = 11; end
+  class C7; def self.foo = 13; end
+  class C8; def self.foo = 17; end
+
+  LN = 10_000
+  RN = 10
+  CS = [C1, C2, C3, C4, C5, C6, C7, C8]
+  rs = RN.times.map{|i|
+    Ractor.new(CS.shuffle){|cs|
+      LN.times.sum{
+        cs.inject(1){|r, c| r * c.foo} # c.foo invalidates method cache entry
+      }
+    }
+  }
+
+  n = CS.inject(1){|r, c| r * c.foo} * LN
+  rs.map{|r| r.take} == Array.new(RN){n}
+}
+
+# check experimental warning
+assert_match /\Atest_ractor\.rb:1:\s+warning:\s+Ractor is experimental/, %q{
+  Warning[:experimental] = $VERBOSE = true
+  STDERR.reopen(STDOUT)
+  eval("Ractor.new{}.take", nil, "test_ractor.rb", 1)
+}, frozen_string_literal: false
+
+# check moved object
+assert_equal 'ok', %q{
+  r = Ractor.new do
+    Ractor.receive
+    GC.start
+    :ok
+  end
+
+  obj = begin
+  raise
+  rescue => e
+    e = Marshal.load(Marshal.dump(e))
+  end
+
+  r.send obj, move: true
+  r.take
+}
+
+## Ractor::Selector
+
+# Selector#empty? returns true
+assert_equal 'true', %q{
+  skip true unless defined? Ractor::Selector
+
+  s = Ractor::Selector.new
+  s.empty?
+}
+
+# Selector#empty? returns false if there is target ractors
+assert_equal 'false', %q{
+  skip false unless defined? Ractor::Selector
+
+  s = Ractor::Selector.new
+  s.add Ractor.new{}
+  s.empty?
+}
+
+# Selector#clear removes all ractors from the waiting list
+assert_equal 'true', %q{
+  skip true unless defined? Ractor::Selector
+
+  s = Ractor::Selector.new
+  s.add Ractor.new{10}
+  s.add Ractor.new{20}
+  s.clear
+  s.empty?
+}
+
+# Selector#wait can wait multiple ractors
+assert_equal '[10, 20, true]', %q{
+  skip [10, 20, true] unless defined? Ractor::Selector
+
+  s = Ractor::Selector.new
+  s.add Ractor.new{10}
+  s.add Ractor.new{20}
+  r, v = s.wait
+  vs = []
+  vs << v
+  r, v = s.wait
+  vs << v
+  [*vs.sort, s.empty?]
+} if defined? Ractor::Selector
+
+# Selector#wait can wait multiple ractors with receiving.
+assert_equal '30', %q{
+  skip 30 unless defined? Ractor::Selector
+
+  RN = 30
+  rs = RN.times.map{
+    Ractor.new{ :v }
+  }
+  s = Ractor::Selector.new(*rs)
+
+  results = []
+  until s.empty?
+    results << s.wait
+
+    # Note that s.wait can raise an exception because other Ractors/Threads
+    # can take from the same ractors in the waiting set.
+    # In this case there is no other takers so `s.wait` doesn't raise an error.
+  end
+
+  results.size
+} if defined? Ractor::Selector
+
+# Selector#wait can support dynamic addition
+assert_equal '600', %q{
+  skip 600 unless defined? Ractor::Selector
+
+  RN = 100
+  s = Ractor::Selector.new
+  rs = RN.times.map{
+    Ractor.new{
+      Ractor.main << Ractor.new{ Ractor.yield :v3; :v4 }
+      Ractor.main << Ractor.new{ Ractor.yield :v5; :v6 }
+      Ractor.yield :v1
+      :v2
+    }
+  }
+
+  rs.each{|r| s.add(r)}
+  h = {v1: 0, v2: 0, v3: 0, v4: 0, v5: 0, v6: 0}
+
+  loop do
+    case s.wait receive: true
+    in :receive, r
+      s.add r
+    in r, v
+      h[v] += 1
+      break if h.all?{|k, v| v == RN}
+    end
+  end
+
+  h.sum{|k, v| v}
+} unless yjit_enabled? # http://ci.rvm.jp/results/trunk-yjit@ruby-sp2-docker/4466770
+
+# Selector should be GCed (free'ed) without trouble
+assert_equal 'ok', %q{
+  skip :ok unless defined? Ractor::Selector
+
+  RN = 30
+  rs = RN.times.map{
+    Ractor.new{ :v }
+  }
+  s = Ractor::Selector.new(*rs)
+  :ok
+}
+
 end # if !ENV['GITHUB_WORKFLOW']
+
+# Chilled strings are not shareable
+assert_equal 'false', %q{
+  Ractor.shareable?("chilled")
+}
+
+# Chilled strings can be made shareable
+assert_equal 'true', %q{
+  shareable = Ractor.make_shareable("chilled")
+  shareable == "chilled" && Ractor.shareable?(shareable)
+}
+
+# require in Ractor
+assert_equal 'true', %q{
+  Module.new do
+    def require feature
+      return Ractor._require(feature) unless Ractor.main?
+      super
+    end
+    Object.prepend self
+    set_temporary_name 'Ractor#require'
+  end
+
+  Ractor.new{
+    begin
+      require 'benchmark'
+      Benchmark.measure{}
+    rescue SystemStackError
+      # prism parser with -O0 build consumes a lot of machine stack
+      Data.define(:real).new(1)
+    end
+  }.take.real > 0
+}
+
+# require_relative in Ractor
+assert_equal 'true', %q{
+  dummyfile = File.join(__dir__, "dummy#{rand}.rb")
+  return true if File.exist?(dummyfile)
+
+  begin
+    File.write dummyfile, ''
+  rescue Exception
+    # skip on any errors
+    return true
+  end
+
+  begin
+    Ractor.new dummyfile do |f|
+      require_relative File.basename(f)
+    end.take
+  ensure
+    File.unlink dummyfile
+  end
+}
+
+# require_relative in Ractor
+assert_equal 'LoadError', %q{
+  dummyfile = File.join(__dir__, "not_existed_dummy#{rand}.rb")
+  return true if File.exist?(dummyfile)
+
+  Ractor.new dummyfile do |f|
+    begin
+      require_relative File.basename(f)
+    rescue LoadError => e
+      e.class
+    end
+  end.take
+}
+
+# autolaod in Ractor
+assert_equal 'true', %q{
+  autoload :Benchmark, 'benchmark'
+
+  r = Ractor.new do
+    begin
+      Benchmark.measure{}
+    rescue SystemStackError
+      # prism parser with -O0 build consumes a lot of machine stack
+      Data.define(:real).new(1)
+    end
+  end
+  r.take.real > 0
+}
+
+# failed in autolaod in Ractor
+assert_equal 'LoadError', %q{
+  dummyfile = File.join(__dir__, "not_existed_dummy#{rand}.rb")
+  autoload :Benchmark, dummyfile
+
+  r = Ractor.new do
+    begin
+      Benchmark.measure{}
+    rescue LoadError => e
+      e.class
+    end
+  end
+  r.take
+}
diff --git a/bootstraptest/test_rjit.rb b/bootstraptest/test_rjit.rb
new file mode 100644
index 0000000000..4c8cd26dff
--- /dev/null
+++ b/bootstraptest/test_rjit.rb
@@ -0,0 +1,80 @@
+# VM_CALL_OPT_SEND + VM_METHOD_TYPE_ATTRSET
+assert_equal '1', %q{
+  class Foo
+    attr_writer :foo
+
+    def bar
+      send(:foo=, 1)
+    end
+  end
+
+  Foo.new.bar
+}
+
+# VM_CALL_OPT_SEND + OPTIMIZED_METHOD_TYPE_CALL
+assert_equal 'foo', %q{
+  def bar(&foo)
+    foo.send(:call)
+  end
+
+  bar { :foo }
+}
+
+# VM_CALL_OPT_SEND + OPTIMIZED_METHOD_TYPE_STRUCT_AREF
+assert_equal 'bar', %q{
+  def bar(foo)
+    foo.send(:bar)
+  end
+
+  bar(Struct.new(:bar).new(:bar))
+}
+
+# AND with offset  DISP32
+assert_equal '2', %q{
+  def foo
+    a = 6;
+    b = {a: 1, b: 1, c: 1, d: 1, e: 1,  f: 1, g: 1, h: a&3}
+    b[:h]
+  end
+
+  foo
+}
+
+# OR with offset DISP32
+assert_equal '6', %q{
+  def foo
+    a = 4;
+    b = {a: 1, b: 1, c: 1, d: 1, e: 1,  f: 1, g: 1, h: a|2}
+    b[:h]
+  end
+
+  foo
+}
+
+# kwargs default w/ checkkeyword + locals (which shouldn't overwrite unspecified_bits)
+assert_equal '1', %q{
+  def foo(bar: 1.to_s)
+    _ = 1
+    bar
+  end
+
+  def entry
+    foo
+  end
+
+  entry
+}
+
+# Updating local type in Context
+assert_normal_exit %q{
+  def foo(flag, object)
+    klass = if flag
+      object
+    end
+    klass ||= object
+    return klass.new
+  end
+
+  foo(false, Object)
+  foo(true, Object)
+}
diff --git a/bootstraptest/test_syntax.rb b/bootstraptest/test_syntax.rb
index 948e2d7809..8301b344c6 100644
--- a/bootstraptest/test_syntax.rb
+++ b/bootstraptest/test_syntax.rb
@@ -528,24 +528,24 @@ assert_equal %q{1}, %q{
   i
 }
 def assert_syntax_error expected, code, message = ''
-  assert_equal "#{expected}",
-    "begin eval(%q{#{code}}, nil, '', 0)"'; rescue SyntaxError => e; e.message[/\A:(?:\d+:)? (.*)/, 1] end', message
+  assert_match /^#{Regexp.escape(expected)}/,
+    "begin eval(%q{#{code}}, nil, '', 0)"'; rescue SyntaxError => e; e.message[/(?:\^~*|\A:(?:\d+:)?(?! syntax errors? found)(?: syntax error,)?) (.*)/, 1] end', message
 end
 assert_syntax_error "unterminated string meets end of file", '().."', '[ruby-dev:29732]'
 assert_equal %q{[]}, %q{$&;[]}, '[ruby-dev:31068]'
-assert_syntax_error "syntax error, unexpected *, expecting '}'", %q{{*0}}, '[ruby-dev:31072]'
-assert_syntax_error "`@0' is not allowed as an instance variable name", %q{@0..0}, '[ruby-dev:31095]'
-assert_syntax_error "identifier $00 is not valid to get", %q{$00..0}, '[ruby-dev:31100]'
-assert_syntax_error "identifier $00 is not valid to set", %q{0..$00=1}
+assert_syntax_error "unexpected *, expecting '}'", %q{{*0}}, '[ruby-dev:31072]'
+assert_syntax_error "'@0' is not allowed as an instance variable name", %q{@0..0}, '[ruby-dev:31095]'
+assert_syntax_error "'$00' is not allowed as a global variable name", %q{$00..0}, '[ruby-dev:31100]'
+assert_syntax_error "'$00' is not allowed as a global variable name", %q{0..$00=1}
 assert_equal %q{0}, %q{[*0];0}, '[ruby-dev:31102]'
-assert_syntax_error "syntax error, unexpected ')'", %q{v0,(*,v1,) = 0}, '[ruby-dev:31104]'
+assert_syntax_error "unexpected ')'", %q{v0,(*,v1,) = 0}, '[ruby-dev:31104]'
 assert_equal %q{1}, %q{
   class << (ary=[]); def []; 0; end; def []=(x); super(0,x);end;end; ary[]+=1
 }, '[ruby-dev:31110]'
 assert_syntax_error "Can't set variable $1", %q{0..$1=1}, '[ruby-dev:31118]'
 assert_valid_syntax %q{1.times{1+(1&&next)}}, '[ruby-dev:31119]'
 assert_valid_syntax %q{x=-1;loop{x+=1&&redo if (x+=1).zero?}}, '[ruby-dev:31119]'
-assert_syntax_error %q{syntax error, unexpected end-of-input}, %q{!}, '[ruby-dev:31243]'
+assert_syntax_error %q{unexpected end-of-input}, %q{!}, '[ruby-dev:31243]'
 assert_equal %q{[nil]}, %q{[()]}, '[ruby-dev:31252]'
 assert_equal %q{true}, %q{!_=()}, '[ruby-dev:31263]'
 assert_equal 'ok', %q{while true; redo; end if 1 == 2; :ok}, '[ruby-dev:31360]'
@@ -629,7 +629,7 @@ assert_equal '2', %q{
 
 assert_match /invalid multibyte char/, %q{
   $stderr = STDOUT
-  eval("\"\xf0".force_encoding("utf-8"))
+  eval("\"\xf0".dup.force_encoding("utf-8"))
 }, '[ruby-dev:32429]'
 
 # method ! and !=
@@ -848,7 +848,7 @@ assert_normal_exit %q{
       def x(a=1, b, *rest); nil end
     end
   end
-}, bug2415
+}, bug2415 unless rjit_enabled? # flaky
 
 assert_normal_exit %q{
   0.times do
@@ -880,7 +880,7 @@ assert_normal_exit %q{
       end
     end
   end
-}, bug2415
+}, bug2415 unless rjit_enabled? # flaky
 
 assert_normal_exit %q{
   a {
@@ -904,3 +904,35 @@ assert_normal_exit %q{
     Class
   end
 }, '[ruby-core:30293]'
+
+assert_equal "false", <<~RUBY, "literal strings are mutable", "--disable-frozen-string-literal"
+  'test'.frozen?
+RUBY
+
+assert_equal "true", <<~RUBY, "literal strings are frozen", "--disable-frozen-string-literal", frozen_string_literal: true
+  'test'.frozen?
+RUBY
+
+assert_equal "true", <<~RUBY, "literal strings are frozen", "--enable-frozen-string-literal"
+  'test'.frozen?
+RUBY
+
+assert_equal "false", <<~RUBY, "literal strings are mutable", "--enable-frozen-string-literal", frozen_string_literal: false
+  'test'.frozen?
+RUBY
+
+assert_equal "false", <<~RUBY, "__FILE__ is mutable", "--disable-frozen-string-literal"
+  __FILE__.frozen?
+RUBY
+
+assert_equal "true", <<~RUBY, "__FILE__ is frozen", "--disable-frozen-string-literal", frozen_string_literal: true
+  __FILE__.frozen?
+RUBY
+
+assert_equal "true", <<~RUBY, "__FILE__ is frozen", "--enable-frozen-string-literal"
+  __FILE__.frozen?
+RUBY
+
+assert_equal "false", <<~RUBY, "__FILE__ is mutable", "--enable-frozen-string-literal", frozen_string_literal: false
+  __FILE__.frozen?
+RUBY
diff --git a/bootstraptest/test_thread.rb b/bootstraptest/test_thread.rb
index 5361828403..4040b68a27 100644
--- a/bootstraptest/test_thread.rb
+++ b/bootstraptest/test_thread.rb
@@ -242,9 +242,22 @@ assert_equal 'true', %{
   end
 }
 
+assert_equal 'true', %{
+  Thread.new{}.join
+  begin
+    Process.waitpid2 fork{
+      Thread.new{
+        sleep 0.1
+      }.join
+    }
+    true
+  rescue NotImplementedError
+    true
+  end
+}
+
 assert_equal 'ok', %{
-  open("zzz_t1.rb", "w") do |f|
-    f.puts <<-END
+  File.write("zzz_t1.rb", <<-END)
       begin
         Thread.new { fork { GC.start } }.join
         pid, status = Process.wait2
@@ -253,7 +266,6 @@ assert_equal 'ok', %{
         $result = :ok
       end
     END
-  end
   require "./zzz_t1.rb"
   $result
 }
@@ -289,7 +301,7 @@ assert_normal_exit %q{
   }.each {|t|
     t.join
   }
-}
+} unless rjit_enabled? # flaky
 
 assert_equal 'ok', %q{
   def m
@@ -408,8 +420,7 @@ assert_equal 'ok', %q{
 }
 
 assert_equal 'ok', %{
-  open("zzz_t2.rb", "w") do |f|
-    f.puts <<-'end;' # do
+  File.write("zzz_t2.rb", <<-'end;') # do
       begin
         m = Thread::Mutex.new
         parent = Thread.current
@@ -431,7 +442,6 @@ assert_equal 'ok', %{
         $result = :ok
       end
     end;
-  end
   require "./zzz_t2.rb"
   $result
 }
@@ -483,7 +493,7 @@ assert_equal 'foo', %q{
   [th1, th2].each {|t| t.join }
   GC.start
   f.call.source
-}
+} unless rjit_enabled? # flaky
 assert_normal_exit %q{
   class C
     def inspect
diff --git a/bootstraptest/test_yjit.rb b/bootstraptest/test_yjit.rb
index d124d180d1..6a1aebccd7 100644
--- a/bootstraptest/test_yjit.rb
+++ b/bootstraptest/test_yjit.rb
@@ -1,32 +1,328 @@
-assert_equal '2022', %q{
- def contrivance(hash, key)
-    # Expect this to compile to an `opt_aref`.
-    hash[key]
+# To run the tests in this file only, with YJIT enabled:
+# make btest BTESTS=bootstraptest/test_yjit.rb RUN_OPTS="--yjit-call-threshold=1"
 
-    # The [] call above tracks that the `hash` local has a VALUE that
-    # is a heap pointer and the guard for the Kernel#itself call below
-    # doesn't check that it's a heap pointer VALUE.
-    #
-    # As you can see from the crash, the call to rb_hash_aref() can set the
-    # `hash` local, making eliding the heap object guard unsound.
-    hash.itself
+# regression test for popping before side exit
+assert_equal "ok", %q{
+  def foo(a, *) = a
+
+  def call(args, &)
+    foo(1) # spill at where the block arg will be
+    foo(*args, &)
+  end
+
+  call([1, 2])
+
+  begin
+    call([])
+  rescue ArgumentError
+    :ok
+  end
+}
+
+# regression test for send processing before side exit
+assert_equal "ok", %q{
+  def foo(a, *) = :foo
+
+  def call(args)
+    send(:foo, *args)
+  end
+
+  call([1, 2])
+
+  begin
+    call([])
+  rescue ArgumentError
+    :ok
+  end
+}
+
+# test discarding extra yield arguments
+assert_equal "2210150001501015", %q{
+  def splat_kw(ary) = yield *ary, a: 1
+
+  def splat(ary) = yield *ary
+
+  def kw = yield 1, 2, a: 0
+
+  def simple = yield 0, 1
+
+  def calls
+    [
+      splat([1, 1, 2]) { |x, y| x + y },
+      splat([1, 1, 2]) { |y, opt = raise| opt + y},
+      splat_kw([0, 1]) { |a:| a },
+      kw { |a:| a },
+      kw { |a| a },
+      simple { 5.itself },
+      simple { |a| a },
+      simple { |opt = raise| opt },
+      simple { |*rest| rest },
+      simple { |opt_kw: 5| opt_kw },
+      # autosplat ineractions
+      [0, 1, 2].yield_self { |a, b| [a, b] },
+      [0, 1, 2].yield_self { |a, opt = raise| [a, opt] },
+      [1].yield_self { |a, opt = 4| a + opt },
+    ]
+  end
+
+  calls.join
+}
+
+# test autosplat with empty splat
+assert_equal "ok", %q{
+  def m(pos, splat) = yield pos, *splat
+
+  m([:ok], []) {|v0,| v0 }
+}
+
+# regression test for send stack shifting
+assert_normal_exit %q{
+  def foo(a, b)
+    a.singleton_methods(b)
+  end
+
+  def call_foo
+    [1, 1, 1, 1, 1, 1, send(:foo, 1, 1)]
+  end
+
+  call_foo
+}
+
+# regression test for keyword splat with yield
+assert_equal 'nil', %q{
+  def splat_kw(kwargs) = yield(**kwargs)
+
+  splat_kw({}) { _1 }.inspect
+}
+
+# regression test for arity check with splat
+assert_equal '[:ae, :ae]', %q{
+  def req_one(a_, b_ = 1) = raise
+
+  def test(args)
+    req_one *args
+  rescue ArgumentError
+    :ae
+  end
+
+  [test(Array.new 5), test([])]
+} unless rjit_enabled? # Not yet working on RJIT
+
+# regression test for arity check with splat and send
+assert_equal '[:ae, :ae]', %q{
+  def two_reqs(a, b_, _ = 1) = a.gsub(a, a)
+
+  def test(name, args)
+    send(name, *args)
+  rescue ArgumentError
+    :ae
+  end
+
+  [test(:two_reqs, ["g", nil, nil, nil]), test(:two_reqs, ["g"])]
+}
+
+# regression test for GC marking stubs in invalidated code
+assert_normal_exit %q{
+  skip true unless GC.respond_to?(:compact)
+  garbage = Array.new(10_000) { [] } # create garbage to cause iseq movement
+  eval(<<~RUBY)
+  def foo(n, garbage)
+    if n == 2
+      # 1.times.each to create a cfunc frame to preserve the JIT frame
+      # which will return to a stub housed in an invalidated block
+      return 1.times.each do
+        Object.define_method(:foo) {}
+        garbage.clear
+        GC.verify_compaction_references(toward: :empty, expand_heap: true)
+      end
+    end
+
+    foo(n + 1, garbage)
+  end
+  RUBY
+
+  foo(1, garbage)
+}
+
+# regression test for callee block handler overlapping with arguments
+assert_equal '3', %q{
+  def foo(_req, *args) = args.last
+
+  def call_foo = foo(0, 1, 2, 3, &->{})
+
+  call_foo
+}
+
+# call leaf builtin with a block argument
+assert_equal '0', "0.abs(&nil)"
+
+# regression test for invokeblock iseq guard
+assert_equal 'ok', %q{
+  skip :ok unless GC.respond_to?(:compact)
+  def foo = yield
+  10.times do |i|
+    ret = eval("foo { #{i} }")
+    raise "failed at #{i}" unless ret == i
+    GC.compact
+  end
+  :ok
+} unless rjit_enabled? # Not yet working on RJIT
+
+# regression test for overly generous guard elision
+assert_equal '[0, :sum, 0, :sum]', %q{
+  # In faulty versions, the following happens:
+  #  1. YJIT puts object on the temp stack with type knowledge
+  #     (CArray or CString) about RBASIC_CLASS(object).
+  #  2. In iter=0, due to the type knowledge, YJIT generates
+  #     a call to sum() without any guard on RBASIC_CLASS(object).
+  #  3. In iter=1, a singleton class is added to the object,
+  #     changing RBASIC_CLASS(object), falsifying the type knowledge.
+  #  4. Because the code from (1) has no class guard, it is incorrectly
+  #     reused and the wrong method is invoked.
+  # Putting a literal is important for gaining type knowledge.
+  def carray(iter)
+    array = []
+    array.sum(iter.times { def array.sum(_) = :sum })
+  end
+
+  def cstring(iter)
+    string = "".dup
+    string.sum(iter.times { def string.sum(_) = :sum })
+  end
+
+  [carray(0), carray(1), cstring(0), cstring(1)]
+}
+
+# regression test for return type of Integer#/
+# It can return a T_BIGNUM when inputs are T_FIXNUM.
+assert_equal 0x3fffffffffffffff.to_s, %q{
+  def call(fixnum_min)
+    (fixnum_min / -1) - 1
   end
 
-  # This is similar to ->(recv, mid) { send(recv, mid).local_variable_set(...) }.
-  # By composing we avoid creating new Ruby frames and so sending :binding
-  # captures the environment of the frame that does the missing key lookup.
-  # We use it to capture the environment inside of `contrivance`.
-  cap_then_set =
-    Kernel.instance_method(:send).method(:bind_call).to_proc >>
-      ->(binding) { binding.local_variable_set(:hash, 2022) }
-  special_missing = Hash.new(&cap_then_set)
+  call(-(2**62))
+}
+
+# regression test for return type of String#<<
+assert_equal 'Sub', %q{
+  def call(sub) = (sub << sub).itself
 
-  # Make YJIT speculate that it's a hash and generate code
-  # that calls rb_hash_aref().
-  contrivance({}, :warmup)
-  contrivance({}, :warmup)
+  class Sub < String; end
 
-  contrivance(special_missing, :binding)
+  call(Sub.new('o')).class
+}
+
+# String#dup with FL_EXIVAR
+assert_equal '["str", "ivar"]', %q{
+  def str_dup(str) = str.dup
+  str = "str"
+  str.instance_variable_set(:@ivar, "ivar")
+  str = str_dup(str)
+  [str, str.instance_variable_get(:@ivar)]
+}
+
+# test splat filling required and feeding rest
+assert_equal '[0, 1, 2, [3, 4]]', %q{
+  public def lead_rest(a, b, *rest)
+    [self, a, b, rest]
+  end
+
+  def call(args) = 0.lead_rest(*args)
+
+  call([1, 2, 3, 4])
+}
+
+# test missing opts are nil initialized
+assert_equal '[[0, 1, nil, 3], [0, 1, nil, 3], [0, 1, nil, 3, []], [0, 1, nil, 3, []]]', %q{
+  public def lead_opts(a, b=binding.local_variable_get(:c), c=3)
+    [self, a, b, c]
+  end
+
+  public def opts_rest(a=raise, b=binding.local_variable_get(:c), c=3, *rest)
+    [self, a, b, c, rest]
+  end
+
+  def call(args)
+    [
+      0.lead_opts(1),
+      0.lead_opts(*args),
+
+      0.opts_rest(1),
+      0.opts_rest(*args),
+    ]
+  end
+
+  call([1])
+}
+
+# test filled optionals with unspecified keyword param
+assert_equal 'ok', %q{
+  def opt_rest_opt_kw(_=1, *, k: :ok) = k
+
+  def call = opt_rest_opt_kw(0)
+
+  call
+}
+
+# test splat empty array with rest param
+assert_equal '[0, 1, 2, []]', %q{
+  public def foo(a=1, b=2, *rest)
+    [self, a, b, rest]
+  end
+
+  def call(args) = 0.foo(*args)
+
+  call([])
+}
+
+# Regression test for yielding with autosplat to block with
+# optional parameters. https://github.com/Shopify/yjit/issues/313
+assert_equal '[:a, :b, :a, :b]', %q{
+  def yielder(arg) = yield(arg) + yield(arg)
+
+  yielder([:a, :b]) do |c = :c, d = :d|
+    [c, d]
+  end
+}
+
+# Regression test for GC mishap while doing shape transition
+assert_equal '[:ok]', %q{
+  # [Bug #19601]
+  class RegressionTest
+    def initialize
+      @a = @b = @fourth_ivar_does_shape_transition = nil
+    end
+
+    def extender
+      @first_extended_ivar = [:ok]
+    end
+  end
+
+  GC.stress = true
+
+  # Used to crash due to GC run in rb_ensure_iv_list_size()
+  # not marking the newly allocated [:ok].
+  RegressionTest.new.extender.itself
+} unless rjit_enabled? # Skip on RJIT since this uncovers a crash
+
+assert_equal 'true', %q{
+  # regression test for tracking type of locals for too long
+  def local_setting_cmp(five)
+    victim = 5
+    five.define_singleton_method(:respond_to?) do |_, _|
+      victim = nil
+    end
+
+    # +1 makes YJIT track that victim is a number and
+    # defined? calls respond_to? from above indirectly
+    unless (victim + 1) && defined?(five.something)
+      # Would return wrong result if we still think `five` is a number
+      victim.nil?
+    end
+  end
+
+  local_setting_cmp(Object.new)
+  local_setting_cmp(Object.new)
 }
 
 assert_equal '18374962167983112447', %q{
@@ -45,7 +341,7 @@ assert_equal '18374962167983112447', %q{
 }
 
 assert_normal_exit %q{
-  # regression test for a leak caught by an asert on --yjit-call-threshold=2
+  # regression test for a leak caught by an assert on --yjit-call-threshold=2
   Foo = 1
 
   eval("def foo = [#{(['Foo,']*256).join}]")
@@ -56,6 +352,29 @@ assert_normal_exit %q{
   Object.send(:remove_const, :Foo)
 }
 
+assert_normal_exit %q{
+  # Test to ensure send on overridden c functions
+  # doesn't corrupt the stack
+  class Bar
+    def bar(x)
+      x
+    end
+  end
+
+  class Foo
+    def bar
+      Bar.new
+    end
+  end
+
+  foo = Foo.new
+  # before this change, this line would error
+  # because "s" would still be on the stack
+  # String.to_s is the overridden method here
+  p foo.bar.bar("s".__send__(:to_s))
+}
+
+
 assert_equal '[nil, nil, nil, nil, nil, nil]', %q{
   [NilClass, TrueClass, FalseClass, Integer, Float, Symbol].each do |klass|
     klass.class_eval("def foo = @foo")
@@ -67,6 +386,80 @@ assert_equal '[nil, nil, nil, nil, nil, nil]', %q{
   end
 }
 
+assert_equal '[nil, nil, nil, nil, nil, nil]', %q{
+  # Tests defined? on non-heap objects
+  [NilClass, TrueClass, FalseClass, Integer, Float, Symbol].each do |klass|
+    klass.class_eval("def foo = defined?(@foo)")
+  end
+
+  [nil, true, false, 0xFABCAFE, 0.42, :cake].map do |instance|
+    instance.foo
+    instance.foo
+  end
+}
+
+assert_equal '[nil, "instance-variable", nil, "instance-variable"]', %q{
+  # defined? on object that changes shape between calls
+  class Foo
+    def foo
+      defined?(@foo)
+    end
+
+    def add
+      @foo = 1
+    end
+
+    def remove
+      self.remove_instance_variable(:@foo)
+    end
+  end
+
+  obj = Foo.new
+  [obj.foo, (obj.add; obj.foo), (obj.remove; obj.foo), (obj.add; obj.foo)]
+}
+
+assert_equal '["instance-variable", 5]', %q{
+  # defined? on object too complex for shape information
+  class Foo
+    def initialize
+      100.times { |i| instance_variable_set("@foo#{i}", i) }
+    end
+
+    def foo
+      [defined?(@foo5), @foo5]
+    end
+  end
+
+  Foo.new.foo
+}
+
+# getinstancevariable with shape too complex
+assert_normal_exit %q{
+  class Foo
+    def initialize
+      @a = 1
+    end
+
+    def getter
+      @foobar
+    end
+  end
+
+  # Initialize ivars in changing order, making the Foo
+  # class have shape too complex
+  100.times do |x|
+    foo = Foo.new
+    foo.instance_variable_set(:"@a#{x}", 1)
+    foo.instance_variable_set(:"@foobar", 777)
+
+    # The getter method eventually sees shape too complex
+    r = foo.getter
+    if r != 777
+      raise "error"
+    end
+  end
+}
+
 assert_equal '0', %q{
   # This is a regression test for incomplete invalidation from
   # opt_setinlinecache. This test might be brittle, so
@@ -209,6 +602,8 @@ assert_equal 'string', %q{
 
 # Check that exceptions work when getting global variable
 assert_equal 'rescued', %q{
+  Warning[:deprecated] = true
+
   module Warning
     def warn(message)
       raise
@@ -362,6 +757,45 @@ assert_equal 'false', %q{
   less_than 2
 }
 
+# BOP redefinition works on Integer#<=
+assert_equal 'false', %q{
+  def le(x, y) = x <= y
+
+  le(2, 2)
+
+  class Integer
+    def <=(_) = false
+  end
+
+  le(2, 2)
+}
+
+# BOP redefinition works on Integer#>
+assert_equal 'false', %q{
+  def gt(x, y) = x > y
+
+  gt(3, 2)
+
+  class Integer
+    def >(_) = false
+  end
+
+  gt(3, 2)
+}
+
+# BOP redefinition works on Integer#>=
+assert_equal 'false', %q{
+  def ge(x, y) = x >= y
+
+  ge(2, 2)
+
+  class Integer
+    def >=(_) = false
+  end
+
+  ge(2, 2)
+}
+
 # Putobject, less-than operator, fixnums
 assert_equal '2', %q{
     def check_index(index)
@@ -805,6 +1239,7 @@ assert_equal 'special', %q{
 
 # Test that object references in generated code get marked and moved
 assert_equal "good", %q{
+  skip :good unless GC.respond_to?(:compact)
   def bar
     "good"
   end
@@ -817,7 +1252,7 @@ assert_equal "good", %q{
   foo
 
   begin
-    GC.verify_compaction_references(double_heap: true, toward: :empty)
+    GC.verify_compaction_references(expand_heap: true, toward: :empty)
   rescue NotImplementedError
     # in case compaction isn't supported
   end
@@ -828,7 +1263,7 @@ assert_equal "good", %q{
 # Test polymorphic getinstancevariable. T_OBJECT -> T_STRING
 assert_equal 'ok', %q{
   @hello = @h1 = @h2 = @h3 = @h4 = 'ok'
-  str = ""
+  str = +""
   str.instance_variable_set(:@hello, 'ok')
 
   public def get
@@ -972,6 +1407,18 @@ assert_equal '[42, :default]', %q{
   ]
 }
 
+# Test default value block for Hash with opt_aref_with
+assert_equal "false", <<~RUBY, frozen_string_literal: false
+  def index_with_string(h)
+    h["foo"]
+  end
+
+  h = Hash.new { |h, k| k.frozen? }
+
+  index_with_string(h)
+  index_with_string(h)
+RUBY
+
 # A regression test for making sure cfp->sp is proper when
 # hitting stubs. See :stub-sp-flush:
 assert_equal 'ok', %q{
@@ -1129,6 +1576,38 @@ assert_equal '42', %q{
   run
 }
 
+# splatting an empty array on a specialized method
+assert_equal 'ok', %q{
+  def run
+    "ok".to_s(*[])
+  end
+
+  run
+  run
+}
+
+# splatting an single element array on a specialized method
+assert_equal '[1]', %q{
+  def run
+    [].<<(*[1])
+  end
+
+  run
+  run
+}
+
+# specialized method with wrong args
+assert_equal 'ok', %q{
+  def run(x)
+    "bad".to_s(123) if x
+  rescue
+    :ok
+  end
+
+  run(false)
+  run(true)
+}
+
 # getinstancevariable on Symbol
 assert_equal '[nil, nil]', %q{
   # @foo to exercise the getinstancevariable instruction
@@ -1235,6 +1714,19 @@ assert_equal '[1, 2, 42]', %q{
   [foo {1}, foo {2}, foo {42}]
 }
 
+# test calling without block param
+assert_equal '[1, false, 2, false]', %q{
+  def bar
+    block_given? && yield
+  end
+
+  def foo(&block)
+    bar(&block)
+  end
+
+  [foo { 1 }, foo, foo { 2 }, foo]
+}
+
 # test calling block param failing
 assert_equal '42', %q{
   def foo(&block)
@@ -1315,7 +1807,7 @@ assert_equal '{}', %q{
 }
 
 # test building hash with values
-assert_equal '{:foo=>:bar}', %q{
+assert_equal '{foo: :bar}', %q{
   def build_hash(val)
     { foo: val }
   end
@@ -1368,6 +1860,46 @@ assert_equal 'foo123', %q{
   make_str("foo", 123)
 }
 
+# test that invalidation of String#to_s doesn't crash
+assert_equal 'meh', %q{
+  def inval_method
+    "".to_s
+  end
+
+  inval_method
+
+  class String
+    def to_s
+      "meh"
+    end
+  end
+
+  inval_method
+}
+
+# test that overriding to_s on a String subclass works consistently
+assert_equal 'meh', %q{
+  class MyString < String
+    def to_s
+      "meh"
+    end
+  end
+
+  def test_to_s(obj)
+    obj.to_s
+  end
+
+  OBJ = MyString.new
+
+  # Should return '' both times
+  test_to_s("")
+  test_to_s("")
+
+  # Can return '' if YJIT optimises String#to_s too aggressively
+  test_to_s(OBJ)
+  test_to_s(OBJ)
+}
+
 # test string interpolation with overridden to_s
 assert_equal 'foo', %q{
   class String
@@ -1384,6 +1916,228 @@ assert_equal 'foo', %q{
   make_str("foo")
 }
 
+# Test that String unary plus returns the same object ID for an unfrozen string.
+assert_equal 'true', <<~RUBY, frozen_string_literal: false
+  def jittable_method
+    str = "bar"
+
+    old_obj_id = str.object_id
+    uplus_str = +str
+
+    uplus_str.object_id == old_obj_id
+  end
+  jittable_method
+RUBY
+
+# Test that String unary plus returns a different unfrozen string when given a frozen string
+assert_equal 'false', %q{
+  # Logic needs to be inside an ISEQ, such as a method, for YJIT to compile it
+  def jittable_method
+    frozen_str = "foo".freeze
+
+    old_obj_id = frozen_str.object_id
+    uplus_str = +frozen_str
+
+    uplus_str.object_id == old_obj_id || uplus_str.frozen?
+  end
+
+  jittable_method
+}
+
+# String-subclass objects should behave as expected inside string-interpolation via concatstrings
+assert_equal 'monkeys / monkeys, yo!', %q{
+  class MyString < String
+    # This is a terrible idea in production code, but we'd like YJIT to match CRuby
+    def to_s
+      super + ", yo!"
+    end
+  end
+
+  def jittable_method
+    m = MyString.new('monkeys')
+    "#{m} / #{m.to_s}"
+  end
+
+  jittable_method
+}
+
+# String-subclass objects should behave as expected for string equality
+assert_equal 'false', %q{
+  class MyString < String
+    # This is a terrible idea in production code, but we'd like YJIT to match CRuby
+    def ==(b)
+      "#{self}_" == b
+    end
+  end
+
+  def jittable_method
+    ma = MyString.new("a")
+
+    # Check equality with string-subclass receiver
+    ma == "a" || ma != "a_" ||
+      # Check equality with string receiver
+      "a_" == ma || "a" != ma ||
+      # Check equality between string subclasses
+      ma != MyString.new("a_") ||
+      # Make sure "string always equals itself" check isn't used with overridden equality
+      ma == ma
+  end
+  jittable_method
+}
+
+# Test to_s duplicates a string subclass object but not a string
+assert_equal 'false', %q{
+  class MyString < String; end
+
+  def jittable_method
+    a = "a"
+    ma = MyString.new("a")
+
+    a.object_id != a.to_s.object_id ||
+      ma.object_id == ma.to_s.object_id
+  end
+  jittable_method
+}
+
+# Test freeze on string subclass
+assert_equal 'true', %q{
+  class MyString < String; end
+
+  def jittable_method
+    fma = MyString.new("a").freeze
+
+    # Freezing a string subclass should not duplicate it
+    fma.object_id == fma.freeze.object_id
+  end
+  jittable_method
+}
+
+# Test unary minus on string subclass
+assert_equal 'true', %q{
+  class MyString < String; end
+
+  def jittable_method
+    ma = MyString.new("a")
+    fma = MyString.new("a").freeze
+
+    # Unary minus on frozen string subclass should not duplicate it
+    fma.object_id == (-fma).object_id &&
+      # Unary minus on unfrozen string subclass should duplicate it
+      ma.object_id != (-ma).object_id
+  end
+  jittable_method
+}
+
+# Test unary plus on string subclass
+assert_equal 'true', %q{
+  class MyString < String; end
+
+  def jittable_method
+    fma = MyString.new("a").freeze
+
+    # Unary plus on frozen string subclass should not duplicate it
+    fma.object_id != (+fma).object_id
+  end
+  jittable_method
+}
+
+# test getbyte on string class
+assert_equal '[97, :nil, 97, :nil, :raised]', %q{
+  def getbyte(s, i)
+   byte = begin
+    s.getbyte(i)
+   rescue TypeError
+    :raised
+   end
+
+   byte || :nil
+  end
+
+  getbyte("a", 0)
+  getbyte("a", 0)
+
+  [getbyte("a", 0), getbyte("a", 1), getbyte("a", -1), getbyte("a", -2), getbyte("a", "a")]
+} unless rjit_enabled? # Not yet working on RJIT
+
+# Basic test for String#setbyte
+assert_equal 'AoZ', %q{
+  s = +"foo"
+  s.setbyte(0, 65)
+  s.setbyte(-1, 90)
+  s
+}
+
+# String#setbyte IndexError
+assert_equal 'String#setbyte', %q{
+  def ccall = "".setbyte(1, 0)
+  begin
+    ccall
+  rescue => e
+    e.backtrace.first.split("'").last
+  end
+}
+
+# String#setbyte TypeError
+assert_equal 'String#setbyte', %q{
+  def ccall = "".setbyte(nil, 0)
+  begin
+    ccall
+  rescue => e
+    e.backtrace.first.split("'").last
+  end
+}
+
+# String#setbyte FrozenError
+assert_equal 'String#setbyte', %q{
+  def ccall = "a".freeze.setbyte(0, 0)
+  begin
+    ccall
+  rescue => e
+    e.backtrace.first.split("'").last
+  end
+}
+
+# non-leaf String#setbyte
+assert_equal 'String#setbyte', %q{
+  def to_int
+    @caller = caller
+    0
+  end
+
+  def ccall = "a".dup.setbyte(self, 98)
+  ccall
+
+  @caller.first.split("'").last
+}
+
+# non-leaf String#byteslice
+assert_equal 'TypeError', %q{
+  def ccall = "".byteslice(nil, nil)
+  begin
+    ccall
+  rescue => e
+    e.class
+  end
+}
+
+# Test << operator on string subclass
+assert_equal 'abab', %q{
+  class MyString < String; end
+
+  def jittable_method
+    a = -"a"
+    mb = MyString.new("b")
+
+    buf = String.new
+    mbuf = MyString.new
+
+    buf << a << mb
+    mbuf << a << mb
+
+    buf + mbuf
+  end
+  jittable_method
+}
 
 # test invokebuiltin as used in struct assignment
 assert_equal '123', %q{
@@ -1511,6 +2265,34 @@ assert_equal '7', %q{
   foo(5,2)
 }
 
+# regression test for argument registers with invalidation
+assert_equal '[0, 1, 2]', %q{
+  def test(n)
+    ret = n
+    binding
+    ret
+  end
+
+  [0, 1, 2].map do |n|
+    test(n)
+  end
+}
+
+# regression test for argument registers
+assert_equal 'true', %q{
+  class Foo
+    def ==(other)
+      other == nil
+    end
+  end
+
+  def test
+    [Foo.new].include?(Foo.new)
+  end
+
+  test
+}
+
 # test pattern matching
 assert_equal '[:ok, :ok]', %q{
   class C
@@ -1576,6 +2358,20 @@ assert_equal '123', %q{
   foo(Foo)
 }
 
+# Test EP == BP invalidation with moving ISEQs
+assert_equal 'ok', %q{
+  skip :ok unless GC.respond_to?(:compact)
+  def entry
+    ok = proc { :ok } # set #entry as an EP-escaping ISEQ
+    [nil].reverse_each do # avoid exiting the JIT frame on the constant
+      GC.compact # move #entry ISEQ
+    end
+    ok # should be read off of escaped EP
+  end
+
+  entry.call
+}
+
 # invokesuper edge case
 assert_equal '[:A, [:A, :B]]', %q{
   class B
@@ -1732,6 +2528,50 @@ assert_equal '[:A, :Btwo]', %q{
   ins.foo
 }
 
+# invokesuper with a block
+assert_equal 'true', %q{
+  class A
+    def foo = block_given?
+  end
+
+  class B < A
+    def foo = super()
+  end
+
+  B.new.foo { }
+  B.new.foo { }
+}
+
+# invokesuper in a block
+assert_equal '[0, 2]', %q{
+  class A
+    def foo(x) = x * 2
+  end
+
+  class B < A
+    def foo
+      2.times.map do |x|
+        super(x)
+      end
+    end
+  end
+
+  B.new.foo
+  B.new.foo
+}
+
+# invokesuper zsuper in a bmethod
+assert_equal 'ok', %q{
+  class Foo
+    define_method(:itself) { super }
+  end
+  begin
+    Foo.new.itself
+  rescue RuntimeError
+    :ok
+  end
+}
+
 # Call to fixnum
 assert_equal '[true, false]', %q{
   def is_odd(obj)
@@ -1772,6 +2612,16 @@ assert_equal '[true, false, true, false]', %q{
   [is_odd(123), is_odd(456), is_odd(bignum), is_odd(bignum+1)]
 }
 
+# Flonum and Flonum
+assert_equal '[2.0, 0.0, 1.0, 4.0]', %q{
+  [1.0 + 1.0, 1.0 - 1.0, 1.0 * 1.0, 8.0 / 2.0]
+}
+
+# Flonum and Fixnum
+assert_equal '[2.0, 0.0, 1.0, 4.0]', %q{
+  [1.0 + 1, 1.0 - 1, 1.0 * 1, 8.0 / 2]
+}
+
 # Call to static and dynamic symbol
 assert_equal 'bar', %q{
   def to_string(obj)
@@ -1812,6 +2662,30 @@ assert_equal '[1, 2, 3, 4, 5]', %q{
   splatarray
 }
 
+# splatkw
+assert_equal '[1, 2]', %q{
+  def foo(a:) = [a, yield]
+
+  def entry(&block)
+    a = { a: 1 }
+    foo(**a, &block)
+  end
+
+  entry { 2 }
+}
+assert_equal '[1, 2]', %q{
+  def foo(a:) = [a, yield]
+
+  def entry(obj, &block)
+    foo(**obj, &block)
+  end
+
+  entry({ a: 3 }) { 2 }
+  obj = Object.new
+  def obj.to_hash = { a: 1 }
+  entry(obj) { 2 }
+}
+
 assert_equal '[1, 1, 2, 1, 2, 3]', %q{
   def expandarray
     arr = [1, 2, 3]
@@ -1866,6 +2740,23 @@ assert_equal '[:not_array, nil, nil]', %q{
   expandarray_not_array(obj)
 }
 
+assert_equal '[1, 2]', %q{
+  class NilClass
+    private
+    def to_ary
+      [1, 2]
+    end
+  end
+
+  def expandarray_redefined_nilclass
+    a, b = nil
+    [a, b]
+  end
+
+  expandarray_redefined_nilclass
+  expandarray_redefined_nilclass
+} unless rjit_enabled?
+
 assert_equal '[1, 2, nil]', %q{
   def expandarray_rhs_too_small
     a, b, c = [1, 2]
@@ -1876,6 +2767,17 @@ assert_equal '[1, 2, nil]', %q{
   expandarray_rhs_too_small
 }
 
+assert_equal '[nil, 2, nil]', %q{
+  def foo(arr)
+    a, b, c = arr
+  end
+
+  a, b, c1 = foo([0, 1])
+  a, b, c2 = foo([0, 1, 2])
+  a, b, c3 = foo([0, 1])
+  [c1, c2, c3]
+}
+
 assert_equal '[1, [2]]', %q{
   def expandarray_splat
     a, *b = [1, 2]
@@ -1965,7 +2867,7 @@ assert_equal '[[:c_return, :String, :string_alias, "events_to_str"]]', %q{
   events.compiled(events)
 
   events
-}
+} unless rjit_enabled? # RJIT calls extra Ruby methods
 
 # test enabling a TracePoint that targets a particular line in a C method call
 assert_equal '[true]', %q{
@@ -2047,7 +2949,7 @@ assert_equal '[[:c_call, :itself]]', %q{
   tp.enable { shouldnt_compile }
 
   events
-}
+} unless rjit_enabled? # RJIT calls extra Ruby methods
 
 # test enabling c_return tracing before compiling
 assert_equal '[[:c_return, :itself, main]]', %q{
@@ -2062,6 +2964,26 @@ assert_equal '[[:c_return, :itself, main]]', %q{
   tp.enable { shouldnt_compile }
 
   events
+} unless rjit_enabled? # RJIT calls extra Ruby methods
+
+# test c_call invalidation
+assert_equal '[[:c_call, :itself]]', %q{
+  # enable the event once to make sure invalidation
+  # happens the second time we enable it
+  TracePoint.new(:c_call) {}.enable{}
+
+  def compiled
+    itself
+  end
+
+  # assume first call compiles
+  compiled
+
+  events = []
+  tp = TracePoint.new(:c_call) { |tp| events << [tp.event, tp.method_id] }
+  tp.enable { compiled }
+
+  events
 }
 
 # test enabling tracing for a suspended fiber
@@ -2088,7 +3010,6 @@ assert_equal '[:itself]', %q{
     itself
   end
 
-
   tracing_ractor = Ractor.new do
     # 1: start tracing
     events = []
@@ -2463,7 +3384,7 @@ assert_equal '[[1, 2, 3, 4]]', %q{
 }
 
 # cfunc kwargs
-assert_equal '{:foo=>123}', %q{
+assert_equal '{foo: 123}', %q{
   def foo(bar)
     bar.store(:value, foo: 123)
     bar[:value]
@@ -2474,7 +3395,7 @@ assert_equal '{:foo=>123}', %q{
 }
 
 # cfunc kwargs
-assert_equal '{:foo=>123}', %q{
+assert_equal '{foo: 123}', %q{
   def foo(bar)
     bar.replace(foo: 123)
   end
@@ -2484,7 +3405,7 @@ assert_equal '{:foo=>123}', %q{
 }
 
 # cfunc kwargs
-assert_equal '{:foo=>123, :bar=>456}', %q{
+assert_equal '{foo: 123, bar: 456}', %q{
   def foo(bar)
     bar.replace(foo: 123, bar: 456)
   end
@@ -2494,7 +3415,7 @@ assert_equal '{:foo=>123, :bar=>456}', %q{
 }
 
 # variadic cfunc kwargs
-assert_equal '{:foo=>123}', %q{
+assert_equal '{foo: 123}', %q{
   def foo(bar)
     bar.merge(foo: 123)
   end
@@ -2618,7 +3539,7 @@ assert_equal "true", %q{
 }
 
 # duphash
-assert_equal '{:foo=>123}', %q{
+assert_equal '{foo: 123}', %q{
   def foo
     {foo: 123}
   end
@@ -2628,7 +3549,7 @@ assert_equal '{:foo=>123}', %q{
 }
 
 # newhash
-assert_equal '{:foo=>2}', %q{
+assert_equal '{foo: 2}', %q{
   def foo
     {foo: 1+1}
   end
@@ -2717,11 +3638,20 @@ assert_equal 'new', %q{
     foo
   end
 
+  def bar
+    :bar
+  end
+
+
   test
   test
 
   RubyVM::YJIT.simulate_oom! if defined?(RubyVM::YJIT)
 
+  # Old simulat_omm! leaves one byte of space and this fills it up
+  bar
+  bar
+
   def foo
     :new
   end
@@ -2837,3 +3767,1575 @@ assert_equal '', %q{
   foo
   foo
 }
+
+# Make sure we're correctly reading RStruct's as.ary union for embedded RStructs
+assert_equal '3,12', %q{
+  pt_struct = Struct.new(:x, :y)
+  p = pt_struct.new(3, 12)
+  def pt_inspect(pt)
+    "#{pt.x},#{pt.y}"
+  end
+
+  # Make sure pt_inspect is JITted
+  10.times { pt_inspect(p) }
+
+  # Make sure it's returning '3,12' instead of e.g. '3,false'
+  pt_inspect(p)
+}
+
+# Regression test for deadlock between branch_stub_hit and ractor_receive_if
+assert_equal '10', %q{
+  r = Ractor.new Ractor.current do |main|
+    main << 1
+    main << 2
+    main << 3
+    main << 4
+    main << 5
+    main << 6
+    main << 7
+    main << 8
+    main << 9
+    main << 10
+  end
+
+  a = []
+  a << Ractor.receive_if{|msg| msg == 10}
+  a << Ractor.receive_if{|msg| msg == 9}
+  a << Ractor.receive_if{|msg| msg == 8}
+  a << Ractor.receive_if{|msg| msg == 7}
+  a << Ractor.receive_if{|msg| msg == 6}
+  a << Ractor.receive_if{|msg| msg == 5}
+  a << Ractor.receive_if{|msg| msg == 4}
+  a << Ractor.receive_if{|msg| msg == 3}
+  a << Ractor.receive_if{|msg| msg == 2}
+  a << Ractor.receive_if{|msg| msg == 1}
+
+  a.length
+}
+
+# checktype
+assert_equal 'false', %q{
+    def function()
+        [1, 2] in [Integer, String]
+    end
+    function()
+}
+
+# opt_send_without_block (VM_METHOD_TYPE_ATTRSET)
+assert_equal 'foo', %q{
+    class Foo
+      attr_writer :foo
+
+      def foo()
+        self.foo = "foo"
+      end
+    end
+    foo = Foo.new
+    foo.foo
+}
+
+# anytostring, intern
+assert_equal 'true', %q{
+    def foo()
+      :"#{true}"
+    end
+    foo()
+}
+
+# toregexp, objtostring
+assert_equal '/true/', %q{
+    def foo()
+      /#{true}/
+    end
+    foo().inspect
+}
+
+# concatstrings, objtostring
+assert_equal '9001', %q{
+    def foo()
+      "#{9001}"
+    end
+    foo()
+}
+
+# opt_send_without_block (VM_METHOD_TYPE_CFUNC)
+assert_equal 'nil', %q{
+    def foo
+      nil.inspect # argc: 0
+    end
+    foo
+}
+assert_equal '4', %q{
+    def foo
+      2.pow(2) # argc: 1
+    end
+    foo
+}
+assert_equal 'aba', %q{
+    def foo
+      "abc".tr("c", "a") # argc: 2
+    end
+    foo
+}
+assert_equal 'true', %q{
+    def foo
+      respond_to?(:inspect) # argc: -1
+    end
+    foo
+}
+assert_equal '["a", "b"]', %q{
+    def foo
+      "a\nb".lines(chomp: true) # kwargs
+    end
+    foo
+}
+
+# invokebuiltin
+assert_equal '123', %q{
+  def foo(obj)
+    obj.foo = 123
+  end
+
+  struct = Struct.new(:foo)
+  obj = struct.new
+  foo(obj)
+}
+
+# invokebuiltin_delegate
+assert_equal '.', %q{
+  def foo(path)
+    Dir.open(path).path
+  end
+  foo(".")
+}
+
+# opt_invokebuiltin_delegate_leave
+assert_equal '[0]', %q{"\x00".unpack("c")}
+
+# opt_send_without_block (VM_METHOD_TYPE_ISEQ)
+assert_equal '1', %q{
+  def foo = 1
+  def bar = foo
+  bar
+}
+assert_equal '[1, 2, 3]', %q{
+  def foo(a, b) = [1, a, b]
+  def bar = foo(2, 3)
+  bar
+}
+assert_equal '[1, 2, 3, 4, 5, 6]', %q{
+  def foo(a, b, c:, d:, e: 0, f: 6) = [a, b, c, d, e, f]
+  def bar = foo(1, 2, c: 3, d: 4, e: 5)
+  bar
+}
+assert_equal '[1, 2, 3, 4]', %q{
+  def foo(a, b = 2) = [a, b]
+  def bar = foo(1) + foo(3, 4)
+  bar
+}
+
+assert_equal '1', %q{
+  def foo(a) = a
+  def bar = foo(1) { 2 }
+  bar
+}
+assert_equal '[1, 2]', %q{
+  def foo(a, &block) = [a, block.call]
+  def bar = foo(1) { 2 }
+  bar
+}
+
+# opt_send_without_block (VM_METHOD_TYPE_IVAR)
+assert_equal 'foo', %q{
+  class Foo
+    attr_reader :foo
+
+    def initialize
+      @foo = "foo"
+    end
+  end
+  Foo.new.foo
+}
+
+# opt_send_without_block (VM_METHOD_TYPE_OPTIMIZED)
+assert_equal 'foo', %q{
+  Foo = Struct.new(:bar)
+  Foo.new("bar").bar = "foo"
+}
+assert_equal 'foo', %q{
+  Foo = Struct.new(:bar)
+  Foo.new("foo").bar
+}
+
+# getblockparamproxy
+assert_equal 'foo', %q{
+  def foo(&block)
+    block.call
+  end
+  foo { "foo" }
+}
+
+# getblockparam
+assert_equal 'foo', %q{
+  def foo(&block)
+    block
+  end
+  foo { "foo" }.call
+}
+
+assert_equal '[1, 2]', %q{
+  def foo
+    x = [2]
+    [1, *x]
+  end
+
+  foo
+  foo
+}
+
+# respond_to? with changing symbol
+assert_equal 'false', %q{
+  def foo(name)
+    :sym.respond_to?(name)
+  end
+  foo(:to_s)
+  foo(:to_s)
+  foo(:not_exist)
+}
+
+# respond_to? with method being defined
+assert_equal 'true', %q{
+  def foo
+    :sym.respond_to?(:not_yet_defined)
+  end
+  foo
+  foo
+  module Kernel
+    def not_yet_defined = true
+  end
+  foo
+}
+
+# respond_to? with undef method
+assert_equal 'false', %q{
+  module Kernel
+    def to_be_removed = true
+  end
+  def foo
+    :sym.respond_to?(:to_be_removed)
+  end
+  foo
+  foo
+  class Object
+    undef_method :to_be_removed
+  end
+  foo
+}
+
+# respond_to? with respond_to_missing?
+assert_equal 'true', %q{
+  class Foo
+  end
+  def foo(x)
+    x.respond_to?(:bar)
+  end
+  foo(Foo.new)
+  foo(Foo.new)
+  class Foo
+    def respond_to_missing?(*) = true
+  end
+  foo(Foo.new)
+}
+
+# bmethod
+assert_equal '[1, 2, 3]', %q{
+  one = 1
+  define_method(:foo) do
+    one
+  end
+
+  3.times.map { |i| foo + i }
+}
+
+# return inside bmethod
+assert_equal 'ok', %q{
+  define_method(:foo) do
+    1.tap { return :ok }
+  end
+
+  foo
+}
+
+# bmethod optional and keywords
+assert_equal '[[1, nil, 2]]', %q{
+  define_method(:opt_and_kwargs) do |a = {}, b: nil, c: nil|
+    [a, b, c]
+  end
+
+  5.times.map { opt_and_kwargs(1, c: 2) }.uniq
+}
+
+# bmethod with forwarded block
+assert_equal '2', %q{
+  define_method(:foo) do |&block|
+    block.call
+  end
+
+  def bar(&block)
+    foo(&block)
+  end
+
+  bar { 1 }
+  bar { 2 }
+}
+
+# bmethod with forwarded block and arguments
+assert_equal '5', %q{
+  define_method(:foo) do |n, &block|
+    n + block.call
+  end
+
+  def bar(n, &block)
+    foo(n, &block)
+  end
+
+  bar(0) { 1 }
+  bar(3) { 2 }
+}
+
+# bmethod with forwarded unwanted block
+assert_equal '1', %q{
+  one = 1
+  define_method(:foo) do
+    one
+  end
+
+  def bar(&block)
+    foo(&block)
+  end
+
+  bar { }
+  bar { }
+}
+
+# test for return stub lifetime issue
+assert_equal '1', %q{
+  def foo(n)
+    if n == 2
+      return 1.times { Object.define_method(:foo) {} }
+    end
+
+    foo(n + 1)
+  end
+
+  foo(1)
+}
+
+# case-when with redefined ===
+assert_equal 'ok', %q{
+  class Symbol
+    def ===(a)
+      true
+    end
+  end
+
+  def cw(arg)
+    case arg
+    when :b
+      :ok
+    when 4
+      :ng
+    end
+  end
+
+  cw(4)
+}
+
+assert_equal 'threw', %q{
+  def foo(args)
+    wrap(*args)
+  rescue ArgumentError
+    'threw'
+  end
+
+  def wrap(a)
+    [a]
+  end
+
+  foo([Hash.ruby2_keywords_hash({})])
+}
+
+assert_equal 'threw', %q{
+  # C call
+  def bar(args)
+    Array(*args)
+  rescue ArgumentError
+    'threw'
+  end
+
+  bar([Hash.ruby2_keywords_hash({})])
+}
+
+# Test instance_of? and is_a?
+assert_equal 'true', %q{
+  1.instance_of?(Integer) && 1.is_a?(Integer)
+}
+
+# Test instance_of? and is_a? for singleton classes
+assert_equal 'true', %q{
+  a = []
+  def a.test = :test
+  a.instance_of?(Array) && a.is_a?(Array)
+}
+
+# Test instance_of? for singleton_class
+# Yes this does really return false
+assert_equal 'false', %q{
+  a = []
+  def a.test = :test
+  a.instance_of?(a.singleton_class)
+}
+
+# Test is_a? for singleton_class
+assert_equal 'true', %q{
+  a = []
+  def a.test = :test
+  a.is_a?(a.singleton_class)
+}
+
+# Test send with splat to a cfunc
+assert_equal 'true', %q{
+  1.send(:==, 1, *[])
+}
+
+# Test empty splat with cfunc
+assert_equal '2', %q{
+  def foo
+    Integer.sqrt(4, *[])
+  end
+  # call twice to deal with constant exiting
+  foo
+  foo
+}
+
+# Test non-empty splat with cfunc
+assert_equal 'Hello World', %q{
+  def bar
+    args = ["Hello "]
+    greeting = +"World"
+    greeting.insert(0, *args)
+    greeting
+  end
+  bar
+}
+
+# Regression: this creates a temp stack with > 127 elements
+assert_normal_exit %q{
+  def foo(a)
+    [
+      a, a, a, a, a, a, a, a, a, a,
+      a, a, a, a, a, a, a, a, a, a,
+      a, a, a, a, a, a, a, a, a, a,
+      a, a, a, a, a, a, a, a, a, a,
+      a, a, a, a, a, a, a, a, a, a,
+      a, a, a, a, a, a, a, a, a, a,
+      a, a, a, a, a, a, a, a, a, a,
+      a, a, a, a, a, a, a, a, a, a,
+      a, a, a, a, a, a, a, a, a, a,
+      a, a, a, a, a, a, a, a, a, a,
+      a, a, a, a, a, a, a, a, a, a,
+      a, a, a, a, a, a, a, a, a, a,
+      a, a, a, a, a, a, a, a,
+    ]
+  end
+
+  def entry
+    foo(1)
+  end
+
+  entry
+}
+
+# Test that splat and rest combined
+# properly dupe the array
+assert_equal "[]", %q{
+  def foo(*rest)
+    rest << 1
+  end
+
+  def test(splat)
+    foo(*splat)
+  end
+
+  EMPTY = []
+  custom = Object.new
+  def custom.to_a
+    EMPTY
+  end
+
+  test(custom)
+  test(custom)
+  EMPTY
+}
+
+# Rest with send
+assert_equal '[1, 2, 3]', %q{
+  def bar(x, *rest)
+    rest.insert(0, x)
+  end
+  send(:bar, 1, 2, 3)
+}
+
+# Fix splat block arg bad compilation
+assert_equal "foo", %q{
+  def literal(*args, &block)
+    s = ''.dup
+    literal_append(s, *args, &block)
+    s
+  end
+
+  def literal_append(sql, v)
+    sql << v
+  end
+
+  literal("foo")
+}
+
+# regression test for accidentally having a parameter truncated
+# due to Rust/C signature mismatch. Used to crash with
+# > [BUG] rb_vm_insn_addr2insn: invalid insn address ...
+# or
+# > ... `Err` value: TryFromIntError(())'
+assert_normal_exit %q{
+  n = 16384
+  eval(
+    "def foo(arg); " + "_=arg;" * n + '_=1;' + "Object; end"
+  )
+  foo 1
+}
+
+# Regression test for CantCompile not using starting_ctx
+assert_normal_exit %q{
+  class Integer
+    def ===(other)
+      false
+    end
+  end
+
+  def my_func(x)
+    case x
+    when 1
+      1
+    when 2
+      2
+    else
+      3
+    end
+  end
+
+  my_func(1)
+}
+
+# Regression test for CantCompile not using starting_ctx
+assert_equal "ArgumentError", %q{
+  def literal(*args, &block)
+    s = ''.dup
+    args = [1, 2, 3]
+    literal_append(s, *args, &block)
+    s
+  end
+
+  def literal_append(sql, v)
+    [sql.inspect, v.inspect]
+  end
+
+  begin
+    literal("foo")
+  rescue ArgumentError
+    "ArgumentError"
+  end
+}
+
+# Rest with block
+# Simplified code from railsbench
+assert_equal '[{"/a" => "b", as: :c, via: :post}, [], nil]', %q{
+  def match(path, *rest, &block)
+    [path, rest, block]
+  end
+
+  def map_method(method, args, &block)
+    options = args.last
+    args.pop
+    options[:via] = method
+    match(*args, options, &block)
+  end
+
+  def post(*args, &block)
+    map_method(:post, args, &block)
+  end
+
+  post "/a" => "b", as: :c
+}
+
+# Test rest and kw_args
+assert_equal '[true, true, true, true]', %q{
+  def my_func(*args, base: nil, sort: true)
+    [args, base, sort]
+  end
+
+  def calling_my_func
+    results = []
+    results << (my_func("test") == [["test"], nil, true])
+    results << (my_func("test", base: :base) == [["test"], :base, true])
+    results << (my_func("test", sort: false) == [["test"], nil, false])
+    results << (my_func("test", "other", base: :base) == [["test", "other"], :base, true])
+    results
+  end
+  calling_my_func
+}
+
+# Test Integer#[] with 2 args
+assert_equal '0', %q{
+  3[0, 0]
+}
+
+# unspecified_bits + checkkeyword
+assert_equal '2', %q{
+  def callee = 1
+
+  # checkkeyword should see unspecified_bits=0 (use bar), not Integer 1 (set bar = foo).
+  def foo(foo, bar: foo) = bar
+
+  def entry(&block)
+    # write 1 at stack[3]. Calling #callee spills stack[3].
+    1 + (1 + (1 + (1 + callee)))
+    # &block is written to a register instead of stack[3]. When &block is popped and
+    # unspecified_bits is pushed, it must be written to stack[3], not to a register.
+    foo(1, bar: 2, &block)
+  end
+
+  entry # call branch_stub_hit (spill temps)
+  entry # doesn't call branch_stub_hit (not spill temps)
+}
+
+# Test rest and optional_params
+assert_equal '[true, true, true, true]', %q{
+  def my_func(stuff, base=nil, sort=true, *args)
+    [stuff, base, sort, args]
+  end
+
+  def calling_my_func
+    results = []
+    results << (my_func("test") == ["test", nil, true, []])
+    results << (my_func("test", :base) == ["test", :base, true, []])
+    results << (my_func("test", :base, false) == ["test", :base, false, []])
+    results << (my_func("test", :base, false, "other", "other") == ["test", :base, false, ["other", "other"]])
+    results
+  end
+  calling_my_func
+}
+
+# Test rest and optional_params and splat
+assert_equal '[true, true, true, true, true]', %q{
+  def my_func(stuff, base=nil, sort=true, *args)
+    [stuff, base, sort, args]
+  end
+
+  def calling_my_func
+    results = []
+    splat = ["test"]
+    results << (my_func(*splat) == ["test", nil, true, []])
+    splat = [:base]
+    results << (my_func("test", *splat) == ["test", :base, true, []])
+    splat = [:base, false]
+    results << (my_func("test", *splat) == ["test", :base, false, []])
+    splat = [:base, false, "other", "other"]
+    results << (my_func("test", *splat) == ["test", :base, false, ["other", "other"]])
+    splat = ["test", :base, false, "other", "other"]
+    results << (my_func(*splat) == ["test", :base, false, ["other", "other"]])
+    results
+  end
+  calling_my_func
+}
+
+# Regression test: rest and optional and splat
+assert_equal 'true', %q{
+  def my_func(base=nil, *args)
+    [base, args]
+  end
+
+  def calling_my_func
+    array = []
+    my_func(:base, :rest1, *array) == [:base, [:rest1]]
+  end
+
+  calling_my_func
+}
+
+# Fix failed case for large splat
+assert_equal 'true', %q{
+  def d(a, b=:b)
+  end
+
+  def calling_func
+    ary = 1380888.times;
+    d(*ary)
+  end
+  begin
+    calling_func
+  rescue ArgumentError
+    true
+  end
+} unless rjit_enabled? # Not yet working on RJIT
+
+# Regression test: register allocator on expandarray
+assert_equal '[]', %q{
+  func = proc { [] }
+  proc do
+    _x, _y = func.call
+  end.call
+}
+
+# Catch TAG_BREAK in a non-FINISH frame with JIT code
+assert_equal '1', %q{
+  def entry
+    catch_break
+  end
+
+  def catch_break
+    while_true do
+      break
+    end
+    1
+  end
+
+  def while_true
+    while true
+      yield
+    end
+  end
+
+  entry
+}
+
+assert_equal '6', %q{
+  class Base
+    def number = 1 + yield
+  end
+
+  class Sub < Base
+    def number = super + 2
+  end
+
+  Sub.new.number { 3 }
+}
+
+# Integer multiplication and overflow
+assert_equal '[6, -6, 9671406556917033397649408, -9671406556917033397649408, 21267647932558653966460912964485513216]', %q{
+  def foo(a, b)
+    a * b
+  end
+
+  r1 = foo(2, 3)
+  r2 = foo(2, -3)
+  r3 = foo(2 << 40, 2 << 41)
+  r4 = foo(2 << 40, -2 << 41)
+  r5 = foo(1 << 62, 1 << 62)
+
+  [r1, r2, r3, r4, r5]
+}
+
+# Integer multiplication and overflow (minimized regression test from test-basic)
+assert_equal '8515157028618240000', %q{2128789257154560000 * 4}
+
+# Inlined method calls
+assert_equal 'nil', %q{
+  def putnil = nil
+  def entry = putnil
+  entry.inspect
+}
+assert_equal '1', %q{
+  def putobject_1 = 1
+  def entry = putobject_1
+  entry
+}
+assert_equal 'false', %q{
+  def putobject(_unused_arg1) = false
+  def entry = putobject(nil)
+  entry
+}
+assert_equal 'true', %q{
+  def entry = yield
+  entry { true }
+}
+assert_equal 'sym', %q{
+  def entry = :sym.to_sym
+  entry
+}
+
+assert_normal_exit %q{
+  ivars = 1024.times.map { |i| "@iv_#{i} = #{i}\n" }.join
+  Foo = Class.new
+  Foo.class_eval "def initialize() #{ivars} end"
+  Foo.new
+}
+
+assert_equal '0', %q{
+  def spill
+    1.to_i # not inlined
+  end
+
+  def inline(_stack1, _stack2, _stack3, _stack4, _stack5)
+    0 # inlined
+  end
+
+  def entry
+    # RegTemps is 00111110 prior to the #inline call.
+    # Its return value goes to stack_idx=0, which conflicts with stack_idx=5.
+    inline(spill, 2, 3, 4, 5)
+  end
+
+  entry
+}
+
+# Integer succ and overflow
+assert_equal '[2, 4611686018427387904]', %q{
+  [1.succ, 4611686018427387903.succ]
+}
+
+# Integer pred and overflow
+assert_equal '[0, -4611686018427387905]', %q{
+  [1.pred, -4611686018427387904.pred]
+}
+
+# Integer right shift
+assert_equal '[0, 1, -4]', %q{
+  [0 >> 1, 2 >> 1, -7 >> 1]
+}
+
+# Integer XOR
+assert_equal '[0, 0, 4]', %q{
+  [0 ^ 0, 1 ^ 1, 7 ^ 3]
+}
+
+assert_equal '[nil, "yield"]', %q{
+  def defined_yield = defined?(yield)
+  [defined_yield, defined_yield {}]
+}
+
+# splat with ruby2_keywords into rest parameter
+assert_equal '[[{a: 1}], {}]', %q{
+  ruby2_keywords def foo(*args) = args
+
+  def bar(*args, **kw) = [args, kw]
+
+  def pass_bar(*args) = bar(*args)
+
+  def body
+    args = foo(a: 1)
+    pass_bar(*args)
+  end
+
+  body
+}
+
+# concatarray
+assert_equal '[1, 2]', %q{
+  def foo(a, b) = [a, b]
+  arr = [2]
+  foo(*[1], *arr)
+}
+
+# pushtoarray
+assert_equal '[1, 2]', %q{
+  def foo(a, b) = [a, b]
+  arr = [1]
+  foo(*arr, 2)
+}
+
+# pop before fallback
+assert_normal_exit %q{
+  class Foo
+    attr_reader :foo
+
+    def try = foo(0, &nil)
+  end
+
+  Foo.new.try
+}
+
+# a kwrest case
+assert_equal '[1, 2, {complete: false}]', %q{
+  def rest(foo: 1, bar: 2, **kwrest)
+    [foo, bar, kwrest]
+  end
+
+  def callsite = rest(complete: false)
+
+  callsite
+}
+
+# splat+kw_splat+opt+rest
+assert_equal '[1, []]', %q{
+  def opt_rest(a = 0, *rest) = [a, rest]
+
+  def call_site(args) = opt_rest(*args, **nil)
+
+  call_site([1])
+}
+
+# splat and nil kw_splat
+assert_equal 'ok', %q{
+  def identity(x) = x
+
+  def splat_nil_kw_splat(args) = identity(*args, **nil)
+
+  splat_nil_kw_splat([:ok])
+}
+
+# empty splat and kwsplat into leaf builtins
+assert_equal '[1, 1, 1]', %q{
+  empty = []
+  [1.abs(*empty), 1.abs(**nil), 1.bit_length(*empty, **nil)]
+}
+
+# splat into C methods with -1 arity
+assert_equal '[[1, 2, 3], [0, 2, 3], [1, 2, 3], [2, 2, 3], [], [], [{}]]', %q{
+  class Foo < Array
+    def push(args) = super(1, *args)
+  end
+
+  def test_cfunc_vargs_splat(sub_instance, array_class, empty_kw_hash)
+    splat = [2, 3]
+    kw_splat = [empty_kw_hash]
+    [
+      sub_instance.push(splat),
+      array_class[0, *splat, **nil],
+      array_class[1, *splat, &nil],
+      array_class[2, *splat, **nil, &nil],
+      array_class.send(:[], *kw_splat),
+      # kw_splat disables keywords hash handling
+      array_class[*kw_splat],
+      array_class[*kw_splat, **nil],
+    ]
+  end
+
+  test_cfunc_vargs_splat(Foo.new, Array, Hash.ruby2_keywords_hash({}))
+}
+
+# Class#new (arity=-1), splat, and ruby2_keywords
+assert_equal '[0, {1 => 1}]', %q{
+  class KwInit
+    attr_reader :init_args
+    def initialize(x = 0, **kw)
+      @init_args = [x, kw]
+    end
+  end
+
+  def test(klass, args)
+    klass.new(*args).init_args
+  end
+
+  test(KwInit, [Hash.ruby2_keywords_hash({1 => 1})])
+}
+
+# Chilled string setivar trigger warning
+assert_match(/literal string will be frozen in the future/, %q{
+  Warning[:deprecated] = true
+  $VERBOSE = true
+  $warning = "no-warning"
+  module ::Warning
+    def self.warn(message)
+      $warning = message.split("warning: ").last.strip
+    end
+  end
+
+  class String
+    def setivar!
+      @ivar = 42
+    end
+  end
+
+  def setivar!(str)
+    str.setivar!
+  end
+
+  10.times { setivar!("mutable".dup) }
+  10.times do
+    setivar!("frozen".freeze)
+  rescue FrozenError
+  end
+
+  setivar!("chilled") # Emit warning
+  $warning
+})
+
+# arity=-2 cfuncs
+assert_equal '["", "1/2", [0, [:ok, 1]]]', %q{
+  def test_cases(file, chain)
+    new_chain = chain.allocate # to call initialize directly
+    new_chain.send(:initialize, [0], ok: 1)
+
+    [
+      file.join,
+      file.join("1", "2"),
+      new_chain.to_a,
+    ]
+  end
+
+  test_cases(File, Enumerator::Chain)
+}
+
+# singleton class should invalidate Type::CString assumption
+assert_equal 'foo', %q{
+  def define_singleton(str, define)
+    if define
+      # Wrap a C method frame to avoid exiting JIT code on defineclass
+      [nil].reverse_each do
+        class << str
+          def +(_)
+            "foo"
+          end
+        end
+      end
+    end
+    "bar"
+  end
+
+  def entry(define)
+    str = ""
+    # When `define` is false, #+ compiles to rb_str_plus() without a class guard.
+    # When the code is reused with `define` is true, the class of `str` is changed
+    # to a singleton class, so the block should be invalidated.
+    str + define_singleton(str, define)
+  end
+
+  entry(false)
+  entry(true)
+}
+
+assert_equal 'ok', %q{
+  def ok
+    :ok
+  end
+
+  def delegator(...)
+    ok(...)
+  end
+
+  def caller
+    send(:delegator)
+  end
+
+  caller
+}
+
+# test inlining of simple iseqs
+assert_equal '[:ok, :ok, :ok]', %q{
+  def identity(x) = x
+  def foo(x, _) = x
+  def bar(_, _, _, _, x) = x
+
+  def tests
+    [
+      identity(:ok),
+      foo(:ok, 2),
+      bar(1, 2, 3, 4, :ok),
+    ]
+  end
+
+  tests
+}
+
+# test inlining of simple iseqs with kwargs
+assert_equal '[:ok, :ok, :ok, :ok, :ok]', %q{
+  def optional_unused(x, opt: :not_ok) = x
+  def optional_used(x, opt: :ok) = opt
+  def required_unused(x, req:) = x
+  def required_used(x, req:) = req
+  def unknown(x) = x
+
+  def tests
+    [
+      optional_unused(:ok),
+      optional_used(:not_ok),
+      required_unused(:ok, req: :not_ok),
+      required_used(:not_ok, req: :ok),
+      begin unknown(:not_ok, unknown_kwarg: :not_ok) rescue ArgumentError; :ok end,
+    ]
+  end
+
+  tests
+}
+
+# test simple iseqs not eligible for inlining
+assert_equal '[:ok, :ok, :ok, :ok, :ok]', %q{
+  def identity(x) = x
+  def arg_splat(x, *args) = x
+  def kwarg_splat(x, **kwargs) = x
+  def block_arg(x, &blk) = x
+  def block_iseq(x) = x
+  def call_forwarding(...) = identity(...)
+
+  def tests
+    [
+      arg_splat(:ok),
+      kwarg_splat(:ok),
+      block_arg(:ok, &proc { :not_ok }),
+      block_iseq(:ok) { :not_ok },
+      call_forwarding(:ok),
+    ]
+  end
+
+  tests
+}
+
+# regression test for invalidating an empty block
+assert_equal '0', %q{
+  def foo = (* = 1).pred
+
+  foo # compile it
+
+  class Integer
+    def to_ary = [] # invalidate
+  end
+
+  foo # try again
+} unless rjit_enabled? # doesn't work on RJIT
+
+# test integer left shift with constant rhs
+assert_equal [0x80000000000, 'a+', :ok].inspect, %q{
+  def shift(val) = val << 43
+
+  def tests
+    int = shift(1)
+    str = shift("a")
+
+    Integer.define_method(:<<) { |_| :ok }
+    redef = shift(1)
+
+    [int, str, redef]
+  end
+
+  tests
+}
+
+# test integer left shift fusion followed by opt_getconstant_path
+assert_equal '33', %q{
+  def test(a)
+    (a << 5) | (Object; a)
+  end
+
+  test(1)
+}
+
+# test String#stebyte with arguments that need conversion
+assert_equal "abc", %q{
+  str = +"a00"
+  def change_bytes(str, one, two)
+    str.setbyte(one, "b".ord)
+    str.setbyte(2, two)
+  end
+
+  to_int_1 = Object.new
+  to_int_99 = Object.new
+  def to_int_1.to_int = 1
+  def to_int_99.to_int = 99
+
+  change_bytes(str, to_int_1, to_int_99)
+  str
+}
+
+# test --yjit-verify-ctx for arrays with a singleton class
+assert_equal "ok", %q{
+  class Array
+    def foo
+      self.singleton_class.define_method(:first) { :ok }
+      first
+    end
+  end
+
+  def test = [].foo
+
+  test
+}
+
+assert_equal '["raised", "Module", "Object"]', %q{
+  def foo(obj)
+    obj.superclass.name
+  end
+
+  ret = []
+
+  begin
+    foo(Class.allocate)
+  rescue TypeError
+    ret << 'raised'
+  end
+
+  ret += [foo(Class), foo(Class.new)]
+}
+
+# test TrueClass#=== before and after redefining TrueClass#==
+assert_equal '[[true, false, false], [true, true, false], [true, :error, :error]]', %q{
+  def true_eqq(x)
+    true === x
+  rescue NoMethodError
+    :error
+  end
+
+  def test
+    [
+      # first one is always true because rb_equal does object comparison before calling #==
+      true_eqq(true),
+      # these will use TrueClass#==
+      true_eqq(false),
+      true_eqq(:truthy),
+    ]
+  end
+
+  results = [test]
+
+  class TrueClass
+    def ==(x)
+      !x
+    end
+  end
+
+  results << test
+
+  class TrueClass
+    undef_method :==
+  end
+
+  results << test
+} unless rjit_enabled? # Not yet working on RJIT
+
+# test FalseClass#=== before and after redefining FalseClass#==
+assert_equal '[[true, false, false], [true, false, true], [true, :error, :error]]', %q{
+  def case_equal(x, y)
+    x === y
+  rescue NoMethodError
+    :error
+  end
+
+  def test
+    [
+      # first one is always true because rb_equal does object comparison before calling #==
+      case_equal(false, false),
+      # these will use #==
+      case_equal(false, true),
+      case_equal(false, nil),
+    ]
+  end
+
+  results = [test]
+
+  class FalseClass
+    def ==(x)
+      !x
+    end
+  end
+
+  results << test
+
+  class FalseClass
+    undef_method :==
+  end
+
+  results << test
+} unless rjit_enabled? # Not yet working on RJIT
+
+# test NilClass#=== before and after redefining NilClass#==
+assert_equal '[[true, false, false], [true, false, true], [true, :error, :error]]', %q{
+  def case_equal(x, y)
+    x === y
+  rescue NoMethodError
+    :error
+  end
+
+  def test
+    [
+      # first one is always true because rb_equal does object comparison before calling #==
+      case_equal(nil, nil),
+      # these will use #==
+      case_equal(nil, true),
+      case_equal(nil, false),
+    ]
+  end
+
+  results = [test]
+
+  class NilClass
+    def ==(x)
+      !x
+    end
+  end
+
+  results << test
+
+  class NilClass
+    undef_method :==
+  end
+
+  results << test
+} unless rjit_enabled? # Not yet working on RJIT
+
+# test struct accessors fire c_call events
+assert_equal '[[:c_call, :x=], [:c_call, :x]]', %q{
+  c = Struct.new(:x)
+  obj = c.new
+
+  events = []
+  TracePoint.new(:c_call) do
+    events << [_1.event, _1.method_id]
+  end.enable do
+    obj.x = 100
+    obj.x
+  end
+
+  events
+}
+
+# regression test for splatting empty array
+assert_equal '1', %q{
+  def callee(foo) = foo
+
+  def test_body(args) = callee(1, *args)
+
+  test_body([])
+  array = Array.new(100)
+  array.clear
+  test_body(array)
+}
+
+# regression test for splatting empty array to cfunc
+assert_normal_exit %q{
+  def test_body(args) = Array(1, *args)
+
+  test_body([])
+  0x100.times do
+    array = Array.new(100)
+    array.clear
+    test_body(array)
+  end
+}
+
+# compiling code shouldn't emit warnings as it may call into more Ruby code
+assert_equal 'ok', <<~'RUBY'
+  # [Bug #20522]
+  $VERBOSE = true
+  Warning[:performance] = true
+
+  module StrictWarnings
+    def warn(msg, **)
+      raise msg
+    end
+  end
+  Warning.singleton_class.prepend(StrictWarnings)
+
+  class A
+    def compiled_method(is_private)
+      @some_ivar = is_private
+    end
+  end
+
+  shape_max_variations = 8
+  if defined?(RubyVM::Shape::SHAPE_MAX_VARIATIONS) && RubyVM::Shape::SHAPE_MAX_VARIATIONS != shape_max_variations
+    raise "Expected SHAPE_MAX_VARIATIONS to be #{shape_max_variations}, got: #{RubyVM::Shape::SHAPE_MAX_VARIATIONS}"
+  end
+
+  100.times do |i|
+    klass = Class.new(A)
+    (shape_max_variations - 1).times do |j|
+      obj = klass.new
+      obj.instance_variable_set("@base_#{i}", 42)
+      obj.instance_variable_set("@ivar_#{j}", 42)
+    end
+    obj = klass.new
+    obj.instance_variable_set("@base_#{i}", 42)
+    begin
+      obj.compiled_method(true)
+    rescue
+      # expected
+    end
+  end
+
+  :ok
+RUBY
+
+assert_equal 'ok', <<~'RUBY'
+  class MyRelation
+    def callee(...)
+      :ok
+    end
+
+    def uncached(...)
+      callee(...)
+    end
+
+    def takes_block(&block)
+      # push blockhandler
+      uncached(&block) # CI1
+    end
+  end
+
+  relation = MyRelation.new
+  relation.takes_block { }
+RUBY
+
+assert_equal 'ok', <<~'RUBY'
+  def _exec_scope(...)
+    instance_exec(...)
+  end
+
+  def ok args, body
+    _exec_scope(*args, &body)
+  end
+
+  ok([], -> { "ok" })
+RUBY
+
+assert_equal 'ok', <<~'RUBY'
+  def _exec_scope(...)
+    instance_exec(...)
+  end
+
+  def ok args, body
+    _exec_scope(*args, &body)
+  end
+
+  ok(["ok"], ->(x) { x })
+RUBY
+
+assert_equal 'ok', <<~'RUBY'
+def baz(a, b)
+  a + b
+end
+
+def bar(...)
+  baz(...)
+end
+
+def foo(a, ...)
+  bar(a, ...)
+end
+
+def test
+  foo("o", "k")
+end
+
+test
+RUBY
+
+# opt_newarray_send pack/buffer
+assert_equal '[true, true]', <<~'RUBY'
+  def pack
+    v = 1.23
+    [v, v*2, v*3].pack("E*").unpack("E*") == [v, v*2, v*3]
+  end
+
+  def with_buffer
+    v = 4.56
+    b = +"x"
+    [v, v*2, v*3].pack("E*", buffer: b)
+    b[1..].unpack("E*") == [v, v*2, v*3]
+  end
+
+  [pack, with_buffer]
+RUBY
+
+# String#[] / String#slice
+assert_equal 'ok', <<~'RUBY'
+  def error(klass)
+    yield
+  rescue klass
+    true
+  end
+
+  def test
+    str = "こんにちは"
+    substr = "にち"
+    failures = []
+
+    # Use many small statements to keep context for each slice call smaller than MAX_CTX_TEMPS
+
+    str[1] == "ん" && str.slice(4) == "は" || failures << :index
+    str[5].nil? && str.slice(5).nil? || failures << :index_end
+
+    str[1, 2] == "んに" && str.slice(2, 1) == "に" || failures << :beg_len
+    str[5, 1] == "" && str.slice(5, 1) == "" || failures << :beg_len_end
+
+    str[1..2] == "んに" && str.slice(2..2) == "に" || failures << :range
+
+    str[/に./] == "にち" && str.slice(/に./) == "にち" || failures << :regexp
+
+    str[/に./, 0] == "にち" && str.slice(/に./, 0) == "にち" || failures << :regexp_cap0
+
+    str[/に(.)/, 1] == "ち" && str.slice(/に(.)/, 1) == "ち" || failures << :regexp_cap1
+
+    str[substr] == substr && str.slice(substr) == substr || failures << :substr
+
+    error(TypeError) { str[Object.new] } && error(TypeError) { str.slice(Object.new, 1) } || failures << :type_error
+    error(RangeError) { str[Float::INFINITY] } && error(RangeError) { str.slice(Float::INFINITY) } || failures << :range_error
+
+    return "ok" if failures.empty?
+    {failures: failures}
+  end
+
+  test
+RUBY
+
+# opt_duparray_send :include?
+assert_equal '[true, false]', <<~'RUBY'
+  def test(x)
+    [:a, :b].include?(x)
+  end
+
+  [
+    test(:b),
+    test(:c),
+  ]
+RUBY
+
+# opt_newarray_send :include?
+assert_equal '[true, false]', <<~'RUBY'
+  def test(x)
+    [Object.new, :a, :b].include?(x.to_sym)
+  end
+
+  [
+    test("b"),
+    test("c"),
+  ]
+RUBY
+
+# YARV: swap and opt_reverse
+assert_equal '["x", "Y", "c", "A", "t", "A", "b", "C", "d"]', <<~'RUBY'
+  class Swap
+    def initialize(s)
+      @a, @b, @c, @d = s.split("")
+    end
+
+    def swap
+      a, b = @a, @b
+      b = b.upcase
+      @a, @b = a, b
+    end
+
+    def reverse_odd
+      a, b, c = @a, @b, @c
+      b = b.upcase
+      @a, @b, @c = a, b, c
+    end
+
+    def reverse_even
+      a, b, c, d = @a, @b, @c, @d
+      a = a.upcase
+      c = c.upcase
+      @a, @b, @c, @d = a, b, c, d
+    end
+  end
+
+  Swap.new("xy").swap + Swap.new("cat").reverse_odd + Swap.new("abcd").reverse_even
+RUBY
diff --git a/bootstraptest/test_yjit_rust_port.rb b/bootstraptest/test_yjit_rust_port.rb
new file mode 100644
index 0000000000..e399e0e49e
--- /dev/null
+++ b/bootstraptest/test_yjit_rust_port.rb
@@ -0,0 +1,422 @@
+# Simple tests that we know we can pass
+# To keep track of what we got working during the Rust port
+# And avoid breaking/losing functionality
+#
+# Say "Thread" here to dodge WASM CI check. We use ractors here
+# which WASM doesn't support and it only greps for "Thread".
+
+# Test for opt_mod
+assert_equal '2', %q{
+  def mod(a, b)
+    a % b
+  end
+
+  mod(7, 5)
+  mod(7, 5)
+}
+
+# Test for opt_mult
+assert_equal '12', %q{
+  def mult(a, b)
+    a * b
+  end
+
+  mult(6, 2)
+  mult(6, 2)
+}
+
+# Test for opt_div
+assert_equal '3', %q{
+  def div(a, b)
+    a / b
+  end
+
+  div(6, 2)
+  div(6, 2)
+}
+
+assert_equal '5', %q{
+  def plus(a, b)
+    a + b
+  end
+
+  plus(3, 2)
+}
+
+assert_equal '1', %q{
+  def foo(a, b)
+    a - b
+  end
+
+  foo(3, 2)
+}
+
+assert_equal 'true', %q{
+  def foo(a, b)
+    a < b
+  end
+
+  foo(2, 3)
+}
+
+# Bitwise left shift
+assert_equal '4', %q{
+  def foo(a, b)
+    1 << 2
+  end
+
+  foo(1, 2)
+}
+
+assert_equal '-7', %q{
+  def foo(a, b)
+    -7
+  end
+
+  foo(1, 2)
+}
+
+# Putstring
+assert_equal 'foo', %q{
+  def foo(a, b)
+    "foo"
+  end
+
+  foo(1, 2)
+}
+
+assert_equal '-6', %q{
+  def foo(a, b)
+    a + -7
+  end
+
+  foo(1, 2)
+}
+
+assert_equal 'true', %q{
+  def foo(a, b)
+    a == b
+  end
+
+  foo(3, 3)
+}
+
+assert_equal 'true', %q{
+  def foo(a, b)
+    a < b
+  end
+
+  foo(3, 5)
+}
+
+assert_equal '777', %q{
+  def foo(a)
+    if a
+      777
+    else
+      333
+    end
+  end
+
+  foo(true)
+}
+
+assert_equal '5', %q{
+  def foo(a, b)
+    while a < b
+      a += 1
+    end
+    a
+  end
+
+  foo(1, 5)
+}
+
+# opt_aref
+assert_equal '2', %q{
+  def foo(a, b)
+    a[b]
+  end
+
+  foo([0, 1, 2], 2)
+}
+
+# Simple function calls with 0, 1, 2 arguments
+assert_equal '-2', %q{
+  def bar()
+    -2
+  end
+
+  def foo(a, b)
+    bar()
+  end
+
+  foo(3, 2)
+}
+assert_equal '2', %q{
+  def bar(a)
+    a
+  end
+
+  def foo(a, b)
+    bar(b)
+  end
+
+  foo(3, 2)
+}
+assert_equal '1', %q{
+  def bar(a, b)
+    a - b
+  end
+
+  def foo(a, b)
+    bar(a, b)
+  end
+
+  foo(3, 2)
+}
+
+# Regression test for assembler bug
+assert_equal '1', %q{
+  def check_index(index)
+    if 0x40000000 < index
+        return -1
+    end
+    1
+  end
+
+  check_index 2
+}
+
+# Setivar test
+assert_equal '2', %q{
+  class Klass
+    attr_accessor :a
+
+    def set()
+        @a = 2
+    end
+
+    def get()
+        @a
+    end
+  end
+
+  o = Klass.new
+  o.set()
+  o.a
+}
+
+# Regression for putobject bug
+assert_equal '1.5', %q{
+  def foo(x)
+    x
+  end
+
+  def bar
+    foo(1.5)
+  end
+
+  bar()
+}
+
+# Getivar with an extended ivar table
+assert_equal '3', %q{
+  class Foo
+    def initialize
+      @x1 = 1
+      @x2 = 1
+      @x3 = 1
+      @x4 = 3
+    end
+
+    def bar
+      @x4
+    end
+  end
+
+  f = Foo.new
+  f.bar
+}
+
+assert_equal 'true', %q{
+  x = [[false, true]]
+  for i, j in x
+    ;
+  end
+  j
+}
+
+# Regression for getivar
+assert_equal '[nil]', %q{
+  [TrueClass].each do |klass|
+    klass.class_eval("def foo = @foo")
+  end
+
+  [true].map do |instance|
+    instance.foo
+  end
+}
+
+# Regression for send
+assert_equal 'ok', %q{
+  def bar(baz: 2)
+    baz
+  end
+
+  def foo
+    bar(1, baz: 123)
+  end
+
+  begin
+    foo
+    foo
+  rescue ArgumentError => e
+    print "ok"
+  end
+}
+
+# Array access regression test
+assert_equal '[0, 1, 2, 3, 4, 5]', %q{
+  def expandarray_useless_splat
+    arr = [0, 1, 2, 3, 4, 5]
+    a, * = arr
+  end
+
+  expandarray_useless_splat
+}
+
+# Make sure we're correctly reading RStruct's as.ary union for embedded RStructs
+assert_equal '3,12', %q{
+  pt_struct = Struct.new(:x, :y)
+  p = pt_struct.new(3, 12)
+  def pt_inspect(pt)
+    "#{pt.x},#{pt.y}"
+  end
+
+  # Make sure pt_inspect is JITted
+  10.times { pt_inspect(p) }
+
+  # Make sure it's returning '3,12' instead of e.g. '3,false'
+  pt_inspect(p)
+}
+
+assert_equal '2', %q{
+  def foo(s)
+    s.foo
+  end
+
+  S = Struct.new(:foo)
+  foo(S.new(1))
+  foo(S.new(2))
+}
+
+# Try to compile new method while OOM
+assert_equal 'ok', %q{
+  def foo
+    :ok
+  end
+
+  RubyVM::YJIT.simulate_oom! if defined?(RubyVM::YJIT)
+
+  foo
+}
+
+# test hitting a branch stub when out of memory
+assert_equal 'ok', %q{
+  def nimai(jita)
+    if jita
+      :ng
+    else
+      :ok
+    end
+  end
+
+  nimai(true)
+  nimai(true)
+
+  RubyVM::YJIT.simulate_oom! if defined?(RubyVM::YJIT)
+
+  nimai(false)
+}
+
+# Ractor.current returns a current ractor
+assert_equal 'Ractor', %q{
+  Ractor.current.class
+}
+
+# Ractor.new returns new Ractor
+assert_equal 'Ractor', %q{
+  Ractor.new{}.class
+}
+
+# Ractor.allocate is not supported
+assert_equal "[:ok, :ok]", %q{
+  rs = []
+  begin
+    Ractor.allocate
+  rescue => e
+    rs << :ok if e.message == 'allocator undefined for Ractor'
+  end
+
+  begin
+    Ractor.new{}.dup
+  rescue
+    rs << :ok if e.message == 'allocator undefined for Ractor'
+  end
+
+  rs
+}
+
+# A return value of a Ractor block will be a message from the Ractor.
+assert_equal 'ok', %q{
+  # join
+  r = Ractor.new do
+    'ok'
+  end
+  r.take
+}
+
+# Passed arguments to Ractor.new will be a block parameter
+# The values are passed with Ractor-communication pass.
+assert_equal 'ok', %q{
+  # ping-pong with arg
+  r = Ractor.new 'ok' do |msg|
+    msg
+  end
+  r.take
+}
+
+# Pass multiple arguments to Ractor.new
+assert_equal 'ok', %q{
+  # ping-pong with two args
+  r =  Ractor.new 'ping', 'pong' do |msg, msg2|
+    [msg, msg2]
+  end
+  'ok' if r.take == ['ping', 'pong']
+}
+
+# Ractor#send passes an object with copy to a Ractor
+# and Ractor.receive in the Ractor block can receive the passed value.
+assert_equal 'ok', %q{
+  r = Ractor.new do
+    msg = Ractor.receive
+  end
+  r.send 'ok'
+  r.take
+}
+
+assert_equal '[1, 2, 3]', %q{
+  def foo(arr)
+    arr << 1
+    arr << 2
+    arr << 3
+    arr
+  end
+
+  def bar()
+    foo([])
+  end
+
+  bar()
+}
diff --git a/builtin.c b/builtin.c
index 21fff95650..3bde2408f8 100644
--- a/builtin.c
+++ b/builtin.c
@@ -3,15 +3,15 @@
 #include "iseq.h"
 #include "builtin.h"
 
-#ifdef CROSS_COMPILING
+#include "builtin_binary.inc"
+
+#ifndef BUILTIN_BINARY_SIZE
 
-#define INCLUDED_BY_BUILTIN_C 1
+#define BUILTIN_LOADED(feature_name, iseq) ((void)0)
 #include "mini_builtin.c"
 
 #else
 
-#include "builtin_binary.inc"
-
 static const unsigned char *
 bin4feature(const struct builtin_binary *bb, const char *feature, size_t *psize)
 {
@@ -39,15 +39,15 @@ rb_load_with_builtin_functions(const char *feature_name, const struct rb_builtin
     size_t size;
     const unsigned char *bin = builtin_lookup(feature_name, &size);
     if (! bin) {
-        rb_bug("builtin_lookup: can not find %s\n", feature_name);
+        rb_bug("builtin_lookup: can not find %s", feature_name);
     }
 
     // load binary
     rb_vm_t *vm = GET_VM();
     if (vm->builtin_function_table != NULL) rb_bug("vm->builtin_function_table should be NULL.");
     vm->builtin_function_table = table;
-    vm->builtin_inline_index = 0;
     const rb_iseq_t *iseq = rb_iseq_ibf_load_bytes((const char *)bin, size);
+    ASSUME(iseq); // otherwise an exception should have raised
     vm->builtin_function_table = NULL;
 
     // exec
@@ -57,6 +57,12 @@ rb_load_with_builtin_functions(const char *feature_name, const struct rb_builtin
 #endif
 
 void
+rb_free_loaded_builtin_table(void)
+{
+    // do nothing
+}
+
+void
 Init_builtin(void)
 {
     // nothing
diff --git a/builtin.h b/builtin.h
index 96339afdb5..fd1c4c307f 100644
--- a/builtin.h
+++ b/builtin.h
@@ -11,17 +11,13 @@ struct rb_builtin_function {
     // for load
     const int index;
     const char * const name;
-
-    // for jit
-    void (*compiler)(FILE *, long, unsigned, bool);
 };
 
-#define RB_BUILTIN_FUNCTION(_i, _name, _fname, _arity, _compiler) {\
-  .name = #_name, \
-  .func_ptr = (void *)_fname, \
+#define RB_BUILTIN_FUNCTION(_i, _name, _fname, _arity) {\
+  .name = _i < 0 ? NULL : #_name, \
+  .func_ptr = (void *)(uintptr_t)_fname, \
   .argc = _arity, \
   .index = _i, \
-  .compiler = _compiler, \
 }
 
 void rb_load_with_builtin_functions(const char *feature_name, const struct rb_builtin_function *table);
@@ -33,28 +29,65 @@ typedef struct rb_execution_context_struct rb_execution_context_t;
 
 /* The following code is generated by the following Ruby script:
 
+typedef = proc {|i, args|
+  "typedef VALUE (*rb_builtin_arity#{i}_function_type)(rb_execution_context_t *ec, VALUE self#{args});"
+}
+puts typedef[0, ""]
+(1..15).each {|i|
+  puts typedef[i, ",\n        " + (0...i).map{"VALUE"}.join(", ")]
+}
 16.times{|i|
-  args = (i > 0 ? ', ' : '') + (0...i).map{"VALUE"}.join(', ')
-  puts "static inline void rb_builtin_function_check_arity#{i}(VALUE (*f)(rb_execution_context_t *ec, VALUE self#{args})){}"
+  puts "static inline void rb_builtin_function_check_arity#{i}(rb_builtin_arity#{i}_function_type f){}"
 }
 */
 
-static inline void rb_builtin_function_check_arity0(VALUE (*f)(rb_execution_context_t *ec, VALUE self)){}
-static inline void rb_builtin_function_check_arity1(VALUE (*f)(rb_execution_context_t *ec, VALUE self, VALUE)){}
-static inline void rb_builtin_function_check_arity2(VALUE (*f)(rb_execution_context_t *ec, VALUE self, VALUE, VALUE)){}
-static inline void rb_builtin_function_check_arity3(VALUE (*f)(rb_execution_context_t *ec, VALUE self, VALUE, VALUE, VALUE)){}
-static inline void rb_builtin_function_check_arity4(VALUE (*f)(rb_execution_context_t *ec, VALUE self, VALUE, VALUE, VALUE, VALUE)){}
-static inline void rb_builtin_function_check_arity5(VALUE (*f)(rb_execution_context_t *ec, VALUE self, VALUE, VALUE, VALUE, VALUE, VALUE)){}
-static inline void rb_builtin_function_check_arity6(VALUE (*f)(rb_execution_context_t *ec, VALUE self, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE)){}
-static inline void rb_builtin_function_check_arity7(VALUE (*f)(rb_execution_context_t *ec, VALUE self, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE)){}
-static inline void rb_builtin_function_check_arity8(VALUE (*f)(rb_execution_context_t *ec, VALUE self, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE)){}
-static inline void rb_builtin_function_check_arity9(VALUE (*f)(rb_execution_context_t *ec, VALUE self, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE)){}
-static inline void rb_builtin_function_check_arity10(VALUE (*f)(rb_execution_context_t *ec, VALUE self, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE)){}
-static inline void rb_builtin_function_check_arity11(VALUE (*f)(rb_execution_context_t *ec, VALUE self, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE)){}
-static inline void rb_builtin_function_check_arity12(VALUE (*f)(rb_execution_context_t *ec, VALUE self, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE)){}
-static inline void rb_builtin_function_check_arity13(VALUE (*f)(rb_execution_context_t *ec, VALUE self, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE)){}
-static inline void rb_builtin_function_check_arity14(VALUE (*f)(rb_execution_context_t *ec, VALUE self, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE)){}
-static inline void rb_builtin_function_check_arity15(VALUE (*f)(rb_execution_context_t *ec, VALUE self, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE)){}
+typedef VALUE (*rb_builtin_arity0_function_type)(rb_execution_context_t *ec, VALUE self);
+typedef VALUE (*rb_builtin_arity1_function_type)(rb_execution_context_t *ec, VALUE self,
+        VALUE);
+typedef VALUE (*rb_builtin_arity2_function_type)(rb_execution_context_t *ec, VALUE self,
+        VALUE, VALUE);
+typedef VALUE (*rb_builtin_arity3_function_type)(rb_execution_context_t *ec, VALUE self,
+        VALUE, VALUE, VALUE);
+typedef VALUE (*rb_builtin_arity4_function_type)(rb_execution_context_t *ec, VALUE self,
+        VALUE, VALUE, VALUE, VALUE);
+typedef VALUE (*rb_builtin_arity5_function_type)(rb_execution_context_t *ec, VALUE self,
+        VALUE, VALUE, VALUE, VALUE, VALUE);
+typedef VALUE (*rb_builtin_arity6_function_type)(rb_execution_context_t *ec, VALUE self,
+        VALUE, VALUE, VALUE, VALUE, VALUE, VALUE);
+typedef VALUE (*rb_builtin_arity7_function_type)(rb_execution_context_t *ec, VALUE self,
+        VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE);
+typedef VALUE (*rb_builtin_arity8_function_type)(rb_execution_context_t *ec, VALUE self,
+        VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE);
+typedef VALUE (*rb_builtin_arity9_function_type)(rb_execution_context_t *ec, VALUE self,
+        VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE);
+typedef VALUE (*rb_builtin_arity10_function_type)(rb_execution_context_t *ec, VALUE self,
+        VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE);
+typedef VALUE (*rb_builtin_arity11_function_type)(rb_execution_context_t *ec, VALUE self,
+        VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE);
+typedef VALUE (*rb_builtin_arity12_function_type)(rb_execution_context_t *ec, VALUE self,
+        VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE);
+typedef VALUE (*rb_builtin_arity13_function_type)(rb_execution_context_t *ec, VALUE self,
+        VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE);
+typedef VALUE (*rb_builtin_arity14_function_type)(rb_execution_context_t *ec, VALUE self,
+        VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE);
+typedef VALUE (*rb_builtin_arity15_function_type)(rb_execution_context_t *ec, VALUE self,
+        VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE, VALUE);
+static inline void rb_builtin_function_check_arity0(rb_builtin_arity0_function_type f){}
+static inline void rb_builtin_function_check_arity1(rb_builtin_arity1_function_type f){}
+static inline void rb_builtin_function_check_arity2(rb_builtin_arity2_function_type f){}
+static inline void rb_builtin_function_check_arity3(rb_builtin_arity3_function_type f){}
+static inline void rb_builtin_function_check_arity4(rb_builtin_arity4_function_type f){}
+static inline void rb_builtin_function_check_arity5(rb_builtin_arity5_function_type f){}
+static inline void rb_builtin_function_check_arity6(rb_builtin_arity6_function_type f){}
+static inline void rb_builtin_function_check_arity7(rb_builtin_arity7_function_type f){}
+static inline void rb_builtin_function_check_arity8(rb_builtin_arity8_function_type f){}
+static inline void rb_builtin_function_check_arity9(rb_builtin_arity9_function_type f){}
+static inline void rb_builtin_function_check_arity10(rb_builtin_arity10_function_type f){}
+static inline void rb_builtin_function_check_arity11(rb_builtin_arity11_function_type f){}
+static inline void rb_builtin_function_check_arity12(rb_builtin_arity12_function_type f){}
+static inline void rb_builtin_function_check_arity13(rb_builtin_arity13_function_type f){}
+static inline void rb_builtin_function_check_arity14(rb_builtin_arity14_function_type f){}
+static inline void rb_builtin_function_check_arity15(rb_builtin_arity15_function_type f){}
 
 PUREFUNC(VALUE rb_vm_lvar_exposed(rb_execution_context_t *ec, int index));
 VALUE rb_vm_lvar_exposed(rb_execution_context_t *ec, int index);
@@ -73,6 +106,14 @@ rb_vm_lvar(rb_execution_context_t *ec, int index)
 #endif
 }
 
+static inline VALUE
+rb_builtin_basic_definition_p(rb_execution_context_t *ec, VALUE klass, VALUE id_sym)
+{
+    return rb_method_basic_definition_p(klass, rb_sym2id(id_sym)) ? Qtrue : Qfalse;
+}
+
+#define LOCAL_PTR(local) local ## __ptr
+
 // dump/load
 
 struct builtin_binary {
diff --git a/ccan/check_type/check_type.h b/ccan/check_type/check_type.h
index e795ad71d0..659e1a5a83 100644
--- a/ccan/check_type/check_type.h
+++ b/ccan/check_type/check_type.h
@@ -44,7 +44,7 @@
  *		 ((encl_type *)						\
  *		  ((char *)(mbr_ptr) - offsetof(enclosing_type, mbr))))
  */
-#if HAVE_TYPEOF
+#if defined(HAVE_TYPEOF) && HAVE_TYPEOF
 #define ccan_check_type(expr, type)			\
 	((typeof(expr) *)0 != (type *)0)
 
diff --git a/ccan/container_of/container_of.h b/ccan/container_of/container_of.h
index b30c347d57..872bb6ea6e 100644
--- a/ccan/container_of/container_of.h
+++ b/ccan/container_of/container_of.h
@@ -112,7 +112,7 @@ static inline char *container_of_or_null_(void *member_ptr, size_t offset)
  *		return i;
  *	}
  */
-#if HAVE_TYPEOF
+#if defined(HAVE_TYPEOF) && HAVE_TYPEOF
 #define ccan_container_of_var(member_ptr, container_var, member) \
 	ccan_container_of(member_ptr, typeof(*container_var), member)
 #else
@@ -131,7 +131,7 @@ static inline char *container_of_or_null_(void *member_ptr, size_t offset)
  * structure memory layout.
  *
  */
-#if HAVE_TYPEOF
+#if defined(HAVE_TYPEOF) && HAVE_TYPEOF
 #define ccan_container_off_var(var, member)		\
 	ccan_container_off(typeof(*var), member)
 #else
diff --git a/ccan/list/list.h b/ccan/list/list.h
index 91787bfdb3..bf692a6937 100644
--- a/ccan/list/list.h
+++ b/ccan/list/list.h
@@ -635,14 +635,16 @@ static inline void ccan_list_prepend_list_(struct ccan_list_head *to,
 
 /* internal macros, do not use directly */
 #define ccan_list_for_each_off_dir_(h, i, off, dir)				\
-	for (i = ccan_list_node_to_off_(ccan_list_debug(h, CCAN_LIST_LOC)->n.dir,	\
+	for (i = 0, \
+	     i = ccan_list_node_to_off_(ccan_list_debug(h, CCAN_LIST_LOC)->n.dir, \
 				   (off));				\
 	ccan_list_node_from_off_((void *)i, (off)) != &(h)->n;		\
 	i = ccan_list_node_to_off_(ccan_list_node_from_off_((void *)i, (off))->dir, \
 			      (off)))
 
 #define ccan_list_for_each_safe_off_dir_(h, i, nxt, off, dir)		\
-	for (i = ccan_list_node_to_off_(ccan_list_debug(h, CCAN_LIST_LOC)->n.dir,	\
+	for (i = 0, \
+	     i = ccan_list_node_to_off_(ccan_list_debug(h, CCAN_LIST_LOC)->n.dir, \
 				   (off)),				\
 	nxt = ccan_list_node_to_off_(ccan_list_node_from_off_(i, (off))->dir,	\
 				(off));					\
@@ -770,7 +772,7 @@ static inline struct ccan_list_node *ccan_list_node_from_off_(void *ptr, size_t
 	(ccan_container_off_var(var, member) +		\
 	 ccan_check_type(var->member, struct ccan_list_node))
 
-#if HAVE_TYPEOF
+#if defined(HAVE_TYPEOF) && HAVE_TYPEOF
 #define ccan_list_typeof(var) typeof(var)
 #else
 #define ccan_list_typeof(var) void *
diff --git a/class.c b/class.c
index 39899d5e05..b39e693837 100644
--- a/class.c
+++ b/class.c
@@ -29,8 +29,51 @@
 #include "internal/variable.h"
 #include "ruby/st.h"
 #include "vm_core.h"
+#include "yjit.h"
 
-#define id_attached id__attached__
+/* Flags of T_CLASS
+ *
+ * 0:    RCLASS_IS_ROOT
+ *           The class has been added to the VM roots. Will always be marked and pinned.
+ *           This is done for classes defined from C to allow storing them in global variables.
+ * 1:    RUBY_FL_SINGLETON
+ *           This class is a singleton class.
+ * 2:    RCLASS_SUPERCLASSES_INCLUDE_SELF
+ *           The RCLASS_SUPERCLASSES contains the class as the last element.
+ *           This means that this class owns the RCLASS_SUPERCLASSES list.
+ * if !SHAPE_IN_BASIC_FLAGS
+ * 4-19: SHAPE_FLAG_MASK
+ *           Shape ID for the class.
+ * endif
+ */
+
+/* Flags of T_ICLASS
+ *
+ * 0:    RICLASS_IS_ORIGIN
+ * 3:    RICLASS_ORIGIN_SHARED_MTBL
+ *           The T_ICLASS does not own the method table.
+ * if !SHAPE_IN_BASIC_FLAGS
+ * 4-19: SHAPE_FLAG_MASK
+ *           Shape ID. This is set but not used.
+ * endif
+ */
+
+/* Flags of T_MODULE
+ *
+ * 0:    RCLASS_IS_ROOT
+ *           The class has been added to the VM roots. Will always be marked and pinned.
+ *           This is done for classes defined from C to allow storing them in global variables.
+ * 1:    RMODULE_ALLOCATED_BUT_NOT_INITIALIZED
+ *           Module has not been initialized.
+ * 2:    RCLASS_SUPERCLASSES_INCLUDE_SELF
+ *           See RCLASS_SUPERCLASSES_INCLUDE_SELF in T_CLASS.
+ * 3:    RMODULE_IS_REFINEMENT
+ *           Module is used for refinements.
+ * if !SHAPE_IN_BASIC_FLAGS
+ * 4-19: SHAPE_FLAG_MASK
+ *           Shape ID for the module.
+ * endif
+ */
 
 #define METACLASS_OF(k) RBASIC(k)->klass
 #define SET_METACLASS_OF(k, cls) RBASIC_SET_CLASS(k, cls)
@@ -64,7 +107,7 @@ push_subclass_entry_to_list(VALUE super, VALUE klass)
 void
 rb_class_subclass_add(VALUE super, VALUE klass)
 {
-    if (super && super != Qundef) {
+    if (super && !UNDEF_P(super)) {
         rb_subclass_entry_t *entry = push_subclass_entry_to_list(super, klass);
         RCLASS_SUBCLASS_ENTRY(klass) = entry;
     }
@@ -106,7 +149,7 @@ rb_class_remove_from_super_subclasses(VALUE klass)
             next->prev = prev;
         }
 
-	xfree(entry);
+        xfree(entry);
     }
 
     RCLASS_SUBCLASS_ENTRY(klass) = NULL;
@@ -123,11 +166,11 @@ rb_class_remove_from_module_subclasses(VALUE klass)
         if (prev) {
             prev->next = next;
         }
-	if (next) {
+        if (next) {
             next->prev = prev;
-	}
+        }
 
-	xfree(entry);
+        xfree(entry);
     }
 
     RCLASS_MODULE_SUBCLASS_ENTRY(klass) = NULL;
@@ -148,11 +191,11 @@ rb_class_foreach_subclass(VALUE klass, void (*f)(VALUE, VALUE), VALUE arg)
     /* do not be tempted to simplify this loop into a for loop, the order of
        operations is important here if `f` modifies the linked list */
     while (cur) {
-	VALUE curklass = cur->klass;
-	cur = cur->next;
+        VALUE curklass = cur->klass;
+        cur = cur->next;
         // do not trigger GC during f, otherwise the cur will become
         // a dangling pointer if the subclass is collected
-	f(curklass, arg);
+        f(curklass, arg);
     }
 }
 
@@ -183,40 +226,27 @@ rb_class_detach_module_subclasses(VALUE klass)
 /**
  * Allocates a struct RClass for a new class.
  *
- * \param flags     initial value for basic.flags of the returned class.
- * \param klass     the class of the returned class.
- * \return          an uninitialized Class object.
- * \pre  \p klass must refer \c Class class or an ancestor of Class.
- * \pre  \code (flags | T_CLASS) != 0  \endcode
- * \post the returned class can safely be \c #initialize 'd.
+ * @param flags     initial value for basic.flags of the returned class.
+ * @param klass     the class of the returned class.
+ * @return          an uninitialized Class object.
+ * @pre  `klass` must refer `Class` class or an ancestor of Class.
+ * @pre  `(flags | T_CLASS) != 0`
+ * @post the returned class can safely be `#initialize` 'd.
  *
- * \note this function is not Class#allocate.
+ * @note this function is not Class#allocate.
  */
 static VALUE
 class_alloc(VALUE flags, VALUE klass)
 {
-    size_t alloc_size = sizeof(struct RClass);
-
-#if USE_RVARGC
-    alloc_size += sizeof(rb_classext_t);
-#endif
+    size_t alloc_size = sizeof(struct RClass) + sizeof(rb_classext_t);
 
     flags &= T_MASK;
-    flags |= FL_PROMOTED1 /* start from age == 2 */;
     if (RGENGC_WB_PROTECTED_CLASS) flags |= FL_WB_PROTECTED;
-    RVARGC_NEWOBJ_OF(obj, struct RClass, klass, flags, alloc_size);
+    NEWOBJ_OF(obj, struct RClass, klass, flags, alloc_size, 0);
 
-#if USE_RVARGC
     memset(RCLASS_EXT(obj), 0, sizeof(rb_classext_t));
-# if SIZEOF_SERIAL_T != SIZEOF_VALUE
-    RCLASS(obj)->class_serial_ptr = ZALLOC(rb_serial_t);
-# endif
-#else
-    obj->ptr = ZALLOC(rb_classext_t);
-#endif
 
     /* ZALLOC
-      RCLASS_IV_TBL(obj) = 0;
       RCLASS_CONST_TBL(obj) = 0;
       RCLASS_M_TBL(obj) = 0;
       RCLASS_IV_INDEX_TBL(obj) = 0;
@@ -226,9 +256,8 @@ class_alloc(VALUE flags, VALUE klass)
       RCLASS_MODULE_SUBCLASSES(obj) = NULL;
      */
     RCLASS_SET_ORIGIN((VALUE)obj, (VALUE)obj);
-    RCLASS_SERIAL(obj) = rb_next_class_serial();
     RB_OBJ_WRITE(obj, &RCLASS_REFINED_CLASS(obj), Qnil);
-    RCLASS_ALLOCATOR(obj) = 0;
+    RCLASS_SET_ALLOCATOR((VALUE)obj, 0);
 
     return (VALUE)obj;
 }
@@ -239,14 +268,14 @@ RCLASS_M_TBL_INIT(VALUE c)
     RCLASS_M_TBL(c) = rb_id_table_create(0);
 }
 
-/*!
+/**
  * A utility function that wraps class_alloc.
  *
  * allocates a class and initializes safely.
- * \param super     a class from which the new class derives.
- * \return          a class object.
- * \pre  \a super must be a class.
- * \post the metaclass of the new class is Class.
+ * @param super     a class from which the new class derives.
+ * @return          a class object.
+ * @pre  `super` must be a class.
+ * @post the metaclass of the new class is Class.
  */
 VALUE
 rb_class_boot(VALUE super)
@@ -282,7 +311,7 @@ rb_class_update_superclasses(VALUE klass)
     VALUE super = RCLASS_SUPER(klass);
 
     if (!RB_TYPE_P(klass, T_CLASS)) return;
-    if (super == Qundef) return;
+    if (UNDEF_P(super)) return;
 
     // If the superclass array is already built
     if (RCLASS_SUPERCLASSES(klass))
@@ -316,13 +345,13 @@ rb_check_inheritable(VALUE super)
 {
     if (!RB_TYPE_P(super, T_CLASS)) {
         rb_raise(rb_eTypeError, "superclass must be an instance of Class (given an instance of %"PRIsVALUE")",
-		 rb_obj_class(super));
+                 rb_obj_class(super));
     }
-    if (RBASIC(super)->flags & FL_SINGLETON) {
-	rb_raise(rb_eTypeError, "can't make subclass of singleton class");
+    if (RCLASS_SINGLETON_P(super)) {
+        rb_raise(rb_eTypeError, "can't make subclass of singleton class");
     }
     if (super == rb_cClass) {
-	rb_raise(rb_eTypeError, "can't make subclass of Class");
+        rb_raise(rb_eTypeError, "can't make subclass of Class");
     }
 }
 
@@ -331,7 +360,13 @@ rb_class_new(VALUE super)
 {
     Check_Type(super, T_CLASS);
     rb_check_inheritable(super);
-    return rb_class_boot(super);
+    VALUE klass = rb_class_boot(super);
+
+    if (super != rb_cObject && super != rb_cBasicObject) {
+        RCLASS_EXT(klass)->max_iv_count = RCLASS_EXT(super)->max_iv_count;
+    }
+
+    return klass;
 }
 
 VALUE
@@ -344,12 +379,12 @@ static void
 clone_method(VALUE old_klass, VALUE new_klass, ID mid, const rb_method_entry_t *me)
 {
     if (me->def->type == VM_METHOD_TYPE_ISEQ) {
-	rb_cref_t *new_cref;
-	rb_vm_rewrite_cref(me->def->body.iseq.cref, old_klass, new_klass, &new_cref);
-	rb_add_method_iseq(new_klass, mid, me->def->body.iseq.iseqptr, new_cref, METHOD_ENTRY_VISI(me));
+        rb_cref_t *new_cref;
+        rb_vm_rewrite_cref(me->def->body.iseq.cref, old_klass, new_klass, &new_cref);
+        rb_add_method_iseq(new_klass, mid, me->def->body.iseq.iseqptr, new_cref, METHOD_ENTRY_VISI(me));
     }
     else {
-	rb_method_entry_set(new_klass, mid, me, METHOD_ENTRY_VISI(me));
+        rb_method_entry_set(new_klass, mid, me, METHOD_ENTRY_VISI(me));
     }
 }
 
@@ -393,45 +428,75 @@ static void
 class_init_copy_check(VALUE clone, VALUE orig)
 {
     if (orig == rb_cBasicObject) {
-	rb_raise(rb_eTypeError, "can't copy the root class");
+        rb_raise(rb_eTypeError, "can't copy the root class");
     }
     if (RCLASS_SUPER(clone) != 0 || clone == rb_cBasicObject) {
-	rb_raise(rb_eTypeError, "already initialized class");
+        rb_raise(rb_eTypeError, "already initialized class");
     }
-    if (FL_TEST(orig, FL_SINGLETON)) {
-	rb_raise(rb_eTypeError, "can't copy singleton class");
+    if (RCLASS_SINGLETON_P(orig)) {
+        rb_raise(rb_eTypeError, "can't copy singleton class");
     }
 }
 
+struct cvc_table_copy_ctx {
+    VALUE clone;
+    struct rb_id_table * new_table;
+};
+
+static enum rb_id_table_iterator_result
+cvc_table_copy(ID id, VALUE val, void *data)
+{
+    struct cvc_table_copy_ctx *ctx = (struct cvc_table_copy_ctx *)data;
+    struct rb_cvar_class_tbl_entry * orig_entry;
+    orig_entry = (struct rb_cvar_class_tbl_entry *)val;
+
+    struct rb_cvar_class_tbl_entry *ent;
+
+    ent = ALLOC(struct rb_cvar_class_tbl_entry);
+    ent->class_value = ctx->clone;
+    ent->cref = orig_entry->cref;
+    ent->global_cvar_state = orig_entry->global_cvar_state;
+    rb_id_table_insert(ctx->new_table, id, (VALUE)ent);
+
+    RB_OBJ_WRITTEN(ctx->clone, Qundef, ent->cref);
+
+    return ID_TABLE_CONTINUE;
+}
+
 static void
 copy_tables(VALUE clone, VALUE orig)
 {
-    if (RCLASS_IV_TBL(clone)) {
-	st_free_table(RCLASS_IV_TBL(clone));
-	RCLASS_IV_TBL(clone) = 0;
-    }
     if (RCLASS_CONST_TBL(clone)) {
-	rb_free_const_table(RCLASS_CONST_TBL(clone));
-	RCLASS_CONST_TBL(clone) = 0;
+        rb_free_const_table(RCLASS_CONST_TBL(clone));
+        RCLASS_CONST_TBL(clone) = 0;
+    }
+    if (RCLASS_CVC_TBL(orig)) {
+        struct rb_id_table *rb_cvc_tbl = RCLASS_CVC_TBL(orig);
+        struct rb_id_table *rb_cvc_tbl_dup = rb_id_table_create(rb_id_table_size(rb_cvc_tbl));
+
+        struct cvc_table_copy_ctx ctx;
+        ctx.clone = clone;
+        ctx.new_table = rb_cvc_tbl_dup;
+        rb_id_table_foreach(rb_cvc_tbl, cvc_table_copy, &ctx);
+        RCLASS_CVC_TBL(clone) = rb_cvc_tbl_dup;
     }
+    rb_id_table_free(RCLASS_M_TBL(clone));
     RCLASS_M_TBL(clone) = 0;
-    if (RCLASS_IV_TBL(orig)) {
-	st_data_t id;
+    if (!RB_TYPE_P(clone, T_ICLASS)) {
+        st_data_t id;
 
-	rb_iv_tbl_copy(clone, orig);
-	CONST_ID(id, "__tmp_classpath__");
-	st_delete(RCLASS_IV_TBL(clone), &id, 0);
-	CONST_ID(id, "__classpath__");
-	st_delete(RCLASS_IV_TBL(clone), &id, 0);
-	CONST_ID(id, "__classid__");
-	st_delete(RCLASS_IV_TBL(clone), &id, 0);
+        rb_iv_tbl_copy(clone, orig);
+        CONST_ID(id, "__tmp_classpath__");
+        rb_attr_delete(clone, id);
+        CONST_ID(id, "__classpath__");
+        rb_attr_delete(clone, id);
     }
     if (RCLASS_CONST_TBL(orig)) {
-	struct clone_const_arg arg;
+        struct clone_const_arg arg;
 
-	arg.tbl = RCLASS_CONST_TBL(clone) = rb_id_table_create(0);
-	arg.klass = clone;
-	rb_id_table_foreach(RCLASS_CONST_TBL(orig), clone_const_i, &arg);
+        arg.tbl = RCLASS_CONST_TBL(clone) = rb_id_table_create(0);
+        arg.klass = clone;
+        rb_id_table_foreach(RCLASS_CONST_TBL(orig), clone_const_i, &arg);
     }
 }
 
@@ -440,7 +505,7 @@ static bool ensure_origin(VALUE klass);
 /**
  * If this flag is set, that module is allocated but not initialized yet.
  */
-enum {RMODULE_ALLOCATED_BUT_NOT_INITIALIZED = RUBY_FL_USER5};
+enum {RMODULE_ALLOCATED_BUT_NOT_INITIALIZED = RUBY_FL_USER1};
 
 static inline bool
 RMODULE_UNINITIALIZED(VALUE module)
@@ -483,21 +548,21 @@ rb_mod_init_copy(VALUE clone, VALUE orig)
     /* cloned flag is refer at constant inline cache
      * see vm_get_const_key_cref() in vm_insnhelper.c
      */
-    FL_SET(clone, RCLASS_CLONED);
-    FL_SET(orig , RCLASS_CLONED);
+    RCLASS_EXT(clone)->cloned = true;
+    RCLASS_EXT(orig)->cloned = true;
 
-    if (!FL_TEST(CLASS_OF(clone), FL_SINGLETON)) {
+    if (!RCLASS_SINGLETON_P(CLASS_OF(clone))) {
         RBASIC_SET_CLASS(clone, rb_singleton_class_clone(orig));
         rb_singleton_class_attached(METACLASS_OF(clone), (VALUE)clone);
     }
-    RCLASS_ALLOCATOR(clone) = RCLASS_ALLOCATOR(orig);
+    RCLASS_SET_ALLOCATOR(clone, RCLASS_ALLOCATOR(orig));
     copy_tables(clone, orig);
     if (RCLASS_M_TBL(orig)) {
-	struct clone_method_arg arg;
-	arg.old_klass = orig;
-	arg.new_klass = clone;
-	RCLASS_M_TBL_INIT(clone);
-	rb_id_table_foreach(RCLASS_M_TBL(orig), clone_method_i, &arg);
+        struct clone_method_arg arg;
+        arg.old_klass = orig;
+        arg.new_klass = clone;
+        RCLASS_M_TBL_INIT(clone);
+        rb_id_table_foreach(RCLASS_M_TBL(orig), clone_method_i, &arg);
     }
 
     if (RCLASS_ORIGIN(orig) == orig) {
@@ -507,7 +572,7 @@ rb_mod_init_copy(VALUE clone, VALUE orig)
         VALUE p = RCLASS_SUPER(orig);
         VALUE orig_origin = RCLASS_ORIGIN(orig);
         VALUE prev_clone_p = clone;
-        VALUE origin_stack = rb_ary_tmp_new(2);
+        VALUE origin_stack = rb_ary_hidden_new(2);
         VALUE origin[2];
         VALUE clone_p = 0;
         long origin_len;
@@ -522,12 +587,14 @@ rb_mod_init_copy(VALUE clone, VALUE orig)
                 rb_bug("non iclass between module/class and origin");
             }
             clone_p = class_alloc(RBASIC(p)->flags, METACLASS_OF(p));
+            /* We should set the m_tbl right after allocation before anything
+             * that can trigger GC to avoid clone_p from becoming old and
+             * needing to fire write barriers. */
+            RCLASS_SET_M_TBL(clone_p, RCLASS_M_TBL(p));
             RCLASS_SET_SUPER(prev_clone_p, clone_p);
             prev_clone_p = clone_p;
-            RCLASS_M_TBL(clone_p) = RCLASS_M_TBL(p);
             RCLASS_CONST_TBL(clone_p) = RCLASS_CONST_TBL(p);
-            RCLASS_IV_TBL(clone_p) = RCLASS_IV_TBL(p);
-            RCLASS_ALLOCATOR(clone_p) = RCLASS_ALLOCATOR(p);
+            RCLASS_SET_ALLOCATOR(clone_p, RCLASS_ALLOCATOR(p));
             if (RB_TYPE_P(clone, T_CLASS)) {
                 RCLASS_SET_INCLUDER(clone_p, clone);
             }
@@ -567,6 +634,8 @@ rb_mod_init_copy(VALUE clone, VALUE orig)
         else {
             rb_bug("no origin for class that has origin");
         }
+
+        rb_class_update_superclasses(clone);
     }
 
     return clone;
@@ -588,62 +657,59 @@ rb_singleton_class_clone_and_attach(VALUE obj, VALUE attach)
     // attached to an object other than `obj`. In which case `obj` does not have
     // a material singleton class attached yet and there is no singleton class
     // to clone.
-    if (!(FL_TEST(klass, FL_SINGLETON) && rb_attr_get(klass, id_attached) == obj)) {
+    if (!(RCLASS_SINGLETON_P(klass) && RCLASS_ATTACHED_OBJECT(klass) == obj)) {
         // nothing to clone
         return klass;
     }
     else {
-	/* copy singleton(unnamed) class */
+        /* copy singleton(unnamed) class */
         bool klass_of_clone_is_new;
-	VALUE clone = class_alloc(RBASIC(klass)->flags, 0);
+        VALUE clone = class_alloc(RBASIC(klass)->flags, 0);
 
-	if (BUILTIN_TYPE(obj) == T_CLASS) {
+        if (BUILTIN_TYPE(obj) == T_CLASS) {
             klass_of_clone_is_new = true;
-	    RBASIC_SET_CLASS(clone, clone);
-	}
-	else {
+            RBASIC_SET_CLASS(clone, clone);
+        }
+        else {
             VALUE klass_metaclass_clone = rb_singleton_class_clone(klass);
             // When `METACLASS_OF(klass) == klass_metaclass_clone`, it means the
             // recursive call did not clone `METACLASS_OF(klass)`.
             klass_of_clone_is_new = (METACLASS_OF(klass) != klass_metaclass_clone);
             RBASIC_SET_CLASS(clone, klass_metaclass_clone);
-	}
-
-	RCLASS_SET_SUPER(clone, RCLASS_SUPER(klass));
-	RCLASS_ALLOCATOR(clone) = RCLASS_ALLOCATOR(klass);
-	if (RCLASS_IV_TBL(klass)) {
-	    rb_iv_tbl_copy(clone, klass);
-	}
-	if (RCLASS_CONST_TBL(klass)) {
-	    struct clone_const_arg arg;
-	    arg.tbl = RCLASS_CONST_TBL(clone) = rb_id_table_create(0);
-	    arg.klass = clone;
-	    rb_id_table_foreach(RCLASS_CONST_TBL(klass), clone_const_i, &arg);
-	}
-	if (attach != Qundef) {
-	    rb_singleton_class_attached(clone, attach);
-	}
-	RCLASS_M_TBL_INIT(clone);
-	{
-	    struct clone_method_arg arg;
-	    arg.old_klass = klass;
-	    arg.new_klass = clone;
-	    rb_id_table_foreach(RCLASS_M_TBL(klass), clone_method_i, &arg);
-	}
+        }
+
+        RCLASS_SET_SUPER(clone, RCLASS_SUPER(klass));
+        rb_iv_tbl_copy(clone, klass);
+        if (RCLASS_CONST_TBL(klass)) {
+            struct clone_const_arg arg;
+            arg.tbl = RCLASS_CONST_TBL(clone) = rb_id_table_create(0);
+            arg.klass = clone;
+            rb_id_table_foreach(RCLASS_CONST_TBL(klass), clone_const_i, &arg);
+        }
+        if (!UNDEF_P(attach)) {
+            rb_singleton_class_attached(clone, attach);
+        }
+        RCLASS_M_TBL_INIT(clone);
+        {
+            struct clone_method_arg arg;
+            arg.old_klass = klass;
+            arg.new_klass = clone;
+            rb_id_table_foreach(RCLASS_M_TBL(klass), clone_method_i, &arg);
+        }
         if (klass_of_clone_is_new) {
             rb_singleton_class_attached(METACLASS_OF(clone), clone);
         }
-	FL_SET(clone, FL_SINGLETON);
+        FL_SET(clone, FL_SINGLETON);
 
-	return clone;
+        return clone;
     }
 }
 
 void
 rb_singleton_class_attached(VALUE klass, VALUE obj)
 {
-    if (FL_TEST(klass, FL_SINGLETON)) {
-	rb_class_ivar_set(klass, id_attached, obj);
+    if (RCLASS_SINGLETON_P(klass)) {
+        RCLASS_SET_ATTACHED_OBJECT(klass, obj);
     }
 }
 
@@ -657,17 +723,17 @@ rb_singleton_class_attached(VALUE klass, VALUE obj)
 static int
 rb_singleton_class_has_metaclass_p(VALUE sklass)
 {
-    return rb_attr_get(METACLASS_OF(sklass), id_attached) == sklass;
+    return RCLASS_ATTACHED_OBJECT(METACLASS_OF(sklass)) == sklass;
 }
 
 int
 rb_singleton_class_internal_p(VALUE sklass)
 {
-    return (RB_TYPE_P(rb_attr_get(sklass, id_attached), T_CLASS) &&
-	    !rb_singleton_class_has_metaclass_p(sklass));
+    return (RB_TYPE_P(RCLASS_ATTACHED_OBJECT(sklass), T_CLASS) &&
+            !rb_singleton_class_has_metaclass_p(sklass));
 }
 
-/*!
+/**
  * whether k has a metaclass
  * @retval 1 if \a k has a metaclass
  * @retval 0 otherwise
@@ -676,25 +742,25 @@ rb_singleton_class_internal_p(VALUE sklass)
     (FL_TEST(METACLASS_OF(k), FL_SINGLETON) && \
      rb_singleton_class_has_metaclass_p(k))
 
-/*!
- * ensures \a klass belongs to its own eigenclass.
- * @return the eigenclass of \a klass
- * @post \a klass belongs to the returned eigenclass.
- *       i.e. the attached object of the eigenclass is \a klass.
+/**
+ * ensures `klass` belongs to its own eigenclass.
+ * @return the eigenclass of `klass`
+ * @post `klass` belongs to the returned eigenclass.
+ *       i.e. the attached object of the eigenclass is `klass`.
  * @note this macro creates a new eigenclass if necessary.
  */
 #define ENSURE_EIGENCLASS(klass) \
     (HAVE_METACLASS_P(klass) ? METACLASS_OF(klass) : make_metaclass(klass))
 
 
-/*!
- * Creates a metaclass of \a klass
- * \param klass     a class
- * \return          created metaclass for the class
- * \pre \a klass is a Class object
- * \pre \a klass has no singleton class.
- * \post the class of \a klass is the returned class.
- * \post the returned class is meta^(n+1)-class when \a klass is a meta^(n)-klass for n >= 0
+/**
+ * Creates a metaclass of `klass`
+ * @param klass     a class
+ * @return          created metaclass for the class
+ * @pre `klass` is a Class object
+ * @pre `klass` has no singleton class.
+ * @post the class of `klass` is the returned class.
+ * @post the returned class is meta^(n+1)-class when `klass` is a meta^(n)-klass for n >= 0
  */
 static inline VALUE
 make_metaclass(VALUE klass)
@@ -706,13 +772,13 @@ make_metaclass(VALUE klass)
     rb_singleton_class_attached(metaclass, klass);
 
     if (META_CLASS_OF_CLASS_CLASS_P(klass)) {
-	SET_METACLASS_OF(klass, metaclass);
-	SET_METACLASS_OF(metaclass, metaclass);
+        SET_METACLASS_OF(klass, metaclass);
+        SET_METACLASS_OF(metaclass, metaclass);
     }
     else {
-	VALUE tmp = METACLASS_OF(klass); /* for a meta^(n)-class klass, tmp is meta^(n)-class of Class class */
-	SET_METACLASS_OF(klass, metaclass);
-	SET_METACLASS_OF(metaclass, ENSURE_EIGENCLASS(tmp));
+        VALUE tmp = METACLASS_OF(klass); /* for a meta^(n)-class klass, tmp is meta^(n)-class of Class class */
+        SET_METACLASS_OF(klass, metaclass);
+        SET_METACLASS_OF(metaclass, ENSURE_EIGENCLASS(tmp));
     }
 
     super = RCLASS_SUPER(klass);
@@ -725,11 +791,11 @@ make_metaclass(VALUE klass)
     return metaclass;
 }
 
-/*!
- * Creates a singleton class for \a obj.
- * \pre \a obj must not a immediate nor a special const.
- * \pre \a obj must not a Class object.
- * \pre \a obj has no singleton class.
+/**
+ * Creates a singleton class for `obj`.
+ * @pre `obj` must not be an immediate nor a special const.
+ * @pre `obj` must not be a Class object.
+ * @pre `obj` has no singleton class.
  */
 static inline VALUE
 make_singleton_class(VALUE obj)
@@ -740,6 +806,7 @@ make_singleton_class(VALUE obj)
     FL_SET(klass, FL_SINGLETON);
     RBASIC_SET_CLASS(obj, klass);
     rb_singleton_class_attached(klass, obj);
+    rb_yjit_invalidate_no_singleton_class(orig_class);
 
     SET_METACLASS_OF(klass, METACLASS_OF(rb_class_real(orig_class)));
     return klass;
@@ -753,7 +820,7 @@ boot_defclass(const char *name, VALUE super)
     ID id = rb_intern(name);
 
     rb_const_set((rb_cObject ? rb_cObject : obj), id, obj);
-    rb_vm_add_root_module(obj);
+    rb_vm_register_global_object(obj);
     return obj;
 }
 
@@ -809,12 +876,33 @@ refinement_import_methods(int argc, VALUE *argv, VALUE refinement)
 }
 # endif
 
+/*!
+ *--
+ * \private
+ * Initializes the world of objects and classes.
+ *
+ * At first, the function bootstraps the class hierarchy.
+ * It initializes the most fundamental classes and their metaclasses.
+ * - \c BasicObject
+ * - \c Object
+ * - \c Module
+ * - \c Class
+ * After the bootstrap step, the class hierarchy becomes as the following
+ * diagram.
+ *
+ * \image html boottime-classes.png
+ *
+ * Then, the function defines classes, modules and methods as usual.
+ * \ingroup class
+ *++
+ */
+
 void
 Init_class_hierarchy(void)
 {
     rb_cBasicObject = boot_defclass("BasicObject", 0);
     rb_cObject = boot_defclass("Object", rb_cBasicObject);
-    rb_gc_register_mark_object(rb_cObject);
+    rb_vm_register_global_object(rb_cObject);
 
     /* resolve class name ASAP for order-independence */
     rb_set_class_path_string(rb_cObject, rb_cObject, rb_fstring_lit("Object"));
@@ -839,24 +927,24 @@ Init_class_hierarchy(void)
 }
 
 
-/*!
- * \internal
+/**
+ * @internal
  * Creates a new *singleton class* for an object.
  *
- * \pre \a obj has no singleton class.
- * \note DO NOT USE the function in an extension libraries. Use \ref rb_singleton_class.
- * \param obj     An object.
- * \param unused  ignored.
- * \return        The singleton class of the object.
+ * @pre `obj` has no singleton class.
+ * @note DO NOT USE the function in an extension libraries. Use @ref rb_singleton_class.
+ * @param obj     An object.
+ * @param unused  ignored.
+ * @return        The singleton class of the object.
  */
 VALUE
 rb_make_metaclass(VALUE obj, VALUE unused)
 {
     if (BUILTIN_TYPE(obj) == T_CLASS) {
-	return make_metaclass(obj);
+        return make_metaclass(obj);
     }
     else {
-	return make_singleton_class(obj);
+        return make_singleton_class(obj);
     }
 }
 
@@ -873,15 +961,15 @@ rb_define_class_id(ID id, VALUE super)
 }
 
 
-/*!
+/**
  * Calls Class#inherited.
- * \param super  A class which will be called #inherited.
+ * @param super  A class which will be called #inherited.
  *               NULL means Object class.
- * \param klass  A Class object which derived from \a super
- * \return the value \c Class#inherited's returns
- * \pre Each of \a super and \a klass must be a \c Class object.
+ * @param klass  A Class object which derived from `super`
+ * @return the value `Class#inherited` returns
+ * @pre Each of `super` and `klass` must be a `Class` object.
  */
-MJIT_FUNC_EXPORTED VALUE
+VALUE
 rb_class_inherited(VALUE super, VALUE klass)
 {
     ID inherited;
@@ -898,24 +986,24 @@ rb_define_class(const char *name, VALUE super)
 
     id = rb_intern(name);
     if (rb_const_defined(rb_cObject, id)) {
-	klass = rb_const_get(rb_cObject, id);
-	if (!RB_TYPE_P(klass, T_CLASS)) {
-	    rb_raise(rb_eTypeError, "%s is not a class (%"PRIsVALUE")",
-		     name, rb_obj_class(klass));
-	}
-	if (rb_class_real(RCLASS_SUPER(klass)) != super) {
-	    rb_raise(rb_eTypeError, "superclass mismatch for class %s", name);
-	}
+        klass = rb_const_get(rb_cObject, id);
+        if (!RB_TYPE_P(klass, T_CLASS)) {
+            rb_raise(rb_eTypeError, "%s is not a class (%"PRIsVALUE")",
+                     name, rb_obj_class(klass));
+        }
+        if (rb_class_real(RCLASS_SUPER(klass)) != super) {
+            rb_raise(rb_eTypeError, "superclass mismatch for class %s", name);
+        }
 
         /* Class may have been defined in Ruby and not pin-rooted */
-        rb_vm_add_root_module(klass);
-	return klass;
+        rb_vm_register_global_object(klass);
+        return klass;
     }
     if (!super) {
-	rb_raise(rb_eArgError, "no super class for `%s'", name);
+        rb_raise(rb_eArgError, "no super class for '%s'", name);
     }
     klass = rb_define_class_id(id, super);
-    rb_vm_add_root_module(klass);
+    rb_vm_register_global_object(klass);
     rb_const_set(rb_cObject, id, klass);
     rb_class_inherited(super, klass);
 
@@ -929,42 +1017,47 @@ rb_define_class_under(VALUE outer, const char *name, VALUE super)
 }
 
 VALUE
-rb_define_class_id_under(VALUE outer, ID id, VALUE super)
+rb_define_class_id_under_no_pin(VALUE outer, ID id, VALUE super)
 {
     VALUE klass;
 
     if (rb_const_defined_at(outer, id)) {
-	klass = rb_const_get_at(outer, id);
-	if (!RB_TYPE_P(klass, T_CLASS)) {
-	    rb_raise(rb_eTypeError, "%"PRIsVALUE"::%"PRIsVALUE" is not a class"
-		     " (%"PRIsVALUE")",
-		     outer, rb_id2str(id), rb_obj_class(klass));
-	}
-	if (rb_class_real(RCLASS_SUPER(klass)) != super) {
-	    rb_raise(rb_eTypeError, "superclass mismatch for class "
-		     "%"PRIsVALUE"::%"PRIsVALUE""
-		     " (%"PRIsVALUE" is given but was %"PRIsVALUE")",
-		     outer, rb_id2str(id), RCLASS_SUPER(klass), super);
-	}
-        /* Class may have been defined in Ruby and not pin-rooted */
-        rb_vm_add_root_module(klass);
+        klass = rb_const_get_at(outer, id);
+        if (!RB_TYPE_P(klass, T_CLASS)) {
+            rb_raise(rb_eTypeError, "%"PRIsVALUE"::%"PRIsVALUE" is not a class"
+                     " (%"PRIsVALUE")",
+                     outer, rb_id2str(id), rb_obj_class(klass));
+        }
+        if (rb_class_real(RCLASS_SUPER(klass)) != super) {
+            rb_raise(rb_eTypeError, "superclass mismatch for class "
+                     "%"PRIsVALUE"::%"PRIsVALUE""
+                     " (%"PRIsVALUE" is given but was %"PRIsVALUE")",
+                     outer, rb_id2str(id), RCLASS_SUPER(klass), super);
+        }
 
-	return klass;
+        return klass;
     }
     if (!super) {
-	rb_raise(rb_eArgError, "no super class for `%"PRIsVALUE"::%"PRIsVALUE"'",
-		 rb_class_path(outer), rb_id2str(id));
+        rb_raise(rb_eArgError, "no super class for '%"PRIsVALUE"::%"PRIsVALUE"'",
+                 rb_class_path(outer), rb_id2str(id));
     }
     klass = rb_define_class_id(id, super);
     rb_set_class_path_string(klass, outer, rb_id2str(id));
     rb_const_set(outer, id, klass);
     rb_class_inherited(super, klass);
-    rb_vm_add_root_module(klass);
 
     return klass;
 }
 
 VALUE
+rb_define_class_id_under(VALUE outer, ID id, VALUE super)
+{
+    VALUE klass = rb_define_class_id_under_no_pin(outer, id, super);
+    rb_vm_register_global_object(klass);
+    return klass;
+}
+
+VALUE
 rb_module_s_alloc(VALUE klass)
 {
     VALUE mod = class_alloc(T_MODULE, klass);
@@ -1008,17 +1101,17 @@ rb_define_module(const char *name)
 
     id = rb_intern(name);
     if (rb_const_defined(rb_cObject, id)) {
-	module = rb_const_get(rb_cObject, id);
-	if (!RB_TYPE_P(module, T_MODULE)) {
-	    rb_raise(rb_eTypeError, "%s is not a module (%"PRIsVALUE")",
-		     name, rb_obj_class(module));
-	}
+        module = rb_const_get(rb_cObject, id);
+        if (!RB_TYPE_P(module, T_MODULE)) {
+            rb_raise(rb_eTypeError, "%s is not a module (%"PRIsVALUE")",
+                     name, rb_obj_class(module));
+        }
         /* Module may have been defined in Ruby and not pin-rooted */
-        rb_vm_add_root_module(module);
-	return module;
+        rb_vm_register_global_object(module);
+        return module;
     }
     module = rb_module_new();
-    rb_vm_add_root_module(module);
+    rb_vm_register_global_object(module);
     rb_const_set(rb_cObject, id, module);
 
     return module;
@@ -1036,20 +1129,20 @@ rb_define_module_id_under(VALUE outer, ID id)
     VALUE module;
 
     if (rb_const_defined_at(outer, id)) {
-	module = rb_const_get_at(outer, id);
-	if (!RB_TYPE_P(module, T_MODULE)) {
-	    rb_raise(rb_eTypeError, "%"PRIsVALUE"::%"PRIsVALUE" is not a module"
-		     " (%"PRIsVALUE")",
-		     outer, rb_id2str(id), rb_obj_class(module));
-	}
+        module = rb_const_get_at(outer, id);
+        if (!RB_TYPE_P(module, T_MODULE)) {
+            rb_raise(rb_eTypeError, "%"PRIsVALUE"::%"PRIsVALUE" is not a module"
+                     " (%"PRIsVALUE")",
+                     outer, rb_id2str(id), rb_obj_class(module));
+        }
         /* Module may have been defined in Ruby and not pin-rooted */
-        rb_gc_register_mark_object(module);
-	return module;
+        rb_vm_register_global_object(module);
+        return module;
     }
     module = rb_module_new();
     rb_const_set(outer, id, module);
     rb_set_class_path_string(module, outer, rb_id2str(id));
-    rb_gc_register_mark_object(module);
+    rb_vm_register_global_object(module);
 
     return module;
 }
@@ -1059,20 +1152,17 @@ rb_include_class_new(VALUE module, VALUE super)
 {
     VALUE klass = class_alloc(T_ICLASS, rb_cClass);
 
-    RCLASS_M_TBL(klass) = RCLASS_M_TBL(module);
+    RCLASS_SET_M_TBL(klass, RCLASS_M_TBL(module));
 
     RCLASS_SET_ORIGIN(klass, klass);
     if (BUILTIN_TYPE(module) == T_ICLASS) {
-	module = METACLASS_OF(module);
+        module = METACLASS_OF(module);
     }
     RUBY_ASSERT(!RB_TYPE_P(module, T_ICLASS));
-    if (!RCLASS_IV_TBL(module)) {
-	RCLASS_IV_TBL(module) = st_init_numtable();
-    }
     if (!RCLASS_CONST_TBL(module)) {
-	RCLASS_CONST_TBL(module) = rb_id_table_create(0);
+        RCLASS_CONST_TBL(module) = rb_id_table_create(0);
     }
-    RCLASS_IV_TBL(klass) = RCLASS_IV_TBL(module);
+
     RCLASS_CVC_TBL(klass) = RCLASS_CVC_TBL(module);
     RCLASS_CONST_TBL(klass) = RCLASS_CONST_TBL(module);
 
@@ -1091,7 +1181,7 @@ ensure_includable(VALUE klass, VALUE module)
     Check_Type(module, T_MODULE);
     rb_module_set_initialized(module);
     if (!NIL_P(rb_refinement_module_get_refined_class(module))) {
-	rb_raise(rb_eArgError, "refinement module is not allowed");
+        rb_raise(rb_eArgError, "refinement module is not allowed");
     }
 }
 
@@ -1104,7 +1194,7 @@ rb_include_module(VALUE klass, VALUE module)
 
     changed = include_modules_at(klass, RCLASS_ORIGIN(klass), module, TRUE);
     if (changed < 0)
-	rb_raise(rb_eArgError, "cyclic include detected");
+        rb_raise(rb_eArgError, "cyclic include detected");
 
     if (RB_TYPE_P(klass, T_MODULE)) {
         rb_subclass_entry_t *iclass = RCLASS_SUBCLASSES(klass);
@@ -1114,8 +1204,8 @@ rb_include_module(VALUE klass, VALUE module)
             iclass = iclass->next;
         }
 
-        int do_include = 1;
         while (iclass) {
+            int do_include = 1;
             VALUE check_class = iclass->klass;
             /* During lazy sweeping, iclass->klass could be a dead object that
              * has not yet been swept. */
@@ -1182,7 +1272,7 @@ static int
 do_include_modules_at(const VALUE klass, VALUE c, VALUE module, int search_super, bool check_cyclic)
 {
     VALUE p, iclass, origin_stack = 0;
-    int method_changed = 0, add_subclass;
+    int method_changed = 0;
     long origin_len;
     VALUE klass_origin = RCLASS_ORIGIN(klass);
     VALUE original_klass = klass;
@@ -1192,8 +1282,8 @@ do_include_modules_at(const VALUE klass, VALUE c, VALUE module, int search_super
 
     while (module) {
         int c_seen = FALSE;
-	int superclass_seen = FALSE;
-	struct rb_id_table *tbl;
+        int superclass_seen = FALSE;
+        struct rb_id_table *tbl;
 
         if (klass == c) {
             c_seen = TRUE;
@@ -1243,12 +1333,11 @@ do_include_modules_at(const VALUE klass, VALUE c, VALUE module, int search_super
         }
 
         // setup T_ICLASS for the include/prepend module
-	iclass = rb_include_class_new(module, super_class);
-	c = RCLASS_SET_SUPER(c, iclass);
+        iclass = rb_include_class_new(module, super_class);
+        c = RCLASS_SET_SUPER(c, iclass);
         RCLASS_SET_INCLUDER(iclass, klass);
-        add_subclass = TRUE;
         if (module != RCLASS_ORIGIN(module)) {
-            if (!origin_stack) origin_stack = rb_ary_tmp_new(2);
+            if (!origin_stack) origin_stack = rb_ary_hidden_new(2);
             VALUE origin[2] = {iclass, RCLASS_ORIGIN(module)};
             rb_ary_cat(origin_stack, origin, 2);
         }
@@ -1257,28 +1346,25 @@ do_include_modules_at(const VALUE klass, VALUE c, VALUE module, int search_super
             RCLASS_SET_ORIGIN(RARRAY_AREF(origin_stack, (origin_len -= 2)), iclass);
             RICLASS_SET_ORIGIN_SHARED_MTBL(iclass);
             rb_ary_resize(origin_stack, origin_len);
-            add_subclass = FALSE;
         }
 
-	if (add_subclass) {
-	    VALUE m = module;
-            if (BUILTIN_TYPE(m) == T_ICLASS) m = METACLASS_OF(m);
-            rb_module_add_to_subclasses_list(m, iclass);
-	}
+        VALUE m = module;
+        if (BUILTIN_TYPE(m) == T_ICLASS) m = METACLASS_OF(m);
+        rb_module_add_to_subclasses_list(m, iclass);
 
-	if (FL_TEST(klass, RMODULE_IS_REFINEMENT)) {
-	    VALUE refined_class =
-		rb_refinement_module_get_refined_class(klass);
+        if (BUILTIN_TYPE(klass) == T_MODULE && FL_TEST(klass, RMODULE_IS_REFINEMENT)) {
+            VALUE refined_class =
+                rb_refinement_module_get_refined_class(klass);
 
             rb_id_table_foreach(RCLASS_M_TBL(module), add_refined_method_entry_i, (void *)refined_class);
-	    FL_SET(c, RMODULE_INCLUDED_INTO_REFINEMENT);
-	}
+            RUBY_ASSERT(BUILTIN_TYPE(c) == T_MODULE);
+        }
 
         tbl = RCLASS_CONST_TBL(module);
-	if (tbl && rb_id_table_size(tbl))
-	    rb_id_table_foreach(tbl, clear_constant_cache_i, NULL);
+        if (tbl && rb_id_table_size(tbl))
+            rb_id_table_foreach(tbl, clear_constant_cache_i, NULL);
       skip:
-	module = RCLASS_SUPER(module);
+        module = RCLASS_SUPER(module);
     }
 
     return method_changed;
@@ -1300,20 +1386,20 @@ move_refined_method(ID key, VALUE value, void *data)
         struct rb_id_table *tbl = RCLASS_M_TBL(klass);
 
         if (me->def->body.refined.orig_me) {
-	    const rb_method_entry_t *orig_me = me->def->body.refined.orig_me, *new_me;
-	    RB_OBJ_WRITE(me, &me->def->body.refined.orig_me, NULL);
-	    new_me = rb_method_entry_clone(me);
+            const rb_method_entry_t *orig_me = me->def->body.refined.orig_me, *new_me;
+            RB_OBJ_WRITE(me, &me->def->body.refined.orig_me, NULL);
+            new_me = rb_method_entry_clone(me);
             rb_method_table_insert(klass, tbl, key, new_me);
-	    rb_method_entry_copy(me, orig_me);
-	    return ID_TABLE_CONTINUE;
-	}
-	else {
+            rb_method_entry_copy(me, orig_me);
+            return ID_TABLE_CONTINUE;
+        }
+        else {
             rb_method_table_insert(klass, tbl, key, me);
-	    return ID_TABLE_DELETE;
-	}
+            return ID_TABLE_DELETE;
+        }
     }
     else {
-	return ID_TABLE_CONTINUE;
+        return ID_TABLE_CONTINUE;
     }
 }
 
@@ -1337,14 +1423,14 @@ ensure_origin(VALUE klass)
 {
     VALUE origin = RCLASS_ORIGIN(klass);
     if (origin == klass) {
-	origin = class_alloc(T_ICLASS, klass);
-	RCLASS_SET_SUPER(origin, RCLASS_SUPER(klass));
-	RCLASS_SET_SUPER(klass, origin);
-	RCLASS_SET_ORIGIN(klass, origin);
-	RCLASS_M_TBL(origin) = RCLASS_M_TBL(klass);
-	RCLASS_M_TBL_INIT(klass);
+        origin = class_alloc(T_ICLASS, klass);
+        RCLASS_SET_M_TBL(origin, RCLASS_M_TBL(klass));
+        RCLASS_SET_SUPER(origin, RCLASS_SUPER(klass));
+        RCLASS_SET_SUPER(klass, origin);
+        RCLASS_SET_ORIGIN(klass, origin);
+        RCLASS_M_TBL_INIT(klass);
         rb_id_table_foreach(RCLASS_M_TBL(origin), cache_clear_refined_method, (void *)klass);
-	rb_id_table_foreach(RCLASS_M_TBL(origin), move_refined_method, (void *)klass);
+        rb_id_table_foreach(RCLASS_M_TBL(origin), move_refined_method, (void *)klass);
         return true;
     }
     return false;
@@ -1364,7 +1450,7 @@ rb_prepend_module(VALUE klass, VALUE module)
     changed = do_include_modules_at(klass, klass, module, FALSE, false);
     RUBY_ASSERT(changed >= 0); // already checked for cyclic prepend above
     if (changed) {
-	rb_vm_check_redefinition_by_prepend(klass);
+        rb_vm_check_redefinition_by_prepend(klass);
     }
     if (RB_TYPE_P(klass, T_MODULE)) {
         rb_subclass_entry_t *iclass = RCLASS_SUBCLASSES(klass);
@@ -1381,17 +1467,18 @@ rb_prepend_module(VALUE klass, VALUE module)
             /* During lazy sweeping, iclass->klass could be a dead object that
              * has not yet been swept. */
             if (!rb_objspace_garbage_object_p(iclass->klass)) {
-                if (klass_had_no_origin && klass_origin_m_tbl == RCLASS_M_TBL(iclass->klass)) {
+                const VALUE subclass = iclass->klass;
+                if (klass_had_no_origin && klass_origin_m_tbl == RCLASS_M_TBL(subclass)) {
                     // backfill an origin iclass to handle refinements and future prepends
-                    rb_id_table_foreach(RCLASS_M_TBL(iclass->klass), clear_module_cache_i, (void *)iclass->klass);
-                    RCLASS_M_TBL(iclass->klass) = klass_m_tbl;
-                    VALUE origin = rb_include_class_new(klass_origin, RCLASS_SUPER(iclass->klass));
-                    RCLASS_SET_SUPER(iclass->klass, origin);
-                    RCLASS_SET_INCLUDER(origin, RCLASS_INCLUDER(iclass->klass));
-                    RCLASS_SET_ORIGIN(iclass->klass, origin);
+                    rb_id_table_foreach(RCLASS_M_TBL(subclass), clear_module_cache_i, (void *)subclass);
+                    RCLASS_M_TBL(subclass) = klass_m_tbl;
+                    VALUE origin = rb_include_class_new(klass_origin, RCLASS_SUPER(subclass));
+                    RCLASS_SET_SUPER(subclass, origin);
+                    RCLASS_SET_INCLUDER(origin, RCLASS_INCLUDER(subclass));
+                    RCLASS_SET_ORIGIN(subclass, origin);
                     RICLASS_SET_ORIGIN_SHARED_MTBL(origin);
                 }
-                include_modules_at(iclass->klass, iclass->klass, module, FALSE);
+                include_modules_at(subclass, subclass, module, FALSE);
             }
 
             iclass = iclass->next;
@@ -1430,10 +1517,10 @@ rb_mod_included_modules(VALUE mod)
 
     for (p = RCLASS_SUPER(mod); p; p = RCLASS_SUPER(p)) {
         if (p != origin && RCLASS_ORIGIN(p) == p && BUILTIN_TYPE(p) == T_ICLASS) {
-	    VALUE m = METACLASS_OF(p);
-	    if (RB_TYPE_P(m, T_MODULE))
-		rb_ary_push(ary, m);
-	}
+            VALUE m = METACLASS_OF(p);
+            if (RB_TYPE_P(m, T_MODULE))
+                rb_ary_push(ary, m);
+        }
     }
     return ary;
 }
@@ -1465,8 +1552,8 @@ rb_mod_include_p(VALUE mod, VALUE mod2)
     Check_Type(mod2, T_MODULE);
     for (p = RCLASS_SUPER(mod); p; p = RCLASS_SUPER(p)) {
         if (BUILTIN_TYPE(p) == T_ICLASS && !FL_TEST(p, RICLASS_IS_ORIGIN)) {
-	    if (METACLASS_OF(p) == mod2) return Qtrue;
-	}
+            if (METACLASS_OF(p) == mod2) return Qtrue;
+        }
     }
     return Qfalse;
 }
@@ -1494,19 +1581,19 @@ rb_mod_ancestors(VALUE mod)
 {
     VALUE p, ary = rb_ary_new();
     VALUE refined_class = Qnil;
-    if (FL_TEST(mod, RMODULE_IS_REFINEMENT)) {
+    if (BUILTIN_TYPE(mod) == T_MODULE && FL_TEST(mod, RMODULE_IS_REFINEMENT)) {
         refined_class = rb_refinement_module_get_refined_class(mod);
     }
 
     for (p = mod; p; p = RCLASS_SUPER(p)) {
         if (p == refined_class) break;
         if (p != RCLASS_ORIGIN(p)) continue;
-	if (BUILTIN_TYPE(p) == T_ICLASS) {
-	    rb_ary_push(ary, METACLASS_OF(p));
-	}
+        if (BUILTIN_TYPE(p) == T_ICLASS) {
+            rb_ary_push(ary, METACLASS_OF(p));
+        }
         else {
-	    rb_ary_push(ary, p);
-	}
+            rb_ary_push(ary, p);
+        }
     }
     return ary;
 }
@@ -1524,7 +1611,7 @@ class_descendants_recursive(VALUE klass, VALUE v)
 {
     struct subclass_traverse_data *data = (struct subclass_traverse_data *) v;
 
-    if (BUILTIN_TYPE(klass) == T_CLASS && !FL_TEST(klass, FL_SINGLETON)) {
+    if (BUILTIN_TYPE(klass) == T_CLASS && !RCLASS_SINGLETON_P(klass)) {
         if (data->buffer && data->count < data->maxcount && !rb_objspace_garbage_object_p(klass)) {
             // assumes that this does not cause GC as long as the length does not exceed the capacity
             rb_ary_push(data->buffer, klass);
@@ -1580,6 +1667,27 @@ class_descendants(VALUE klass, bool immediate_only)
  *     A.subclasses        #=> [D, B]
  *     B.subclasses        #=> [C]
  *     C.subclasses        #=> []
+ *
+ *  Anonymous subclasses (not associated with a constant) are
+ *  returned, too:
+ *
+ *     c = Class.new(A)
+ *     A.subclasses        # => [#<Class:0x00007f003c77bd78>, D, B]
+ *
+ *  Note that the parent does not hold references to subclasses
+ *  and doesn't prevent them from being garbage collected. This
+ *  means that the subclass might disappear when all references
+ *  to it are dropped:
+ *
+ *     # drop the reference to subclass, it can be garbage-collected now
+ *     c = nil
+ *
+ *     A.subclasses
+ *     # It can be
+ *     #  => [#<Class:0x00007f003c77bd78>, D, B]
+ *     # ...or just
+ *     #  => [D, B]
+ *     # ...depending on whether garbage collector was run
  */
 
 VALUE
@@ -1588,6 +1696,33 @@ rb_class_subclasses(VALUE klass)
     return class_descendants(klass, true);
 }
 
+/*
+ *  call-seq:
+ *     attached_object -> object
+ *
+ *  Returns the object for which the receiver is the singleton class.
+ *
+ *  Raises an TypeError if the class is not a singleton class.
+ *
+ *     class Foo; end
+ *
+ *     Foo.singleton_class.attached_object        #=> Foo
+ *     Foo.attached_object                        #=> TypeError: `Foo' is not a singleton class
+ *     Foo.new.singleton_class.attached_object    #=> #<Foo:0x000000010491a370>
+ *     TrueClass.attached_object                  #=> TypeError: `TrueClass' is not a singleton class
+ *     NilClass.attached_object                   #=> TypeError: `NilClass' is not a singleton class
+ */
+
+VALUE
+rb_class_attached_object(VALUE klass)
+{
+    if (!RCLASS_SINGLETON_P(klass)) {
+        rb_raise(rb_eTypeError, "'%"PRIsVALUE"' is not a singleton class", klass);
+    }
+
+    return RCLASS_ATTACHED_OBJECT(klass);
+}
+
 static void
 ins_methods_push(st_data_t name, st_data_t ary)
 {
@@ -1600,10 +1735,10 @@ ins_methods_i(st_data_t name, st_data_t type, st_data_t ary)
     switch ((rb_method_visibility_t)type) {
       case METHOD_VISI_UNDEF:
       case METHOD_VISI_PRIVATE:
-	break;
+        break;
       default: /* everything but private */
-	ins_methods_push(name, ary);
-	break;
+        ins_methods_push(name, ary);
+        break;
     }
     return ST_CONTINUE;
 }
@@ -1612,7 +1747,7 @@ static int
 ins_methods_type_i(st_data_t name, st_data_t type, st_data_t ary, rb_method_visibility_t visi)
 {
     if ((rb_method_visibility_t)type == visi) {
-	ins_methods_push(name, ary);
+        ins_methods_push(name, ary);
     }
     return ST_CONTINUE;
 }
@@ -1635,6 +1770,12 @@ ins_methods_pub_i(st_data_t name, st_data_t type, st_data_t ary)
     return ins_methods_type_i(name, type, ary, METHOD_VISI_PUBLIC);
 }
 
+static int
+ins_methods_undef_i(st_data_t name, st_data_t type, st_data_t ary)
+{
+    return ins_methods_type_i(name, type, ary, METHOD_VISI_UNDEF);
+}
+
 struct method_entry_arg {
     st_table *list;
     int recur;
@@ -1648,20 +1789,20 @@ method_entry_i(ID key, VALUE value, void *data)
     rb_method_visibility_t type;
 
     if (me->def->type == VM_METHOD_TYPE_REFINED) {
-	VALUE owner = me->owner;
-	me = rb_resolve_refined_method(Qnil, me);
-	if (!me) return ID_TABLE_CONTINUE;
-	if (!arg->recur && me->owner != owner) return ID_TABLE_CONTINUE;
+        VALUE owner = me->owner;
+        me = rb_resolve_refined_method(Qnil, me);
+        if (!me) return ID_TABLE_CONTINUE;
+        if (!arg->recur && me->owner != owner) return ID_TABLE_CONTINUE;
     }
     if (!st_is_member(arg->list, key)) {
-	if (UNDEFINED_METHOD_ENTRY_P(me)) {
-	    type = METHOD_VISI_UNDEF; /* none */
-	}
-	else {
-	    type = METHOD_ENTRY_VISI(me);
-	    RUBY_ASSERT(type != METHOD_VISI_UNDEF);
-	}
-	st_add_direct(arg->list, key, (st_data_t)type);
+        if (UNDEFINED_METHOD_ENTRY_P(me)) {
+            type = METHOD_VISI_UNDEF; /* none */
+        }
+        else {
+            type = METHOD_ENTRY_VISI(me);
+            RUBY_ASSERT(type != METHOD_VISI_UNDEF);
+        }
+        st_add_direct(arg->list, key, (st_data_t)type);
     }
     return ID_TABLE_CONTINUE;
 }
@@ -1678,7 +1819,7 @@ static bool
 particular_class_p(VALUE mod)
 {
     if (!mod) return false;
-    if (FL_TEST(mod, FL_SINGLETON)) return true;
+    if (RCLASS_SINGLETON_P(mod)) return true;
     if (BUILTIN_TYPE(mod) == T_ICLASS) return true;
     return false;
 }
@@ -1702,14 +1843,14 @@ class_instance_method_list(int argc, const VALUE *argv, VALUE mod, int obj, int
     }
 
     if (!recur && RCLASS_ORIGIN(mod) != mod) {
-	mod = RCLASS_ORIGIN(mod);
-	prepended = 1;
+        mod = RCLASS_ORIGIN(mod);
+        prepended = 1;
     }
 
     for (; mod; mod = RCLASS_SUPER(mod)) {
         add_instance_method_list(mod, &me_arg);
-	if (BUILTIN_TYPE(mod) == T_ICLASS && !prepended) continue;
-	if (!recur) break;
+        if (BUILTIN_TYPE(mod) == T_ICLASS && !prepended) continue;
+        if (!recur) break;
     }
     ary = rb_ary_new2(me_arg.list->num_entries);
     st_foreach(me_arg.list, func, ary);
@@ -1743,6 +1884,15 @@ class_instance_method_list(int argc, const VALUE *argv, VALUE mod, int obj, int
  *     B.instance_methods(true).include?(:method1) #=> true
  *     C.instance_methods(false)                   #=> [:method3]
  *     C.instance_methods.include?(:method2)       #=> true
+ *
+ *  Note that method visibility changes in the current class, as well as aliases,
+ *  are considered as methods of the current class by this method:
+ *
+ *     class C < B
+ *       alias method4 method2
+ *       protected :method2
+ *     end
+ *     C.instance_methods(false).sort               #=> [:method2, :method3, :method4]
  */
 
 VALUE
@@ -1806,6 +1956,21 @@ rb_class_public_instance_methods(int argc, const VALUE *argv, VALUE mod)
 
 /*
  *  call-seq:
+ *     mod.undefined_instance_methods   -> array
+ *
+ *  Returns a list of the undefined instance methods defined in <i>mod</i>.
+ *  The undefined methods of any ancestors are not included.
+ */
+
+VALUE
+rb_class_undefined_instance_methods(VALUE mod)
+{
+    VALUE include_super = Qfalse;
+    return class_instance_method_list(1, &include_super, mod, 0, ins_methods_undef_i);
+}
+
+/*
+ *  call-seq:
  *     obj.methods(regular=true)    -> array
  *
  *  Returns a list of the names of public and protected methods of
@@ -1839,7 +2004,7 @@ rb_obj_methods(int argc, const VALUE *argv, VALUE obj)
 {
     rb_check_arity(argc, 0, 1);
     if (argc > 0 && !RTEST(argv[0])) {
-	return rb_obj_singleton_methods(argc, argv, obj);
+        return rb_obj_singleton_methods(argc, argv, obj);
     }
     return class_instance_method_list(argc, argv, CLASS_OF(obj), 1, ins_methods_i);
 }
@@ -1931,22 +2096,22 @@ rb_obj_singleton_methods(int argc, const VALUE *argv, VALUE obj)
     int recur = TRUE;
 
     if (rb_check_arity(argc, 0, 1)) recur = RTEST(argv[0]);
-    if (RB_TYPE_P(obj, T_CLASS) && FL_TEST(obj, FL_SINGLETON)) {
+    if (RCLASS_SINGLETON_P(obj)) {
         rb_singleton_class(obj);
     }
     klass = CLASS_OF(obj);
     origin = RCLASS_ORIGIN(klass);
     me_arg.list = st_init_numtable();
     me_arg.recur = recur;
-    if (klass && FL_TEST(klass, FL_SINGLETON)) {
-	if ((mtbl = RCLASS_M_TBL(origin)) != 0) rb_id_table_foreach(mtbl, method_entry_i, &me_arg);
-	klass = RCLASS_SUPER(klass);
+    if (klass && RCLASS_SINGLETON_P(klass)) {
+        if ((mtbl = RCLASS_M_TBL(origin)) != 0) rb_id_table_foreach(mtbl, method_entry_i, &me_arg);
+        klass = RCLASS_SUPER(klass);
     }
     if (recur) {
-	while (klass && (FL_TEST(klass, FL_SINGLETON) || RB_TYPE_P(klass, T_ICLASS))) {
-	    if (klass != origin && (mtbl = RCLASS_M_TBL(klass)) != 0) rb_id_table_foreach(mtbl, method_entry_i, &me_arg);
-	    klass = RCLASS_SUPER(klass);
-	}
+        while (klass && (RCLASS_SINGLETON_P(klass) || RB_TYPE_P(klass, T_ICLASS))) {
+            if (klass != origin && (mtbl = RCLASS_M_TBL(klass)) != 0) rb_id_table_foreach(mtbl, method_entry_i, &me_arg);
+            klass = RCLASS_SUPER(klass);
+        }
     }
     ary = rb_ary_new2(me_arg.list->num_entries);
     st_foreach(me_arg.list, ins_methods_i, ary);
@@ -2018,7 +2183,7 @@ rb_undef_methods_from(VALUE klass, VALUE super)
 {
     struct rb_id_table *mtbl = RCLASS_M_TBL(super);
     if (mtbl) {
-	rb_id_table_foreach(mtbl, undef_method_i, (void *)klass);
+        rb_id_table_foreach(mtbl, undef_method_i, (void *)klass);
     }
 }
 
@@ -2047,13 +2212,13 @@ rb_special_singleton_class(VALUE obj)
     return special_singleton_class_of(obj);
 }
 
-/*!
- * \internal
- * Returns the singleton class of \a obj. Creates it if necessary.
+/**
+ * @internal
+ * Returns the singleton class of `obj`. Creates it if necessary.
  *
- * \note DO NOT expose the returned singleton class to
+ * @note DO NOT expose the returned singleton class to
  *       outside of class.c.
- *       Use \ref rb_singleton_class instead for
+ *       Use @ref rb_singleton_class instead for
  *       consistency of the metaclass hierarchy.
  */
 static VALUE
@@ -2066,28 +2231,29 @@ singleton_class_of(VALUE obj)
       case T_BIGNUM:
       case T_FLOAT:
       case T_SYMBOL:
-	rb_raise(rb_eTypeError, "can't define singleton");
+        rb_raise(rb_eTypeError, "can't define singleton");
 
       case T_FALSE:
       case T_TRUE:
       case T_NIL:
-	klass = special_singleton_class_of(obj);
-	if (NIL_P(klass))
-	    rb_bug("unknown immediate %p", (void *)obj);
-	return klass;
+        klass = special_singleton_class_of(obj);
+        if (NIL_P(klass))
+            rb_bug("unknown immediate %p", (void *)obj);
+        return klass;
 
       case T_STRING:
-        if (FL_TEST_RAW(obj, RSTRING_FSTR)) {
+        if (CHILLED_STRING_P(obj)) {
+            CHILLED_STRING_MUTATED(obj);
+        }
+        else if (FL_TEST_RAW(obj, RSTRING_FSTR)) {
             rb_raise(rb_eTypeError, "can't define singleton");
         }
     }
 
     klass = METACLASS_OF(obj);
-    if (!(FL_TEST(klass, FL_SINGLETON) &&
-          rb_attr_get(klass, id_attached) == obj)) {
-	rb_serial_t serial = RCLASS_SERIAL(klass);
-	klass = rb_make_metaclass(obj, klass);
-	RCLASS_SERIAL(klass) = serial;
+    if (!(RCLASS_SINGLETON_P(klass) &&
+          RCLASS_ATTACHED_OBJECT(klass) == obj)) {
+        klass = rb_make_metaclass(obj, klass);
     }
 
     RB_FL_SET_RAW(klass, RB_OBJ_FROZEN_RAW(obj));
@@ -2099,21 +2265,21 @@ void
 rb_freeze_singleton_class(VALUE x)
 {
     /* should not propagate to meta-meta-class, and so on */
-    if (!(RBASIC(x)->flags & FL_SINGLETON)) {
-	VALUE klass = RBASIC_CLASS(x);
-	if (klass && (klass = RCLASS_ORIGIN(klass)) != 0 &&
-	    FL_TEST(klass, (FL_SINGLETON|FL_FREEZE)) == FL_SINGLETON) {
-	    OBJ_FREEZE_RAW(klass);
-	}
+    if (!RCLASS_SINGLETON_P(x)) {
+        VALUE klass = RBASIC_CLASS(x);
+        if (klass && // no class when hidden from ObjectSpace
+            FL_TEST(klass, (FL_SINGLETON|FL_FREEZE)) == FL_SINGLETON) {
+            OBJ_FREEZE(klass);
+        }
     }
 }
 
-/*!
- * Returns the singleton class of \a obj, or nil if obj is not a
+/**
+ * Returns the singleton class of `obj`, or nil if obj is not a
  * singleton object.
  *
- * \param obj an arbitrary object.
- * \return the singleton class or nil.
+ * @param obj an arbitrary object.
+ * @return the singleton class or nil.
  */
 VALUE
 rb_singleton_class_get(VALUE obj)
@@ -2121,11 +2287,11 @@ rb_singleton_class_get(VALUE obj)
     VALUE klass;
 
     if (SPECIAL_CONST_P(obj)) {
-	return rb_special_singleton_class(obj);
+        return rb_special_singleton_class(obj);
     }
     klass = METACLASS_OF(obj);
-    if (!FL_TEST(klass, FL_SINGLETON)) return Qnil;
-    if (rb_attr_get(klass, id_attached) != obj) return Qnil;
+    if (!RCLASS_SINGLETON_P(klass)) return Qnil;
+    if (RCLASS_ATTACHED_OBJECT(klass) != obj) return Qnil;
     return klass;
 }
 
@@ -2189,20 +2355,20 @@ rb_define_attr(VALUE klass, const char *name, int read, int write)
     rb_attr(klass, rb_intern(name), read, write, FALSE);
 }
 
-MJIT_FUNC_EXPORTED VALUE
+VALUE
 rb_keyword_error_new(const char *error, VALUE keys)
 {
     long i = 0, len = RARRAY_LEN(keys);
     VALUE error_message = rb_sprintf("%s keyword%.*s", error, len > 1, "s");
 
     if (len > 0) {
-	rb_str_cat_cstr(error_message, ": ");
-	while (1) {
+        rb_str_cat_cstr(error_message, ": ");
+        while (1) {
             const VALUE k = RARRAY_AREF(keys, i);
-	    rb_str_append(error_message, rb_inspect(k));
-	    if (++i >= len) break;
-	    rb_str_cat_cstr(error_message, ", ");
-	}
+            rb_str_append(error_message, rb_inspect(k));
+            if (++i >= len) break;
+            rb_str_cat_cstr(error_message, ", ");
+        }
     }
 
     return rb_exc_new_str(rb_eArgError, error_message);
@@ -2221,7 +2387,7 @@ unknown_keyword_error(VALUE hash, const ID *table, int keywords)
 {
     int i;
     for (i = 0; i < keywords; i++) {
-	st_data_t key = ID2SYM(table[i]);
+        st_data_t key = ID2SYM(table[i]);
         rb_hash_stlike_delete(hash, &key, NULL);
     }
     rb_keyword_error("unknown", rb_hash_keys(hash));
@@ -2245,8 +2411,8 @@ rb_extract_keywords(VALUE *orighash)
     VALUE hash = *orighash;
 
     if (RHASH_EMPTY_P(hash)) {
-	*orighash = 0;
-	return hash;
+        *orighash = 0;
+        return hash;
     }
     rb_hash_foreach(hash, separate_symbol, (st_data_t)&parthash);
     *orighash = parthash[1];
@@ -2272,36 +2438,36 @@ rb_get_kwargs(VALUE keyword_hash, const ID *table, int required, int optional, V
     if (NIL_P(keyword_hash)) keyword_hash = 0;
 
     if (optional < 0) {
-	rest = 1;
-	optional = -1-optional;
+        rest = 1;
+        optional = -1-optional;
     }
     if (required) {
-	for (; i < required; i++) {
-	    VALUE keyword = ID2SYM(table[i]);
-	    if (keyword_hash) {
+        for (; i < required; i++) {
+            VALUE keyword = ID2SYM(table[i]);
+            if (keyword_hash) {
                 if (extract_kwarg(keyword, values[i])) {
-		    continue;
-		}
-	    }
-	    if (NIL_P(missing)) missing = rb_ary_tmp_new(1);
-	    rb_ary_push(missing, keyword);
-	}
-	if (!NIL_P(missing)) {
-	    rb_keyword_error("missing", missing);
-	}
+                    continue;
+                }
+            }
+            if (NIL_P(missing)) missing = rb_ary_hidden_new(1);
+            rb_ary_push(missing, keyword);
+        }
+        if (!NIL_P(missing)) {
+            rb_keyword_error("missing", missing);
+        }
     }
     j = i;
     if (optional && keyword_hash) {
-	for (i = 0; i < optional; i++) {
+        for (i = 0; i < optional; i++) {
             if (extract_kwarg(ID2SYM(table[required+i]), values[required+i])) {
-		j++;
-	    }
-	}
+                j++;
+            }
+        }
     }
     if (!rest && keyword_hash) {
-	if (RHASH_SIZE(keyword_hash) > (unsigned int)(values ? 0 : j)) {
-	    unknown_keyword_error(keyword_hash, table, required+optional);
-	}
+        if (RHASH_SIZE(keyword_hash) > (unsigned int)(values ? 0 : j)) {
+            unknown_keyword_error(keyword_hash, table, required+optional);
+        }
     }
     if (values && !keyword_hash) {
         for (i = 0; i < required + optional; i++) {
@@ -2332,30 +2498,30 @@ rb_scan_args_parse(int kw_flag, const char *fmt, struct rb_scan_args_t *arg)
 
     if (ISDIGIT(*p)) {
         arg->n_lead = *p - '0';
-	p++;
-	if (ISDIGIT(*p)) {
+        p++;
+        if (ISDIGIT(*p)) {
             arg->n_opt = *p - '0';
-	    p++;
-	}
+            p++;
+        }
     }
     if (*p == '*') {
         arg->f_var = 1;
-	p++;
+        p++;
     }
     if (ISDIGIT(*p)) {
         arg->n_trail = *p - '0';
-	p++;
+        p++;
     }
     if (*p == ':') {
         arg->f_hash = 1;
-	p++;
+        p++;
     }
     if (*p == '&') {
         arg->f_block = 1;
-	p++;
+        p++;
     }
     if (*p != '\0') {
-	rb_fatal("bad scan arg format: %s", fmt);
+        rb_fatal("bad scan arg format: %s", fmt);
     }
 }
 
@@ -2391,37 +2557,37 @@ rb_scan_args_assign(const struct rb_scan_args_t *arg, int argc, const VALUE *con
     for (i = 0; i < n_lead; i++) {
         var = rb_scan_args_next_param();
         if (var) *var = argv[argi];
-	argi++;
+        argi++;
     }
     /* capture optional arguments */
     for (i = 0; i < n_opt; i++) {
         var = rb_scan_args_next_param();
         if (argi < argc - n_trail) {
             if (var) *var = argv[argi];
-	    argi++;
-	}
-	else {
-	    if (var) *var = Qnil;
-	}
+            argi++;
+        }
+        else {
+            if (var) *var = Qnil;
+        }
     }
     /* capture variable length arguments */
     if (f_var) {
         int n_var = argc - argi - n_trail;
 
         var = rb_scan_args_next_param();
-	if (0 < n_var) {
+        if (0 < n_var) {
             if (var) *var = rb_ary_new_from_values(n_var, &argv[argi]);
-	    argi += n_var;
-	}
-	else {
-	    if (var) *var = rb_ary_new();
-	}
+            argi += n_var;
+        }
+        else {
+            if (var) *var = rb_ary_new();
+        }
     }
     /* capture trailing mandatory arguments */
     for (i = 0; i < n_trail; i++) {
         var = rb_scan_args_next_param();
         if (var) *var = argv[argi];
-	argi++;
+        argi++;
     }
     /* capture an option hash - phase 2: assignment */
     if (f_hash) {
@@ -2431,12 +2597,12 @@ rb_scan_args_assign(const struct rb_scan_args_t *arg, int argc, const VALUE *con
     /* capture iterator block */
     if (f_block) {
         var = rb_scan_args_next_param();
-	if (rb_block_given_p()) {
-	    *var = rb_block_proc();
-	}
-	else {
-	    *var = Qnil;
-	}
+        if (rb_block_given_p()) {
+            *var = rb_block_proc();
+        }
+        else {
+            *var = Qnil;
+        }
     }
 
     if (argi == argc) {
diff --git a/common.mk b/common.mk
index 9068a298a6..0ea360ce62 100644
--- a/common.mk
+++ b/common.mk
author	Benoit Daloze <eregontp@gmail.com>	2019-06-27 21:02:33 +0200
committer	Benoit Daloze <eregontp@gmail.com>	2019-06-27 21:02:33 +0200
commit	c940397116c5aef76b1c0d05561c11d43ef596a7 (patch)
tree	df0094c1f2252c9c49b1284414e7e9b0a5a879e8 /spec/ruby/core/integer/to_int_spec.rb
parent	310a42e89c431f9650c6727f934f35c5e6f9a6cc (diff)