use RB_TYPE_P() instead of comparison of TYPE()

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@35763 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
author: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> 2012-05-23 07:13:21 +0000
committer: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> 2012-05-23 07:13:21 +0000
commit: b0dd250dc95ea0fae89c3201967039d582fbf156 (patch)
tree: fb9483ca974a305e496eb87e960dcfecf7b9115f /include/ruby/ruby.h
parent: 87c8c5edf43a7f7d33d5fe75f51ef410a03b93b1 (diff)
0 files changed, 0 insertions, 0 deletions
diff --git a/.dir-locals.el b/.dir-locals.el
new file mode 100644
index 0000000000..8f4b96445c
--- /dev/null
+++ b/.dir-locals.el
@@ -0,0 +1,39 @@
+;; Copyright (c) 2018 Urabe, Shyouhei.  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.
+
+((nil .
+     ((indent-tabs-mode . nil)
+      (require-final-newline . t)
+      (tab-width . 8)
+      (show-trailing-whitespace . t)
+      (whitespace-line-column . 80))) ;; See also [Misc #12277]
+
+ ;; (bat-mode . ((buffer-file-coding-system . utf-8-dos)))
+
+ (ruby-mode . ((ruby-indent-level . 2)))
+
+ (rdoc-mode . ((fill-column . 74)))
+
+ (yaml-mode . ((yaml-indent-offset . 2)))
+
+ (makefile-mode . ((indent-tabs-mode . t)))
+
+ (c-mode . ((c-file-style . "ruby")))
+
+ (c++-mode . ((c-file-style . "ruby")))
+
+ (change-log-mode .
+     ((buffer-file-coding-system . us-ascii)
+      (indent-tabs-mode . t)
+      (change-log-indent-text . 2)
+      (add-log-time-format . (lambda (&optional x y)
+        (let* ((time (or x (current-time)))
+	       (system-time-locale "C")
+	       (diff (+ (cadr time) 32400))
+	       (lo (% diff 65536))
+	       (hi (+ (car time) (/ diff 65536))))
+        (format-time-string "%a %b %e %H:%M:%S %Y" (list hi lo) t)))))))
diff --git a/.document b/.document
index 0cc939508e..82ca602bfb 100644
--- a/.document
+++ b/.document
@@ -9,9 +9,33 @@
 
 # prelude
 prelude.rb
-
 rbconfig.rb
 
+array.rb
+ast.rb
+dir.rb
+gc.rb
+hash.rb
+io.rb
+kernel.rb
+marshal.rb
+numeric.rb
+nilclass.rb
+pack.rb
+pathname_builtin.rb
+ractor.rb
+string.rb
+symbol.rb
+timev.rb
+thread_sync.rb
+trace_point.rb
+warning.rb
+yjit.rb
+zjit.rb
+
+# Errno::*
+known_errors.inc
+
 # the lib/ directory (which has its own .document file)
 lib
 
@@ -19,16 +43,14 @@ lib
 ext
 
 # rdoc files
-NEWS
+NEWS.md
 
 README.md
 README.ja.md
 
 COPYING
 COPYING.ja
-CONTRIBUTING.md
 
-# win32/README.win32 linked from README.md
-win32
+LEGAL
 
 doc
diff --git a/.editorconfig b/.editorconfig
index cb2729fff9..4633a7acae 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -23,5 +23,8 @@ indent_size = 2
 [{*[Mm]akefile*,*.mak,*.mk,depend}]
 indent_style = tab
 
+[enc/*]
+indent_size = 2
+
 [reg*.[ch]]
 indent_size = 2
diff --git a/.gdbinit b/.gdbinit
index 1806196a42..bda544c641 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*)($arg0))->as.ary) @ (RSHAPE_CAPACITY(rb_obj_shape_id($arg0)))
     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*)($arg0))->as.heap.aux.shared
-	printf " "
+        printf "(shared) shared="
+        output/x ((struct RArray*)($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)
@@ -156,14 +138,16 @@ define rp
   else
   if ($flags & RUBY_T_MASK) == RUBY_T_HASH
     printf "%sT_HASH%s: ", $color_type, $color_end,
-    if (((struct RHash *)($arg0))->basic->flags & RHASH_ST_TABLE_FLAG)
-      printf "st len=%ld ", ((struct RHash *)($arg0))->as.st->num_entries
+    if (((struct RHash *)($arg0))->basic.flags & RHASH_ST_TABLE_FLAG)
+      set $st = (struct st_table *)((uintptr_t)($arg0) + sizeof(struct RHash))
+      printf "st len=%ld ", $st->num_entries
+      print $st
     else
       printf "li len=%ld bound=%ld ", \
-        ((((struct RHash *)($arg0))->basic->flags & RHASH_ARRAY_LEN_MASK) >> RHASH_ARRAY_LEN_SHIFT), \
-        ((((struct RHash *)($arg0))->basic->flags & RHASH_ARRAY_BOUND_MASK) >> RHASH_ARRAY_BOUND_SHIFT)
+        ((((struct RHash *)($arg0))->basic.flags & RHASH_AR_TABLE_SIZE_MASK) >> RHASH_AR_TABLE_SIZE_SHIFT), \
+        ((((struct RHash *)($arg0))->basic.flags & RHASH_AR_TABLE_BOUND_MASK) >> RHASH_AR_TABLE_BOUND_SHIFT)
+	print (struct ar_table_struct *)((uintptr_t)($arg0) + sizeof(struct RHash))
     end
-    print (struct RHash *)($arg0)
   else
   if ($flags & RUBY_T_MASK) == RUBY_T_STRUCT
     set $len = (($flags & (RUBY_FL_USER1|RUBY_FL_USER2)) ? \
@@ -201,12 +185,19 @@ define rp
     print (struct RBasic *)($arg0)
   else
   if ($flags & RUBY_T_MASK) == RUBY_T_DATA
-    if ((struct RTypedData *)($arg0))->typed_flag == 1
-      printf "%sT_DATA%s(%s): ", $color_type, $color_end, ((struct RTypedData *)($arg0))->type->wrap_struct_name
-      print (struct RTypedData *)($arg0)
+    if ($flags & RUBY_TYPED_FL_IS_TYPED_DATA)
+      set $data = (struct RTypedData *)($arg0)
+      set $type = (const rb_data_type_t *)($data->type & ~1)
+      printf "%sT_DATA%s(%s): ", $color_type, $color_end, $type->wrap_struct_name
+      print *$type
+      if ($data->type & 1)
+        print (void *)&$data->data
+      else
+        print $data
+      end
     else
       printf "%sT_DATA%s: ", $color_type, $color_end
-      print (struct RData *)($arg0)
+      print *(struct RData *)($arg0)
     end
   else
   if ($flags & RUBY_T_MASK) == RUBY_T_MATCH
@@ -265,6 +256,10 @@ define rp
     printf "%sT_ZOMBIE%s: ", $color_type, $color_end
     print (struct RData *)($arg0)
   else
+  if ($flags & RUBY_T_MASK) == RUBY_T_MOVED
+    printf "%sT_MOVED%s: ", $color_type, $color_end
+    print *(struct RMoved *)$arg0
+  else
     printf "%sunknown%s: ", $color_type, $color_end
     print (struct RBasic *)($arg0)
   end
@@ -300,6 +295,7 @@ define rp
   end
   end
   end
+  end
 end
 document rp
   Print a Ruby's VALUE.
@@ -435,13 +431,11 @@ 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
@@ -449,13 +443,11 @@ 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
 
@@ -538,14 +530,14 @@ document rp_bignum
 end
 
 define rp_class
+  set $class_and_classext = (struct RClass_and_rb_classext_t *)($arg0)
   printf "(struct RClass *) %p", (void*)$arg0
-  if ((struct RClass *)($arg0))->ptr.origin_ != $arg0
-    printf " -> %p", ((struct RClass *)($arg0))->ptr.origin_
+  if $class_and_classext->classext->origin_ != (VALUE)$arg0
+    printf " -> %p", $class_and_classext->classext->origin_
   end
   printf "\n"
   rb_classname $arg0
-  print/x *(struct RClass *)($arg0)
-  print *((struct RClass *)($arg0))->ptr
+  print/x *$class_and_classext
 end
 document rp_class
   Print the content of a Class/Module.
@@ -684,11 +676,6 @@ 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
@@ -863,22 +850,22 @@ 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
@@ -916,10 +903,10 @@ document rb_method_entry
 end
 
 define rb_classname
-  # up to 128bit int
-  set $rb_classname = rb_mod_name($arg0)
-  if $rb_classname != RUBY_Qnil
-    rp $rb_classname
+  set $rb_classname = ((struct RClass_and_rb_classext_t*)$arg0)->classext->classpath
+  if $rb_classname != RUBY_Qfalse
+    print_string $rb_classname
+    printf "\n"
   else
     echo anonymous class/module\n
   end
@@ -956,7 +943,7 @@ 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
@@ -974,8 +961,8 @@ 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)
@@ -1073,9 +1060,9 @@ define print_id
   else
     set $serial = (rb_id_serial_t)$id
   end
-  if $serial && $serial <= global_symbols.last_id
+  if $serial && $serial <= ruby_global_symbols.last_id
     set $idx = $serial / ID_ENTRY_UNIT
-    set $ids = (struct RArray *)global_symbols.ids
+    set $ids = (struct RArray *)ruby_global_symbols.ids
     set $flags = $ids->basic.flags
     if ($flags & RUBY_FL_USER1)
       set $idsptr = $ids->as.ary
@@ -1097,11 +1084,11 @@ define print_id
           set $arylen = $ary->as.heap.len
         end
         set $result = $aryptr[($serial % ID_ENTRY_UNIT) * ID_ENTRY_SIZE + $t]
-	if $result != RUBY_Qnil
+        if $result != RUBY_Qnil
           print_string $result
-	else
-	  echo undef
-	end
+        else
+          echo undef
+        end
       end
     end
   end
@@ -1126,7 +1113,7 @@ 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
@@ -1274,9 +1261,9 @@ document rb_count_objects
   Counts all objects grouped by type.
 end
 
-# Details: https://bugs.ruby-lang.org/projects/ruby-trunk/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
@@ -1311,16 +1298,14 @@ 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
   printf "RUBY_FL_WB_PROTECTED: %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_WB_PROTECTED ? "1" : "0"
-  printf "RUBY_FL_PROMOTED0   : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_PROMOTED0 ? "1" : "0"
-  printf "RUBY_FL_PROMOTED1   : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_PROMOTED1 ? "1" : "0"
+  printf "RUBY_FL_PROMOTED    : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_PROMOTED ? "1" : "0"
   printf "RUBY_FL_FINALIZE    : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_FINALIZE ? "1" : "0"
-  printf "RUBY_FL_TAINT       : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_TAINT ? "1" : "0"
-  printf "RUBY_FL_UNTRUSTED   : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_UNTRUSTED ? "1" : "0"
+  printf "RUBY_FL_SHAREABLE   : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_SHAREABLE ? "1" : "0"
   printf "RUBY_FL_EXIVAR      : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_EXIVAR ? "1" : "0"
   printf "RUBY_FL_FREEZE      : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_FREEZE ? "1" : "0"
 
@@ -1344,3 +1329,8 @@ 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..d98646febf
--- /dev/null
+++ b/.git-blame-ignore-revs
@@ -0,0 +1,41 @@
+# 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
+5062c0c621d887367af8a054e5e5d83d7ec57dd3
+
+# 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
+7a56c316418980b8a41fcbdc94067b2bda2ad112
+e90282be7ba1bc8e3119f6e1a2c80356ceb3f80a
+26a9e0b4e31f7b5a9cbd755e0a15823a8fa51bae
+2f53985da9ee593fe524d408256835667938c7d7
diff --git a/.gitattributes b/.gitattributes
index 6ca2f89462..6ac6e6fcc3 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -1,6 +1,9 @@
 *.gemspec diff=ruby
 *.rb diff=ruby
+*.inc.rs linguist-generated=true
 bin svn-properties=svn:ignore=ruby
 bin/* diff=ruby
 tool/update-deps diff=ruby
 tool/make-snapshot diff=ruby
+tool/format-release diff=ruby
+tool/leaked-globals diff=ruby
diff --git a/.github/SECURITY.md b/.github/SECURITY.md
new file mode 100644
index 0000000000..56baa29942
--- /dev/null
+++ b/.github/SECURITY.md
@@ -0,0 +1,9 @@
+# Security Policy
+
+## Supported Versions
+
+See <https://www.ruby-lang.org/en/downloads/branches/>.
+
+## Reporting a Vulnerability
+
+See <https://www.ruby-lang.org/en/security/>.
diff --git a/.github/actions/capiext/action.yml b/.github/actions/capiext/action.yml
new file mode 100644
index 0000000000..49562725f4
--- /dev/null
+++ b/.github/actions/capiext/action.yml
@@ -0,0 +1,86 @@
+name: rubyspec C-API extensions
+
+inputs:
+  builddir:
+    required: false
+    default: '.'
+  make:
+    required: false
+    default: 'make -s'
+
+outputs:
+  key:
+    value: >-
+      ${{
+      !steps.restore.outputs.cache-hit &&
+      github.ref == 'refs/heads/master' &&
+      steps.config.outputs.key
+      }}
+
+runs:
+  using: composite
+
+  steps:
+    - id: config
+      shell: bash
+      run: |
+        eval $(grep -e '^arch *=' -e '^ruby_version *=' -e '^DLEXT *=' Makefile |
+            sed 's/ *= */=/')
+        case "${ruby_version}" in
+        *+*) key=capiexts-${arch}-${ruby_version}-${{ hashFiles('src/spec/ruby/optional/capi/ext/*.[ch]') }};;
+        *)   key=;;
+        esac
+        echo version=$ruby_version >> $GITHUB_OUTPUT
+        echo key="$key" >> $GITHUB_OUTPUT
+        echo DLEXT=$DLEXT >> $GITHUB_OUTPUT
+      working-directory: ${{ inputs.builddir }}
+
+    - name: Restore previous CAPI extensions
+      uses: actions/cache/restore@0400d5f644dc74513175e3cd8d07132dd4860809 # v4.2.4
+      id: cache
+      with:
+        path: ${{ inputs.builddir }}/spec/ruby/optional/capi/ext/
+        key: ${{ steps.config.outputs.key }}
+      if: ${{ steps.config.outputs.key }}
+
+    - name: Run test-spec with previous CAPI extension binaries
+      id: check
+      shell: bash
+      run: |
+        touch spec/ruby/optional/capi/ext/*.$DLEXT
+        [ ! -f spec/ruby/optional/capi/ext/\*.$DLEXT ]
+        ${{ inputs.make }} SPECOPTS=optional/capi test-spec
+      env:
+        DLEXT: ${{ steps.config.outputs.DLEXT }}
+      working-directory: ${{ inputs.builddir }}
+      if: ${{ steps.cache.outputs.cache-hit }}
+
+    - name: Strip CAPI extensions
+      id: strip
+      shell: bash
+      run: |
+        rm -f spec/ruby/optional/capi/ext/*.c
+        [ "$DLEXT" = bundle ] || # separated to .dSYM directories
+        strip spec/ruby/optional/capi/ext/*.$DLEXT
+      env:
+        DLEXT: ${{ steps.config.outputs.DLEXT }}
+      working-directory: ${{ inputs.builddir }}
+      if: >-
+        ${{true
+        && ! steps.cache.outputs.cache-hit
+        && github.ref_name == 'master'
+        }}
+
+    - name: Save CAPI extensions
+      uses: actions/cache/save@0400d5f644dc74513175e3cd8d07132dd4860809 # v4.2.4
+      with:
+        path: ${{ inputs.builddir }}/spec/ruby/optional/capi/ext/
+        key: ${{ steps.config.outputs.key }}
+      if: ${{ steps.strip.outcome == 'success' }}
+
+    - shell: bash
+      run: |
+        echo "::error::Change from ${prev} detected; bump up ABI version"
+      env:
+        prev: ${{ steps.config.outputs.version }}
+      if: ${{ always() && steps.check.outcome == 'failure' }}
diff --git a/.github/actions/compilers/action.yml b/.github/actions/compilers/action.yml
new file mode 100644
index 0000000000..ab5b56a889
--- /dev/null
+++ b/.github/actions/compilers/action.yml
@@ -0,0 +1,133 @@
+name: Compiles ruby in a container
+description: >-
+  Makes ruby using a dedicated container
+
+inputs:
+  tag:
+    required: false
+    default: clang-20
+    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`
+
+  test_all:
+    required: false
+    default: ''
+    description: >-
+      Whether to run `make test-all` with options for test-all.
+
+  test_spec:
+    required: false
+    default: ''
+    description: >-
+      Whether to run `make test-spec` with 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='${{ inputs.check }}'
+        --env INPUT_TEST_ALL='${{ inputs.test_all }}'
+        --env INPUT_TEST_SPEC='${{ inputs.test_spec }}'
+        --env INPUT_ENABLE_SHARED='${{ 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='${{ github.ref }}'
+        --env GITHUB_ACTIONS
+        --env GITHUB_RUN_ID
+        --env GITHUB_REPOSITORY
+        --env GITHUB_WORKFLOW
+        --env GITHUB_RUN_NUMBER
+        --env GITHUB_EVENT_NAME
+        --env GITHUB_SHA
+        --env GITHUB_HEAD_REF
+        --env GITHUB_SERVER_URL
+        'ghcr.io/ruby/ruby-ci-image:${{ inputs.tag }}'
diff --git a/.github/actions/compilers/entrypoint.sh b/.github/actions/compilers/entrypoint.sh
new file mode 100755
index 0000000000..b554151091
--- /dev/null
+++ b/.github/actions/compilers/entrypoint.sh
@@ -0,0 +1,90 @@
+#! /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 + $(nproc)))"
+
+case "x${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,+ \
+    --without-git                  \
+    ${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
+    ) >> ${builddir}/ext/Setup
+    set +x
+    echo "::endgroup::"
+fi
+
+if [ -n "$INPUT_TEST_ALL" ]; then
+  tests=" -- $INPUT_TEST_ALL"
+else
+  tests=" -- ruby -ext-"
+fi
+
+pushd ${builddir}
+
+grouped make showflags
+grouped make all
+# grouped make install
+
+# Run only `make test` by default. Run other tests if specified.
+grouped make test
+if [[ -n "$INPUT_CHECK" ]]; then grouped make test-tool; fi
+if [[ -n "$INPUT_CHECK" || -n "$INPUT_TEST_ALL" ]]; then grouped make test-all TESTS="$tests"; fi
+if [[ -n "$INPUT_CHECK" || -n "$INPUT_TEST_SPEC" ]]; then grouped env CHECK_LEAKS=true make test-spec MSPECOPT="$INPUT_TEST_SPEC"; fi
diff --git a/.github/actions/launchable/setup/action.yml b/.github/actions/launchable/setup/action.yml
new file mode 100644
index 0000000000..16af8fc3fd
--- /dev/null
+++ b/.github/actions/launchable/setup/action.yml
@@ -0,0 +1,313 @@
+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.
+
+outputs:
+  stdout_report_path:
+    value: ${{ steps.global.outputs.stdout_report_path }}
+    description: >-
+      Report file path for standard output.
+
+  stderr_report_path:
+    value: ${{ steps.global.outputs.stderr_report_path }}
+    description: >-
+      Report file path for standard error.
+
+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
+        && !endsWith(inputs.os, 'ppc64le') && !endsWith(inputs.os, 's390x') }}
+
+    - 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
+        && !endsWith(inputs.os, 'ppc64le') && !endsWith(inputs.os, 's390x') }}
+
+    - name: Set up Java ppc64le
+      uses: actions/setup-java@7a445ee88d4e23b52c33fdc7601e40278616c7f8 # v4.0.0
+      with:
+        distribution: 'semeru'
+        architecture: 'ppc64le'
+        java-version: '17'
+      if: >-
+        ${{ steps.enable-launchable.outputs.enable-launchable
+        && endsWith(inputs.os, 'ppc64le') }}
+
+    - name: Set up Java s390x
+      uses: actions/setup-java@7a445ee88d4e23b52c33fdc7601e40278616c7f8 # v4.0.0
+      with:
+        distribution: 'semeru'
+        architecture: 's390x'
+        java-version: '17'
+      if: >-
+        ${{ steps.enable-launchable.outputs.enable-launchable
+        && endsWith(inputs.os, 's390x') }}
+
+    - name: Set global vars
+      id: global
+      shell: bash
+      run: |
+        test_all_enabled="${{ 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_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
+        echo stdout_report_path="launchable_stdout.log" >> $GITHUB_OUTPUT
+        echo stderr_report_path="launchable_stderr.log" >> $GITHUB_OUTPUT
+      if: steps.enable-launchable.outputs.enable-launchable
+
+    - name: Set environment variables for Launchable
+      shell: bash
+      run: |
+        : # GITHUB_PULL_REQUEST_URL are used for commenting test reports in Launchable Github App.
+        : # https://github.com/launchableinc/cli/blob/v1.80.1/launchable/utils/link.py#L42
+        echo "GITHUB_PULL_REQUEST_URL=${{ 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
+        : # To prevent a slowdown in CI, disable request retries when the Launchable server is unstable.
+        echo "LAUNCHABLE_SKIP_TIMEOUT_RETRY=1" >> $GITHUB_ENV
+        echo "LAUNCHABLE_COMMIT_TIMEOUT=1" >> $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')
+          || endsWith(inputs.os, 'ppc64le')
+          || endsWith(inputs.os, 's390x'))
+        }}
+
+    - name: Set up Launchable
+      id: setup-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_setup target var -- refers ${target} prefixed variables
+        launchable_setup() {
+          local target=$1 session
+          eval [ "\${${target}_enabled}" = "true" ] || return
+          eval local suite=\${${target}_test_suite}
+          session=$(launchable record session \
+            --build "${build_name}" \
+            --observation \
+            --flavor os="${{ inputs.os }}" \
+            --flavor test_task="${{ inputs.test-task }}" \
+            --flavor test_opts="${test_opts}" \
+            --flavor workflow="${{ github.workflow }}" \
+            --test-suite ${suite} \
+            )
+          echo "${target}_session=${session}" >> $GITHUB_OUTPUT
+        }
+
+        launchable record build --name "${build_name}"
+        if launchable_setup test_all; then
+          echo "TESTS=${TESTS:+$TESTS }--launchable-test-reports=${test_all_report_file}" >> $GITHUB_ENV
+        fi
+        if launchable_setup btest; then
+          echo "BTESTS=${BTESTS:+$BTESTS }--launchable-test-reports=${btest_report_file}" >> $GITHUB_ENV
+        fi
+        if launchable_setup test_spec; then
+          echo "SPECOPTS=${SPECOPTS:$SPECOPTS }--launchable-test-reports=${test_spec_report_dir}" >> $GITHUB_ENV
+          echo test_spec_enabled=true >> $GITHUB_OUTPUT
+        fi
+
+        echo launchable_setup_dir=$(pwd) >> $GITHUB_OUTPUT
+      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_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: make test-spec report directory in build directory
+      shell: bash
+      working-directory: ${{ inputs.builddir }}
+      run: mkdir "${test_spec_report_dir}"
+      if: ${{ steps.setup-launchable.outputs.test_spec_enabled == 'true' }}
+      env:
+        test_spec_report_dir: ${{ steps.global.outputs.test_spec_report_dir }}
+
+    - name: Clean up test results in Launchable
+      uses: gacts/run-and-post-run@674528335da98a7afc80915ff2b4b860a0b3553a # v1.4.0
+      with:
+        shell: bash
+        working-directory: ${{ inputs.builddir }}
+        post: |
+          rm -f "${test_all_report_file}"
+          rm -f "${btest_report_file}"
+          rm -fr "${test_spec_report_dir}"
+          rm -f launchable_stdout.log
+          rm -f launchable_stderr.log
+      if: always() && steps.setup-launchable.outcome == 'success'
+      env:
+        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: ${{ inputs.builddir }}
+        post: |
+          if [[ "${test_all_enabled}" = "true" ]]; then \
+            launchable record attachment \
+              --session "${test_all_session}" \
+              "${stdout_report_path}" \
+              "${stderr_report_path}"; \
+            launchable record tests \
+              --session "${test_all_session}" \
+              raw "${test_all_report_file}" || true; \
+          fi
+
+          if [[ "${btest_enabled}" = "true" ]]; then \
+            launchable record attachment \
+              --session "${btest_session}" \
+              "${stdout_report_path}" \
+              "${stderr_report_path}"; \
+            launchable record tests \
+              --session "${btest_session}" \
+              raw "${btest_report_file}" || true; \
+          fi
+
+          if [[ "${test_spec_enabled}" = "true" ]]; then \
+            launchable record attachment \
+              --session "${test_spec_session}" \
+              "${stdout_report_path}" \
+              "${stderr_report_path}"; \
+            launchable record tests \
+              --session "${test_spec_session}" \
+              raw ${test_spec_report_dir}/* || true; \
+          fi
+      if: ${{ always() && steps.setup-launchable.outcome == 'success' }}
+      env:
+        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 }}
+        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: ${{ steps.setup-launchable.outputs.test_all_session }}
+        btest_session: ${{ steps.setup-launchable.outputs.btest_session }}
+        test_spec_session: ${{ steps.setup-launchable.outputs.test_spec_session }}
+        stdout_report_path: ${{ steps.global.outputs.stdout_report_path }}
+        stderr_report_path: ${{ steps.global.outputs.stderr_report_path }}
+        LAUNCHABLE_SETUP_DIR: ${{ steps.setup-launchable.outputs.launchable_setup_dir }}
diff --git a/.github/actions/setup/directories/action.yml b/.github/actions/setup/directories/action.yml
new file mode 100644
index 0000000000..0e8ffd59ef
--- /dev/null
+++ b/.github/actions/setup/directories/action.yml
@@ -0,0 +1,194 @@
+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.
+
+  make-command:
+    required: false
+    type: string
+    default: 'make'
+    description: >-
+      The command of `make`.
+
+  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=`sudo true && 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@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+      with:
+        path: ${{ inputs.srcdir }}
+        fetch-depth: ${{ inputs.fetch-depth }}
+
+    - uses: actions/cache@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
+      with:
+        path: ${{ inputs.srcdir }}/.downloaded-cache
+        key: ${{ runner.os }}-${{ runner.arch }}-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 + $(nproc)))" >> "$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 $HOME/.config || :
+        declare -a dirs # -A is not supported by old bash, e.g. macos
+        SAVE_IFS="$IFS" IFS=:; set $PATH
+        for d do
+          while [ -d "$d" ]; do
+            case "$IFS${dirs[*]}$IFS" in *"$IFS$d$IFS"*) ;; *) dirs+=("$d");; esac
+            d="${d%/*}"
+          done
+        done
+        IFS="$SAVE_IFS"
+        sudo chmod -v go-w "${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='cd ${{ inputs.builddir }} && ${{ inputs.make-command }} 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@81b6ce503cde93862cec047c54652e45c5dca991 # v1.4.3
+      with:
+        working-directory:
+        post: |
+          ${{ steps.dummy-files.outputs.clean }}
+          ${{ steps.clean.outputs.distclean }}
+          ${{ steps.clean.outputs.remained-files }}
+          ${{ steps.clean.outputs.final }}
+      # rmdir randomly fails due to launchable files
+      continue-on-error: true
diff --git a/.github/actions/setup/macos/action.yml b/.github/actions/setup/macos/action.yml
new file mode 100644
index 0000000000..d0072ff828
--- /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${arch} || :
diff --git a/.github/actions/slack/action.yml b/.github/actions/slack/action.yml
new file mode 100644
index 0000000000..4a398da1d1
--- /dev/null
+++ b/.github/actions/slack/action.yml
@@ -0,0 +1,51 @@
+name: Post a message to slack
+description: >-
+  We have our ruby/action-slack webhook.  However its arguments are
+  bit verbose to be listed in every workflow files.  Better merge them
+  into one.
+
+inputs:
+  SLACK_WEBHOOK_URL:
+    required: true
+    description: >-
+      The URL to post the payload.  This is an input because it tends
+      to be stored in a secrets vault and a composite action cannot
+      look into one.
+
+  label:
+    required: false
+    description: >-
+      Human-readable description of the run, something like "DEBUG=1".
+      This need not be unique among runs.
+
+  event_name:
+    required: false
+    default: 'push'
+    description: >-
+      Target event to trigger notification. Notify only push by default.
+
+  extra_channel_id:
+    required: false
+    description: >-
+      Slack channel ID to notify besides #alerts and #alerts-emoji.
+
+outputs: {} # Nothing?
+
+runs:
+  using: composite
+
+  steps:
+    - uses: ruby/action-slack@54175162371f1f7c8eb94d7c8644ee2479fcd375 # v3.2.2
+      with:
+        payload: |
+          {
+            "ci": "GitHub Actions",
+            "env": "${{ 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 }}"
+            ${{ inputs.extra_channel_id && format(', "extra_channel_id": "{0}"', inputs.extra_channel_id) }}
+          }
+      env:
+        SLACK_WEBHOOK_URL: ${{ inputs.SLACK_WEBHOOK_URL }}
+      if: ${{ github.event_name == inputs.event_name && startsWith(github.repository, 'ruby/') }}
diff --git a/.github/auto_request_review.yml b/.github/auto_request_review.yml
new file mode 100644
index 0000000000..38496d5ceb
--- /dev/null
+++ b/.github/auto_request_review.yml
@@ -0,0 +1,20 @@
+files:
+  'yjit*': [team:jit]
+  'yjit/**/*': [team:jit]
+  'yjit/src/cruby_bindings.inc.rs': []
+  'bootstraptest/test_yjit*': [team:jit]
+  'test/ruby/test_yjit*': [team:jit]
+  'zjit*': [team:jit]
+  'zjit/**/*': [team:jit]
+  'zjit/src/cruby_bindings.inc.rs': []
+  'test/ruby/test_zjit*': [team:jit]
+  'defs/jit.mk': [team:jit]
+  'tool/zjit_bisect.rb': [team:jit]
+  'doc/jit/*': [team:jit]
+  # Skip github workflow files because the team don't necessarily need to review dependabot updates for GitHub Actions. It's noisy in notifications, and they're auto-merged anyway.
+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
+  # files are modified as well. To be enabled after fixing the behavior.
+  #last_files_match_only: true
diff --git a/.github/dependabot.yml b/.github/dependabot.yml
new file mode 100644
index 0000000000..2c2982d1d4
--- /dev/null
+++ b/.github/dependabot.yml
@@ -0,0 +1,22 @@
+version: 2
+updates:
+  - package-ecosystem: 'github-actions'
+    directory: '/'
+    schedule:
+      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'
+  - package-ecosystem: 'vcpkg'
+    directory: '/'
+    schedule:
+      interval: 'daily'
diff --git a/.github/labeler.yml b/.github/labeler.yml
new file mode 100644
index 0000000000..e81aed8e98
--- /dev/null
+++ b/.github/labeler.yml
@@ -0,0 +1,6 @@
+Documentation:
+- changed-files:
+  - all-globs-to-all-files: doc/**
+
+Backport:
+- base-branch: 'ruby_3_\d'
diff --git a/.github/workflows/annocheck.yml b/.github/workflows/annocheck.yml
new file mode 100644
index 0000000000..899d601aef
--- /dev/null
+++ b/.github/workflows/annocheck.yml
@@ -0,0 +1,110 @@
+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.pull_request.title, '[DOC]')
+      || 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@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        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@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
+        with:
+          ruby-version: '3.1'
+          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..207315a084
--- /dev/null
+++ b/.github/workflows/auto_request_review.yml
@@ -0,0 +1,20 @@
+name: Auto Request Review
+on:
+  pull_request_target:
+    types: [opened, ready_for_review, reopened]
+    branches: [master]
+
+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_AUTO_REQUEST_REVIEW_TOKEN }}
diff --git a/.github/workflows/auto_review_pr.yml b/.github/workflows/auto_review_pr.yml
new file mode 100644
index 0000000000..ad0e63ba12
--- /dev/null
+++ b/.github/workflows/auto_review_pr.yml
@@ -0,0 +1,33 @@
+name: Auto Review PR
+on:
+  pull_request_target:
+    types: [opened, ready_for_review, reopened]
+    branches: [master]
+
+permissions:
+  contents: read
+
+jobs:
+  auto-review-pr:
+    name: Auto Review PR
+    runs-on: ubuntu-latest
+    if: ${{ github.repository == 'ruby/ruby' && github.base_ref == 'master' }}
+
+    permissions:
+      pull-requests: write
+      contents: read
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6.0.1
+
+      - uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
+        with:
+          ruby-version: '3.4'
+          bundler: none
+
+      - name: Auto Review PR
+        run: ruby tool/auto_review_pr.rb "$GITHUB_PR_NUMBER"
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          GITHUB_PR_NUMBER: ${{ github.event.pull_request.number }}
diff --git a/.github/workflows/baseruby.yml b/.github/workflows/baseruby.yml
new file mode 100644
index 0000000000..d3e734f885
--- /dev/null
+++ b/.github/workflows/baseruby.yml
@@ -0,0 +1,74 @@
+name: BASERUBY Check
+
+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-22.04
+
+    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]')
+      )}}
+
+    strategy:
+      matrix:
+        ruby:
+          - ruby-3.1
+          - ruby-3.2
+          - ruby-3.3
+
+    steps:
+      - uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          bundler: none
+
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+
+      - uses: ./.github/actions/setup/ubuntu
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          makeup: true
+
+      - run: ./configure --disable-install-doc
+
+      - run: make all
+
+      - run: make test
+
+      - uses: ./.github/actions/slack
+        with:
+          label: ${{ matrix.ruby }}
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() }}
diff --git a/.github/workflows/bundled_gems.yml b/.github/workflows/bundled_gems.yml
new file mode 100644
index 0000000000..59f64e8312
--- /dev/null
+++ b/.github/workflows/bundled_gems.yml
@@ -0,0 +1,190 @@
+name: bundled_gems
+
+env:
+  UPDATE_ENABLED: true
+
+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:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          token: ${{ (github.repository == 'ruby/ruby' && !startsWith(github.event_name, 'pull')) && secrets.MATZBOT_AUTO_UPDATE_TOKEN || secrets.GITHUB_TOKEN }}
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          # Skip overwriting MATZBOT_AUTO_UPDATE_TOKEN
+          checkout: '' # false (ref: https://github.com/actions/runner/issues/2238)
+
+      - name: Set ENV
+        run: |
+          echo "TODAY=$(date +%F)" >> $GITHUB_ENV
+
+      - name: Download previous gems list
+        run: |
+          mkdir -p .downloaded-cache
+          for data in bundled_gems.json default_gems.json; do
+            ln -s .downloaded-cache/$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
+        if: ${{ env.UPDATE_ENABLED == 'true' }}
+
+      - name: Update spec/bundler/support/builders.rb
+        run: |
+          #!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
+        if: ${{ env.UPDATE_ENABLED == 'true' }}
+
+      - name: Maintain updated gems list in NEWS
+        run: |
+          ruby tool/update-NEWS-gemlist.rb bundled
+        if: ${{ env.UPDATE_ENABLED == 'true' }}
+
+      - name: Check diffs
+        id: diff
+        run: |
+          news= gems=
+          git diff --color --no-ext-diff --ignore-submodules --exit-code -- NEWS.md ||
+          news=true
+          git diff --color --no-ext-diff --ignore-submodules --exit-code -- gems/bundled_gems ||
+          gems=true
+          git add -- NEWS.md gems/bundled_gems
+          git add -- spec/bundler/support/builders.rb
+          echo news=$news >> $GITHUB_OUTPUT
+          echo gems=$gems >> $GITHUB_OUTPUT
+          echo update=${news:-$gems} >> $GITHUB_OUTPUT
+
+      - name: Commit
+        id: commit
+        run: |
+          git pull --ff-only origin ${GITHUB_REF#refs/heads/}
+          message="Update bundled gems list"
+          if [ -z "${gems}" ]; then
+            git commit --message="[DOC] ${message} at ${GITHUB_SHA:0:30}"
+          else
+            git commit --message="${message} as of ${TODAY}"
+          fi
+        env:
+          TODAY: ${{ steps.bundled_gems.outputs.latest_date || env.TODAY }}
+          EMAIL: svn-admin@ruby-lang.org
+          GIT_AUTHOR_NAME: git
+          GIT_COMMITTER_NAME: git
+          gems: ${{ steps.diff.outputs.gems }}
+        if: ${{ steps.diff.outputs.update }}
+
+      - name: Development revision of bundled gems
+        run: |
+          #!ruby
+          file = "gems/bundled_gems"
+
+          SECONDS_IN_DAY = 86400
+          today = Time.new("#{ENV['TODAY']}Z")
+          if !(december = today.month == 12)
+            days = 30
+          elsif (days = 26 - today.day).positive?
+            days += 4
+          else
+            puts "::info:: just after released"
+            exit
+          end
+
+          since = "#{today.year-1}-12-26"
+          ref = ENV['GITHUB_REF']
+          puts "::group::\e[94mfetching \e[1m#{file}\e[22m since \e[1m#{since}\e[22m from \e[1m#{ref}\e[m"
+          system(*%W[git fetch --shallow-since=#{since} --no-tags origin #{ref}], exception: true)
+          puts "::endgroup::"
+
+          puts "\e[94mchecking development version bundled gems older than \e[1m#{days}\e[22m days\e[m"
+          limit = today.to_i - days * SECONDS_IN_DAY
+          old = 0
+          IO.popen(%W"git blame --line-porcelain -- #{file}") do |blame|
+            while head = blame.gets("\n\t") and s = blame.gets
+              next unless (gem = s.split(/\s+|#.*/)).size > 3
+              time = head[/^committer-time \K\d+/].to_i
+              next if (d = limit - time) <= 0
+              d /= SECONDS_IN_DAY
+              line = head[/\A\h+ \d+ \K\d+/].to_i
+              level = if d < days; 'warning'; else old += 1; 'error'; end
+              d += days
+              puts "::#{level} file=#{file},line=#{line},title=Older than #{d} days::#{gem[0]} #{gem[3]}"
+            end
+          end
+          abort "::error title=Too long-standing gems::The release comes soon." if december and old.nonzero?
+        shell: ruby {0}
+        env:
+          file: ${{ steps.logs.outputs.file }}
+          days: ${{ steps.logs.outputs.days }}
+
+      - name: Install libraries
+        uses: ./.github/actions/setup/ubuntu
+        if: ${{ steps.diff.outputs.gems }}
+
+      - name: Build
+        run: |
+          ./autogen.sh
+          ./configure -C --disable-install-doc
+          make
+        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
+        timeout-minutes: 30
+        env:
+          RUBY_TESTOPTS: '-q --tty=no'
+          TEST_BUNDLED_GEMS_ALLOW_FAILURES: ''
+        if: ${{ steps.diff.outputs.gems }}
+
+      - name: Push
+        run: |
+          git push origin ${GITHUB_REF#refs/heads/}
+        if: >-
+          ${{
+          github.repository == 'ruby/ruby' &&
+          !startsWith(github.event_name, 'pull') &&
+          steps.commit.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/check_dependencies.yml b/.github/workflows/check_dependencies.yml
new file mode 100644
index 0000000000..c5dec65e48
--- /dev/null
+++ b/.github/workflows/check_dependencies.yml
@@ -0,0 +1,59 @@
+name: Check Dependencies
+on:
+  push:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man/*'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
+  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-deps:
+    name: Dependency checks
+
+    strategy:
+      matrix:
+        os: [ubuntu-latest]
+      fail-fast: true
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+
+      - uses: ./.github/actions/setup/ubuntu
+        if: ${{ contains(matrix.os, 'ubuntu') }}
+
+      - uses: ./.github/actions/setup/macos
+        if: ${{ contains(matrix.os, 'macos') }}
+
+      - uses: ./.github/actions/setup/directories
+
+      - uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
+        with:
+          ruby-version: '3.1'
+          bundler: none
+
+      - name: Run configure
+        run: ./configure -C --disable-install-doc --disable-rubygems --with-gcc 'optflags=-O0' 'debugflags=-save-temps=obj -g'
+
+      - run: make fix-depends
+
+      - run: git diff --no-ext-diff --ignore-submodules --exit-code
+
+      - uses: ./.github/actions/slack
+        with:
+          label: ${{ matrix.os }} / Dependencies need to update
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() }}
diff --git a/.github/workflows/check_misc.yml b/.github/workflows/check_misc.yml
new file mode 100644
index 0000000000..2a2bd1df53
--- /dev/null
+++ b/.github/workflows/check_misc.yml
@@ -0,0 +1,127 @@
+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@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          token: ${{ (github.repository == 'ruby/ruby' && !startsWith(github.event_name, 'pull')) && secrets.MATZBOT_AUTO_UPDATE_TOKEN || secrets.GITHUB_TOKEN }}
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          makeup: true
+          # Skip overwriting MATZBOT_AUTO_UPDATE_TOKEN
+          checkout: '' # false (ref: https://github.com/actions/runner/issues/2238)
+
+      - name: Check for code styles
+        run: |
+          set -x
+          ruby tool/auto-style.rb "$GITHUB_OLD_SHA" "$GITHUB_NEW_SHA"
+        env:
+          GITHUB_OLD_SHA: ${{ github.event.pull_request.base.sha }}
+          GITHUB_NEW_SHA: ${{ github.event.pull_request.merge_commit_sha }}
+        # Skip 'push' events because post_push.yml fixes them on push
+        if: ${{ github.repository == 'ruby/ruby' && startsWith(github.event_name, 'pull') }}
+
+      - name: Check for bash specific substitution in configure.ac
+        run: |
+          git grep -n '\${[A-Za-z_0-9]*/' -- configure.ac && exit 1 || :
+
+      - name: Check for header macros
+        run: |
+          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
+
+      - id: now
+        run: |
+          date +"mon=%-m"%n"day=%-d" >> $GITHUB_OUTPUT
+        env:
+          TZ: Tokyo/Asia
+
+      - id: deprecation
+        run: |
+          eval $(sed -n 's/^#define RUBY_API_VERSION_\(MAJOR\|MINOR\) /\1=/p' include/ruby/version.h)
+          if git --no-pager grep --color -o 'rb_warn_deprecated_to_remove_at('$MAJOR'\.'$MINOR',.*' -- '*.c' >&2; then
+              false
+          else
+              true
+          fi
+        continue-on-error: ${{ steps.now.outputs.mon < 12 }}
+
+      - name: Check if to generate documents
+        id: rdoc
+        run: |
+          set -- $(sed 's/#.*//;/^rdoc /!d' gems/bundled_gems)
+          { echo version=$2; echo ref=$4; } >> $GITHUB_OUTPUT
+          echo RDOC='ruby -W0 --disable-gems tool/rdoc-srcdir -q' >> $GITHUB_ENV
+
+      - name: Checkout rdoc
+        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          repository: ruby/rdoc
+          ref: ${{ steps.rdoc.outputs.ref }}
+          path: .bundle/gems/rdoc-${{ steps.rdoc.outputs.version }}
+        if: ${{ steps.rdoc.outputs.ref != '' }}
+
+      - name: Generate rdoc
+        run: |
+          set -x
+          gempath=$(ruby -e 'print Gem.user_dir, "/bin"')
+          PATH=$gempath:$PATH
+          gem install --user bundler
+          bundle config --local path vendor/bundle
+          bundle install --jobs 4
+          bundle exec rake generate
+        working-directory: .bundle/gems/rdoc-${{ steps.rdoc.outputs.version }}
+        if: ${{ steps.rdoc.outputs.ref != '' }}
+
+      - name: Core docs coverage
+        run: |
+          $RDOC -C -x ^ext -x ^lib .
+
+      - name: Generate docs
+        id: docs
+        run: |
+          $RDOC --op html .
+          echo htmlout=ruby-html-${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.pull_request.title, '[DOC]')
+          || contains(github.event.pull_request.labels.*.name, 'Documentation')
+          }}
+
+      - name: Upload docs
+        uses: actions/upload-artifact@v6.0.0
+        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
new file mode 100644
index 0000000000..a92c93b476
--- /dev/null
+++ b/.github/workflows/codeql-analysis.yml
@@ -0,0 +1,121 @@
+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 * * *'
+  workflow_dispatch:
+
+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:
+  analyze:
+    name: Analyze
+    runs-on: ubuntu-latest
+    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.pull_request.title, '[DOC]')
+      || 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: Checkout repository
+        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+
+      - 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
+
+      - uses: ./.github/actions/setup/directories
+
+      - 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: Initialize CodeQL
+        uses: github/codeql-action/init@e296a935590eb16afc0c0108289f68c87e2a89a5 # v4.30.7
+        with:
+          languages: ${{ matrix.language }}
+          trap-caching: false
+          debug: true
+
+      - name: Autobuild
+        uses: github/codeql-action/autobuild@e296a935590eb16afc0c0108289f68c87e2a89a5 # v4.30.7
+
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@e296a935590eb16afc0c0108289f68c87e2a89a5 # v4.30.7
+        with:
+          category: '/language:${{ matrix.language }}'
+          upload: False
+          output: sarif-results
+
+      - 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: ${{ matrix.language == 'ruby' }}
+        continue-on-error: true
+
+      - name: Upload SARIF
+        uses: github/codeql-action/upload-sarif@e296a935590eb16afc0c0108289f68c87e2a89a5 # v4.30.7
+        with:
+          sarif_file: sarif-results/${{ matrix.language }}.sarif
+        continue-on-error: true
diff --git a/.github/workflows/compilers.yml b/.github/workflows/compilers.yml
new file mode 100644
index 0000000000..8c0ca54e0b
--- /dev/null
+++ b/.github/workflows/compilers.yml
@@ -0,0 +1,335 @@
+# 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') }}
+
+permissions:
+  contents: read
+
+# Each job is split so that they roughly take 30min to run through.
+jobs:
+  compile-if:
+    name: 'omnibus compilations, trigger'
+    runs-on: ubuntu-latest
+    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:
+      - run: true
+        working-directory:
+
+  compile1:
+    name: 'omnibus compilations, #1'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    timeout-minutes: 60
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        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:
+          tag: clang-18
+          with_gcc: 'clang-18 -flto=auto'
+          optflags: '-O2'
+          enable_shared: false
+        timeout-minutes: 30
+      - { uses: './.github/actions/compilers', name: '-O0', with: { optflags: '-O0 -march=x86-64 -mtune=generic' }, timeout-minutes: 5 }
+      # - { 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' }}
+    timeout-minutes: 60
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        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 15 LTO'
+        uses: './.github/actions/compilers'
+        with:
+          tag: gcc-15
+          with_gcc: 'gcc-15 -flto=auto -ffat-lto-objects -Werror=lto-type-mismatch'
+          optflags: '-O2'
+          enable_shared: false
+        timeout-minutes: 10
+      - { uses: './.github/actions/compilers', name: 'ext/Setup', with: { static_exts: 'etc json/* */escape' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'GCC 15', with: { tag: 'gcc-15' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'GCC 14', with: { tag: 'gcc-14' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'GCC 13', with: { tag: 'gcc-13' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'GCC 12', with: { tag: 'gcc-12' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'GCC 11', with: { tag: 'gcc-11' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'GCC 10', with: { tag: 'gcc-10' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'GCC 9',  with: { tag: 'gcc-9'  }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'GCC 8',  with: { tag: 'gcc-8'  }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'GCC 7',  with: { tag: 'gcc-7'  }, timeout-minutes: 5 }
+
+  compile3:
+    name: 'omnibus compilations, #3'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    timeout-minutes: 60
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        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 22', with: { tag: 'clang-22' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'clang 21', with: { tag: 'clang-21' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'clang 20', with: { tag: 'clang-20' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'clang 19', with: { tag: 'clang-19' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'clang 18', with: { tag: 'clang-18' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'clang 17', with: { tag: 'clang-17' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'clang 16', with: { tag: 'clang-16' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'clang 15', with: { tag: 'clang-15' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'clang 14', with: { tag: 'clang-14' }, timeout-minutes: 5 }
+
+  compile4:
+    name: 'omnibus compilations, #4'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    timeout-minutes: 60
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        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' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'clang 12', with: { tag: 'clang-12' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'clang 11', with: { tag: 'clang-11' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'clang 10', with: { tag: 'clang-10' }, timeout-minutes: 5 }
+        # llvm-objcopy<=9 doesn't have --wildcard. It compiles, but leaves Rust symbols in libyjit.o and fail `make test-leaked-globals`.
+      - { uses: './.github/actions/compilers', name: 'clang 9',  with: { tag: 'clang-9',   append_configure: '--disable-yjit --disable-zjit' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'clang 8',  with: { tag: 'clang-8',   append_configure: '--disable-yjit --disable-zjit' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'clang 7',  with: { tag: 'clang-7',   append_configure: '--disable-yjit --disable-zjit' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'clang 6',  with: { tag: 'clang-6.0', append_configure: '--disable-yjit --disable-zjit' }, timeout-minutes: 5 }
+
+  compile5:
+    name: 'omnibus compilations, #5'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    timeout-minutes: 60
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        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' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'C11',   with: { CFLAGS:   '-std=c11   -Werror=pedantic -pedantic-errors -Wno-strict-prototypes' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'C17',   with: { CFLAGS:   '-std=c17   -Werror=pedantic -pedantic-errors -Wno-strict-prototypes' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'C23',   with: { CFLAGS:   '-std=c2x   -Werror=pedantic -pedantic-errors -Wno-strict-prototypes' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'C++98', with: { CXXFLAGS: '-std=c++98 -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'C++11', with: { CXXFLAGS: '-std=c++11 -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'C++14', with: { CXXFLAGS: '-std=c++14 -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'C++17', with: { CXXFLAGS: '-std=c++17 -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' }, timeout-minutes: 5 }
+
+  compile6:
+    name: 'omnibus compilations, #6'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    timeout-minutes: 60
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        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' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'C++23', with: { CXXFLAGS: '-std=c++23 -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'C++26', with: { CXXFLAGS: '-std=c++26 -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'gmp',                 with: { append_configure: '--with-gmp', test_all: 'ruby/test_bignum.rb', test_spec: "/github/workspace/src/spec/ruby/core/integer" }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'jemalloc',            with: { append_configure: '--with-jemalloc' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'valgrind',            with: { append_configure: '--with-valgrind' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'coroutine=ucontext',  with: { append_configure: '--with-coroutine=ucontext' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'coroutine=pthread',   with: { append_configure: '--with-coroutine=pthread' }, timeout-minutes: 5 }
+
+  compile7:
+    name: 'omnibus compilations, #7'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    timeout-minutes: 60
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        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-zjit' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'disable-yjit',        with: { append_configure: '--disable-yjit' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'disable-zjit',        with: { append_configure: '--disable-zjit' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'disable-dln',         with: { append_configure: '--disable-dln' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'enable-mkmf-verbose', with: { append_configure: '--enable-mkmf-verbose' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'disable-rubygems',    with: { append_configure: '--disable-rubygems' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'RUBY_DEVEL',          with: { append_configure: '--enable-devel' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'OPT_THREADED_CODE=0',            with: { cppflags: '-DOPT_THREADED_CODE=0' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'OPT_THREADED_CODE=1',            with: { cppflags: '-DOPT_THREADED_CODE=1' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'OPT_THREADED_CODE=2',            with: { cppflags: '-DOPT_THREADED_CODE=2' }, timeout-minutes: 5 }
+
+  compile8:
+    name: 'omnibus compilations, #8'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    timeout-minutes: 60
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        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' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'RUBY_DEBUG',                     with: { cppflags: '-DRUBY_DEBUG' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'ARRAY_DEBUG',                    with: { cppflags: '-DARRAY_DEBUG' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'BIGNUM_DEBUG',                   with: { cppflags: '-DBIGNUM_DEBUG' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'CCAN_LIST_DEBUG',                with: { cppflags: '-DCCAN_LIST_DEBUG' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'CPDEBUG=-1',                     with: { cppflags: '-DCPDEBUG=-1' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'ENC_DEBUG',                      with: { cppflags: '-DENC_DEBUG' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'GC_DEBUG',                       with: { cppflags: '-DGC_DEBUG' }, timeout-minutes: 5 }
+
+  compile9:
+    name: 'omnibus compilations, #9'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    timeout-minutes: 60
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        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' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'ID_TABLE_DEBUG',                 with: { cppflags: '-DID_TABLE_DEBUG' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'RGENGC_DEBUG=-1',                with: { cppflags: '-DRGENGC_DEBUG=-1' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'SYMBOL_DEBUG',                   with: { cppflags: '-DSYMBOL_DEBUG' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'RGENGC_CHECK_MODE',              with: { cppflags: '-DRGENGC_CHECK_MODE' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'VM_CHECK_MODE',                  with: { cppflags: '-DVM_CHECK_MODE' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'USE_EMBED_CI=0',                 with: { cppflags: '-DUSE_EMBED_CI=0' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'USE_FLONUM=0',                   with: { cppflags: '-DUSE_FLONUM=0', append_configure: '--disable-yjit --disable-zjit' }, timeout-minutes: 5 }
+
+  compileX:
+    name: 'omnibus compilations, #10'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    timeout-minutes: 60
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        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' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'USE_SYMBOL_GC=0',                with: { cppflags: '-DUSE_SYMBOL_GC=0' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'USE_THREAD_CACHE=0',             with: { cppflags: '-DUSE_THREAD_CACHE=0' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'USE_RUBY_DEBUG_LOG=1',           with: { cppflags: '-DUSE_RUBY_DEBUG_LOG=1' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'USE_DEBUG_COUNTER',              with: { cppflags: '-DUSE_DEBUG_COUNTER=1' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'SHARABLE_MIDDLE_SUBSTRING',      with: { cppflags: '-DSHARABLE_MIDDLE_SUBSTRING=1' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'DEBUG_FIND_TIME_NUMGUESS',       with: { cppflags: '-DDEBUG_FIND_TIME_NUMGUESS' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'DEBUG_INTEGER_PACK',             with: { cppflags: '-DDEBUG_INTEGER_PACK' }, timeout-minutes: 5 }
+
+  compileB:
+    name: 'omnibus compilations, #11'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    timeout-minutes: 60
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        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' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'GC_ENABLE_LAZY_SWEEP=0',         with: { cppflags: '-DGC_ENABLE_LAZY_SWEEP=0' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'GC_PROFILE_DETAIL_MEMORY',       with: { cppflags: '-DGC_PROFILE_DETAIL_MEMORY' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'GC_PROFILE_MORE_DETAIL',         with: { cppflags: '-DGC_PROFILE_MORE_DETAIL' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'MALLOC_ALLOCATED_SIZE_CHECK',    with: { cppflags: '-DMALLOC_ALLOCATED_SIZE_CHECK' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'RGENGC_ESTIMATE_OLDMALLOC',      with: { cppflags: '-DRGENGC_ESTIMATE_OLDMALLOC' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'RGENGC_PROFILE',                 with: { cppflags: '-DRGENGC_PROFILE' }, timeout-minutes: 5 }
+
+  compileC:
+    name: 'omnibus compilations, #12'
+    runs-on: ubuntu-latest
+    needs: compile-if
+    if: ${{ needs.compile-if.result == 'success' }}
+    timeout-minutes: 60
+    services: { docuum: { image: 'stephanmisc/docuum', options: '--init', volumes: [ '/root', '/var/run/docker.sock:/var/run/docker.sock' ] } }
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        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' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'VM_DEBUG_VERIFY_METHOD_CACHE',   with: { cppflags: '-DVM_DEBUG_VERIFY_METHOD_CACHE' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'YJIT_FORCE_ENABLE',              with: { cppflags: '-DYJIT_FORCE_ENABLE' }, timeout-minutes: 5 }
+      - { uses: './.github/actions/compilers', name: 'UNIVERSAL_PARSER',               with: { cppflags: '-DUNIVERSAL_PARSER' }, timeout-minutes: 5 }
+
+  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: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with: { sparse-checkout-cone-mode: false, sparse-checkout: /.github }
+      - uses: ./.github/actions/slack
+        with:
+          label: 'omnibus'
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ contains(needs.*.result, 'failure') || contains(needs.*.result, 'cancelled') }}
+      - run: false
+        working-directory:
+        if: ${{ contains(needs.*.result, 'failure') || contains(needs.*.result, 'cancelled') }}
+
+defaults:
+  run:
+    working-directory: build
diff --git a/.github/workflows/cygwin.yml b/.github/workflows/cygwin.yml
new file mode 100644
index 0000000000..ac73991fe8
--- /dev/null
+++ b/.github/workflows/cygwin.yml
@@ -0,0 +1,71 @@
+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.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:
+      - run: git config --global core.autocrlf input
+
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+
+      - 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 rubygems
+
+      - name: configure
+        run: |
+          ./autogen.sh
+          ./configure --disable-install-doc
+        shell: C:\cygwin\bin\bash.EXE --noprofile --norc -e -o igncr -o pipefail {0}
+
+      - name: Extract bundled gems
+        run: |
+          make ruby -j5
+          make extract-gems
+        shell: C:\cygwin\bin\bash.EXE --noprofile --norc -e -o igncr -o pipefail {0}
+
+      - name: make all
+        timeout-minutes: 30
+        run: make -j4 V=1
+        shell: C:\cygwin\bin\bash.EXE --noprofile --norc -e -o igncr -o pipefail {0}
+
+      - uses: ./.github/actions/slack
+        with:
+          label: Cygwin
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() }}
diff --git a/.github/workflows/default_gems_list.yml b/.github/workflows/default_gems_list.yml
new file mode 100644
index 0000000000..1c7e2195c8
--- /dev/null
+++ b/.github/workflows/default_gems_list.yml
@@ -0,0 +1,99 @@
+name: Update default gems list
+on: [push, pull_request, merge_group]
+
+env:
+  UPDATE_NEWS_ENABLED: true
+
+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_list:
+    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@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          token: ${{ (github.repository == 'ruby/ruby' && !startsWith(github.event_name, 'pull')) && secrets.MATZBOT_AUTO_UPDATE_TOKEN || secrets.GITHUB_TOKEN }}
+
+      - id: gems
+        run: true
+        if: ${{ github.ref == 'refs/heads/master' }}
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          makeup: true
+          # Skip overwriting MATZBOT_AUTO_UPDATE_TOKEN
+          checkout: '' # false (ref: https://github.com/actions/runner/issues/2238)
+        if: ${{ steps.gems.outcome == 'success' }}
+
+      - name: Download previous gems list
+        run: |
+          data=default_gems.json
+          mkdir -p .downloaded-cache
+          ln -s .downloaded-cache/$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' && env.UPDATE_NEWS_ENABLED == 'true' }}
+
+      - 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..a95c7005c4
--- /dev/null
+++ b/.github/workflows/dependabot_automerge.yml
@@ -0,0 +1,32 @@
+# from https://github.com/gofiber/swagger/blob/main/.github/workflows/dependabot_automerge.yml
+name: Dependabot auto-merge
+on:
+  pull_request:
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  automerge:
+    runs-on: ubuntu-latest
+    if: github.event.pull_request.user.login == 'dependabot[bot]' && github.repository == 'ruby/ruby'
+    steps:
+      - name: Dependabot metadata
+        uses: dependabot/fetch-metadata@21025c705c08248db411dc16f3619e6b5f9ea21a # v2.5.0
+        id: metadata
+
+      - name: Wait for status checks
+        uses: lewagon/wait-on-check-action@3603e826ee561ea102b58accb5ea55a1a7482343 # v1.4.1
+        with:
+          repo-token: ${{ secrets.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_DEPENDABOT_MERGE_TOKEN }}
diff --git a/.github/workflows/labeler.yml b/.github/workflows/labeler.yml
new file mode 100644
index 0000000000..16dbac1afa
--- /dev/null
+++ b/.github/workflows/labeler.yml
@@ -0,0 +1,12 @@
+name: "Pull Request Labeler"
+on:
+- pull_request_target
+
+jobs:
+  labeler:
+    permissions:
+      contents: read
+      pull-requests: write
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/labeler@v6
diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
new file mode 100644
index 0000000000..29adcab39a
--- /dev/null
+++ b/.github/workflows/macos.yml
@@ -0,0 +1,202 @@
+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
+      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.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@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        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: ${{ matrix.test_task == 'test-bundled-gems' }}
+
+      - run: make
+
+      - run: make hello
+
+      - name: runirb
+        run: |
+          echo IRB::VERSION | make runirb RUNOPT="-- -f"
+
+      - name: Set test options for skipped tests
+        run: |
+          set -x
+          TESTS="$(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
+        id: launchable
+        uses: ./.github/actions/launchable/setup
+        with:
+          os: ${{ matrix.os }}
+          test-opts: ${{ matrix.test_opts }}
+          launchable-token: ${{ secrets.LAUNCHABLE_TOKEN }}
+          builddir: build
+          srcdir: src
+        continue-on-error: true
+        timeout-minutes: 3
+
+      - name: Set extra test options
+        run: |
+          echo "TESTS=$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 ${{ matrix.test_task }}
+        run: |
+          test -n "${LAUNCHABLE_STDOUT}" && exec 1> >(tee "${LAUNCHABLE_STDOUT}")
+          test -n "${LAUNCHABLE_STDERR}" && exec 2> >(tee "${LAUNCHABLE_STDERR}")
+
+          ulimit -c unlimited
+          make -s ${{ matrix.test_task }} ${TESTS:+TESTS="$TESTS"}
+        timeout-minutes: 90
+        env:
+          RUBY_TESTOPTS: '-q --tty=no'
+          TEST_BUNDLED_GEMS_ALLOW_FAILURES: ''
+          PRECHECK_BUNDLED_GEMS: 'no'
+          LAUNCHABLE_STDOUT: ${{ steps.launchable.outputs.stdout_report_path }}
+          LAUNCHABLE_STDERR: ${{ steps.launchable.outputs.stderr_report_path }}
+
+      - name: make skipped tests
+        run: |
+          make -s test-all TESTS="${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 }}
+
+      - name: CAPI extensions
+        uses: ./.github/actions/capiext
+        with:
+          builddir: build
+        env:
+          RUBY_TESTOPTS: '-v --tty=no'
+        if: ${{ contains(matrix.extra_checks, 'capi') }}
+
+      - 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
new file mode 100644
index 0000000000..5c639ad48b
--- /dev/null
+++ b/.github/workflows/mingw.yml
@@ -0,0 +1,243 @@
+name: MinGW
+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: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:
+  contents: read
+
+# Notes:
+# Actions console encoding causes issues, see test-all & test-spec steps
+#
+jobs:
+  make:
+    runs-on: windows-${{ matrix.os }}
+
+    name: ${{ github.workflow }} (${{ matrix.msystem }})
+
+    env:
+      MSYSTEM: ${{ matrix.msystem }}
+      MSYS2_ARCH: >-
+        ${{
+        contains(matrix.msystem, 'arm64') && 'aarch64' ||
+        contains(matrix.msystem, '64') && 'x86_64' || 'i686'
+        }}
+      MINGW_PACKAGE_PREFIX: >-
+        mingw-w${{
+        endsWith(matrix.msystem, '64') && '64' || '32'
+        }}-${{
+        startsWith(matrix.msystem, 'clang') && 'clang' ||
+        startsWith(matrix.msystem, 'ucrt') && 'ucrt' ||
+        'mingw'
+        }}-${{
+        contains(matrix.msystem, 'arm64') && 'aarch64' ||
+        endsWith(matrix.msystem, '64') && 'x86_64' || 'i686'
+        }}
+      CFLAGS: '-mtune=generic -O3 -pipe'
+      CXXFLAGS: '-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:
+          # 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'
+            os: 2022
+            test_task: 'check'
+            test-all-opts: '--name=!/TestObjSpace#test_reachable_objects_during_iteration/'
+          - msystem: 'CLANGARM64'
+            os: 11-arm
+            test_task: 'check'
+      fail-fast: false
+
+    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: msys2/setup-msys2@4f806de0a5a7294ffabaff804b38a9b435a73bda # v2.30.0
+        id: msys2
+        with:
+          msystem: ${{ matrix.msystem }}
+          update: true
+          install: >-
+            git
+            make
+            ruby
+            autoconf
+            ${{ env.MINGW_PACKAGE_PREFIX }}-gcc
+            ${{ env.MINGW_PACKAGE_PREFIX }}-ragel
+            ${{ env.MINGW_PACKAGE_PREFIX }}-openssl
+            ${{ env.MINGW_PACKAGE_PREFIX }}-libyaml
+            ${{ env.MINGW_PACKAGE_PREFIX }}-libffi
+
+      - name: Set up env
+        id: setup-env
+        working-directory:
+        run: |
+          $msys2 = ${env:MSYS2_LOCATION}
+          $msystem = ${env:MSYSTEM}.ToLower()
+          echo $msys2\usr\bin $msys2\$msystem\bin |
+            Tee-Object ${env:GITHUB_PATH} -Append -Encoding utf-8
+
+          # Use the fast device for the temporary directory.
+          # %TEMP% is inconsistent with %TMP% and test-all expects they are consistent.
+          # https://github.com/actions/virtual-environments/issues/712#issuecomment-613004302
+          $tmp = ${env:RUNNER_TEMP}
+          echo HOME=$home TMP=$tmp TEMP=$tmp TMPDIR=$tmp |
+            Tee-Object ${env:GITHUB_ENV} -Append -Encoding utf-8
+        shell: pwsh             # cmd.exe does not strip spaces before `|`.
+        env:
+          MSYS2_LOCATION: ${{ steps.msys2.outputs.msys2-location }}
+          MSYSTEM: ${{ matrix.msystem }}
+
+      - name: Remove Strawberry Perl pkg-config
+        working-directory:
+        # `pkg-config.bat` included in Strawberry Perl is written in
+        # Perl and doesn't work when another msys2 `perl` precede its
+        # own `perl`.
+        #
+        # ```
+        # Can't find C:\Strawberry\perl\bin\pkg-config.bat on PATH, '.' not in PATH.
+        # ```
+        run: |
+          Get-Command pkg-config.bat | % { ren $_.path ($_.path + "~") }
+        shell: pwsh
+
+      - name: Misc system & package info
+        working-directory:
+        run: |
+          group() { echo ::group::$'\e[94;1m'"$*"$'\e[m'; }
+          endgroup() { echo ::endgroup::; }
+
+          group Path
+          cygpath -wa / . $(type -p cygpath bash sh)
+          endgroup
+
+          I() {
+              group $1
+              run Where type -pa $1 && { [ $# -eq 1 ] || run Version "$@"; } ||
+                  failed+=($1)
+              endgroup
+          }
+          run() { local w m=$1; shift; w="$("$@")" && show "$m" && indent "$w"; }
+          indent() { [ -z "$1" ] || echo "$1" | /bin/sed '/^$/!s/^/  /'; }
+          show() { echo $'\e[96m'"$*"$'\e[m'; }
+
+          failed=()
+
+          I gcc.exe --version
+          I ragel.exe --version
+          I make.exe --version
+          I openssl.exe version
+          I libcrypto-3-x64.dll
+          I libssl-3-x64.dll
+
+          group Packages
+          pacman -Qs $MINGW_PACKAGE_PREFIX-* | /bin/sed -n "s,local/$MINGW_PACKAGE_PREFIX-,,p"
+          endgroup
+
+          [ ${#failed[@]} -eq 0 ]
+        shell: sh
+
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          sparse-checkout-cone-mode: false
+          sparse-checkout: /.github
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          srcdir: src
+          builddir: build
+          makeup: true
+          # Set fetch-depth: 10 so that Launchable can receive commits information.
+          fetch-depth: 10
+
+      - name: configure
+        run: >
+          ../src/configure --disable-install-doc --prefix=/.
+          --build=$CHOST --host=$CHOST --target=$CHOST
+        shell: sh
+        env:
+          CHOST: ${{ env.MSYS2_ARCH }}-w64-mingw32
+
+      - name: make all
+        timeout-minutes: 30
+        run: make -j4
+
+      - name: make install
+        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
+        timeout-minutes: 3
+
+      - name: test
+        timeout-minutes: 30
+        run: make test test-tool
+        env:
+          GNUMAKEFLAGS: ''
+          RUBY_TESTOPTS: '-v --tty=no'
+        if: ${{ matrix.test_task == 'check' || matrix.test_task == 'test' }}
+
+      - name: test-all
+        timeout-minutes: 45
+        run: |
+          make ${{ StartsWith(matrix.test_task, 'test/') && matrix.test_task || 'test-all' }}
+        env:
+          RUBY_TESTOPTS: >-
+            --retry --job-status=normal --show-skip --timeout-scale=1.5 -j4
+            ${{ 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 ${{ StartsWith(matrix.test_task, 'spec/') && matrix.test_task || 'test-spec' }}
+        if: ${{ matrix.test_task == 'check' || matrix.test_task == 'test-spec' || StartsWith(matrix.test_task, 'spec/') }}
+
+      - uses: ./src/.github/actions/slack
+        with:
+          label: ${{ matrix.msystem }} / ${{ matrix.test_task }}
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() }}
+
+defaults:
+  run:
+    working-directory: build
+    shell: cmd
diff --git a/.github/workflows/modgc.yml b/.github/workflows/modgc.yml
new file mode 100644
index 0000000000..1d14934df8
--- /dev/null
+++ b/.github/workflows/modgc.yml
@@ -0,0 +1,176 @@
+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_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.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@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        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@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
+        with:
+          ruby-version: '3.1'
+          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: |
+          echo 'EXCLUDES=../src/test/.excludes-mmtk' >> $GITHUB_ENV
+          echo 'MSPECOPT=-B../src/spec/mmtk.mspec' >> $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
+        id: 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
+        timeout-minutes: 3
+
+      - name: make ${{ matrix.test_task }}
+        run: |
+          test -n "${LAUNCHABLE_STDOUT}" && exec 1> >(tee "${LAUNCHABLE_STDOUT}")
+          test -n "${LAUNCHABLE_STDERR}" && exec 2> >(tee "${LAUNCHABLE_STDERR}")
+
+          $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: ''
+          PRECHECK_BUNDLED_GEMS: 'no'
+          LAUNCHABLE_STDOUT: ${{ steps.launchable.outputs.stdout_report_path }}
+          LAUNCHABLE_STDERR: ${{ steps.launchable.outputs.stderr_report_path }}
+
+      - 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() }}
+
+defaults:
+  run:
+    working-directory: build
diff --git a/.github/workflows/parse_y.yml b/.github/workflows/parse_y.yml
new file mode 100644
index 0000000000..87facc8a55
--- /dev/null
+++ b/.github/workflows/parse_y.yml
@@ -0,0 +1,100 @@
+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.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@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          sparse-checkout-cone-mode: false
+          sparse-checkout: /.github
+
+      - uses: ./.github/actions/setup/ubuntu
+
+      - uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
+        with:
+          ruby-version: '3.1'
+          bundler: none
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          srcdir: src
+          builddir: build
+          makeup: true
+          clean: true
+          dummy-files: ${{ matrix.test_task == 'check' }}
+
+      - name: Run configure
+        run: ../src/configure -C --disable-install-doc cppflags=-DRUBY_DEBUG --with-parser=parse.y
+
+      - run: make
+
+      - run: make TESTRUN_SCRIPT='-renvutil -v -e "exit EnvUtil.current_parser == %[parse.y]"' run
+        env:
+          RUNOPT0: -I$(tooldir)/lib
+
+      - 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: ''
+
+      - 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/post_push.yml b/.github/workflows/post_push.yml
new file mode 100644
index 0000000000..318444c0a2
--- /dev/null
+++ b/.github/workflows/post_push.yml
@@ -0,0 +1,85 @@
+name: Post-push
+on:
+  push:
+    branches:
+      - master
+      - 'ruby_*_*'
+jobs:
+  hooks:
+    name: Post-push hooks
+    runs-on: ubuntu-latest
+    if: ${{ github.repository == 'ruby/ruby' }}
+    steps:
+      - name: Sync git.ruby-lang.org
+        run: |
+          mkdir -p ~/.ssh
+          (umask 066; printenv RUBY_GIT_SYNC_PRIVATE_KEY > ~/.ssh/id_ed25519)
+          ssh-keyscan -t ed25519 git.ruby-lang.org >> ~/.ssh/known_hosts
+          ssh -i ~/.ssh/id_ed25519 git-sync@git.ruby-lang.org "sudo -u git /home/git/git.ruby-lang.org/bin/update-ruby.sh $GITHUB_REF"
+        env:
+          GITHUB_REF: ${{ github.ref }}
+          RUBY_GIT_SYNC_PRIVATE_KEY: ${{ secrets.RUBY_GIT_SYNC_PRIVATE_KEY }}
+        if: ${{ github.ref == 'refs/heads/master' || startsWith(github.ref, 'refs/heads/ruby_') }}
+
+      - name: Fetch changesets on bugs.ruby-lang.org
+        run: |
+          curl "https://bugs.ruby-lang.org/sys/fetch_changesets?key=${REDMINE_SYS_API_KEY}" -s --fail-with-body -w '* status: %{http_code}\n'
+        env:
+          REDMINE_SYS_API_KEY: ${{ secrets.REDMINE_SYS_API_KEY }}
+        if: ${{ github.ref == 'refs/heads/master' || startsWith(github.ref, 'refs/heads/ruby_') }}
+
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          fetch-depth: 500 # for notify-slack-commits
+          token: ${{ secrets.MATZBOT_AUTO_UPDATE_TOKEN }}
+
+      - name: Notify commit to Slack
+        run: ruby tool/notify-slack-commits.rb "$GITHUB_OLD_SHA" "$GITHUB_NEW_SHA" refs/heads/master
+        env:
+          GITHUB_OLD_SHA: ${{ github.event.before }}
+          GITHUB_NEW_SHA: ${{ github.event.after }}
+          SLACK_WEBHOOK_URL_ALERTS: ${{ secrets.SLACK_WEBHOOK_URL_ALERTS }}
+          SLACK_WEBHOOK_URL_COMMITS: ${{ secrets.SLACK_WEBHOOK_URL_COMMITS }}
+          SLACK_WEBHOOK_URL_RUBY_JP: ${{ secrets.SLACK_WEBHOOK_URL_RUBY_JP }}
+        if: ${{ github.ref == 'refs/heads/master' }}
+
+      - name: Notify commit to ruby-cvs
+        run: |
+          SENDMAIL="ssh -i ${HOME}/.ssh/id_ed25519 git-sync@git.ruby-lang.org /usr/sbin/sendmail" \
+            ruby tool/commit-email.rb . ruby-cvs@g.ruby-lang.org \
+            "$GITHUB_OLD_SHA" "$GITHUB_NEW_SHA" "$GITHUB_REF" \
+            --viewer-uri "https://github.com/ruby/ruby/commit/" \
+            --error-to cvs-admin@ruby-lang.org
+        env:
+          GITHUB_OLD_SHA: ${{ github.event.before }}
+          GITHUB_NEW_SHA: ${{ github.event.after }}
+          GITHUB_REF: ${{ github.ref }}
+        if: ${{ github.ref == 'refs/heads/master' || startsWith(github.ref, 'refs/heads/ruby_') }}
+
+      - name: Auto-correct code styles
+        run: |
+          set -x
+          ruby tool/auto-style.rb "$GITHUB_OLD_SHA" "$GITHUB_NEW_SHA" refs/heads/master
+        env:
+          GITHUB_OLD_SHA: ${{ github.event.before }}
+          GITHUB_NEW_SHA: ${{ github.event.after }}
+          GIT_AUTHOR_NAME: git
+          GIT_COMMITTER_NAME: git
+          EMAIL: svn-admin@ruby-lang.org
+        if: ${{ github.ref == 'refs/heads/master' }}
+
+      - name: Push PR notes to GitHub
+        run: ruby tool/notes-github-pr.rb "$(pwd)/.git" "$GITHUB_OLD_SHA" "$GITHUB_NEW_SHA" refs/heads/master
+        env:
+          GITHUB_OLD_SHA: ${{ github.event.before }}
+          GITHUB_NEW_SHA: ${{ github.event.after }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          GIT_AUTHOR_NAME: git
+          GIT_COMMITTER_NAME: git
+          EMAIL: svn-admin@ruby-lang.org
+        if: ${{ github.ref == 'refs/heads/master' }}
+
+      - 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/pr-playground.yml b/.github/workflows/pr-playground.yml
new file mode 100644
index 0000000000..f3c0556429
--- /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@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8.0.0
+        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: ${comment}`);
+            await postComment(comment, pr);
+
diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
new file mode 100644
index 0000000000..3caeee9a3b
--- /dev/null
+++ b/.github/workflows/publish.yml
@@ -0,0 +1,107 @@
+name: Publish Ruby packages
+
+on:
+  repository_dispatch:
+    types:
+      - release
+  workflow_dispatch:
+    inputs:
+      version:
+        description: 'Version of the Ruby package to release'
+        required: true
+        default: '3.3.4'
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6.0.1
+
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: 3.3.4
+
+      - name: Store Ruby version
+        run: |
+          echo "RUBY_VERSION=${{ 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-${{ env.RUBY_VERSION }}.zip
+
+      - name: Create a release on GitHub
+        run: |
+          RELEASE_TAG=$(ruby tool/ruby-version.rb tag "${{ env.RUBY_VERSION }}")
+          echo $RELEASE_TAG
+          PREVIOUS_RELEASE_TAG=$(ruby tool/ruby-version.rb previous-tag "${{ env.RUBY_VERSION }}")
+          echo $PREVIOUS_RELEASE_TAG
+          tool/gen-github-release.rb $PREVIOUS_RELEASE_TAG $RELEASE_TAG --no-dry-run
+        env:
+          GITHUB_TOKEN: ${{ secrets.MATZBOT_AUTO_UPDATE_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: Build and push Docker images
+        run: |
+          curl -L -X POST \
+            -H "Authorization: Bearer ${{ secrets.MATZBOT_GITHUB_WORKFLOW_TOKEN }}" \
+            -H "Accept: application/vnd.github+json" \
+            -H "X-GitHub-Api-Version: 2022-11-28" \
+            https://api.github.com/repos/ruby/docker-images/actions/workflows/build.yml/dispatches \
+            -d '{"ref": "master", "inputs": {"ruby_version": "${{ env.RUBY_VERSION }}"}}'
+
+      - 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: Store the latest LTS version of OpenSSL
+        run: |
+          echo "OPENSSL_VERSION=`curl -s https://api.github.com/repos/openssl/openssl/releases | jq -r '.[].tag_name | select(startswith("openssl-3.0"))' | sort -Vr | head -n1 | cut -d'-' -f2`" >> $GITHUB_ENV
+
+      - 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": "${{ env.OPENSSL_VERSION }}"}}'
+
+      - 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/release.yml b/.github/workflows/release.yml
new file mode 100644
index 0000000000..5d4474d978
--- /dev/null
+++ b/.github/workflows/release.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/rust-warnings.yml b/.github/workflows/rust-warnings.yml
new file mode 100644
index 0000000000..a2e3208e52
--- /dev/null
+++ b/.github/workflows/rust-warnings.yml
@@ -0,0 +1,60 @@
+# Surface Rust warnings on PRs that touch any Rust code.
+# Not a required check so we never block people over new warnings
+# that might come from a new Rust version being released.
+name: Rust warnings
+on:
+  pull_request:
+    types:
+      - opened
+      - synchronize
+      - reopened
+    paths:
+      - '**.rs'
+      - '!**.inc.rs'
+  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:
+  rust-warnings:
+    env:
+      GITPULLOPTIONS: --no-tags origin ${{ github.ref }}
+
+    runs-on: ubuntu-24.04
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+
+      - name: Install Rust
+        run: rustup default beta
+
+      - name: Rust warnings
+        shell: bash
+        run: |
+          set -eu
+          cargo check --quiet --all-features --message-format=json \
+            | jq -r 'select(.message.level | IN("warning", "error")) | .message.rendered' \
+            | tee messages.txt
+          (exit "${PIPESTATUS[0]}") && ! grep --quiet '[^[:space:]]' messages.txt
+
+      - name: "📜 `rustdoc` warnings"
+        shell: bash
+        run: |
+          set -eu
+          cargo doc --document-private-items --all --no-deps --message-format=json \
+            | jq -r 'select(.message.level | IN("warning", "error")) | .message.rendered' \
+            | tee messages.txt
+          (exit "${PIPESTATUS[0]}") && ! grep --quiet '[^[:space:]]' messages.txt
diff --git a/.github/workflows/scorecards.yml b/.github/workflows/scorecards.yml
new file mode 100644
index 0000000000..c607098997
--- /dev/null
+++ b/.github/workflows/scorecards.yml
@@ -0,0 +1,78 @@
+# 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: Scorecard 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: '39 3 * * 5'
+  # push:
+  #   branches: [ "master" ]
+
+# Declare default permissions as read only.
+permissions: read-all
+
+jobs:
+  analysis:
+    name: Scorecard analysis
+    runs-on: ubuntu-latest
+    # `publish_results: true` only works when run from the default branch. conditional can be removed if disabled.
+    if: github.event.repository.default_branch == github.ref_name || github.event_name == 'pull_request'
+    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@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          persist-credentials: false
+
+      - name: "Run analysis"
+        uses: ossf/scorecard-action@4eaacf0543bb3f2c246792bd56e8cdeffafb205a # v2.4.3
+        with:
+          results_file: results.sarif
+          results_format: sarif
+          # (Optional) "write" 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 Scorecard on a *private* repository
+          # To create the PAT, follow the steps in https://github.com/ossf/scorecard-action?tab=readme-ov-file#authentication-with-fine-grained-pat-optional.
+          # repo_token: ${{ secrets.SCORECARD_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
+
+          # (Optional) Uncomment file_mode if you have a .gitattributes with files marked export-ignore
+          # file_mode: git
+
+      # 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@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0
+        with:
+          name: SARIF file
+          path: results.sarif
+          retention-days: 5
+
+      # Upload the results to GitHub's code scanning dashboard (optional).
+      # Commenting out will disable upload of results to your repo's Code Scanning dashboard
+      - name: "Upload to code-scanning"
+        uses: github/codeql-action/upload-sarif@v4
+        with:
+          sarif_file: results.sarif
diff --git a/.github/workflows/spec_guards.yml b/.github/workflows/spec_guards.yml
new file mode 100644
index 0000000000..cf4661555c
--- /dev/null
+++ b/.github/workflows/spec_guards.yml
@@ -0,0 +1,67 @@
+name: Rubyspec Version Guards Check
+
+on:
+  push:
+    paths:
+      - '.github/workflows/spec_guards.yml'
+      - 'spec/**'
+      - '!spec/*.md'
+  pull_request:
+    paths:
+      - '.github/workflows/spec_guards.yml'
+      - '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-22.04
+
+    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]')
+      )}}
+
+    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-3.2
+          - ruby-3.3
+          - ruby-3.4
+          - ruby-4.0
+      fail-fast: false
+
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+
+      - uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          bundler: none
+
+      - run: gem install webrick
+
+      - run: ruby ../mspec/bin/mspec
+        working-directory: spec/ruby
+        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() }}
diff --git a/.github/workflows/sync_default_gems.yml b/.github/workflows/sync_default_gems.yml
new file mode 100644
index 0000000000..9ff97d5a4e
--- /dev/null
+++ b/.github/workflows/sync_default_gems.yml
@@ -0,0 +1,77 @@
+name: Sync default gems
+
+env:
+  DEFAULT_GEM_SYNC_ENABLED: true
+
+on:
+  workflow_dispatch:
+    inputs:
+      gem:
+        required: true
+        description: 'Name of the gem to be synchronized'
+        type: string
+      before:
+        required: true
+        description: 'Gem commit SHA before sync'
+        type: string
+      after:
+        required: true
+        description: 'Gem commit SHA after sync'
+        type: string
+
+jobs:
+  sync_default_gems:
+    name: Sync default gem ${{ github.event.inputs.gem }}
+
+    permissions:
+      contents: write # for Git to git push
+
+    runs-on: ubuntu-latest
+
+    if: ${{ github.repository == 'ruby/ruby' }}
+
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        name: Check out ruby/ruby
+        with:
+          token: ${{ github.repository == 'ruby/ruby' && secrets.MATZBOT_AUTO_UPDATE_TOKEN || secrets.GITHUB_TOKEN }}
+
+      - uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
+        with:
+          ruby-version: '3.4'
+          bundler: none
+
+      - name: Run tool/sync_default_gems.rb
+        id: sync
+        run: |
+          ruby_before=$(git rev-parse HEAD)
+          set -x
+          ruby tool/sync_default_gems.rb "${gem_name}" "${gem_before}..${gem_after}"
+          if [[ "$(git rev-parse HEAD)" != "$ruby_before" ]]; then
+            echo update=true >> $GITHUB_OUTPUT
+          fi
+        env:
+          gem_name: ${{ github.event.inputs.gem }}
+          gem_before: ${{ github.event.inputs.before }}
+          gem_after: ${{ github.event.inputs.after }}
+          EMAIL: svn-admin@ruby-lang.org
+          GIT_AUTHOR_NAME: git
+          GIT_COMMITTER_NAME: git
+
+      - name: Push
+        run: |
+          git pull --rebase origin ${GITHUB_REF#refs/heads/}
+          git push origin ${GITHUB_REF#refs/heads/}
+        if: ${{ steps.sync.outputs.update && env.DEFAULT_GEM_SYNC_ENABLED == 'true' }}
+        env:
+          EMAIL: svn-admin@ruby-lang.org
+          GIT_AUTHOR_NAME: git
+          GIT_COMMITTER_NAME: git
+
+      - uses: ./.github/actions/slack
+        with:
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+          label: "${{ github.event.inputs.gem }} (<https://github.com/${{ github.event.inputs.gem == 'rubygems' && 'rubygems' || 'ruby' }}/${{ github.event.inputs.gem }}/compare/${{ github.event.inputs.before }}...${{ github.event.inputs.after }}|diff>)"
+          event_name: workflow_dispatch
+          extra_channel_id: C05FPKAU743 # alerts-sync
+        if: ${{ failure() }}
diff --git a/.github/workflows/ubuntu.yml b/.github/workflows/ubuntu.yml
new file mode 100644
index 0000000000..88c19b6fe6
--- /dev/null
+++ b/.github/workflows/ubuntu.yml
@@ -0,0 +1,269 @@
+name: Ubuntu
+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:
+        # We enumerate every job in matrix.include to save build time
+        include:
+          - 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-24.04
+            extra_checks: [capi]
+          # ubuntu-24.04-arm jobs don't start on ruby/ruby as of 2025-10-29
+          #- test_task: check
+          #  os: ubuntu-24.04-arm
+      fail-fast: false
+
+    env: &make-env
+      GITPULLOPTIONS: --no-tags origin ${{ github.ref }}
+      RUBY_DEBUG: ci
+
+    runs-on: ${{ matrix.os || 'ubuntu-22.04' }}
+
+    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: &make-steps
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          sparse-checkout-cone-mode: false
+          sparse-checkout: /.github
+
+      - uses: ./.github/actions/setup/ubuntu
+        with:
+          arch: ${{ matrix.arch }}
+
+      - uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
+        with:
+          ruby-version: '3.1'
+          bundler: none
+        if: >-
+          ${{ !endsWith(matrix.os, 'arm')
+          && !endsWith(matrix.os, 'ppc64le') && !endsWith(matrix.os, 's390x') }}
+
+      - 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 }}
+          configure: ${{ matrix.configure }}
+        run: >-
+          $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 == 'test-bundled-gems' }}
+
+      - run: $SETARCH make
+
+      - run: $SETARCH make hello
+
+      - name: runirb
+        run: |
+          echo IRB::VERSION | $SETARCH make runirb RUNOPT="-- -f"
+
+      - name: Set test options for skipped tests
+        run: |
+          set -x
+          TESTS="$(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
+        id: 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
+        timeout-minutes: 3
+
+      # Avoid possible test failures with the zlib applying the following patch
+      # on s390x CPU architecture.
+      # https://github.com/madler/zlib/pull/410
+      - name: Disable DFLTCC
+        run: echo "DFLTCC=0" >> $GITHUB_ENV
+        if: ${{ endsWith(matrix.os, 's390x') }}
+
+      - name: make ${{ matrix.test_task }}
+        run: |
+          test -n "${LAUNCHABLE_STDOUT}" && exec 1> >(tee "${LAUNCHABLE_STDOUT}")
+          test -n "${LAUNCHABLE_STDERR}" && exec 2> >(tee "${LAUNCHABLE_STDERR}")
+
+          $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'
+          TEST_BUNDLED_GEMS_ALLOW_FAILURES: ''
+          PRECHECK_BUNDLED_GEMS: 'no'
+          LAUNCHABLE_STDOUT: ${{ steps.launchable.outputs.stdout_report_path }}
+          LAUNCHABLE_STDERR: ${{ steps.launchable.outputs.stderr_report_path }}
+
+      - 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: ${{ matrix.continue-on-skipped_tests || false }}
+
+      - name: test-pc
+        run: |
+          DESTDIR=${RUNNER_TEMP-${TMPDIR-/tmp}}/installed
+          $SETARCH make test-pc "DESTDIR=$DESTDIR"
+
+      - name: CAPI extensions
+        uses: ./.github/actions/capiext
+        with:
+          builddir: build
+          make: '$SETARCH make'
+        env:
+          RUBY_TESTOPTS: '-v --tty=no'
+        if: ${{ contains(matrix.extra_checks, 'capi') }}
+
+      - uses: ./.github/actions/slack
+        with:
+          label: ${{ matrix.test_task }} ${{ matrix.configure }}${{ matrix.arch }}${{ matrix.os }}
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() }}
+
+  make-ibm:
+    strategy:
+      matrix:
+        include:
+          - test_task: check
+            os: ubuntu-24.04-ppc64le
+          - test_task: check
+            os: ubuntu-24.04-s390x
+      fail-fast: false
+
+    env: *make-env
+
+    runs-on: ${{ matrix.os }}
+
+    if: >-
+      ${{github.repository == 'ruby/ruby'
+      && !(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: *make-steps
+
+  # Separated from `make` job to avoid making it a required status check
+  ruby-bench:
+    strategy:
+      matrix:
+        include:
+          # Using the same setup as ZJIT jobs
+          - bench_opts: '--warmup=1 --bench=1 --excludes=lobsters'
+
+    runs-on: ubuntu-24.04
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+
+      - uses: ./.github/actions/setup/ubuntu
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          srcdir: src
+          builddir: build
+          makeup: true
+
+      - name: Run configure
+        run: ../src/configure -C --disable-install-doc --prefix="$(pwd)/install"
+
+      - run: make install
+
+      - name: Checkout ruby-bench
+        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          repository: ruby/ruby-bench
+          path: ruby-bench
+
+      # If you want to skip failing benchmark, consider using `--excludes`.
+      # e.g. `bench_opts: '--warmup=1 --bench=1 --excludes=railsbench,lobsters'`
+      - name: Run ruby-bench
+        run: ruby run_benchmarks.rb -e "ruby::../build/install/bin/ruby" ${{ matrix.bench_opts }}
+        working-directory: ruby-bench
+
+      - uses: ./.github/actions/slack
+        with:
+          label: ruby-bench ${{ matrix.bench_opts }} ${{ matrix.ruby_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: ubuntu-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/wasm.yml b/.github/workflows/wasm.yml
new file mode 100644
index 0000000000..0d2a6f0545
--- /dev/null
+++ b/.github/workflows/wasm.yml
@@ -0,0 +1,179 @@
+name: WebAssembly
+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' }
+#         # -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' }
+      fail-fast: false
+
+    env:
+      RUBY_TESTOPTS: '-q --tty=no'
+      GITPULLOPTIONS: --no-tags origin ${{ github.ref }}
+      WASI_SDK_VERSION_MAJOR: 25
+      WASI_SDK_VERSION_MINOR: 0
+      BINARYEN_VERSION: 113
+      WASMTIME_VERSION: v15.0.0
+
+    runs-on: ubuntu-22.04
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          sparse-checkout-cone-mode: false
+          sparse-checkout: /.github
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          srcdir: src
+          builddir: build
+          makeup: true
+
+      - name: Install libraries
+        run: |
+          set -ex
+          sudo apt-get update -q || :
+          sudo apt-get install --no-install-recommends -q -y ruby make autoconf git wget
+
+          wasi_sdk_deb="wasi-sdk-${WASI_SDK_VERSION_MAJOR}.${WASI_SDK_VERSION_MINOR}-x86_64-linux.deb"
+          wget "https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-${WASI_SDK_VERSION_MAJOR}/${wasi_sdk_deb}"
+          sudo dpkg -i "$wasi_sdk_deb"
+          rm -f "$wasi_sdk_deb"
+
+          mkdir build-sdk
+          pushd build-sdk
+
+          wasmtime_url="https://github.com/bytecodealliance/wasmtime/releases/download/${WASMTIME_VERSION}/wasmtime-${WASMTIME_VERSION}-x86_64-linux.tar.xz"
+          wget -O - "$wasmtime_url" | tar xJf -
+          sudo ln -fs "$PWD/wasmtime-${WASMTIME_VERSION}-x86_64-linux/wasmtime" /usr/local/bin/wasmtime
+
+          binaryen_tarball="binaryen-version_${BINARYEN_VERSION}-x86_64-linux.tar.gz"
+          binaryen_url="https://github.com/WebAssembly/binaryen/releases/download/version_${BINARYEN_VERSION}/${binaryen_tarball}"
+          wget -O - "$binaryen_url" | tar xfz -
+          sudo ln -fs "$PWD/binaryen-version_${BINARYEN_VERSION}/bin/wasm-opt" /usr/local/bin/wasm-opt
+        working-directory: src
+
+      - name: Set ENV
+        run: |
+          echo "WASI_SDK_PATH=/opt/wasi-sdk" >> $GITHUB_ENV
+
+      - uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
+        with:
+          ruby-version: '3.1'
+          bundler: none
+
+      - name: Build baseruby
+        run: |
+          set -ex
+          mkdir ../baseruby
+          pushd ../baseruby
+          ../src/configure --prefix=$PWD/install
+          make
+          make install
+
+      - name: Download config.guess with wasi version
+        run: |
+          rm tool/config.guess tool/config.sub
+          ruby tool/downloader.rb -d tool -e gnu config.guess config.sub
+        working-directory: src
+
+      - name: Run configure
+        run: |
+          ../src/configure \
+            --host wasm32-unknown-wasi \
+            --with-baseruby=$PWD/../baseruby/install/bin/ruby \
+            --with-static-linked-ext \
+            --with-ext=cgi/escape,continuation,coverage,date,digest/bubblebabble,digest,digest/md5,digest/rmd160,digest/sha1,digest/sha2,etc,fcntl,json,json/generator,json/parser,objspace,pathname,rbconfig/sizeof,ripper,stringio,strscan,monitor \
+            LDFLAGS=" \
+              -Xlinker --stack-first \
+              -Xlinker -z -Xlinker stack-size=16777216 \
+            " \
+            optflags="${{ matrix.entry.optflags }}" \
+            debugflags="${{ matrix.entry.debugflags }}" \
+            wasmoptflags="${{ matrix.entry.wasmoptflags }} ${{ matrix.entry.debugflags }}"
+
+      # miniruby may not be built when cross-compling
+      - run: make mini ruby
+
+      - run: make install DESTDIR=$PWD/../install
+      - run: tar cfz ../install.tar.gz -C ../install .
+
+      - name: Upload artifacts
+        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0
+        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@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0
+        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
new file mode 100644
index 0000000000..1d44a5482c
--- /dev/null
+++ b/.github/workflows/windows.yml
@@ -0,0 +1,201 @@
+name: Windows
+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: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:
+  contents: read
+
+jobs:
+  make:
+    strategy:
+      matrix:
+        include:
+          - os: 2022
+            vc: 2022
+            test_task: check
+          - os: 2025
+            vc: 2022
+            test_task: check
+          - os: 11-arm
+            test_task: 'btest test-basic test-tool' # check and test-spec are broken yet.
+            target: arm64
+          - os: 2025
+            vc: 2022
+            test_task: test-bundled-gems
+      fail-fast: false
+
+    runs-on: windows-${{ matrix.os }}
+
+    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]')
+      )}}
+
+    name: Windows ${{ matrix.os }}/Visual C++ ${{ matrix.vc }} (${{ matrix.test_task }})
+
+    env:
+      GITPULLOPTIONS: --no-tags origin ${{ github.ref }}
+      VCPKG_DEFAULT_TRIPLET: ${{ matrix.target || 'x64' }}-windows
+
+    steps:
+      - run: md build
+        working-directory:
+
+      - uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
+        with:
+          # windows-11-arm has only 3.4.1, 3.4.2, 3.4.3, head
+          ruby-version: ${{ !endsWith(matrix.os, 'arm') && '3.1' || '3.4' }}
+          bundler: none
+          windows-toolchain: none
+
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          sparse-checkout-cone-mode: false
+          sparse-checkout: /.github
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          srcdir: src
+          builddir: build
+          make-command: nmake
+          clean: true
+
+      - name: Install tools with scoop
+        run: |
+          Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser
+          iwr -useb get.scoop.sh | iex
+          Join-Path (Resolve-Path ~).Path "scoop\shims" >> $Env:GITHUB_PATH
+          scoop install vcpkg uutils-coreutils
+        shell: pwsh
+
+      - name: Restore vcpkg artifact
+        id: restore-vcpkg
+        uses: actions/cache/restore@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
+        with:
+          path: src\vcpkg_installed
+          key: windows-${{ matrix.os }}-vcpkg-${{ hashFiles('src/vcpkg.json') }}
+
+      - name: Install libraries with vcpkg
+        run: |
+          vcpkg install --vcpkg-root=%USERPROFILE%\scoop\apps\vcpkg\current
+        working-directory: src
+        if: ${{ ! steps.restore-vcpkg.outputs.cache-hit }}
+
+      - name: Save vcpkg artifact
+        uses: actions/cache/save@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
+        with:
+          path: src\vcpkg_installed
+          key: windows-${{ matrix.os }}-vcpkg-${{ hashFiles('src/vcpkg.json') }}
+        if: ${{ ! steps.restore-vcpkg.outputs.cache-hit && (github.ref_name == 'master' || startsWith(github.ref_name, 'ruby_')) }}
+
+      - 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 up VC ${{ matrix.vc }}
+          set | sort > old.env
+          call ..\src\win32\vssetup.cmd ^
+            -arch=${{ matrix.target || 'amd64' }} ^
+            ${{ matrix.vcvars && '-vcvars_ver=' || '' }}${{ matrix.vcvars }}
+          nmake -f nul
+          set TMP=%RUNNER_TEMP%
+          set TEMP=%RUNNER_TEMP%
+          set MAKEFLAGS=l
+          set /a TEST_JOBS=(15 * %NUMBER_OF_PROCESSORS% / 10) > nul
+          set RUBY_OPT_DIR=%GITHUB_WORKSPACE:\=/%/src/vcpkg_installed/%VCPKG_DEFAULT_TRIPLET%
+          set | sort > new.env
+          comm -13 old.env new.env >> %GITHUB_ENV%
+          del *.env
+
+      - name: baseruby version
+        run: ruby -v
+
+      - name: compiler version
+        run: cl
+
+      - name: volume info
+        run: Get-Volume
+        shell: pwsh
+
+      # 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=%RUBY_OPT_DIR%
+          --with-gmp
+
+      - 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
+
+      # windows-11-arm runner cannot run `ruby tool/file2lastrev.rb --revision.h --output=revision.h`
+      - name: make revision.h
+        run: |
+          win32\lastrev.bat | win32\ifchange.bat --timestamp=.revision.time revision.h -
+          type revision.h
+        working-directory: src
+
+      - run: nmake
+
+      - name: Set up Launchable
+        uses: ./.github/actions/launchable/setup
+        with:
+          os: windows-${{ matrix.os }}
+          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' }}
+        timeout-minutes: 3
+
+      - run: nmake ${{ matrix.test_task || 'check' }}
+        env:
+          RUBY_TESTOPTS: -j${{ env.TEST_JOBS || 4 }}
+        timeout-minutes: 70
+
+      - uses: ./.github/actions/slack
+        with:
+          label: Windows ${{ matrix.os }} / VC ${{ matrix.vc }} / ${{ matrix.test_task || 'check' }}
+          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: windows-latest
+    needs: [make]
+    steps:
+      - run: exit 1
+        working-directory:
+        if: ${{ contains(needs.*.result, 'failure') || contains(needs.*.result, 'cancelled') }}
+
+defaults:
+  run:
+    working-directory: build
+    shell: cmd
diff --git a/.github/workflows/wsl.yml b/.github/workflows/wsl.yml
new file mode 100644
index 0000000000..640f18ce42
--- /dev/null
+++ b/.github/workflows/wsl.yml
@@ -0,0 +1,70 @@
+name: Ubuntu on WSL
+
+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:
+
+jobs:
+  wsl:
+    runs-on: windows-2025
+
+    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:
+      - name: Install or update WSL
+        uses: Ubuntu/WSL/.github/actions/wsl-install@main
+        with:
+          distro: Ubuntu-24.04
+
+      - name: Install dependencies
+        uses: Ubuntu/WSL/.github/actions/wsl-bash@main
+        with:
+         distro: Ubuntu-24.04
+         working-dir: /tmp/github/
+         exec: |
+            DEBIAN_FRONTEND=noninteractive sudo apt update
+            DEBIAN_FRONTEND=noninteractive sudo apt install -y ruby build-essential autoconf libssl-dev libyaml-dev zlib1g-dev libgmp-dev libffi-dev
+
+      - name: Check out the repository
+        uses: Ubuntu/WSL/.github/actions/wsl-checkout@main
+        with:
+          distro: Ubuntu-24.04
+          working-dir: /tmp/github/
+          submodules: true
+
+      - name: Build
+        uses: Ubuntu/WSL/.github/actions/wsl-bash@main
+        with:
+         distro: Ubuntu-24.04
+         working-dir: /tmp/github/
+         exec: |
+            ./autogen.sh
+            ./configure --disable-install-doc
+            make ruby -j4
+            make extract-gems
+            make -j4
+
+      - name: Test
+        uses: Ubuntu/WSL/.github/actions/wsl-bash@main
+        with:
+         distro: Ubuntu-24.04
+         working-dir: /tmp/github/
+         exec: |
+            ./ruby -v
+            # make check TESTS="-j4" MSPECOPT="-j"
diff --git a/.github/workflows/yjit-macos.yml b/.github/workflows/yjit-macos.yml
new file mode 100644
index 0000000000..a59b4d6508
--- /dev/null
+++ b/.github/workflows/yjit-macos.yml
@@ -0,0 +1,198 @@
+name: YJIT macOS
+on:
+  push:
+    branches:
+      - master
+    paths-ignore:
+      - 'doc/**'
+      - '**/man/*'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
+  pull_request:
+    types:
+      - opened
+      - synchronize
+      - reopened
+    # 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.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@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+
+      - 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.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@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        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: Verify that --yjit-dump-disasm works
+        run: |
+          ./miniruby --yjit-call-threshold=1 --yjit-dump-disasm -e0 | \
+          wc -l | \
+          ruby -ne 'raise "Disassembly seems broken in dev build (output has too few lines)" unless $_.to_i > 10'
+        if: ${{ contains(matrix.configure, 'jit=dev') }}
+
+      - name: Set ENV for YJIT
+        run: |
+          echo "RUBY_YJIT_ENABLE=1" >> $GITHUB_ENV
+          echo "RUBY_CRASH_REPORT=$(pwd)/rb_crash_%p.txt" >> $GITHUB_ENV
+
+      - name: Set test options for skipped tests
+        run: |
+          set -x
+          TESTS="$(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
+        id: 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
+        timeout-minutes: 3
+
+      - name: make ${{ matrix.test_task }}
+        run: |
+          test -n "${LAUNCHABLE_STDOUT}" && exec 1> >(tee "${LAUNCHABLE_STDOUT}")
+          test -n "${LAUNCHABLE_STDERR}" && exec 2> >(tee "${LAUNCHABLE_STDERR}")
+
+          set -x
+          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: ''
+          SYNTAX_SUGGEST_TIMEOUT: '5'
+          PRECHECK_BUNDLED_GEMS: 'no'
+          LAUNCHABLE_STDOUT: ${{ steps.launchable.outputs.stdout_report_path }}
+          LAUNCHABLE_STDERR: ${{ steps.launchable.outputs.stderr_report_path }}
+        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 }}
+
+      - name: Dump crash logs
+        if: ${{ failure() }}
+        continue-on-error: true
+        run: |
+          tail --verbose --lines=+1 rb_crash_*.txt
+          exit 1
+
+      - 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:
+      - name: ${{ github.workflow }} jobs have failed
+        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
new file mode 100644
index 0000000000..150f0b3275
--- /dev/null
+++ b/.github/workflows/yjit-ubuntu.yml
@@ -0,0 +1,240 @@
+name: YJIT Ubuntu
+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
+
+    # GitHub Action's image seems to already contain a Rust 1.58.0.
+    runs-on: ubuntu-22.04
+
+    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@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+
+      # 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-22.04
+
+    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@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+
+      # 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:
+        include:
+          - test_task: 'yjit-bindgen'
+            hint: 'To fix: use patch in logs'
+            # Build with YJIT+ZJIT for output that works in the most number of configurations
+            configure: '--with-gcc=clang-14 --enable-yjit=dev --enable-zjit'
+            libclang_path: '/usr/lib/llvm-14/lib/libclang.so.1'
+
+          - 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'
+
+    env:
+      GITPULLOPTIONS: --no-tags origin ${{ github.ref }}
+      RUN_OPTS: ${{ matrix.yjit_opts }}
+      YJIT_BENCH_OPTS: ${{ matrix.yjit_bench_opts }}
+      SPECOPTS: ${{ matrix.specopts }}
+      RUBY_DEBUG: ci
+      RUST_BACKTRACE: 1
+
+    runs-on: ubuntu-22.04
+
+    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@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          sparse-checkout-cone-mode: false
+          sparse-checkout: /.github
+
+      - uses: ./.github/actions/setup/ubuntu
+
+      - uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
+        with:
+          ruby-version: '3.1'
+          bundler: none
+
+      - 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: Install Rust
+        if: ${{ matrix.rust_version }}
+        run: rustup install ${{ matrix.rust_version }} --profile minimal
+
+      - name: Remove cargo
+        # Since this tests a `rustc` build for release, remove `cargo` to ensure
+        # that only `rustc` is used.
+        if: ${{ contains(matrix.configure, 'rustc') }}
+        run: sudo rm $(which -a cargo | uniq)
+
+      - name: Run configure
+        run: ../src/configure -C --disable-install-doc --prefix=$(pwd)/install ${{ matrix.configure }}
+
+      - run: make incs
+
+      - run: make prepare-gems
+        if: ${{ matrix.test_task == 'test-bundled-gems' }}
+
+      - run: make
+
+      - name: Verify that --yjit-dump-disasm works
+        run: |
+          ./miniruby --yjit-call-threshold=1 --yjit-dump-disasm -e0 | \
+          wc -l | \
+          ruby -ne 'raise "Disassembly seems broken in dev build (output has too few lines)" unless $_.to_i > 10'
+        if: ${{ contains(matrix.configure, 'jit=dev') }}
+
+      - name: Set ENV for YJIT
+        run: |
+          echo "RUBY_YJIT_ENABLE=1" >> $GITHUB_ENV
+          echo "RUBY_CRASH_REPORT=$(pwd)/rb_crash_%p.txt" >> $GITHUB_ENV
+
+      # Check that the binary was built with YJIT
+      - name: Check YJIT enabled
+        run: ./miniruby --yjit -v | grep "+YJIT"
+
+      - name: Set up Launchable
+        id: launchable
+        uses: ./.github/actions/launchable/setup
+        with:
+          os: ubuntu-22.04
+          test-opts: ${{ matrix.configure }}
+          launchable-token: ${{ secrets.LAUNCHABLE_TOKEN }}
+          builddir: build
+          srcdir: src
+          is-yjit: true
+        continue-on-error: true
+        timeout-minutes: 3
+
+      - name: make ${{ matrix.test_task }}
+        run: |
+          test -n "${LAUNCHABLE_STDOUT}" && exec 1> >(tee "${LAUNCHABLE_STDOUT}")
+          test -n "${LAUNCHABLE_STDERR}" && exec 2> >(tee "${LAUNCHABLE_STDERR}")
+
+          set -x
+          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: ''
+          PRECHECK_BUNDLED_GEMS: 'no'
+          SYNTAX_SUGGEST_TIMEOUT: '5'
+          YJIT_BINDGEN_DIFF_OPTS: '--exit-code'
+          LIBCLANG_PATH: ${{ matrix.libclang_path }}
+          LAUNCHABLE_STDOUT: ${{ steps.launchable.outputs.stdout_report_path }}
+          LAUNCHABLE_STDERR: ${{ steps.launchable.outputs.stderr_report_path }}
+        continue-on-error: ${{ matrix.continue-on-test_task || false }}
+
+      - name: Dump crash logs
+        if: ${{ failure() }}
+        continue-on-error: true
+        run: |
+          tail --verbose --lines=+1 rb_crash_*.txt
+          exit 1
+
+      - 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() }}
+
+  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:
+    working-directory: build
diff --git a/.github/workflows/zjit-macos.yml b/.github/workflows/zjit-macos.yml
new file mode 100644
index 0000000000..a638907811
--- /dev/null
+++ b/.github/workflows/zjit-macos.yml
@@ -0,0 +1,214 @@
+name: ZJIT macOS
+on:
+  push:
+    branches:
+      - master
+    paths-ignore:
+      - 'doc/**'
+      - '**/man/*'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
+  pull_request:
+    types:
+      - opened
+      - synchronize
+      - reopened
+    # 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:
+      fail-fast: false
+      matrix:
+        include:
+          - test_task: 'check'
+            run_opts: '--zjit-call-threshold=1'
+            specopts: '-T --zjit-call-threshold=1'
+            configure: '--enable-zjit=dev'
+
+          - test_task: 'check'
+            run_opts: '--zjit-disable-hir-opt --zjit-call-threshold=1'
+            specopts: '-T --zjit-disable-hir-opt -T --zjit-call-threshold=1'
+            configure: '--enable-zjit=dev'
+
+          - test_task: 'zjit-check' # zjit-test + quick feedback of test_zjit.rb
+            configure: '--enable-yjit=dev --enable-zjit'
+            rust_version: "1.85.0"
+
+          - test_task: 'ruby'
+            hint: 'combo build test'
+            configure: '--enable-yjit --enable-zjit'
+
+    env:
+      GITPULLOPTIONS: --no-tags origin ${{ github.ref }}
+      RUN_OPTS: ${{ matrix.run_opts }}
+      SPECOPTS: ${{ matrix.specopts }}
+      TESTOPTS: ${{ matrix.testopts }}
+      ZJIT_RB_BUG: 1
+
+    runs-on: macos-14
+
+    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@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        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: Install Rust
+        if: ${{ matrix.rust_version }}
+        run: |
+          rustup install ${{ matrix.rust_version }} --profile minimal
+          rustup default ${{ matrix.rust_version }}
+
+      - uses: taiki-e/install-action@v2
+        with:
+          tool: nextest@0.9
+        if: ${{ matrix.test_task == 'zjit-check' }}
+
+      - name: Run configure
+        run: ../src/configure -C --disable-install-doc ${{ matrix.configure }}
+
+      - run: make
+
+      - name: Verify that --zjit-dump-disasm works
+        run: |
+          ./miniruby --zjit-call-threshold=1 --zjit-dump-disasm -e0 | \
+          wc -l | \
+          ruby -ne 'raise "Disassembly seems broken in dev build (output has too few lines)" unless $_.to_i > 10'
+        if: ${{ contains(matrix.configure, 'jit=dev') }}
+
+      - name: Set ENV for ZJIT
+        run: |
+          echo "RUBY_CRASH_REPORT=$(pwd)/rb_crash_%p.txt" >> $GITHUB_ENV
+
+      - name: make ${{ matrix.test_task }}
+        run: |
+          set -x
+          make -s ${{ matrix.test_task }} ${TESTS:+TESTS="$TESTS"} \
+            RUN_OPTS="$RUN_OPTS" \
+            SPECOPTS="$SPECOPTS" \
+            TESTOPTS="$TESTOPTS"
+        timeout-minutes: 60
+        env:
+          RUBY_TESTOPTS: '-q --tty=no'
+          EXCLUDES: '../src/test/.excludes-zjit'
+          TEST_BUNDLED_GEMS_ALLOW_FAILURES: ''
+          SYNTAX_SUGGEST_TIMEOUT: '5'
+          PRECHECK_BUNDLED_GEMS: 'no'
+        continue-on-error: ${{ matrix.continue-on-test_task || false }}
+
+      - name: Dump crash logs
+        if: ${{ failure() }}
+        continue-on-error: true
+        run: |
+          tail --verbose --lines=+1 rb_crash_*.txt
+          exit 1
+
+      - 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() }}
+
+  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') }}
+
+  # Separated from `make` job to avoid making it a required status check for now
+  ruby-bench:
+    strategy:
+      matrix:
+        include:
+          # Test --call-threshold=2 with 2 iterations in total
+          - ruby_opts: '--zjit-call-threshold=2'
+            bench_opts: '--warmup=1 --bench=1 --excludes=lobsters'
+            configure: '--enable-zjit=dev_nodebug' # --enable-zjit=dev is too slow
+
+    runs-on: macos-14
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+
+      - uses: ./.github/actions/setup/macos
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          srcdir: src
+          builddir: build
+          makeup: true
+
+      - name: Run configure
+        run: ../src/configure -C --disable-install-doc --prefix="$(pwd)/install" ${{ matrix.configure }}
+
+      - run: make install
+
+      # setup/directories set MAKEFLAGS=-j4 for macOS, which randomly fails sqlite3.gem builds
+      - name: Unset MAKEFLAGS
+        run: echo "MAKEFLAGS=" >> "$GITHUB_ENV"
+
+      - name: Checkout ruby-bench
+        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          repository: ruby/ruby-bench
+          path: ruby-bench
+
+      # If you want to skip failing benchmark, consider using `--excludes`.
+      # e.g. `bench_opts: '--warmup=1 --bench=1 --excludes=railsbench,lobsters'`
+      - name: Run ruby-bench
+        run: ruby run_benchmarks.rb -e "zjit::../build/install/bin/ruby ${{ matrix.ruby_opts }}" ${{ matrix.bench_opts }}
+        working-directory: ruby-bench
+
+      - uses: ./.github/actions/slack
+        with:
+          label: ruby-bench ${{ matrix.bench_opts }} ${{ matrix.ruby_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/zjit-ubuntu.yml b/.github/workflows/zjit-ubuntu.yml
new file mode 100644
index 0000000000..28bfec963e
--- /dev/null
+++ b/.github/workflows/zjit-ubuntu.yml
@@ -0,0 +1,267 @@
+name: ZJIT Ubuntu
+on:
+  push:
+    branches:
+      - master
+    paths-ignore:
+      - 'doc/**'
+      - '**/man/*'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+      - '.*.yml'
+  pull_request:
+    types:
+      - opened
+      - synchronize
+      - reopened
+    # 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:
+  lint:
+    name: cargo clippy
+
+    runs-on: ubuntu-22.04
+
+    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@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+
+      - run: cargo clippy --all-targets --all-features
+        working-directory: zjit
+
+  make:
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - test_task: 'check'
+            run_opts: '--zjit-call-threshold=1'
+            specopts: '-T --zjit-call-threshold=1'
+            configure: '--enable-zjit=dev'
+
+          - test_task: 'check'
+            run_opts: '--zjit-disable-hir-opt --zjit-call-threshold=1'
+            specopts: '-T --zjit-disable-hir-opt -T --zjit-call-threshold=1'
+            configure: '--enable-zjit=dev'
+
+            # The optimizer benefits from at least 1 iteration of profiling. Also, many
+            # regression tests in bootstraptest/test_yjit.rb assume call-threshold=2.
+          - test_task: 'btest'
+            run_opts: '--zjit-call-threshold=2'
+            configure: '--enable-zjit=dev'
+
+          - test_task: 'zjit-check' # zjit-test + quick feedback of test_zjit.rb
+            configure: '--enable-yjit --enable-zjit=dev'
+            rust_version: '1.85.0'
+
+          - test_task: 'zjit-bindgen'
+            hint: 'To fix: use patch in logs'
+            # Build with YJIT+ZJIT for output that works in the most number of configurations
+            configure: '--enable-zjit=dev --enable-yjit --with-gcc=clang-16'
+            clang_path: '/usr/bin/clang-16'
+            runs-on: 'ubuntu-24.04' # for clang-16
+
+          - test_task: 'test-bundled-gems'
+            configure: '--enable-zjit=dev'
+            run_opts: '--zjit-call-threshold=1'
+
+    env:
+      GITPULLOPTIONS: --no-tags origin ${{ github.ref }}
+      RUN_OPTS: ${{ matrix.run_opts }}
+      YJIT_BENCH_OPTS: ${{ matrix.yjit_bench_opts }}
+      SPECOPTS: ${{ matrix.specopts }}
+      TESTOPTS: ${{ matrix.testopts }}
+      RUBY_DEBUG: ci
+      BUNDLE_JOBS: 8 # for yjit-bench
+      RUST_BACKTRACE: 1
+      ZJIT_RB_BUG: 1
+
+    runs-on: ${{ matrix.runs-on || 'ubuntu-22.04' }}
+
+    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@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          sparse-checkout-cone-mode: false
+          sparse-checkout: /.github
+
+      - uses: ./.github/actions/setup/ubuntu
+
+      - uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
+        with:
+          ruby-version: '3.1'
+          bundler: none
+
+      - uses: taiki-e/install-action@v2
+        with:
+          tool: nextest@0.9
+        if: ${{ matrix.test_task == 'zjit-check' }}
+
+      - 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: Install Rust
+        if: ${{ matrix.rust_version }}
+        run: |
+          rustup install ${{ matrix.rust_version }} --profile minimal
+          rustup default ${{ matrix.rust_version }}
+
+      - name: Install rustfmt
+        if: ${{ matrix.test_task == 'zjit-bindgen' }}
+        run: rustup component add rustfmt
+
+      - name: Run configure
+        run: ../src/configure -C --disable-install-doc --prefix=$(pwd)/install ${{ matrix.configure }}
+
+      - run: make incs
+
+      - run: make prepare-gems
+        if: ${{ matrix.test_task == 'test-bundled-gems' }}
+
+      - run: make
+
+      - name: Verify that --zjit-dump-disasm works
+        run: |
+          ./miniruby --zjit-call-threshold=1 --zjit-dump-disasm -e0 | \
+          wc -l | \
+          ruby -ne 'raise "Disassembly seems broken in dev build (output has too few lines)" unless $_.to_i > 10'
+        if: ${{ contains(matrix.configure, 'jit=dev') }}
+
+      # Check that the binary was built with ZJIT
+      - name: Check ZJIT enabled
+        run: ./miniruby --zjit -v | grep "+ZJIT"
+        if: ${{ matrix.configure != '--disable-zjit' }}
+
+      - name: Set ENV for ZJIT
+        run: |
+          echo "RUBY_CRASH_REPORT=$(pwd)/rb_crash_%p.txt" >> $GITHUB_ENV
+
+      - name: make ${{ matrix.test_task }}
+        run: |
+          set -x
+          make -s ${{ matrix.test_task }} ${TESTS:+TESTS="$TESTS"} \
+            RUN_OPTS="$RUN_OPTS" MSPECOPT=--debug SPECOPTS="$SPECOPTS" \
+            TESTOPTS="$TESTOPTS" \
+            ZJIT_BINDGEN_DIFF_OPTS="$ZJIT_BINDGEN_DIFF_OPTS"
+        timeout-minutes: 90
+        env:
+          RUBY_TESTOPTS: '-q --tty=no'
+          EXCLUDES: '../src/test/.excludes-zjit'
+          TEST_BUNDLED_GEMS_ALLOW_FAILURES: ''
+          PRECHECK_BUNDLED_GEMS: 'no'
+          SYNTAX_SUGGEST_TIMEOUT: '5'
+          ZJIT_BINDGEN_DIFF_OPTS: '--exit-code'
+          CLANG_PATH: ${{ matrix.clang_path }}
+        continue-on-error: ${{ matrix.continue-on-test_task || false }}
+
+      - name: Dump crash logs
+        if: ${{ failure() }}
+        continue-on-error: true
+        run: |
+          tail --verbose --lines=+1 rb_crash_*.txt
+          exit 1
+
+      - 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() }}
+
+  result:
+    if: ${{ always() }}
+    name: ${{ github.workflow }} result
+    runs-on: ubuntu-22.04
+    needs: [make]
+    steps:
+      - name: ${{ github.workflow }} jobs have failed
+        run: exit 1
+        working-directory:
+        if: ${{ contains(needs.*.result, 'failure') || contains(needs.*.result, 'cancelled') }}
+
+  # Separated from `make` job to avoid making it a required status check for now
+  ruby-bench:
+    strategy:
+      matrix:
+        include:
+          # Test --call-threshold=2 with 2 iterations in total
+          - ruby_opts: '--zjit-call-threshold=2'
+            bench_opts: '--warmup=1 --bench=1 --excludes=lobsters'
+            configure: '--enable-zjit=dev_nodebug' # --enable-zjit=dev is too slow
+
+    runs-on: ubuntu-24.04
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.labels.*.name, 'Documentation')
+      || (github.event_name == 'push' && github.event.pull_request.user.login == 'dependabot[bot]')
+      )}}
+
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+
+      - uses: ./.github/actions/setup/ubuntu
+
+      - uses: ./.github/actions/setup/directories
+        with:
+          srcdir: src
+          builddir: build
+          makeup: true
+
+      - name: Run configure
+        run: ../src/configure -C --disable-install-doc --prefix="$(pwd)/install" ${{ matrix.configure }}
+
+      - run: make install
+
+      - name: Checkout ruby-bench
+        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          repository: ruby/ruby-bench
+          path: ruby-bench
+
+      # If you want to skip failing benchmark, consider using `--excludes`.
+      # e.g. `bench_opts: '--warmup=1 --bench=1 --excludes=railsbench,lobsters'`
+      - name: Run ruby-bench
+        run: ruby run_benchmarks.rb -e "zjit::../build/install/bin/ruby ${{ matrix.ruby_opts }}" ${{ matrix.bench_opts }}
+        working-directory: ruby-bench
+
+      - uses: ./.github/actions/slack
+        with:
+          label: ruby-bench ${{ matrix.bench_opts }} ${{ matrix.ruby_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/.gitignore b/.gitignore
index 9849721d2a..6cf5fb5f32 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,26 +4,33 @@
 *.a
 *.bak
 *.bc
+*.bundle
 *.dSYM
 *.dmyh
 *.dylib
 *.elc
 *.i
+*.ii
 *.inc
 *.log
 *.o
+*.o.tmp
 *.obj
 *.old
 *.orig
 *.pch
 *.pdb
+*.rbinc
+*.rbbin
 *.rej
 *.s
 *.sav
+*.sl
+*.so
+*.so.*
 *.swp
 *.yarb
 *~
-.*-*
 .*.list
 .*.time
 .DS_Store
@@ -33,6 +40,8 @@
 .pc
 .ppack
 .svn
+.time
+.ruby-version
 Makefile
 cygruby*.def
 extconf.h
@@ -41,6 +50,8 @@ y.tab.c
 *.gcda
 *.gcno
 *.gcov
+*.vscode
+!misc/.vscode
 lcov*.info
 
 # /
@@ -51,7 +62,11 @@ lcov*.info
 /*.pc
 /*.rc
 /*_prelude.c
+/.downloaded-cache
+/.top-enc.mk
+/build*/
 /COPYING.LIB
+/ChangeLog
 /Doxyfile
 /GNUmakefile
 /README.atheos
@@ -109,23 +124,34 @@ lcov*.info
 /rename2.h
 /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
@@ -139,27 +165,36 @@ lcov*.info
 /enc/jis/props.h
 /enc/unicode/data
 
+# /coroutine/
+!/coroutine/**/*.s
+!/coroutine/**/*.S
+
 # /enc/trans/
 /enc/trans/*.c
 /enc/trans/*.def
 /enc/trans/*.exp
 /enc/trans/*.lib
-/enc/trans/.time
 
 # /exe/
+/exe/goruby
 /exe/ruby
-/exe/.time
 
 # /ext/
 /ext/extinit.c
 /ext/configure-ext.mk
 /ext/*/exts.mk
 
+# /ext/-test-/cxxanyargs
+/ext/-test-/cxxanyargs/failure*.failed
+
 # /ext/-test-/win32/dln/
 /ext/-test-/win32/dln/dlntest.dll
 /ext/-test-/win32/dln/dlntest.exp
 /ext/-test-/win32/dln/dlntest.lib
 
+# /ext/-test-/gems
+/ext/-test-/gems
+
 # /ext/etc/
 /ext/etc/constdefs.h
 
@@ -172,7 +207,10 @@ 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
@@ -187,7 +225,14 @@ lcov*.info
 /gems/src
 /gems/*-*
 
-# /spec/bundler
+# /lib/
+/lib/ruby/[1-9]*.*
+/lib/ruby/vendor_ruby
+
+# /misc/
+/misc/**/__pycache__
+
+# for `make test-bundler`
 /.rspec_status
 
 # /tool/
@@ -196,9 +241,40 @@ lcov*.info
 
 # /win32/
 /win32/*.ico
-/win32/.time
 
-# MJIT
-/rb_mjit_header.h
-/mjit_config.h
-/include/ruby-*/*/rb_mjit_min_header-*.h
+
+# YJIT
+/yjit-bench
+/yjit_exit_locations.dump
+
+# Rust
+/target
+
+# /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
+/prism/srcs.mk
+
+# tool/update-NEWS-gemlist.rb
+/bundled_gems.json
+/default_gems.json
+/gems/default_gems
diff --git a/.indent.pro b/.indent.pro
index 6a207a0554..1d61cbcad1 100644
--- a/.indent.pro
+++ b/.indent.pro
@@ -2,12 +2,15 @@
 -nbbb
 -nbc
 -br
+-brs
 -nbs
 -ncdb
--ce
--cli0.5
+-nce
+-cdw
+-cli2
+-cbi2
 -ndj
--ei
+-ncs
 -nfc1
 -i4
 -l120
@@ -16,6 +19,14 @@
 -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
new file mode 100644
index 0000000000..89265cafd4
--- /dev/null
+++ b/.rdoc_options
@@ -0,0 +1,39 @@
+---
+page_dir: doc
+charset: UTF-8
+encoding: UTF-8
+main_page: index.md
+title: Documentation for Ruby development version
+visibility: :private
+rdoc_include:
+- doc
+
+exclude:
+- \.gemspec\z
+- lib/set/subclass_compatible.rb
+
+autolink_excluded_words:
+- Box
+- Class
+- Method
+- Module
+- Process
+- RDoc
+- Ruby
+- Set
+- ZJIT
+- YJIT
+
+canonical_root: https://docs.ruby-lang.org/en/master
+
+footer_content:
+  Ruby:
+    Documentation: index.html
+    Official Website: https://www.ruby-lang.org/
+    Playground: https://ruby.github.io/play-ruby/
+  Resources:
+    GitHub: https://github.com/ruby/ruby
+    Issue Tracker: https://bugs.ruby-lang.org/projects/ruby-master/issues
+    RubyGems: https://rubygems.org/
+  Community:
+    X: https://x.com/rubylangorg
diff --git a/.rspec_parallel b/.rspec_parallel
new file mode 100644
index 0000000000..aaff198a32
--- /dev/null
+++ b/.rspec_parallel
@@ -0,0 +1,2 @@
+--format progress
+--format ParallelTests::RSpec::RuntimeLogger --out tmp/parallel_runtime_rspec.log
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 8652e7d388..0000000000
--- a/.travis.yml
+++ /dev/null
@@ -1,360 +0,0 @@
-# Copyright (C) 2011 Urabe, Shyouhei.  All rights reserved.
-#
-# This file is  a part of the programming language  Ruby.  Permission is hereby
-# granted,  to either  redistribute  or  modify this  file,  provided that  the
-# conditions  mentioned in  the file  COPYING are  met.  Consult  the  file for
-# details.
-
-# This is  a Travis-CI  build configuration file.   The list  of configurations
-# available is located in
-#
-#     http://about.travis-ci.org/docs/user/build-configuration/
-#
-# and as Ruby itself is a project written in C language,
-#
-#     http://about.travis-ci.org/docs/user/languages/c/
-#
-# is also a good place to look at.
-
-language: c
-dist: trusty
-
-sudo: false
-addons:
-  apt:
-    config:
-      retries: true
-    update: true
-    sources:
-      - ubuntu-toolchain-r-test
-    packages:
-      - gcc-8
-      - libffi-dev
-      - libgdbm-dev
-      - libgmp-dev
-      - libjemalloc-dev
-      - libncurses5-dev
-      - libncursesw5-dev
-      - libreadline6-dev
-      - libssl-dev
-      - libyaml-dev
-      - openssl
-      - valgrind
-      - zlib1g-dev
-  homebrew:
-    packages:
-      - gdbm
-      - gmp
-      - libffi
-      - openssl@1.1
-      - zlib
-
-.org.ruby-lang.ci.matrix-definitions:
-
-  - &cron-only
-    if: (type = cron) AND (branch = trunk) AND (fork = false)
-
-  - &make-test-only
-    script:
-      - "$SETARCH make -s test TESTOPTS=--color=never"
-
-  - &linux
-    os: linux
-    compiler: gcc-8
-
-  - &osx
-    os: osx
-    compiler: clang
-    before_install:
-      # Bare "brew update" nukes everything.
-      # These steps are very carefully chosen to avoid breaking things.
-      - brew_core_dir=/usr/local/Homebrew/Library/Taps/homebrew/homebrew-core/
-      - git -C $brew_core_dir fetch -q origin
-      - git -C $brew_core_dir checkout -q 25590710e3f7af9cfa173c5cd3eb41a0532107b6
-      - HOMEBREW_NO_AUTO_UPDATE=1 brew upgrade openssl@1.1
-      - /usr/local/opt/openssl@1.1/bin/openssl version
-
-  # --------
-
-  - &x86_64-linux
-    name: x86_64-linux
-    <<: *linux
-
-  - &jemalloc
-    name: --with-jemalloc
-    <<: *linux
-    <<: *cron-only
-    env:
-      - "CONFIG_FLAG='--with-gmp --with-jemalloc --with-valgrind'"
-
-  - &VM_CHECK_MODE
-    name: VM_CHECK_MODE=3
-    <<: *linux
-    <<: *cron-only
-    <<: *make-test-only
-    env:
-      - "CFLAGS=-DVM_CHECK_MODE=0x0003"
-
-  - &FIBER_USE_sjlj
-    name: FIBER_USE_NATIVE=0
-    <<: *linux
-    <<: *cron-only
-    env:
-      - "CFLAGS=-DFIBER_USE_NATIVE=0"
-
-  - &TOKEN_THREADED_CODE
-    name: TOKEN_THREADED_CODE
-    <<: *linux
-    <<: *cron-only
-    <<: *make-test-only
-    env:
-      - "CFLAGS=-DOPT_THREADED_CODE=1"
-
-  - &CALL_THREADED_CODE
-    name: CALL_THREADED_CODE
-    <<: *linux
-    <<: *cron-only
-    <<: *make-test-only
-    env:
-      - "CFLAGS=-DOPT_THREADED_CODE=2"
-
-  - &NO_THREADED_CODE
-    name: NO_THREADED_CODE
-    <<: *linux
-    <<: *cron-only
-    <<: *make-test-only
-    env:
-      - "CFLAGS=-DOPT_THREADED_CODE=3"
-
-  - &ASAN
-    name: -fsanitize=address
-    <<: *linux
-    #<<: *cron-only
-    <<: *make-test-only
-    compiler: clang
-    env:
-      - "ASAN_OPTIONS=detect_leaks=0"
-      - "CFLAGS='-ggdb3 -O1 -march=native -fsanitize=address -fno-omit-frame-pointer'"
-      - "LD=clang"
-      - "LDFLAGS=-fsanitize=address"
-
-  - &MSAN
-    name: -fsanitize=memory
-    <<: *linux
-    #<<: *cron-only
-    <<: *make-test-only
-    compiler: clang
-    env:
-      - "CFLAGS='-fsanitize=memory'"
-      - "LD=clang"
-      - "LDFLAGS=-fsanitize=memory"
-
-  - &UBSAN
-    name: -fsanitize=undefined
-    <<: *linux
-    #<<: *cron-only
-    <<: *make-test-only
-    compiler: clang
-    env:
-      - "CFLAGS='-ggdb3 -O1 -march=native -fsanitize=undefined,integer,nullability -fno-omit-frame-pointer -DUNALIGNED_WORD_ACCESS=0'"
-      - "LD=clang"
-      - "LDFLAGS=-fsanitize=undefined,integer,nullability"
-
-  - &i686-linux
-    name: i686-linux
-    <<: *linux
-    sudo: required
-    compiler: "'gcc-8 -m32'"
-    env:
-      - "CONFIG_FLAG='debugflags=-g0'"
-      - "SETARCH='setarch i686 --verbose --3gb'"
-    addons:
-      apt:
-        config:
-          retries: true
-        update: true
-        sources:
-          - ubuntu-toolchain-r-test
-        packages:
-          - gcc-8-multilib
-          - libffi-dev:i386
-          - libffi6:i386
-          - libgdbm-dev:i386
-          - libgdbm3:i386
-          - libncurses5-dev:i386
-          - libncurses5:i386
-          - libncursesw5-dev:i386
-          - libreadline6-dev:i386
-          - libreadline6:i386
-          - libssl-dev:i386
-          - libssl1.0.0:i386
-          - linux-libc-dev:i386
-          - zlib1g-dev:i386
-          - zlib1g:i386
-
-  - &pedanticism
-    name: "-ansi -pedantic"
-    <<: *linux
-    <<: *make-test-only
-    compiler: "'clang -ansi -Werror=pedantic -pedantic-errors -std=iso9899:1990'"
-    env:
-      - "CONFIG_FLAG="
-      - "JOBS="
-    # construct warnflags (using bashism...)
-    before_install: |
-      warnflags_array=(
-        -Wall
-        -Wextra
-        -Werror=declaration-after-statement
-        -Werror=deprecated-declarations
-        -Werror=division-by-zero
-        -Werror=extra-tokens
-        -Werror=implicit-function-declaration
-        -Werror=implicit-int
-        -Werror=long-long
-        -Werror=pointer-arith
-        -Werror=shorten-64-to-32
-        -Werror=write-strings
-        -Wmissing-noreturn
-        -Wno-constant-logical-operand
-        -Wno-extended-offsetof
-        -Wno-missing-field-initializers
-        -Wno-overlength-strings
-        -Wno-parentheses-equality
-        -Wno-self-assign
-        -Wno-tautological-compare
-        -Wno-unused-local-typedef
-        -Wno-unused-parameter
-        -Wunused-variable
-      )
-      CONFIG_FLAG_ARRAY=(
-        warnflags="${warnflags_array[*]}"
-        LDFLAGS=-Wno-unused-command-line-argument)
-
-  - &rubyspec
-    name: ruby/spec on Ruby 2.3 # to ensure version guards are correctly added
-    <<: *linux
-    language: ruby
-    rvm: 2.3.8
-    addons:
-      apt:
-        packages:
-    before_install:
-    install:
-    before_script: chmod -R u+w spec/ruby
-    # -j randomly hangs. Using -fs to make sure we can know problematic spec on failure.
-    script: ruby -C spec/ruby ../mspec/bin/mspec -fs .
-
-  - &x86_64-darwin17
-    name: x86_64-darwin17
-    <<: *osx
-    env:
-      - "CONFIG_FLAG='--with-opt-dir=/usr/local/opt/openssl@1.1:/usr/local/opt/zlib'"
-      - "JOBS=" # osx build randomly fails with `-j`
-      # `-v` prints too long outputs, but sometimes it osx build hangs and we can't know which test is bad without `-v`.
-      - "TEST_ALL_TESTOPTS='-v --color=never --job-status=normal --excludes=$(TESTSDIR)/excludes/_travis'"
-
-  - &universal-darwin17
-    name: uinversal.x86_64h-darwin17
-    <<: *osx
-    <<: *cron-only
-    <<: *make-test-only
-    env:
-      - "CONFIG_FLAG='--with-arch=x86_64h,x86_64,i386'"
-      - "JOBS=\"-j`sysctl -n hw.activecpu`\""
-
-matrix:
-  include:
-    # to reduce time for finishing all jobs, run the slowest osx build first.
-    - <<: *x86_64-darwin17
-    - <<: *universal-darwin17
-    - <<: *x86_64-linux
-    - <<: *i686-linux
-    - <<: *jemalloc
-    - <<: *pedanticism
-    - <<: *ASAN
-    - <<: *MSAN
-    - <<: *UBSAN
-    - <<: *VM_CHECK_MODE
-    - <<: *FIBER_USE_sjlj
-    - <<: *TOKEN_THREADED_CODE
-    - <<: *CALL_THREADED_CODE
-    - <<: *NO_THREADED_CODE
-    - <<: *rubyspec
-  allow_failures:
-    - name: uinversal.x86_64h-darwin17
-    - name: -fsanitize=address
-    - name: -fsanitize=memory
-    - name: -fsanitize=undefined
-  fast_finish: true
-
-before_script:
-  - "echo JOBS=${JOBS=-j`nproc`} SETARCH=${SETARCH=}"
-  - "$SETARCH uname -a"
-  - "$SETARCH uname -r"
-  - "rm -fr .ext autom4te.cache"
-  - "echo $TERM"
-  - "> config.status"
-  - "sed -f tool/prereq.status Makefile.in common.mk > Makefile"
-  - "make update-config_files"
-  - "make touch-unicode-files"
-  - "make -s $JOBS srcs UNICODE_FILES=."
-  - "rm config.status Makefile rbconfig.rb .rbconfig.time"
-  - "mkdir build config_1st config_2nd"
-  - "chmod -R a-w ."
-  - "chmod u+w build config_1st config_2nd"
-  - "cd build"
-  - "$SETARCH ../configure -C --disable-install-doc --prefix=/tmp/ruby-prefix --with-gcc=\"$CC\" $CONFIG_FLAG \"${CONFIG_FLAG_ARRAY[@]}\""
-  - "cp -pr config.cache config.status .ext/include ../config_1st"
-  - "$SETARCH make reconfig"
-  - "cp -pr config.cache config.status .ext/include ../config_2nd"
-  - "(cd .. && exec diff -ru config_1st config_2nd)"
-  - "$SETARCH make -s $JOBS && make install"
-
-script:
-  - "$SETARCH make -s test TESTOPTS=--color=never"
-  - "export TEST_ALL_TESTOPTS=\"${TEST_ALL_TESTOPTS:- -q --color=never --job-status=normal}\""
-  - "$SETARCH make -s $JOBS test-all -o exts TESTOPTS=\"$TEST_ALL_TESTOPTS\""
-  - "$SETARCH make -s $JOBS test-spec MSPECOPT=-fs" # not using `-j` because sometimes `mspec -j` silently dies
-
-# Branch matrix.  Not all branches are Travis-ready so we limit branches here.
-branches:
-  only:
-    - trunk
-    - ruby_2_3
-    - ruby_2_4
-    - ruby_2_5
-    - /^feature\//
-    - /^bug\//
-    - /^travis-/
-
-# We want to be notified when something happens.
-notifications:
-  irc:
-    channels:
-      - "chat.freenode.net#ruby-core"
-      - "chat.freenode.net#ruby-ja"
-    on_success: change # [always|never|change] # default: always
-    on_failure: always # [always|never|change] # default: always
-    template:
-      - "%{message} by @%{author}: See %{build_url}"
-
-  slack:
-    rooms:
-      - secure: i1GLETSKye85ea6dGNA3MxI/5myChmMFiZtBd5C69xK+s1sBFqEgOSbaSf9KHc0CYrHVyNhQMaZRruieV7xS+6Pfs0Zvxf1DO6QQTWC2KhkqwFDLvZncAzjoyASdR90hbr+iRPOngQ+HJuE94zemALAwEqNAinzA74PMiJXktqY= # ruby:<token>#commits
-      - secure: ah7UEHBvncXT7bM5mvYIQAO+tIyV/wl7nXLb7wQD16dO2v8Gragy0mWjB79Q09hrrMGmp6H9bCDpdGS80boIA5EHaHoG4QaP0i9bsSt8U2AMWgZtfyIgQKJ4H2kXkGlrjO+AXTgnIkP7LNjdgAVUUTGQPb26T3QmoN2Splt+fIQ= # ruby:<token>#alerts
-    on_pull_requests: false
-    on_success: change
-    on_failure: always
-
-  email:
-    - ko1c-failure@atdot.net
-
-# Local Variables:
-# mode: YAML
-# coding: utf-8-unix
-# indent-tabs-mode: nil
-# tab-width: 4
-# fill-column: 79
-# default-justification: full
-# End:
diff --git a/BSDL b/BSDL
index a009caefea..66d93598aa 100644
--- a/BSDL
+++ b/BSDL
@@ -4,10 +4,10 @@ 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.
+   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.
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
 
 THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index ffdf2dd4b8..35e79dd3b9 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -1,4 +1 @@
-Please see the [official issue tracker] and wiki [HowToContribute].
-
-[official issue tracker]: https://bugs.ruby-lang.org
-[HowToContribute]: https://bugs.ruby-lang.org/projects/ruby/wiki/HowToContribute
+See ["Contributing to Ruby"](https://docs.ruby-lang.org/en/master/contributing/contributing_md.html), which includes setup and build instructions.
diff --git a/COPYING b/COPYING
index f06056fb45..428ce03ed7 100644
--- a/COPYING
+++ b/COPYING
@@ -1,56 +1,58 @@
+{日本語}[rdoc-ref:COPYING.ja]
+
 Ruby is copyrighted free software by Yukihiro Matsumoto <matz@netlab.jp>.
 You can redistribute it and/or modify it under either the terms of the
 2-clause BSDL (see the file BSDL), or the conditions below:
 
-  1. You may make and give away verbatim copies of the source form of the
-     software without restriction, provided that you duplicate all of the
-     original copyright notices and associated disclaimers.
+1. You may make and give away verbatim copies of the source form of the
+   software without restriction, provided that you duplicate all of the
+   original copyright notices and associated disclaimers.
 
-  2. You may modify your copy of the software in any way, provided that
-     you do at least ONE of the following:
+2. You may modify your copy of the software in any way, provided that
+   you do at least ONE of the following:
 
-       a) place your modifications in the Public Domain or otherwise
-          make them Freely Available, such as by posting said
-          modifications to Usenet or an equivalent medium, or by allowing
-          the author to include your modifications in the software.
+   a. place your modifications in the Public Domain or otherwise
+      make them Freely Available, such as by posting said
+      modifications to Usenet or an equivalent medium, or by allowing
+      the author to include your modifications in the software.
 
-       b) use the modified software only within your corporation or
-          organization.
+   b. use the modified software only within your corporation or
+      organization.
 
-       c) give non-standard binaries non-standard names, with
-          instructions on where to get the original software distribution.
+   c. give non-standard binaries non-standard names, with
+      instructions on where to get the original software distribution.
 
-       d) make other distribution arrangements with the author.
+   d. make other distribution arrangements with the author.
 
-  3. You may distribute the software in object code or binary form,
-     provided that you do at least ONE of the following:
+3. You may distribute the software in object code or binary form,
+   provided that you do at least ONE of the following:
 
-       a) distribute the binaries and library files of the software,
-          together with instructions (in the manual page or equivalent)
-          on where to get the original distribution.
+   a. distribute the binaries and library files of the software,
+      together with instructions (in the manual page or equivalent)
+      on where to get the original distribution.
 
-       b) accompany the distribution with the machine-readable source of
-          the software.
+   b. accompany the distribution with the machine-readable source of
+      the software.
 
-       c) give non-standard binaries non-standard names, with
-          instructions on where to get the original software distribution.
+   c. give non-standard binaries non-standard names, with
+      instructions on where to get the original software distribution.
 
-       d) make other distribution arrangements with the author.
+   d. make other distribution arrangements with the author.
 
-  4. You may modify and include the part of the software into any other
-     software (possibly commercial).  But some files in the distribution
-     are not written by the author, so that they are not under these terms.
+4. You may modify and include the part of the software into any other
+   software (possibly commercial).  But some files in the distribution
+   are not written by the author, so that they are not under these terms.
 
-     For the list of those files and their copying conditions, see the
-     file LEGAL.
+   For the list of those files and their copying conditions, see the
+   file LEGAL.
 
-  5. The scripts and library files supplied as input to or produced as
-     output from the software do not automatically fall under the
-     copyright of the software, but belong to whomever generated them,
-     and may be sold commercially, and may be aggregated with this
-     software.
+5. The scripts and library files supplied as input to or produced as
+   output from the software do not automatically fall under the
+   copyright of the software, but belong to whomever generated them,
+   and may be sold commercially, and may be aggregated with this
+   software.
 
-  6. THIS SOFTWARE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
-     IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
-     WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
-     PURPOSE.
+6. THIS SOFTWARE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
+   IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+   WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+   PURPOSE.
diff --git a/COPYING.ja b/COPYING.ja
index e50d01c8d1..5de2dbcc8f 100644
--- a/COPYING.ja
+++ b/COPYING.ja
@@ -1,51 +1,53 @@
+{English}[rdoc-ref:COPYING]
+
 本プログラムはフリーソフトウェアです．2-clause BSDL
 または以下に示す条件で本プログラムを再配布できます
 2-clause BSDLについてはBSDLファイルを参照して下さい．
 
-  1. 複製は制限なく自由です．
+1. 複製は制限なく自由です．
 
-  2. 以下の条件のいずれかを満たす時に本プログラムのソースを
-     自由に変更できます．
+2. 以下の条件のいずれかを満たす時に本プログラムのソースを
+   自由に変更できます．
 
-     (a) ネットニューズにポストしたり，作者に変更を送付する
-         などの方法で，変更を公開する．
+   a.  ネットニューズにポストしたり，作者に変更を送付する
+       などの方法で，変更を公開する．
 
-     (b) 変更した本プログラムを自分の所属する組織内部だけで
-         使う．
+   b.  変更した本プログラムを自分の所属する組織内部だけで
+       使う．
 
-     (c) 変更点を明示したうえ，ソフトウェアの名前を変更する．
-         そのソフトウェアを配布する時には変更前の本プログラ
-         ムも同時に配布する．または変更前の本プログラムのソー
-         スの入手法を明示する．
+   c.  変更点を明示したうえ，ソフトウェアの名前を変更する．
+       そのソフトウェアを配布する時には変更前の本プログラ
+       ムも同時に配布する．または変更前の本プログラムのソー
+       スの入手法を明示する．
 
-     (d) その他の変更条件を作者と合意する．
+   d.  その他の変更条件を作者と合意する．
 
-  3. 以下の条件のいずれかを満たす時に本プログラムをコンパイ
-     ルしたオブジェクトコードや実行形式でも配布できます．
+3. 以下の条件のいずれかを満たす時に本プログラムをコンパイ
+   ルしたオブジェクトコードや実行形式でも配布できます．
 
-     (a) バイナリを受け取った人がソースを入手できるように，
-         ソースの入手法を明示する．
+   a.  バイナリを受け取った人がソースを入手できるように，
+       ソースの入手法を明示する．
 
-     (b) 機械可読なソースコードを添付する．
+   b.  機械可読なソースコードを添付する．
 
-     (c) 変更を行ったバイナリは名前を変更したうえ，オリジナ
-         ルのソースコードの入手法を明示する．
+   c.  変更を行ったバイナリは名前を変更したうえ，オリジナ
+       ルのソースコードの入手法を明示する．
 
-     (d) その他の配布条件を作者と合意する．
+   d.  その他の配布条件を作者と合意する．
 
-  4. 他のプログラムへの引用はいかなる目的であれ自由です．た
-     だし，本プログラムに含まれる他の作者によるコードは，そ
-     れぞれの作者の意向による制限が加えられる場合があります．
+4. 他のプログラムへの引用はいかなる目的であれ自由です．た
+   だし，本プログラムに含まれる他の作者によるコードは，そ
+   れぞれの作者の意向による制限が加えられる場合があります．
 
-     それらファイルの一覧とそれぞれの配布条件などに付いては
-     LEGALファイルを参照してください．
+   それらファイルの一覧とそれぞれの配布条件などに付いては
+   LEGALファイルを参照してください．
 
-  5. 本プログラムへの入力となるスクリプトおよび，本プログラ
-     ムからの出力の権利は本プログラムの作者ではなく，それぞ
-     れの入出力を生成した人に属します．また，本プログラムに
-     組み込まれるための拡張ライブラリについても同様です．
+5. 本プログラムへの入力となるスクリプトおよび，本プログラ
+   ムからの出力の権利は本プログラムの作者ではなく，それぞ
+   れの入出力を生成した人に属します．また，本プログラムに
+   組み込まれるための拡張ライブラリについても同様です．
 
-  6. 本プログラムは無保証です．作者は本プログラムをサポート
-     する意志はありますが，プログラム自身のバグあるいは本プ
-     ログラムの実行などから発生するいかなる損害に対しても責
-     任を持ちません．
+6. 本プログラムは無保証です．作者は本プログラムをサポート
+   する意志はありますが，プログラム自身のバグあるいは本プ
+   ログラムの実行などから発生するいかなる損害に対しても責
+   任を持ちません．
diff --git a/Cargo.lock b/Cargo.lock
new file mode 100644
index 0000000000..9a4b2ebbba
--- /dev/null
+++ b/Cargo.lock
@@ -0,0 +1,193 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
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+version = "0.13.0"
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+checksum = "015ef5d5ca1743e3f94af9509ba6bd2886523cfee46e48d15c2ef5216fd4ac9a"
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+ "capstone-sys",
+ "libc",
+]
+
+[[package]]
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+ "cc",
+ "libc",
+]
+
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+ "shlex",
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+
+[[package]]
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+ "libc",
+ "windows-sys",
+]
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+ "console",
+ "once_cell",
+ "similar",
+]
+
+[[package]]
+name = "jit"
+version = "0.1.0"
+
+[[package]]
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+
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+
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+checksum = "42f5e15c9953c5e4ccceeb2e7382a716482c34515315f7b03532b8b4e8393d2d"
+
+[[package]]
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+version = "0.0.0"
+dependencies = [
+ "yjit",
+ "zjit",
+]
+
+[[package]]
+name = "shlex"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64"
+
+[[package]]
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+
+[[package]]
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+checksum = "282be5f36a8ce781fad8c8ae18fa3f9beff57ec1b52cb3de0789201425d9a33d"
+dependencies = [
+ "windows-targets",
+]
+
+[[package]]
+name = "windows-targets"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9b724f72796e036ab90c1021d4780d4d3d648aca59e491e6b98e725b84e99973"
+dependencies = [
+ "windows_aarch64_gnullvm",
+ "windows_aarch64_msvc",
+ "windows_i686_gnu",
+ "windows_i686_gnullvm",
+ "windows_i686_msvc",
+ "windows_x86_64_gnu",
+ "windows_x86_64_gnullvm",
+ "windows_x86_64_msvc",
+]
+
+[[package]]
+name = "windows_aarch64_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "32a4622180e7a0ec044bb555404c800bc9fd9ec262ec147edd5989ccd0c02cd3"
+
+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09ec2a7bb152e2252b53fa7803150007879548bc709c039df7627cabbd05d469"
+
+[[package]]
+name = "windows_i686_gnu"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e9b5ad5ab802e97eb8e295ac6720e509ee4c243f69d781394014ebfe8bbfa0b"
+
+[[package]]
+name = "windows_i686_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0eee52d38c090b3caa76c563b86c3a4bd71ef1a819287c19d586d7334ae8ed66"
+
+[[package]]
+name = "windows_i686_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "240948bc05c5e7c6dabba28bf89d89ffce3e303022809e73deaefe4f6ec56c66"
+
+[[package]]
+name = "windows_x86_64_gnu"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "147a5c80aabfbf0c7d901cb5895d1de30ef2907eb21fbbab29ca94c5b08b1a78"
+
+[[package]]
+name = "windows_x86_64_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "24d5b23dc417412679681396f2b49f3de8c1473deb516bd34410872eff51ed0d"
+
+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"
+
+[[package]]
+name = "yjit"
+version = "0.1.0"
+dependencies = [
+ "capstone",
+ "jit",
+]
+
+[[package]]
+name = "zjit"
+version = "0.0.1"
+dependencies = [
+ "capstone",
+ "insta",
+ "jit",
+]
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000000..521129d92d
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,60 @@
+# This is the root Cargo [workspace](https://doc.rust-lang.org/cargo/reference/workspaces.html)
+# and the root package for all the rust code that are statically linked into ruby. Rust tooling
+# limitations means all Rust code need to share a single archive library (staticlib) at the
+# integration point with non-rust code. (See rustlang/rust#44322 and #104707 for a taste of
+# the linking challenges.)
+#
+# Do not add required dependencies. This is a policy that helps downstream consumers and give
+# us tight control over what we ship. All of the optional dependencies are used exclusively
+# during development.
+#
+# Release builds avoid Cargo entirely because offline builds can fail even when none of the
+# optional dependencies are built (rust-lang/cargo#10352).
+
+[workspace]
+members = ["zjit", "yjit", "jit"]
+
+[package]
+name = "ruby"
+version = "0.0.0"
+edition = "2024"
+rust-version = "1.85.0"
+publish = false # Don't publish to crates.io
+
+[dependencies]
+yjit = { path = "yjit", optional = true }
+zjit = { path = "zjit", optional = true }
+
+[lib]
+crate-type = ["staticlib"]
+path = "ruby.rs"
+
+[features]
+disasm = ["yjit?/disasm", "zjit?/disasm"]
+runtime_checks = ["yjit?/runtime_checks", "zjit?/runtime_checks"]
+yjit = [ "dep:yjit" ]
+zjit = [ "dep:zjit" ]
+
+[profile.dev]
+opt-level = 0
+debug = true
+debug-assertions = true
+overflow-checks = true
+
+[profile.dev_nodebug]
+inherits = "dev"
+
+[profile.stats]
+inherits = "release"
+
+[profile.release]
+# NOTE: --enable-yjit and zjit builds use `rustc` without going through Cargo. You
+# might want to update the `rustc` invocation if you change this profile.
+opt-level = 3
+# The extra robustness that comes from checking for arithmetic overflow is
+# worth the performance cost for the compiler.
+overflow-checks = true
+# Generate debug info
+debug = true
+# Use ThinLTO. Much smaller output for a small amount of build time increase.
+lto = "thin"
diff --git a/LEGAL b/LEGAL
index 4ff1726cba..2777aa2c14 100644
--- a/LEGAL
+++ b/LEGAL
@@ -1,159 +1,248 @@
-LEGAL NOTICE INFORMATION
-------------------------
+# -*- rdoc -*-
+
+= LEGAL NOTICE INFORMATION
+--------------------------
 
 All the files in this distribution are covered under either the Ruby's
 license (see the file COPYING) or public-domain except some files
 mentioned below.
 
-ccan/build_assert/build_assert.h
-ccan/check_type/check_type.h
-ccan/container_of/container_of.h
-ccan/str/str.h
+[addr2line.c]
+
+  A part of this file is from FreeBSD.
 
-  These files are licensed under the CC0.
+  >>>
+    Copyright (c) 1986, 1988, 1991, 1993::
+    The Regents of the University of California.  All rights reserved.
 
-    https://creativecommons.org/choose/zero/
+    (c) UNIX System Laboratories, Inc.
 
-ccan/list/list.h
+    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.
 
-  This file is licensed under the MIT License.
+    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.
 
-    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:
+	@(#)subr_prf.c	8.3 (Berkeley) 1/21/94
+
+
+[ccan/build_assert/build_assert.h]
+[ccan/check_type/check_type.h]
+[ccan/container_of/container_of.h]
+[ccan/str/str.h]
+
+  These files are licensed under the {CC0}[https://creativecommons.org/choose/zero/].
+
+[ccan/list/list.h]
+
+  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-ref:@MIT+License].
+
+[include/ruby/onigmo.h]
+[include/ruby/oniguruma.h]
+[regcomp.c]
+[regenc.c]
+[regenc.h]
+[regerror.c]
+[regexec.c]
+[regint.h]
+[regparse.c]
+[regparse.h]
+[enc/ascii.c]
+[enc/big5.c]
+[enc/cp949.c]
+[enc/emacs_mule.c]
+[enc/encdb.c]
+[enc/euc_jp.c]
+[enc/euc_kr.c]
+[enc/euc_tw.c]
+[enc/gb18030.c]
+[enc/gb2312.c]
+[enc/gbk.c]
+[enc/iso_8859_1.c]
+[enc/iso_8859_10.c]
+[enc/iso_8859_11.c]
+[enc/iso_8859_13.c]
+[enc/iso_8859_14.c]
+[enc/iso_8859_15.c]
+[enc/iso_8859_16.c]
+[enc/iso_8859_2.c]
+[enc/iso_8859_3.c]
+[enc/iso_8859_4.c]
+[enc/iso_8859_5.c]
+[enc/iso_8859_6.c]
+[enc/iso_8859_7.c]
+[enc/iso_8859_8.c]
+[enc/iso_8859_9.c]
+[enc/koi8_r.c]
+[enc/koi8_u.c]
+[enc/shift_jis.c]
+[enc/unicode.c]
+[enc/us_ascii.c]
+[enc/utf_16be.c]
+[enc/utf_16le.c]
+[enc/utf_32be.c]
+[enc/utf_32le.c]
+[enc/utf_8.c]
+[enc/windows_1251.c]
+[enc/windows_31j.c]
+
+  Onigmo (Oniguruma-mod) LICENSE
+
+  >>>
+    Copyright (c) 2002-2009::  K.Kosako  <sndgk393 AT ybb DOT ne DOT jp>
+    Copyright (c) 2011-2014::  K.Takata  <kentkt AT csc DOT jp>
+    All rights reserved.
 
-    The above copyright notice and this permission notice shall be included in
-    all copies or substantial portions of the Software.
+    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.
 
-    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.
-
-include/ruby/onigmo.h:
-include/ruby/oniguruma.h:
-regcomp.c:
-regenc.[ch]:
-regerror.c:
-regexec.c:
-regint.h:
-regparse.[ch]:
-enc/ascii.c
-enc/big5.c
-enc/cp949.c
-enc/emacs_mule.c
-enc/encdb.c
-enc/euc_jp.c
-enc/euc_kr.c
-enc/euc_tw.c
-enc/gb18030.c
-enc/gb2312.c
-enc/gbk.c
-enc/iso_8859_1.c
-enc/iso_8859_10.c
-enc/iso_8859_11.c
-enc/iso_8859_13.c
-enc/iso_8859_14.c
-enc/iso_8859_15.c
-enc/iso_8859_16.c
-enc/iso_8859_2.c
-enc/iso_8859_3.c
-enc/iso_8859_4.c
-enc/iso_8859_5.c
-enc/iso_8859_6.c
-enc/iso_8859_7.c
-enc/iso_8859_8.c
-enc/iso_8859_9.c
-enc/koi8_r.c
-enc/koi8_u.c
-enc/shift_jis.c
-enc/unicode.c
-enc/us_ascii.c
-enc/utf_16be.c
-enc/utf_16le.c
-enc/utf_32be.c
-enc/utf_32le.c
-enc/utf_8.c
-enc/windows_1251.c
-
-Onigmo (Oniguruma-mod) LICENSE
-------------------------------
-
-/*-
- * Copyright (c) 2002-2009  K.Kosako  <sndgk393 AT ybb DOT ne DOT jp>
- * Copyright (c) 2011-2014  K.Takata  <kentkt AT csc DOT jp>
- * All rights reserved.
- *
- * 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.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
- */
-
-
-Oniguruma LICENSE
------------------
-
-/*-
- * Copyright (c) 2002-2009  K.Kosako  <sndgk393 AT ybb DOT ne DOT jp>
- * All rights reserved.
- *
- * 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.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
- */
-
-https://github.com/k-takata/Onigmo/
-https://github.com/kkos/oniguruma
-https://svnweb.freebsd.org/ports/head/devel/oniguruma/
-
-   When this software is partly used or it is distributed with Ruby,
-   this of Ruby follows the license of Ruby.
-
-enc/trans/GB/GB12345%UCS.src:
-enc/trans/GB/UCS%GB12345.src:
-enc/trans/GB/GB2312%UCS.src:
-enc/trans/GB/UCS%GB2312.src:
+    THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+
+  Oniguruma LICENSE
+
+  >>>
+    Copyright (c) 2002-2009::  K.Kosako  <sndgk393 AT ybb DOT ne DOT jp>
+    All rights reserved.
+
+    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.
+
+    THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+
+  * https://github.com/k-takata/Onigmo/
+  * https://github.com/kkos/oniguruma
+  * https://svnweb.freebsd.org/ports/head/devel/oniguruma/
+
+    When this software is partly used or it is distributed with Ruby,
+    this of Ruby follows the license of Ruby.
+
+[enc/windows_1250.c]
+[enc/windows_1252.c]
 
+  >>>
+    Copyright (c) 2006-2007::  Byte      <byte AT mail DOT kna DOT ru>
+                               K.Kosako  <sndgk393 AT ybb DOT ne DOT jp>
+    All rights reserved.
+
+    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.
+
+    THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+
+[enc/cesu_8.c]
+[enc/windows_1253.c]
+[enc/windows_1254.c]
+[enc/windows_1257.c]
+
+  >>>
+    Copyright (c) 2002-2007::  K.Kosako  <sndgk393 AT ybb DOT ne DOT jp>
+    All rights reserved.
+
+    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.
+
+    THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+
+[enc/trans/GB/GB12345%UCS.src]
+[enc/trans/GB/UCS%GB12345.src]
+[enc/trans/GB/GB2312%UCS.src]
+[enc/trans/GB/UCS%GB2312.src]
+
+  These files have this explanatory texts.
+
+  >>>
     This mapping data was created from files provided by Unicode, Inc.
     (The Unicode Consortium). The files were used to create a product supporting
     Unicode, as explicitly permitted in the files' copyright notices.
@@ -161,56 +250,82 @@ enc/trans/GB/UCS%GB2312.src:
     files for any particular purpose, and has ceased to publish the files many
     years ago.
 
-enc/trans/JIS/JISX0201-KANA%UCS.src:
-enc/trans/JIS/JISX0208@1990%UCS.src:
-enc/trans/JIS/JISX0212%UCS.src:
-enc/trans/JIS/UCS%JISX0201-KANA.src:
-enc/trans/JIS/UCS%JISX0208@1990.src:
-enc/trans/JIS/UCS%JISX0212.src:
+[enc/trans/JIS/JISX0201-KANA%UCS.src]
+[enc/trans/JIS/JISX0208\@1990%UCS.src]
+[enc/trans/JIS/JISX0212%UCS.src]
+[enc/trans/JIS/UCS%JISX0201-KANA.src]
+[enc/trans/JIS/UCS%JISX0208@1990.src]
+[enc/trans/JIS/UCS%JISX0212.src]
+
+  These files are copyrighted as the following.
 
+  >>>
     © 2015 Unicode®, Inc.
+
     For terms of use, see http://www.unicode.org/terms_of_use.html
 
-enc/trans/JIS/JISX0213-1%UCS@BMP.src:
-enc/trans/JIS/JISX0213-1%UCS@SIP.src:
-enc/trans/JIS/JISX0213-2%UCS@BMP.src:
-enc/trans/JIS/JISX0213-2%UCS@SIP.src:
+[enc/trans/JIS/JISX0213-1%UCS@BMP.src]
+[enc/trans/JIS/JISX0213-1%UCS@SIP.src]
+[enc/trans/JIS/JISX0213-2%UCS@BMP.src]
+[enc/trans/JIS/JISX0213-2%UCS@SIP.src]
+
+  These files are copyrighted as the following.
+
+  >>>
+    Copyright (C) 2001:: earthian@tama.or.jp, All Rights Reserved.
+    Copyright (C) 2001:: I'O, All Rights Reserved.
+    Copyright (C) 2006:: Project X0213, All Rights Reserved.
+    You can use, modify, distribute this table freely.
+
+[enc/trans/JIS/UCS@BMP%JISX0213-1.src]
+[enc/trans/JIS/UCS@BMP%JISX0213-2.src]
+[enc/trans/JIS/UCS@SIP%JISX0213-1.src]
+[enc/trans/JIS/UCS@SIP%JISX0213-2.src]
+
+  These files are copyrighted as the following.
+
+  >>>
+    Copyright (C) 2001:: earthian@tama.or.jp, All Rights Reserved.
+    Copyright (C) 2001:: I'O, All Rights Reserved.
+    You can use, modify, distribute this table freely.
+
+[enc/trans/ucm/glibc-BIG5-2.3.3.ucm]
+[enc/trans/ucm/glibc-BIG5HKSCS-2.3.3.ucm]
 
- 	Copyright (C) 2001 earthian@tama.or.jp, All Rights Reserved.
- 	Copyright (C) 2001 I'O, All Rights Reserved.
- 	Copyright (C) 2006 Project X0213, All Rights Reserved.
- 	You can use, modify, distribute this table freely.
+  >>>
+    Copyright (C) 2001-2005:: International Business Machines
+                              Corporation and others.  All Rights Reserved.
 
-enc/trans/JIS/UCS@BMP%JISX0213-1.src:
-enc/trans/JIS/UCS@BMP%JISX0213-2.src:
-enc/trans/JIS/UCS@SIP%JISX0213-1.src:
-enc/trans/JIS/UCS@SIP%JISX0213-2.src:
+[enc/trans/ucm/windows-950-2000.ucm]
+[enc/trans/ucm/windows-950_hkscs-2001.ucm]
 
- 	Copyright (C) 2001 earthian@tama.or.jp, All Rights Reserved.
- 	Copyright (C) 2001 I'O, All Rights Reserved.
- 	You can use, modify, distribute this table freely.
+  >>>
+    Copyright (C) 2001-2002:: International Business Machines
+                              Corporation and others.  All Rights Reserved.
 
-configure:
+
+[configure]
 
   This file is free software.
 
-    Copyright (C) 1992, 93, 94, 95, 96 Free Software Foundation, Inc.
+  >>>
+    Copyright (C) 1992-1996, 1998-2012:: Free Software Foundation, Inc.
 
     This configure script is free software; the Free Software Foundation
     gives unlimited permission to copy, distribute and modify it.
 
-tool/config.guess:
-tool/config.sub:
+[tool/config.guess]
+[tool/config.sub]
 
   As long as you distribute these files with the file configure, they
   are covered under the Ruby's license.
 
-      Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999
-      Free Software Foundation, Inc.
+  >>>
+    Copyright 1992-2018:: Free Software Foundation, Inc.
 
     This file is free software; you can redistribute it and/or modify it
     under the terms of the GNU General Public License as published by
-    the Free Software Foundation; either version 2 of the License, or
+    the Free Software Foundation; either version 3 of the License, or
     (at your option) any later version.
 
     This program is distributed in the hope that it will be useful, but
@@ -219,54 +334,85 @@ tool/config.sub:
     General Public License for more details.
 
     You should have received a copy of the GNU General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+    along with this program; if not, see <https://www.gnu.org/licenses/>.
 
     As a special exception to the GNU General Public License, if you
     distribute this file as part of a program that contains a
     configuration script generated by Autoconf, you may include it under
-    the same distribution terms that you use for the rest of that program.
+    the same distribution terms that you use for the rest of that
+    program.  This Exception is an additional permission under section 7
+    of the GNU General Public License, version 3 ("GPLv3").
+
+[tool/lib/test/*]
+[tool/lib/core_assertions.rb]
+
+  Some of methods on these files are based on MiniTest 4. MiniTest 4 is
+  distributed under the MIT License.
+
+  >>>
+    Copyright (c) Ryan Davis, seattle.rb
+
+    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.
 
-parse.c:
+[parse.c]
+[parse.h]
 
-  This file is licensed under the GPL, but is incorporated into Ruby and
+  These files are licensed under the GPL, but are incorporated into Ruby and
   redistributed under the terms of the Ruby license, as permitted by the
   exception to the GPL below.
 
-     Copyright (C) 1984, 1989, 1990, 2000, 2001, 2002, 2003, 2004, 2005, 2006
-     Free Software Foundation, Inc.
+  >>>
+    Copyright (C) 1984, 1989-1990, 2000-2015, 2018:: Free Software Foundation, Inc.
 
-     This program is free software; you can redistribute it and/or modify
-     it under the terms of the GNU General Public License as published by
-     the Free Software Foundation; either version 2, or (at your option)
-     any later version.
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
 
-     This program is distributed in the hope that it will be useful,
-     but WITHOUT ANY WARRANTY; without even the implied warranty of
-     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-     GNU General Public License for more details.
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-     You should have received a copy of the GNU General Public License
-     along with this program; if not, write to the Free Software
-     Foundation, Inc., 51 Franklin Street, Fifth Floor,
-     Boston, MA 02110-1301, USA.  */
+    As a special exception, you may create a larger work that contains
+    part or all of the Bison parser skeleton and distribute that work
+    under terms of your choice, so long as that work isn't itself a
+    parser generator using the skeleton or a modified version thereof
+    as a parser skeleton.  Alternatively, if you modify or redistribute
+    the parser skeleton itself, you may (at your option) remove this
+    special exception, which will cause the skeleton and the resulting
+    Bison output files to be licensed under the GNU General Public
+    License without this special exception.
 
-  /* As a special exception, you may create a larger work that contains
-     part or all of the Bison parser skeleton and distribute that work
-     under terms of your choice, so long as that work isn't itself a
-     parser generator using the skeleton or a modified version thereof
-     as a parser skeleton.  Alternatively, if you modify or redistribute
-     the parser skeleton itself, you may (at your option) remove this
-     special exception, which will cause the skeleton and the resulting
-     Bison output files to be licensed under the GNU General Public
-     License without this special exception.
+    This special exception was added by the Free Software Foundation in
+    version 2.2 of Bison.
 
-     This special exception was added by the Free Software Foundation in
-     version 2.2 of Bison.  */
+[missing/dtoa.c]
 
-util.c (partly):
+  This file is under these licenses.
 
-    Copyright (c) 1991, 2000, 2001 by Lucent Technologies.
+  >>>
+    Copyright (c) 1991, 2000, 2001:: by Lucent Technologies.
 
     Permission to use, copy, modify, and distribute this software for any
     purpose without fee is hereby granted, provided that this entire notice
@@ -279,71 +425,74 @@ util.c (partly):
     REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
     OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
 
-win32/win32.[ch]:
+  >>>
+    Copyright (c) 2004-2008:: David Schultz <das@FreeBSD.ORG>
+                              All rights reserved.
+
+    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.
+
+    THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+
+[win32/win32.c]
+[include/ruby/win32.h]
 
   You can apply the Artistic License to these files. (or GPL,
   alternatively)
 
-    Copyright (c) 1993, Intergraph Corporation
+  >>>
+    Copyright (c) 1993:: Intergraph Corporation
 
     You may distribute under the terms of either the GNU General Public
     License or the Artistic License, as specified in the perl README file.
 
-util.c (partly):
-
-   Copyright (c) 2004-2008 David Schultz <das@FreeBSD.ORG>
-   All rights reserved.
-
-   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.
-
-   THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
-
-random.c
+[missing/mt19937.c]
 
   This file is under the new-style BSD license.
 
-    A C-program for MT19937, with initialization improved 2002/2/10.
+  >>>
+    A C-program for MT19937, with initialization improved 2002/2/10.::
     Coded by Takuji Nishimura and Makoto Matsumoto.
+
     This is a faster version by taking Shawn Cokus's optimization,
     Matthe Bellew's simplification, Isaku Wada's real version.
 
     Before using, initialize the state by using init_genrand(seed)
     or init_by_array(init_key, key_length).
 
-    Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
-    All rights reserved.
+    Copyright (C) 1997 - 2002:: Makoto Matsumoto and Takuji Nishimura,
+                                All rights reserved.
 
     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.
+    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.
+    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.
 
-      3. The names of its contributors may not be used to endorse or promote
-	 products derived from this software without specific prior written
-	 permission.
+    3. The names of its contributors may not be used to endorse or promote
+       products derived from this software without specific prior written
+       permission.
 
     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
@@ -364,12 +513,13 @@ random.c
 
   The Wayback Machine url: http://web.archive.org/web/19990429082237/http://www.math.keio.ac.jp/matumoto/emt.html
 
-vm_dump.c:procstat_vm
+[missing/procstat_vm.c]
 
   This file is under the new-style BSD license.
 
-    Copyright (c) 2007 Robert N. M. Watson
-    All rights reserved.
+  >>>
+    Copyright (c) 2007:: Robert N. M. Watson
+                         All rights reserved.
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
@@ -394,146 +544,65 @@ vm_dump.c:procstat_vm
 
     $FreeBSD: head/usr.bin/procstat/procstat_vm.c 261780 2014-02-11 21:57:37Z jhb $
 
-vsnprintf.c:
+[vsnprintf.c]
 
-  This file is under the old-style BSD license.  Note that the
-  paragraph 3 below is now null and void.
+  This file is under the {old-style BSD license}[rdoc-ref:@Old-style+BSD+license].
 
-    Copyright (c) 1990, 1993
-         The Regents of the University of California.  All rights reserved.
+  >>>
+    Copyright (c) 1990, 1993::
+    The Regents of the University of California.  All rights reserved.
 
     This code is derived from software contributed to Berkeley by
     Chris Torek.
 
-    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.
-    3. 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.
-
-    IMPORTANT NOTE:
-    --------------
-    From ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change
-    paragraph 3 above is now null and void.
-
-st.c:
-strftime.c:
-include/ruby/st.h:
-missing/acosh.c:
-missing/alloca.c:
-missing/dup2.c:
-missing/erf.c:
-missing/finite.c:
-missing/hypot.c:
-missing/isinf.c:
-missing/isnan.c:
-missing/lgamma_r.c:
-missing/memcmp.c:
-missing/memmove.c:
-missing/strchr.c:
-missing/strerror.c:
-missing/strstr.c:
-missing/tgamma.c:
-ext/date/date_strftime.c:
-ext/digest/sha1/sha1.[ch]:
-ext/sdbm/_sdbm.c:
-ext/sdbm/sdbm.h:
+[st.c]
+[strftime.c]
+[include/ruby/st.h]
+[missing/acosh.c]
+[missing/alloca.c]
+[missing/erf.c]
+[missing/hypot.c]
+[missing/lgamma_r.c]
+[missing/memcmp.c]
+[missing/memmove.c]
+[missing/strchr.c]
+[missing/strerror.c]
+[missing/strstr.c]
+[missing/tgamma.c]
+[ext/date/date_strftime.c]
+[ext/digest/sha1/sha1.c]
+[ext/digest/sha1/sha1.h]
 
   These files are all under public domain.
 
-missing/crypt.c:
+[missing/crypt.c]
 
-  This file is under the old-style BSD license.  Note that the
-  paragraph 3 below is now null and void.
+  This file is under the {old-style BSD license}[rdoc-ref:@Old-style+BSD+license].
 
-    Copyright (c) 1989, 1993
-    	The Regents of the University of California.  All rights reserved.
+  >>>
+    Copyright (c) 1989, 1993::
+    The Regents of the University of California.  All rights reserved.
 
     This code is derived from software contributed to Berkeley by
     Tom Truscott.
 
-    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.
-    3. 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.
+[missing/setproctitle.c]
 
-missing/setproctitle.c
-
-  This file is under the old-style BSD license.  Note that the
-  paragraph 3 below is now null and void.
-
-    Copyright 2003 Damien Miller
-    Copyright (c) 1983, 1995-1997 Eric P. Allman
-    Copyright (c) 1988, 1993
-    	The Regents of the University of California.  All rights reserved.
-
-    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.
-    3. 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 file is under the {old-style BSD license}[rdoc-ref:@Old-style+BSD+license].
 
-    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.
+  >>>
+    Copyright 2003:: Damien Miller
+    Copyright (c) 1983, 1995-1997:: Eric P. Allman
+    Copyright (c) 1988, 1993::
+    The Regents of the University of California.  All rights reserved.
 
-missing/strlcat.c
-missing/strlcpy.c
+[missing/strlcat.c]
+[missing/strlcpy.c]
 
   These files are under an ISC-style license.
 
-    Copyright (c) 1998, 2015 Todd C. Miller <Todd.Miller@courtesan.com>
+  >>>
+    Copyright (c) 1998, 2015:: Todd C. Miller <Todd.Miller@courtesan.com>
 
     Permission to use, copy, modify, and distribute this software for any
     purpose with or without fee is hereby granted, provided that the above
@@ -547,23 +616,26 @@ missing/strlcpy.c
     ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
     OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
-missing/langinfo.c
+[missing/langinfo.c]
 
   This file is from http://www.cl.cam.ac.uk/~mgk25/ucs/langinfo.c.
   Ruby uses a modified version. The file contains the following
   author/copyright notice:
 
-  Markus.Kuhn@cl.cam.ac.uk -- 2002-03-11
-  Permission to use, copy, modify, and distribute this software
-  for any purpose and without fee is hereby granted. The author
-  disclaims all warranties with regard to this software.
+  >>>
+    Markus.Kuhn@cl.cam.ac.uk -- 2002-03-11::
+    Permission to use, copy, modify, and distribute this software
+    for any purpose and without fee is hereby granted. The author
+    disclaims all warranties with regard to this software.
 
-ext/digest/md5/md5.[ch]:
+[ext/digest/md5/md5.c]
+[ext/digest/md5/md5.h]
 
   These files are under the following license.  Ruby uses modified
   versions of them.
 
-    Copyright (C) 1999, 2000 Aladdin Enterprises.  All rights reserved.
+  >>>
+    Copyright (C) 1999, 2000:: Aladdin Enterprises.  All rights reserved.
 
     This software is provided 'as-is', without any express or implied
     warranty.  In no event will the authors be held liable for any damages
@@ -584,23 +656,27 @@ ext/digest/md5/md5.[ch]:
     L. Peter Deutsch
     ghost@aladdin.com
 
-ext/digest/rmd160/rmd160.[ch]:
+[ext/digest/rmd160/rmd160.c]
+[ext/digest/rmd160/rmd160.h]
 
   These files have the following copyright information, and by the
   author we are allowed to use it under the new-style BSD license.
 
-    AUTHOR:   Antoon Bosselaers, ESAT-COSIC
+  >>>
+    AUTHOR::  Antoon Bosselaers, ESAT-COSIC
               (Arranged for libc by Todd C. Miller)
-    DATE:     1 March 1996
+    DATE::    1 March 1996
 
-    Copyright (c) Katholieke Universiteit Leuven
+    Copyright (c):: Katholieke Universiteit Leuven
     1996, All Rights Reserved
 
-ext/digest/sha2/sha2.[ch]:
+[ext/digest/sha2/sha2.c]
+[ext/digest/sha2/sha2.h]
 
   These files are under the new-style BSD license.
 
-    Copyright 2000 Aaron D. Gifford.  All rights reserved.
+  >>>
+    Copyright 2000:: Aaron D. Gifford.  All rights reserved.
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
@@ -626,96 +702,71 @@ ext/digest/sha2/sha2.[ch]:
     OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     SUCH DAMAGE.
 
-ext/json/generator/generator.c:
-
-    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:
-
-  Copyright 2009 Aaron Patterson, et al.
-
-  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/psych/yaml:
-
-  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/socket/addrinfo.h:
-ext/socket/getaddrinfo.c:
-ext/socket/getnameinfo.c:
+[ext/json/vendor/fpconv.c]
+
+  This file is under the {Boost Software License}[rdoc-ref:@Boost+Software+License+1.0].
+
+[ext/json/vendor/jeaiii-ltoa.h]
+
+  >>>
+    Copyright (c) 2024,2025 Enrico Thierbach - https://github.com/radiospiel
+    Copyright (c) 2022 James Edward Anhalt III - https://github.com/jeaiii/itoa
+
+    {MIT License}[rdoc-ref:@MIT+License]
+
+[ext/json/vendor/ryu.h]
+  This file is adapted from the Ryu algorithm by Ulf Adams https://github.com/ulfjack/ryu.
+  It is dual-licensed under {Apache License 2.0}[rdoc-ref:@Apache+License+2.0] OR
+  {Boost Software License 1.0}[rdoc-ref:@Boost+Software+License+1.0].
+
+[ext/psych]
+[test/psych]
+
+  The files under these directories are under the following license.
+
+  >>>
+    Copyright 2009:: Aaron Patterson, et al.
+
+    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]
+
+  >>>
+    C) Copyright 1998:: by Akinori Ito.
+
+    This software may be redistributed freely for this purpose, in full
+    or in part, provided that this entire copyright notice is included
+    on any copies of this software and applications and derivations thereof.
+
+    This software is provided on an "as is" basis, without warranty of any
+    kind, either expressed or implied, as to any matter including, but not
+    limited to warranty of fitness of purpose, or merchantability, or
+    results obtained from use of this software.
+
+[ext/socket/addrinfo.h]
+[ext/socket/getaddrinfo.c]
+[ext/socket/getnameinfo.c]
 
   These files are under the new-style BSD license.
 
-    Copyright (C) 1995, 1996, 1997, 1998, and 1999 WIDE Project.
+  >>>
+    Copyright (C) 1995, 1996, 1997, 1998, and 1999:: WIDE Project.
     All rights reserved.
 
     Redistribution and use in source and binary forms, with or without
@@ -742,15 +793,16 @@ ext/socket/getnameinfo.c:
     OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     SUCH DAMAGE.
 
-ext/win32ole/win32ole.c:
+[ext/win32ole/win32ole.c]
 
   You can apply the Artistic License to this file. (or GPL,
   alternatively)
 
-    (c) 1995 Microsoft Corporation. All rights reserved.
+  >>>
+    (c) 1995:: Microsoft Corporation. All rights reserved.
     Developed by ActiveWare Internet Corp., http://www.ActiveWare.com
 
-    Other modifications Copyright (c) 1997, 1998 by Gurusamy Sarathy
+    Other modifications Copyright (c) 1997, 1998:: by Gurusamy Sarathy
     <gsar@umich.edu> and Jan Dubois <jan.dubois@ibm.net>
 
     You may distribute under the terms of either the GNU General Public
@@ -759,16 +811,17 @@ ext/win32ole/win32ole.c:
 
   The Wayback Machine url: http://web.archive.org/web/19970607104352/http://www.activeware.com:80/
 
-lib/rdoc/generator/template/darkfish/css/fonts.css:
+[lib/rdoc/generator/template/darkfish/css/fonts.css]
 
-  This file is licensed under the SIL Open Font License.
+  This file is licensed under the {SIL Open Font License}[http://scripts.sil.org/OFL].
 
-    http://scripts.sil.org/OFL
+[spec/mspec]
+[spec/ruby]
 
-spec/mspec:
-spec/ruby:
+  The files under these directories are under the following license.
 
-    Copyright (c) 2008 Engine Yard, Inc. All rights reserved.
+  >>>
+    Copyright (c) 2008:: Engine Yard, Inc. All rights reserved.
 
     Permission is hereby granted, free of charge, to any person
     obtaining a copy of this software and associated documentation
@@ -791,90 +844,457 @@ spec/ruby:
     FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     OTHER DEALINGS IN THE SOFTWARE.
 
-lib/rubygems.rb:
-lib/rubygems:
-test/rubygems:
+[lib/rubygems.rb]
+[lib/rubygems]
+[test/rubygems]
+
+  RubyGems is under the following license.
+
+  >>>
+    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-ref:@MIT+License], or the conditions
+    below:
+
+    1. You may make and give away verbatim copies of the source form of the
+       software without restriction, provided that you duplicate all of the
+       original copyright notices and associated disclaimers.
+
+    2. You may modify your copy of the software in any way, provided that
+       you do at least ONE of the following:
+
+       a. place your modifications in the Public Domain or otherwise
+          make them Freely Available, such as by posting said
+          modifications to Usenet or an equivalent medium, or by allowing
+          the author to include your modifications in the software.
+
+       b. use the modified software only within your corporation or
+          organization.
+
+       c. give non-standard executables non-standard names, with
+          instructions on where to get the original software distribution.
+
+       d. make other distribution arrangements with the author.
+
+    3. You may distribute the software in object code or executable
+       form, provided that you do at least ONE of the following:
+
+       a. distribute the executables and library files of the software,
+          together with instructions (in the manual page or equivalent)
+          on where to get the original distribution.
+
+       b. accompany the distribution with the machine-readable source of
+          the software.
+
+       c. give non-standard executables non-standard names, with
+          instructions on where to get the original software distribution.
+
+       d. make other distribution arrangements with the author.
+
+    4. You may modify and include the part of the software into any other
+       software (possibly commercial).
+
+    5. The scripts and library files supplied as input to or produced as
+       output from the software do not automatically fall under the
+       copyright of the software, but belong to whomever generated them,
+       and may be sold commercially, and may be aggregated with this
+       software.
+
+    6. THIS SOFTWARE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
+       IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+       WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+       PURPOSE.
+
+[lib/bundler]
+[lib/bundler.rb]
+[spec/bundler]
 
-  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 (see the file MIT.txt), or the
-  conditions below:
+  Bundler is under the following license.
 
-  1. You may make and give away verbatim copies of the source form of the
-     software without restriction, provided that you duplicate all of the
-     original copyright notices and associated disclaimers.
+  >>>
+    Portions copyright (c) 2010:: Andre Arko
+    Portions copyright (c) 2009:: Engine Yard
 
-  2. You may modify your copy of the software in any way, provided that
-     you do at least ONE of the following:
+    {MIT License}[rdoc-ref:@MIT+License]
 
-     a. place your modifications in the Public Domain or otherwise
-        make them Freely Available, such as by posting said
-        modifications to Usenet or an equivalent medium, or by allowing
-        the author to include your modifications in the software.
+[lib/bundler/vendor/thor]
 
-     b. use the modified software only within your corporation or
-        organization.
+  Thor is under the following license.
 
-     c. give non-standard executables non-standard names, with
-        instructions on where to get the original software distribution.
+  >>>
+    Copyright (c) 2008 Yehuda Katz, Eric Hodel, et al.
 
-     d. make other distribution arrangements with the author.
+    {MIT License}[rdoc-ref:@MIT+License]
 
-  3. You may distribute the software in object code or executable
-     form, provided that you do at least ONE of the following:
+[lib/rubygems/vendor/molinillo]
 
-     a. distribute the executables and library files of the software,
-        together with instructions (in the manual page or equivalent)
-        on where to get the original distribution.
+  molinillo is under the following license.
 
-     b. accompany the distribution with the machine-readable source of
-        the software.
+  >>>
+    Copyright (c) 2014 Samuel E. Giddins segiddins@segiddins.me
 
-     c. give non-standard executables non-standard names, with
-        instructions on where to get the original software distribution.
+    {MIT License}[rdoc-ref:@MIT+License]
 
-     d . make other distribution arrangements with the author.
+[lib/bundler/vendor/pub_grub]
 
-  4. You may modify and include the part of the software into any other
-     software (possibly commercial).
+  pub_grub is under the following license.
 
-  5. The scripts and library files supplied as input to or produced as
-     output from the software do not automatically fall under the
-     copyright of the software, but belong to whomever generated them,
-     and may be sold commercially, and may be aggregated with this
-     software.
+  >>>
+    Copyright (c) 2018 John Hawthorn
 
-  6. THIS SOFTWARE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
-     IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
-     WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
-     PURPOSE.
+    {MIT License}[rdoc-ref:@MIT+License]
 
-lib/bundler:
-lib/bundler.rb:
-lib/bundler.gemspec:
-spec/bundler:
-man/bundle-*,gemfile.*:
+[lib/bundler/vendor/connection_pool]
 
-  Portions copyright (c) 2010 Andre Arko
-  Portions copyright (c) 2009 Engine Yard
+  connection_pool is under the following license.
 
-  MIT License
+  >>>
+    Copyright (c) 2011 Mike Perham
 
-  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:
+    {MIT License}[rdoc-ref:@MIT+License]
 
-  The above copyright notice and this permission notice shall be
-  included in all copies or substantial portions of the Software.
+[lib/bundler/vendor/net-http-persistent]
 
-  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.
+  net-http-persistent is under the following license.
+
+  >>>
+    Copyright (c) Eric Hodel, Aaron Patterson
+
+    {MIT License}[rdoc-ref:@MIT+License]
+
+[lib/did_you_mean]
+[lib/did_you_mean.rb]
+[test/did_you_mean]
+
+  did_you_mean is under the following license.
+
+  >>>
+    Copyright (c) 2014-2016 Yuki Nishijima
+
+    {MIT License}[rdoc-ref:@MIT+License]
+
+[lib/error_highlight]
+[lib/error_highlight.rb]
+[test/error_highlight]
+
+  error_highlight is under the following license.
+
+  >>>
+    Copyright (c) 2021 Yusuke Endoh
+
+    {MIT License}[rdoc-ref:@MIT+License]
+
+[benchmark/so_ackermann.rb]
+[benchmark/so_array.rb]
+[benchmark/so_binary_trees.rb]
+[benchmark/so_concatenate.rb]
+[benchmark/so_count_words.yml]
+[benchmark/so_exception.rb]
+[benchmark/so_fannkuch.rb]
+[benchmark/so_fasta.rb]
+[benchmark/so_k_nucleotide.yml]
+[benchmark/so_lists.rb]
+[benchmark/so_mandelbrot.rb]
+[benchmark/so_matrix.rb]
+[benchmark/so_meteor_contest.rb]
+[benchmark/so_nbody.rb]
+[benchmark/so_nested_loop.rb]
+[benchmark/so_nsieve.rb]
+[benchmark/so_nsieve_bits.rb]
+[benchmark/so_object.rb]
+[benchmark/so_partial_sums.rb]
+[benchmark/so_pidigits.rb]
+[benchmark/so_random.rb]
+[benchmark/so_reverse_complement.yml]
+[benchmark/so_sieve.rb]
+[benchmark/so_spectralnorm.rb]
+
+  These files are very old copy of then-called "The Great Computer Language
+  Shootout".  LEGAL SITUATION OF THESE FILES ARE UNCLEAR because the original
+  site has been lost.  Upstream diverged to delete several benchmarks listed
+  above.
+
+== MIT License
+>>>
+      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.
+
+== Old-style BSD license
+>>>
+      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.
+      3. 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.
+
+      IMPORTANT NOTE::
+
+      From ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change
+      paragraph 3 above is now null and void.
+
+== Boost Software License 1.0
+
+>>>
+      Boost Software License - Version 1.0 - August 17th, 2003
+
+      Permission is hereby granted, free of charge, to any person or organization
+      obtaining a copy of the software and accompanying documentation covered by
+      this license (the "Software") to use, reproduce, display, distribute,
+      execute, and transmit the Software, and to prepare derivative works of the
+      Software, and to permit third-parties to whom the Software is furnished to
+      do so, all subject to the following:
+
+      The copyright notices in the Software and this entire statement, including
+      the above license grant, this restriction and the following disclaimer,
+      must be included in all copies of the Software, in whole or in part, and
+      all derivative works of the Software, unless such copies or derivative
+      works are solely in the form of machine-executable object code generated by
+      a source language processor.
+
+      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, TITLE AND NON-INFRINGEMENT. IN NO EVENT
+      SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
+      FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
+      ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+      DEALINGS IN THE SOFTWARE.
+
+== Apache License 2.0
+
+>>>
+      Apache License
+      Version 2.0, January 2004
+      http://www.apache.org/licenses/
+
+      TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+      1. Definitions.
+
+         "License" shall mean the terms and conditions for use, reproduction,
+         and distribution as defined by Sections 1 through 9 of this document.
+
+         "Licensor" shall mean the copyright owner or entity authorized by
+         the copyright owner that is granting the License.
+
+         "Legal Entity" shall mean the union of the acting entity and all
+         other entities that control, are controlled by, or are under common
+         control with that entity. For the purposes of this definition,
+         "control" means (i) the power, direct or indirect, to cause the
+         direction or management of such entity, whether by contract or
+         otherwise, or (ii) ownership of fifty percent (50%) or more of the
+         outstanding shares, or (iii) beneficial ownership of such entity.
+
+         "You" (or "Your") shall mean an individual or Legal Entity
+         exercising permissions granted by this License.
+
+         "Source" form shall mean the preferred form for making modifications,
+         including but not limited to software source code, documentation
+         source, and configuration files.
+
+         "Object" form shall mean any form resulting from mechanical
+         transformation or translation of a Source form, including but
+         not limited to compiled object code, generated documentation,
+         and conversions to other media types.
+
+         "Work" shall mean the work of authorship, whether in Source or
+         Object form, made available under the License, as indicated by a
+         copyright notice that is included in or attached to the work
+         (an example is provided in the Appendix below).
+
+         "Derivative Works" shall mean any work, whether in Source or Object
+         form, that is based on (or derived from) the Work and for which the
+         editorial revisions, annotations, elaborations, or other modifications
+         represent, as a whole, an original work of authorship. For the purposes
+         of this License, Derivative Works shall not include works that remain
+         separable from, or merely link (or bind by name) to the interfaces of,
+         the Work and Derivative Works thereof.
+
+         "Contribution" shall mean any work of authorship, including
+         the original version of the Work and any modifications or additions
+         to that Work or Derivative Works thereof, that is intentionally
+         submitted to Licensor for inclusion in the Work by the copyright owner
+         or by an individual or Legal Entity authorized to submit on behalf of
+         the copyright owner. For the purposes of this definition, "submitted"
+         means any form of electronic, verbal, or written communication sent
+         to the Licensor or its representatives, including but not limited to
+         communication on electronic mailing lists, source code control systems,
+         and issue tracking systems that are managed by, or on behalf of, the
+         Licensor for the purpose of discussing and improving the Work, but
+         excluding communication that is conspicuously marked or otherwise
+         designated in writing by the copyright owner as "Not a Contribution."
+
+         "Contributor" shall mean Licensor and any individual or Legal Entity
+         on behalf of whom a Contribution has been received by Licensor and
+         subsequently incorporated within the Work.
+
+      2. Grant of Copyright License. Subject to the terms and conditions of
+         this License, each Contributor hereby grants to You a perpetual,
+         worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+         copyright license to reproduce, prepare Derivative Works of,
+         publicly display, publicly perform, sublicense, and distribute the
+         Work and such Derivative Works in Source or Object form.
+
+      3. Grant of Patent License. Subject to the terms and conditions of
+         this License, each Contributor hereby grants to You a perpetual,
+         worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+         (except as stated in this section) patent license to make, have made,
+         use, offer to sell, sell, import, and otherwise transfer the Work,
+         where such license applies only to those patent claims licensable
+         by such Contributor that are necessarily infringed by their
+         Contribution(s) alone or by combination of their Contribution(s)
+         with the Work to which such Contribution(s) was submitted. If You
+         institute patent litigation against any entity (including a
+         cross-claim or counterclaim in a lawsuit) alleging that the Work
+         or a Contribution incorporated within the Work constitutes direct
+         or contributory patent infringement, then any patent licenses
+         granted to You under this License for that Work shall terminate
+         as of the date such litigation is filed.
+
+      4. Redistribution. You may reproduce and distribute copies of the
+         Work or Derivative Works thereof in any medium, with or without
+         modifications, and in Source or Object form, provided that You
+         meet the following conditions:
+
+         a.  You must give any other recipients of the Work or
+             Derivative Works a copy of this License; and
+
+         b.  You must cause any modified files to carry prominent notices
+             stating that You changed the files; and
+
+         c.  You must retain, in the Source form of any Derivative Works
+             that You distribute, all copyright, patent, trademark, and
+             attribution notices from the Source form of the Work,
+             excluding those notices that do not pertain to any part of
+             the Derivative Works; and
+
+         d.  If the Work includes a "NOTICE" text file as part of its
+             distribution, then any Derivative Works that You distribute must
+             include a readable copy of the attribution notices contained
+             within such NOTICE file, excluding those notices that do not
+             pertain to any part of the Derivative Works, in at least one
+             of the following places: within a NOTICE text file distributed
+             as part of the Derivative Works; within the Source form or
+             documentation, if provided along with the Derivative Works; or,
+             within a display generated by the Derivative Works, if and
+             wherever such third-party notices normally appear. The contents
+             of the NOTICE file are for informational purposes only and
+             do not modify the License. You may add Your own attribution
+             notices within Derivative Works that You distribute, alongside
+             or as an addendum to the NOTICE text from the Work, provided
+             that such additional attribution notices cannot be construed
+             as modifying the License.
+
+         You may add Your own copyright statement to Your modifications and
+         may provide additional or different license terms and conditions
+         for use, reproduction, or distribution of Your modifications, or
+         for any such Derivative Works as a whole, provided Your use,
+         reproduction, and distribution of the Work otherwise complies with
+         the conditions stated in this License.
+
+      5. Submission of Contributions. Unless You explicitly state otherwise,
+         any Contribution intentionally submitted for inclusion in the Work
+         by You to the Licensor shall be under the terms and conditions of
+         this License, without any additional terms or conditions.
+         Notwithstanding the above, nothing herein shall supersede or modify
+         the terms of any separate license agreement you may have executed
+         with Licensor regarding such Contributions.
+
+      6. Trademarks. This License does not grant permission to use the trade
+         names, trademarks, service marks, or product names of the Licensor,
+         except as required for reasonable and customary use in describing the
+         origin of the Work and reproducing the content of the NOTICE file.
+
+      7. Disclaimer of Warranty. Unless required by applicable law or
+         agreed to in writing, Licensor provides the Work (and each
+         Contributor provides its Contributions) on an "AS IS" BASIS,
+         WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+         implied, including, without limitation, any warranties or conditions
+         of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+         PARTICULAR PURPOSE. You are solely responsible for determining the
+         appropriateness of using or redistributing the Work and assume any
+         risks associated with Your exercise of permissions under this License.
+
+      8. Limitation of Liability. In no event and under no legal theory,
+         whether in tort (including negligence), contract, or otherwise,
+         unless required by applicable law (such as deliberate and grossly
+         negligent acts) or agreed to in writing, shall any Contributor be
+         liable to You for damages, including any direct, indirect, special,
+         incidental, or consequential damages of any character arising as a
+         result of this License or out of the use or inability to use the
+         Work (including but not limited to damages for loss of goodwill,
+         work stoppage, computer failure or malfunction, or any and all
+         other commercial damages or losses), even if such Contributor
+         has been advised of the possibility of such damages.
+
+      9. Accepting Warranty or Additional Liability. While redistributing
+         the Work or Derivative Works thereof, You may choose to offer,
+         and charge a fee for, acceptance of support, warranty, indemnity,
+         or other liability obligations and/or rights consistent with this
+         License. However, in accepting such obligations, You may act only
+         on Your own behalf and on Your sole responsibility, not on behalf
+         of any other Contributor, and only if You agree to indemnify,
+         defend, and hold each Contributor harmless for any liability
+         incurred by, or claims asserted against, such Contributor by reason
+         of your accepting any such warranty or additional liability.
+
+      END OF TERMS AND CONDITIONS
+
+      APPENDIX: How to apply the Apache License to your work.
+
+      >>>
+         To apply the Apache License to your work, attach the following
+         boilerplate notice, with the fields enclosed by brackets "[]"
+         replaced with your own identifying information. (Don't include
+         the brackets!)  The text should be enclosed in the appropriate
+         comment syntax for the file format. We also recommend that a
+         file or class name and description of purpose be included on the
+         same "printed page" as the copyright notice for easier
+         identification within third-party archives.
+
+      Copyright [yyyy] [name of copyright owner]
+
+      Licensed under the Apache License, Version 2.0 (the "License");
+      you may not use this file except in compliance with the License.
+      You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+      Unless required by applicable law or agreed to in writing, software
+      distributed under the License is distributed on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+      See the License for the specific language governing permissions and
+      limitations under the License.
diff --git a/Makefile.in b/Makefile.in
deleted file mode 100644
index c2b2c509fb..0000000000
--- a/Makefile.in
+++ /dev/null
@@ -1,642 +0,0 @@
-SHELL = /bin/sh
-NULLCMD = @NULLCMD@
-n=$(NULLCMD)
-ECHO1 = $(V:1=$n)
-RUNCMD = $(SHELL)
-CDPATH = .
-CHDIR = @CHDIR@
-exec = exec
-NULL = /dev/null
-PATH_SEPARATOR = @PATH_SEPARATOR@
-
-#### Start of system configuration section. ####
-
-srcdir = @srcdir@
-top_srcdir = $(srcdir)
-hdrdir = $(srcdir)/include
-PLATFORM_DIR = @PLATFORM_DIR@
-
-CC_WRAPPER = @XCC_WRAPPER@
-CC = @CC@
-CPP = @CPP@
-LD = @LD@
-YACC = bison
-PURIFY =
-AUTOCONF = autoconf
-ACLOCAL = aclocal
-CONFIGURE = @CONFIGURE@
-@SET_MAKE@
-MKFILES = @MAKEFILES@
-BASERUBY = @BASERUBY@
-HAVE_BASERUBY = @HAVE_BASERUBY@
-TEST_RUNNABLE = @TEST_RUNNABLE@
-CROSS_COMPILING = @CROSS_COMPILING@
-DOXYGEN = @DOXYGEN@
-
-prefix = @prefix@
-exec_prefix = @exec_prefix@
-bindir = @bindir@
-sbindir = @sbindir@
-libdir = @libdir@
-libexecdir = @libexecdir@
-datarootdir = @datarootdir@
-datadir = @datadir@
-arch = @arch@
-sitearch = @sitearch@
-sitedir = @sitedir@
-archlibdir = @archlibdir@
-ruby_version = @ruby_version@
-RUBY_VERSION_NAME = @RUBY_VERSION_NAME@
-UNIVERSAL_ARCHNAMES = @UNIVERSAL_ARCHNAMES@
-
-TESTUI = console
-TESTS =
-INSTALLDOC = @INSTALLDOC@
-DOCTARGETS = @RDOCTARGET@ @CAPITARGET@
-
-EXTOUT = @EXTOUT@
-TIMESTAMPDIR  = $(EXTOUT)/.timestamp
-arch_hdrdir = $(EXTOUT)/include/$(arch)
-VPATH = $(arch_hdrdir)/ruby:$(hdrdir)/ruby:$(srcdir):$(srcdir)/missing
-
-empty =
-CC_VERSION = @CC_VERSION@
-OUTFLAG = @OUTFLAG@$(empty)
-COUTFLAG = @COUTFLAG@$(empty)
-CPPOUTFLAG = $(COUTFLAG)
-ARCH_FLAG = @ARCH_FLAG@
-CFLAGS_NO_ARCH = @CFLAGS@
-CFLAGS = $(CFLAGS_NO_ARCH) $(ARCH_FLAG)
-cflags = @cflags@
-optflags = @optflags@
-debugflags = @debugflags@
-warnflags = @warnflags@ @strict_warnflags@
-cppflags = @cppflags@
-MATHN = @MATHN@
-XCFLAGS = @XCFLAGS@ $(MATHN:yes=-DCANONICALIZATION_FOR_MATHN)
-USE_RUBYGEMS = @USE_RUBYGEMS@
-USE_RUBYGEMS_ = $(USE_RUBYGEMS:yes=)
-CPPFLAGS = @CPPFLAGS@ $(INCFLAGS) $(USE_RUBYGEMS_:no=-DDISABLE_RUBYGEMS=1)
-MJIT_SUPPORT = @MJIT_SUPPORT@
-MJIT_HEADER_FLAGS = @MJIT_HEADER_FLAGS@
-MJIT_HEADER_SUFFIX =
-MJIT_HEADER_ARCH =
-MJIT_HEADER_INSTALL_DIR = @MJIT_HEADER_INSTALL_DIR@
-MJIT_CC = @MJIT_CC@
-MJIT_CFLAGS = @MJIT_CFLAGS@
-MJIT_OPTFLAGS = @MJIT_OPTFLAGS@
-MJIT_DEBUGFLAGS = @MJIT_DEBUGFLAGS@
-MJIT_LDSHARED = @MJIT_LDSHARED@
-MJIT_DLDFLAGS = @DLDFLAGS@
-MJIT_HEADER   = rb_mjit_header.h
-MJIT_MIN_HEADER_NAME = rb_mjit_min_header-$(RUBY_PROGRAM_VERSION).h
-MJIT_MIN_HEADER = $(MJIT_HEADER_BUILD_DIR)/$(MJIT_MIN_HEADER_NAME)
-MJIT_HEADER_BUILD_DIR = $(EXTOUT)/include/$(arch)
-LDFLAGS = @STATIC@ $(CFLAGS) @LDFLAGS@
-EXTLDFLAGS = @EXTLDFLAGS@
-XLDFLAGS = @XLDFLAGS@ $(EXTLDFLAGS)
-EXTLIBS =
-LIBS = @LIBS@ $(EXTLIBS)
-MISSING = @LIBOBJS@ @ALLOCA@
-ENABLE_SHARED = @ENABLE_SHARED@
-LDSHARED = @LIBRUBY_LDSHARED@
-DLDSHARED = @DLDSHARED@
-DLDFLAGS = @LIBRUBY_DLDFLAGS@ $(XLDFLAGS) $(ARCH_FLAG)
-SOLIBS = @SOLIBS@
-ENABLE_DEBUG_ENV = @ENABLE_DEBUG_ENV@
-MAINLIBS = @MAINLIBS@
-ARCHMINIOBJS = @MINIOBJS@
-DLNOBJ = @DLNOBJ@
-ENCOBJS = @ENCOBJS@
-EXTOBJS = @EXTOBJS@
-BUILTIN_ENCOBJS = @BUILTIN_ENCOBJS@
-BUILTIN_TRANSSRCS = @BUILTIN_TRANSSRCS@
-BUILTIN_TRANSOBJS = @BUILTIN_TRANSOBJS@
-POSTLINK = @POSTLINK@
-
-RUBY_BASE_NAME=@RUBY_BASE_NAME@
-RUBY_PROGRAM_VERSION=@RUBY_PROGRAM_VERSION@
-RUBY_API_VERSION=@RUBY_API_VERSION@
-RUBY_INSTALL_NAME=@RUBY_INSTALL_NAME@
-RUBY_SO_NAME=@RUBY_SO_NAME@
-EXEEXT = @EXEEXT@
-LIBEXT = @LIBEXT@
-PROGRAM=$(RUBY_INSTALL_NAME)$(EXEEXT)
-RUBY = $(RUBY_INSTALL_NAME)
-MINIRUBY = @MINIRUBY@\
-	$(MINIRUBYOPT)
-# RUNRUBY_COMMAND:: runruby.rb or baseruby. do not append options directly
-RUNRUBY_COMMAND = @RUNRUBY_COMMAND@
-# RUNRUBY:: run ruby with RUN_OPTS which is passed to ruby
-RUNRUBY = @RUNRUBY@ $(RUN_OPTS)
-# RUNRUBY_DEBUGGER:: debugging option for runruby.rb
-RUNRUBY_DEBUGGER = --debugger='gdb -x run.gdb --quiet --args'
-XRUBY = @XRUBY@
-BTESTRUBY = @BTESTRUBY@\
-	$(MINIRUBYOPT)
-INSTALL = @INSTALL@
-INSTALL_DATA = @INSTALL_DATA@
-INSTALL_SCRIPT = @INSTALL_SCRIPT@
-INSTALL_PROGRAM = @INSTALL_PROGRAM@
-XRUBY_LIBDIR = @XRUBY_LIBDIR@
-XRUBY_RUBYLIBDIR = @XRUBY_RUBYLIBDIR@
-XRUBY_RUBYHDRDIR = @XRUBY_RUBYHDRDIR@
-BOOTSTRAPRUBY = @BOOTSTRAPRUBY@
-
-#### End of system configuration section. ####
-
-MAJOR=	@MAJOR@
-MINOR=	@MINOR@
-TEENY=	@TEENY@
-RUBY_PROGRAM_VERSION = @RUBY_PROGRAM_VERSION@
-
-LIBRUBY_A     = @LIBRUBY_A@
-LIBRUBY_SO    = @LIBRUBY_SO@
-LIBRUBY_SONAME= @LIBRUBY_SONAME@
-LIBRUBY_ALIASES= @LIBRUBY_ALIASES@
-LIBRUBY	      = @LIBRUBY@
-LIBRUBYARG    = @LIBRUBYARG@
-LIBRUBYARG_STATIC = @LIBRUBYARG_STATIC@
-LIBRUBYARG_SHARED = @LIBRUBYARG_SHARED@
-LIBRUBY_RELATIVE = @LIBRUBY_RELATIVE@
-LIBRUBY_A_OBJS = @LIBRUBY_A_OBJS@
-
-DTRACE_REBUILD_OBJS = $(DTRACE_REBUILD:yes=$(DTRACE_DEPENDENT_OBJS))
-
-DTRACE_DEPENDENT_OBJS = array.$(OBJEXT) \
-			eval.$(OBJEXT) \
-			gc.$(OBJEXT) \
-			hash.$(OBJEXT) \
-			load.$(OBJEXT) \
-			object.$(OBJEXT) \
-			parse.$(OBJEXT) \
-			string.$(OBJEXT) \
-			symbol.$(OBJEXT) \
-			vm.$(OBJEXT)
-
-THREAD_MODEL  = @THREAD_MODEL@
-
-PREP          = @PREP@
-ARCHFILE      = @ARCHFILE@
-SETUP         =
-EXTSTATIC     = @EXTSTATIC@
-ENCSTATIC     = @ENCSTATIC@
-SET_LC_MESSAGES = env LC_MESSAGES=C
-
-MAKEDIRS      = @MKDIR_P@
-CP            = cp
-MV            = mv
-RM            = rm -f
-RMDIR         = @RMDIR@
-RMDIRS        = @RMDIRS@
-RMALL         = @RMALL@
-NM            = @NM@
-AR            = @AR@
-ARFLAGS       = @ARFLAGS@$(empty)
-RANLIB        = @RANLIB@
-AS            = @AS@
-ASFLAGS       = @ASFLAGS@ $(INCFLAGS)
-IFCHANGE      = $(srcdir)/tool/ifchange
-OBJDUMP       = @OBJDUMP@
-OBJCOPY       = @OBJCOPY@
-HAVE_GIT      = @HAVE_GIT@
-GIT           = @GIT@
-VCS           = @VCS@
-VCSUP         = @VCSUP@
-DTRACE        = @DTRACE@ @DTRACE_OPT@
-DTRACE_EXT    = @DTRACE_EXT@
-DTRACE_OBJ    = @DTRACE_OBJ@
-DTRACE_REBUILD= @DTRACE_REBUILD@
-DTRACE_GLOMMED_OBJ = $(DTRACE_REBUILD:yes=ruby-glommed.$(OBJEXT))
-
-OBJEXT        = @OBJEXT@
-ASMEXT        = S
-SOEXT         = @SOEXT@
-DLEXT         = @DLEXT@
-MANTYPE	      = @MANTYPE@
-SYMBOL_PREFIX = @SYMBOL_PREFIX@
-
-INSTALLED_LIST= .installed.list
-
-NEWLINE_C     = enc/trans/newline.c
-MINIPRELUDE_C = miniprelude.c
-PRELUDE_C     = prelude.c
-GOLF_PRELUDE_C= golf_prelude.c
-RBCONFIG      = .rbconfig.time
-
-MAINSRC = $(MAINOBJ:@OBJEXT@=c)
-
-SRC_FILE      = $<
-OS_SRC_FILE   = $<
-DEST_FILE     = $@
-OS_DEST_FILE  = $@
-
-MESSAGE_BEGIN = @for line in
-MESSAGE_END = ; do echo "$$line"; done
-ECHO_BEGIN = @sep=''; for word in
-ECHO_END = ; do echo @ECHO_N@ "$$sep'$$word'@ECHO_C@"; sep=' '; done; echo
-
-DESTDIR       = @DESTDIR@
-
-configure_args = @configure_args@
-#### End of variables
-
-.SUFFIXES: .inc .h .c .y .i .$(DTRACE_EXT)
-
-all:
-
-# Prevent GNU make v3 from overflowing arg limit on SysV.
-.NOEXPORT:
-
-miniruby$(EXEEXT):
-		@-if test -f $@; then $(MV) -f $@ $@.old; $(RM) $@.old; fi
-		$(ECHO) linking $@
-		$(Q) $(PURIFY) $(CC) $(LDFLAGS) $(XLDFLAGS) $(NORMALMAINOBJ) $(MINIOBJS) $(COMMONOBJS) $(MAINLIBS) $(LIBS) $(OUTFLAG)$@
-		$(Q) $(POSTLINK)
-
-$(PROGRAM):
-		@$(RM) $@
-		$(ECHO) linking $@
-		$(Q) $(PURIFY) $(CC) $(LDFLAGS) $(XLDFLAGS) $(MAINOBJ) $(EXTOBJS) $(LIBRUBYARG) $(MAINLIBS) $(LIBS) $(EXTLIBS) $(OUTFLAG)$@
-		$(Q) $(POSTLINK)
-
-PRE_LIBRUBY_UPDATE = [ -n "$(LIBRUBY_SO_UPDATE)" ] || $(exec) $(RM) $(LIBRUBY_EXTS)
-
-# We must `rm' the library each time this rule is invoked because "updating" a
-# MAB library on Apple/NeXT (see --enable-fat-binary in configure) is not
-# supported.
-$(LIBRUBY_A):
-		@$(RM) $@
-		@-[ -z "$(EXTSTATIC)" ] || $(PRE_LIBRUBY_UPDATE)
-		$(ECHO) linking static-library $@
-		$(Q) $(AR) $(ARFLAGS) $@ $(LIBRUBY_A_OBJS) $(INITOBJS)
-		@-$(RANLIB) $@ 2> /dev/null || true
-
-verify-static-library: $(LIBRUBY_A)
-		$(ECHO) verifying static-library $@
-		@$(PURIFY) $(CC) $(LDFLAGS) $(XLDFLAGS) $(MAINOBJ) $(LIBRUBY_A) $(MAINLIBS) $(EXTLIBS) $(LIBS) $(OUTFLAG)conftest$(EXEEXT)
-		@$(RMALL) conftest$(EXEEXT) conftest.c conftest.dSYM
-
-$(LIBRUBY_SO):
-		@-[ -n "$(EXTSTATIC)" ] || $(PRE_LIBRUBY_UPDATE)
-		$(ECHO) linking shared-library $@
-		$(Q) $(LDSHARED) $(DLDFLAGS) $(OBJS) $(DLDOBJS) $(SOLIBS) $(EXTSOLIBS) $(OUTFLAG)$@
-		-$(Q) $(OBJCOPY) -w -L '$(SYMBOL_PREFIX)Init_*' -L '$(SYMBOL_PREFIX)ruby_static_id_*' \
-			-L '$(SYMBOL_PREFIX)*_threadptr_*' -L '$(SYMBOL_PREFIX)*_ec_*' $@
-		$(Q) $(POSTLINK)
-		@-$(MINIRUBY) -e 'so, *aliases = ARGV; aliases.uniq!; aliases.delete(File.basename(so)); \
-				  aliases.each { |link| File.delete link rescue nil; File.symlink so, link }' \
-				$(LIBRUBY_SO) $(LIBRUBY_ALIASES) || true
-
-LIBRUBY_WITH_EXT = @LIBRUBY_WITH_EXT@
-$(LIBRUBY_$(LIBRUBY_WITH_EXT)): $(LIBRUBY_SO_UPDATE)
-
-ruby_pc = @ruby_pc@
-ruby.pc: $(ruby_pc)
-$(ruby_pc): config.status
-		@./config.status --file=$@:$(srcdir)/template/ruby.pc.in
-
-ruby-runner.h: template/ruby-runner.h.in config.status
-		@./config.status --file=$@:$(srcdir)/template/$(@F).in
-
-$(RBCONFIG): $(PREP)
-
-rbconfig.rb: $(RBCONFIG)
-
-install-cross: $(arch)-fake.rb $(RBCONFIG) rbconfig.rb $(arch_hdrdir)/ruby/config.h \
-	$(LIBRUBY_A) $(LIBRUBY_SO) $(ARCHFILE)
-	$(ECHO) installing cross-compiling stuff
-	$(Q) $(MAKEDIRS) $(XRUBY_RUBYLIBDIR)/$(arch) $(XRUBY_RUBYHDRDIR)/$(arch)/ruby
-	$(Q) sed '/^\$$:\.unshift/q' $(arch)-fake.rb > fake.rb
-	$(Q) $(BASERUBY) -p \
-	-e '~/^\s*CONFIG\["LDFLAGS"\]/ and' \
-	-e '$$_[/(?=\s*"$$)/] = %q[ #{(CONFIG["LIBPATHFLAG"]%File.dirname(__FILE__)).strip}]' \
-	rbconfig.rb > fake-rbconfig.rb
-	$(INSTALL_SCRIPT) fake.rb $(XRUBY_RUBYLIBDIR)/$(arch)/fake.rb
-	$(INSTALL_SCRIPT) fake-rbconfig.rb $(XRUBY_RUBYLIBDIR)/$(arch)/rbconfig.rb
-	@$(RM) fake.rb fake-rbconfig.rb
-	$(INSTALL_DATA) $(arch_hdrdir)/ruby/config.h $(XRUBY_RUBYHDRDIR)/$(arch)/ruby
-	$(INSTALL_DATA) $(top_srcdir)/include/ruby/win32.h $(XRUBY_RUBYHDRDIR)/ruby
-	$(INSTALL_DATA) $(LIBRUBY) $(LIBRUBY_A) $(XRUBY_RUBYLIBDIR)/$(arch)
-	$(INSTALL_PROGRAM) $(LIBRUBY_SO) $(XRUBY_RUBYLIBDIR)/$(arch)
-
-Makefile:	$(srcdir)/Makefile.in $(srcdir)/enc/Makefile.in
-
-$(MKFILES): config.status $(srcdir)/version.h
-		@[ -f $@ ] && mv $@ $@.old
-		MAKE=$(MAKE) $(SHELL) ./config.status $@
-		@cmp $@ $@.old > /dev/null 2>&1 && echo $@ unchanged && exit 0; \
-		{ \
-		    echo "all:; -@rm -f conftest.mk"; \
-		    echo "conftest.mk: .force; @echo AUTO_REMAKE"; \
-		    echo ".force:"; \
-		} > conftest.mk || exit 1; \
-		$(MAKE) -f conftest.mk | grep '^AUTO_REMAKE$$' >/dev/null 2>&1 || \
-		{ echo "$@ updated, restart."; exit 1; }
-
-uncommon.mk: $(srcdir)/common.mk
-		sed 's/{\$$([^(){}]*)[^{}]*}//g' $< > $@
-
-.PHONY: reconfig
-reconfig-args = $(srcdir)/$(CONFIGURE) $(configure_args)
-config.status-args = ./config.status --recheck
-reconfig-exec-0 = test -t 1 && { CONFIGURE_TTY=yes; export CONFIGURE_TTY; }; exec 3>&1; exit `exec 4>&1; { "$$@" 3>&- 4>&-; echo $$? 1>&4; } | fgrep -v '(cached)' 1>&3 3>&- 4>&-`
-reconfig-exec-1 = set -x; "$$@"
-
-reconfig config.status:	$(srcdir)/$(CONFIGURE) $(srcdir)/enc/Makefile.in \
-			$(srcdir)/include/ruby/version.h
-	@PWD= MINIRUBY="$(MINIRUBY)"; export MINIRUBY; \
-	set $(SHELL) $($@-args); $(reconfig-exec-$(V))
-
-$(srcdir)/$(CONFIGURE): $(srcdir)/configure.ac $(srcdir)/aclocal.m4
-	$(CHDIR) $(srcdir) && exec $(AUTOCONF) -o $(@F)
-
-$(srcdir)/aclocal.m4:
-	$(CHDIR) $(srcdir) && \
-	type $(ACLOCAL) >/dev/null 2>&1 && exec $(ACLOCAL); \
-	touch $(@F)
-
-prereq: $(srcdir)/$(CONFIGURE)
-
-incs: id.h
-all-incs: probes.h
-
-# Things which should be considered:
-# * with gperf v.s. without gperf
-# * committers may have various versions of gperf
-# * ./configure v.s. ../ruby/configure
-# * GNU make v.s. HP-UX make	# HP-UX make invokes the action if lex.c and keywords has same mtime.
-# * svn checkout generate a file with mtime as current time
-# * ext4 and XFS has a mtime with fractional part
-lex.c: defs/keywords
-	@\
-	if cmp -s $(srcdir)/defs/lex.c.src $?; then \
-	  [ $(Q) ] && echo copying $@ || set -x; \
-	  $(CP) $(srcdir)/lex.c.blt $@; \
-	else \
-	  [ $(Q) ] && echo generating $@ || set -x; \
-	  gperf -C -P -p -j1 -i 1 -g -o -t -N rb_reserved_word -k1,3,$$ $? \
-	  | sed -f $(srcdir)/tool/gperf.sed \
-	  > $@.tmp && \
-	  $(MV) $@.tmp $@ && \
-	  $(CP) $? $(srcdir)/defs/lex.c.src && \
-	  $(CP) $@ $(srcdir)/lex.c.blt; \
-	fi
-
-JIS_PROPS_OPTIONS = -k1,3 -7 -c -j1 -i1 -t -C -P -t --ignore-case -H onig_jis_property_hash -Q onig_jis_property_pool -N onig_jis_property
-
-$(srcdir)/enc/jis/props.h: enc/jis/props.kwd
-	$(MAKEDIRS) $(@D)
-	@set +e; \
-	if cmp -s $(?:.kwd=.src) $?; then \
-	  set -x; \
-	  $(CP) $(?:.kwd=.h.blt) $@; \
-	else \
-	  set -x; \
-	  gperf $(JIS_PROPS_OPTIONS) $? | \
-	  sed -f $(srcdir)/tool/gperf.sed > $@ && \
-	  $(CP) $? $(?:.kwd=.src) && \
-	  $(CP) $@ $(?:.kwd=.h.blt); \
-	fi
-
-.c.@OBJEXT@:
-	@$(ECHO) compiling $<
-	$(Q) $(CC) $(CFLAGS) $(XCFLAGS) $(CPPFLAGS) $(COUTFLAG)$@ -c $<
-
-.s.@OBJEXT@:
-	@$(ECHO) assembling $<
-	$(Q) $(AS) $(ASFLAGS) -o $@ $<
-
-.c.S:
-	@$(ECHO) translating $<
-	$(Q) $(CC) $(CFLAGS) $(XCFLAGS) $(CPPFLAGS) $(COUTFLAG)$@ -S $<
-
-.c.i:
-	@$(ECHO) preprocessing $<
-	$(Q) $(CPP) $(warnflags) $(XCFLAGS) $(CPPFLAGS) $(COUTFLAG)$@ -E $< > $@
-
-.d.h:
-	@$(ECHO) translating probes $<
-	$(Q) $(DTRACE) -o $@.tmp -h -C $(INCFLAGS) -s $<
-	$(Q) sed -e 's/RUBY_/RUBY_DTRACE_/g' -e 's/PROBES_H_TMP/RUBY_PROBES_H/' -e 's/(char \*/(const char */g' -e 's/, char \*/, const char */g' $@.tmp > $@
-	$(Q) $(RM) $@.tmp
-
-.dmyh.h:
-	@$(ECHO) making dummy $(DEST_FILE)
-	$(Q)echo '#include "$(*F).dmyh"' > $@
-
-probes.stamp: $(DTRACE_REBUILD_OBJS)
-	$(Q) if test -f $@ -o -f probes.$(OBJEXT); then \
-	  $(RM) $(DTRACE_REBUILD_OBJS) $@; \
-	  $(ECHO0) "rebuilding objects which were modified by \"dtrace -G\""; \
-	  $(MAKE) $(DTRACE_REBUILD_OBJS); \
-	fi
-	$(Q) touch $@
-
-probes.$(OBJEXT): $(srcdir)/probes.d $(DTRACE_REBUILD:yes=probes.stamp)
-	@$(ECHO) processing probes in object files
-	$(Q) $(RM) $@
-	$(Q) $(DTRACE) -G -C $(INCFLAGS) -s $(srcdir)/probes.d -o $@ $(DTRACE_REBUILD_OBJS)
-
-main: mjit-headers
-yes-mjit-headers: $(MJIT_MIN_HEADER)
-clean-local::
-	$(Q)$(RM) $(MJIT_HEADER) $(MJIT_HEADER:.h=)$(MJIT_HEADER_SUFFIX:%=*).h
-	$(Q)$(RM) $(MJIT_MIN_HEADER) $(MJIT_MIN_HEADER:.h=)$(MJIT_HEADER_SUFFIX:%=*).h
-	$(Q)$(RM) $(MJIT_HEADER_INSTALL_DIR)/rb_mjit_min_header-*.h
-	$(Q)$(RM) $(TIMESTAMPDIR)/$(MJIT_HEADER:.h=)$(MJIT_HEADER_SUFFIX).time mjit_config.h
-	$(Q)$(RM) -r mjit_build_dir.*
-	-$(Q) $(RMDIRS) $(MJIT_HEADER_INSTALL_DIR) 2> $(NULL) || exit 0
-
-# DTrace static library hacks described here:
-# http://mail.opensolaris.org/pipermail/dtrace-discuss/2005-August/000207.html
-ruby-glommed.$(OBJEXT):
-	@$(ECHO) generating a glommed object with DTrace probes for static library
-	$(Q) $(LD) -r -o $@ $(OBJS)
-
-clean-local::
-	$(Q)$(RM) ext/extinit.c ext/extinit.$(OBJEXT) ext/ripper/y.output \
-		enc/encinit.c enc/encinit.$(OBJEXT)
-	-$(Q)$(RM) $(pkgconfig_DATA)
-	-$(Q)$(RMALL) exe/ ruby-runner.h *.dSYM
-
-distclean-local::
-	$(Q)$(RM) ext/config.cache $(RBCONFIG) Doxyfile
-	-$(Q)$(RM) run.gdb
-	-$(Q)$(RM) $(INSTALLED_LIST) $(arch_hdrdir)/ruby/config.h verconf.h
-	-$(Q)$(RMDIRS) $(arch_hdrdir)/ruby 2> /dev/null || true
-
-ext/clean.sub gems/clean.sub:: ext/clean.mk
-ext/distclean.sub gems/distclean.sub:: ext/distclean.mk
-ext/realclean.sub gems/realclean.sub:: ext/realclean.mk
-
-ext/clean.mk ext/distclean.mk ext/realclean.mk::
-	-$(Q) if [ -f $(EXTS_MK) ]; then exec $(MAKE) -f $(EXTS_MK) $(@F:.mk=); fi
-
-ext/clean:: ext/clean.sub
-ext/distclean:: ext/distclean.sub
-ext/realclean:: ext/realclean.sub
-gems/clean:: gems/clean.sub
-gems/distclean:: gems/distclean.sub
-gems/realclean:: gems/realclean.sub
-
-ext/clean.sub ext/distclean.sub ext/realclean.sub \
-gems/clean.sub gems/distclean.sub gems/realclean.sub::
-	$(Q) set dummy `echo "${EXTS}" | tr , ' '`; shift; \
-	test "$$#" = 0 && set .; \
-	set dummy `\
-	    cd $(@D) 2>/dev/null && \
-	    find "$$@" \( -name Makefile -o -name exts.mk \) -print | \
-	    sed -n 's:^\./::;s:^:$(@D)/:;s:/[^/][^/]*$$::p' | sort -u; \
-	`; shift; \
-	for dir do \
-	    $(RM) "$$dir/exts.mk"; \
-	    if [ -f "$$dir/Makefile" ]; then \
-		echo $(@F:.sub=)ing "$$dir"; \
-		(cd "$$dir" && exec $(MAKE) $(mflags) $(@F:.sub=)); \
-	    fi; \
-	done || true
-
-ext/distclean ext/realclean gems/distclean gems/realclean::
-	$(Q) set dummy `echo "${EXTS}" | tr , ' '`; shift; \
-	test "$$#" = 0 && set .; \
-	cd $(@D) 2>/dev/null && \
-	find "$$@" -type d -empty -exec $(RMDIRS) {} + 2> /dev/null || true
-	$(Q) $(RMDIRS) $(@D) 2> /dev/null || true
-
-clean-enc distclean-enc realclean-enc:
-	@test -f "$(ENC_MK)" || exit 0; \
-	echo $(@:-enc=ing) encodings; \
-	exec $(MAKE) $(MAKE_ENC) $(@:-enc=)
-
-ext/extinit.$(OBJEXT): ext/extinit.c $(SETUP)
-	$(ECHO) compiling $@
-	$(Q) $(CC) $(CFLAGS) $(XCFLAGS) $(CPPFLAGS) $(COUTFLAG)$@ -c ext/extinit.c
-
-enc/encinit.$(OBJEXT): enc/encinit.c $(SETUP)
-
-test-bundled-gems-run:
-	$(Q) set -e; while read gem _; do \
-	  echo testing $$gem gem && \
-	  $(XRUBY) -C $(srcdir)/gems/src/$$gem -Ilib ../../../.bundle/bin/rake; \
-	done < $(srcdir)/gems/bundled_gems
-
-update-src::
-	@$(CHDIR) "$(srcdir)" && LC_TIME=C exec $(VCSUP)
-
-update-download:: update-config_files
-
-after-update:: prereq
-
-gcov:
-	$(Q) $(BASERUBY) $(srcdir)/tool/run-gcov.rb
-
-lcov:
-	$(Q) $(BASERUBY) $(srcdir)/tool/run-lcov.rb
-
-update-benchmark-driver:
-	$(Q) $(srcdir)/tool/git-refresh -C $(srcdir)/benchmark $(Q1:0=-q) \
-		--branch $(BENCHMARK_DRIVER_GIT_REF) \
-		$(BENCHMARK_DRIVER_GIT_URL) benchmark-driver $(GIT_OPTS)
-
-update-doclie:
-	$(Q) $(srcdir)/tool/git-refresh -C $(srcdir)/coverage $(Q1:0=-q) \
-		--branch $(DOCLIE_GIT_REF) \
-		$(DOCLIE_GIT_URL) doclie $(GIT_OPTS)
-
-update-simplecov-html:
-	$(Q) $(srcdir)/tool/git-refresh -C $(srcdir)/coverage $(Q1:0=-q) \
-		--branch $(SIMPLECOV_HTML_GIT_REF) \
-		$(SIMPLECOV_HTML_GIT_URL) simplecov-html $(GIT_OPTS)
-
-update-simplecov:
-	$(Q) $(srcdir)/tool/git-refresh -C $(srcdir)/coverage $(Q1:0=-q) \
-		--branch $(SIMPLECOV_GIT_REF)  \
-		$(SIMPLECOV_GIT_URL) simplecov $(GIT_OPTS)
-
-update-coverage: update-simplecov update-simplecov-html update-doclie
-
-INSNS	= opt_sc.inc optinsn.inc optunifs.inc insns.inc insns_info.inc \
-	  vmtc.inc vm.inc mjit_compile.inc
-
-$(INSNS): $(srcdir)/insns.def vm_opts.h \
-	  $(srcdir)/defs/opt_operand.def $(srcdir)/defs/opt_insn_unif.def \
-	  $(srcdir)/tool/insns2vm.rb
-	$(ECHO) generating $@
-	$(Q) $(BASERUBY) -Ku $(srcdir)/tool/insns2vm.rb $(INSNS2VMOPT) $@
-
-verconf.h: $(RBCONFIG)
-
-loadpath: verconf.h
-	@$(CPP) $(XCFLAGS) $(CPPFLAGS) $(srcdir)/loadpath.c | \
-	sed -e '1,/^const char ruby_initial_load_paths/d;/;/,$$d' \
-	    -e '/^ /!d;s/ *"\\0"$$//;s/" *"//g'
-
-un-runnable:
-	$(ECHO) cannot make runnable, configure with --enable-load-relative.
-	$(Q) exit 1
-
-mjit_config.h:
-	$(ECHO) making $@
-	@{ \
-	quote() { \
-	    printf "#define $$1"; shift; \
-	    $${1+printf} $${1+' "%s"'$$sep} $${1+"$$@"}; \
-	    echo; \
-	}; \
-	parse_arch_flag() { \
-	    while [ "$$#" -gt 0 ]; do \
-	        case "$$1" in \
-	        -arch) \
-	            shift; \
-	            archs="$${archs:+$$archs }$$1"; \
-	            shift; \
-	            ;; \
-	        *) \
-	            arch_flag="$${arch_flag:+$${arch_flag} }$$1"; \
-	            shift; \
-	            ;; \
-	        esac; \
-	    done; \
-	}; \
-	test "$(Q)" = @ || set -x; \
-	archs="$(UNIVERSAL_ARCHNAMES)"; \
-	arch_flag=""; \
-	parse_arch_flag $(ARCH_FLAG); \
-	need_mjit_archflag="$${archs}$${arch_flag}"; \
-	echo '#ifndef RUBY_MJIT_CONFIG_H'; \
-	echo '#define RUBY_MJIT_CONFIG_H 1'; \
-	echo; \
-	sep=; \
-	quote MJIT_MIN_HEADER_NAME "/$(MJIT_HEADER_INSTALL_DIR)/$(MJIT_MIN_HEADER_NAME)"; \
-	sep=,; \
-	quote "MJIT_CC_COMMON  " $(MJIT_CC); \
-	quote "MJIT_CFLAGS     $${need_mjit_archflag:+ MJIT_ARCHFLAG}" $(MJIT_CFLAGS); \
-	quote "MJIT_OPTFLAGS   " $(MJIT_OPTFLAGS); \
-	quote "MJIT_DEBUGFLAGS " $(MJIT_DEBUGFLAGS); \
-	quote "MJIT_LDSHARED   " $(MJIT_LDSHARED); \
-	quote "MJIT_DLDFLAGS   $${need_mjit_archflag:+ MJIT_ARCHFLAG}" $(MJIT_DLDFLAGS); \
-	quote "MJIT_LIBS       " $(LIBRUBYARG_SHARED); \
-	quote 'PRELOADENV       "@PRELOADENV@"'; \
-	$${archs:+echo} $${archs:+'#if 0'}; \
-	for arch in $$archs; do \
-	    echo "#elif defined __$${arch%=*}__"; \
-	    quote "  MJIT_ARCHFLAG " -arch $${arch%=*}; \
-	done; \
-	$${archs:+echo} $${archs:+'#else'}; \
-	if [ "$${arch_flag}" != "" ]; then \
-	    quote "  MJIT_ARCHFLAG " $${arch_flag}; \
-	fi; \
-	$${archs:+echo} $${archs:+'#endif'}; \
-	echo; \
-	echo '#endif /* RUBY_MJIT_CONFIG_H */'; \
-	} > $@
-
-yes-test-all: mjit_build_dir.$(SOEXT)
-mjit_build_dir.$(SOEXT): $(MJIT_MIN_HEADER)
-	$(ECHO) making $@
-	$(Q) { \
-	echo 'const char MJIT_BUILD_DIR[] = "'"`$(CHDIR) . && pwd`"'";'; \
-	} > $(@:.$(SOEXT)=.c)
-	$(Q) cat $(@:.$(SOEXT)=.c)
-	$(Q) $(DLDSHARED) $(MJIT_DLDFLAGS) $(ARCH_FLAG) $(CFLAGS) $(CPPFLAGS) $(@:.$(SOEXT)=.c) $(OUTFLAG)$@
diff --git a/NEWS b/NEWS
deleted file mode 100644
index a4b07925b3..0000000000
--- a/NEWS
+++ /dev/null
@@ -1,494 +0,0 @@
-# -*- rdoc -*-
-
-= NEWS for Ruby 2.6.0
-
-This document is a list of user visible feature changes made between
-releases except for bug fixes.
-
-Note that each entry is kept so brief that no reason behind or reference
-information is supplied with.  For a full list of changes with all
-sufficient information, see the ChangeLog file or Redmine
-(e.g. <tt>https://bugs.ruby-lang.org/issues/$FEATURE_OR_BUG_NUMBER</tt>)
-
-== Changes since the 2.5.0 release
-
-=== Language changes
-
-* <code>$SAFE</code> is a process global state and we can set 0 again. [Feature #14250]
-
-* refinements take place at block passing.  [Feature #14223]
-
-* +else+ without +rescue+ now causes a syntax error.  [EXPERIMENTAL]
-
-* constant names may start with a non-ASCII capital letter. [Feature #13770]
-
-* An endless range is introduced.  You can write a range that has no end,
-  like <code>(0..)</code>.  The following shows typical use cases.  [Feature #12912]
-
-    ary[1..]                            # identical to ary[1..-1]
-    (1..).each {|index| ... }           # infinite loop from index 1
-    ary.zip(1..) {|elem, index| ... }   # ary.each.with_index(1) { }
-
-* Non-Symbol key in keyword arguments hash causes an exception.
-
-* "shadowing outer local variable" warning was removed.  [Feature #12490]
-  You can now write the following without warning.
-
-    user = users.find {|user| cond(user) }
-
-* Print exception backtrace and error message in reverse order when the
-  exception is not caught and STDOUT is unchanged and a tty. [Feature #8661]
-
-* Print `cause` of the exception if the exception is not caught and printed
-  its backtraces and error message [Feature #8257]
-
-=== Core classes updates (outstanding ones only)
-
-[Array]
-
-  [New methods]
-
-    * Added Array#union and Array#difference instance methods.  [Feature #14097]
-
-  [Modified methods]
-
-    * Array#to_h now maps elements to new keys and values by the
-      block if given.  [Feature #15143]
-
-  [Aliased methods]
-
-    * Array#filter is a new alias for Array#select. [Feature #13784]
-    * Array#filter! is a new alias for Array#select!. [Feature #13784]
-
-[Binding]
-
-  [New methods]
-
-    * added Binding#source_location.  [Feature #14230]
-
-      This method returns the source location of the binding, a 2-element
-      array of <code>__FILE__</code> and <code>__LINE__</code>.
-      Traditionally, the same information could be retrieved by
-      <code>eval("[__FILE__, __LINE__]", binding)</code>, but we are
-      planning to change this behavior so that Kernel#eval ignores
-      binding's source location [Bug #4352].  So, users should use this
-      newly-introduced method instead of Kernel#eval.
-
-[Dir]
-
-  [New methods]
-
-    * added Dir#each_child and Dir#children instance methods. [Feature #13969]
-
-[Enumerable]
-
-  [Modified methods]
-
-    * Enumerable#to_h now maps elements to new keys and values by the block if
-      given.  [Feature #15143]
-
-  [Aliased methods]
-
-    * Enumerable#filter is a new alias for Enumerable#select. [Feature #13784]
-
-[Enumerator::ArithmeticSequence]
-
-  * This is a new class to represent a generator of an arithmetic sequence,
-    that is a number sequence defined by a common difference. It can be used
-    for representing what is similar to Python's slice. You can get an
-    instance of this class from Numeric#step and Range#step.
-
-[Enumerator::Lazy]
-
-  [Aliased methods]
-
-    * Enumerator::Lazy#filter is a new alias for
-      Enumerator::Lazy#select.  [Feature #13784]
-
-[ENV]
-
-  [Modified methods]
-
-    * ENV.to_h now maps names and values to new keys and values
-      by the block if given.  [Feature #15143]
-
-[Exception]
-
-  [New options]
-
-    * Exception#full_message takes +:highlight+ and +:order+
-      options. [Bug #14324]
-
-[Hash]
-
-  [Modified methods]
-
-    * Hash#merge, merge!, and update now accept multiple
-      arguments.  [Feature #15111]
-
-    * Hash#to_h now maps keys and values to new keys and values
-      by the block if given.  [Feature #15143]
-
-  [Aliased methods]
-
-    * Hash#filter is a new alias for Hash#select.  [Feature #13784]
-
-    * Hash#filter! is a new alias for Hash#select!. [Feature #13784]
-
-[IO]
-
-  [New options]
-
-    * new mode character <code>'x'</code> to open files for exclusive
-      access. [Feature #11258]
-
-[Kernel]
-
-  [Aliased methods]
-
-    * Kernel#then is a new alias for Kernel#yield_self. [Feature #14594]
-
-  [New options]
-
-    * Kernel#Complex, Kernel#Float, Kernel#Integer, and
-      Kernel#Rational take +:exception+ option to specify the way of
-      error handling.  [Feature #12732]
-
-    * Kernel#system takes +:exception+ option to raise an exception
-      on failure.  [Feature #14386]
-
-  [Incompatible changes]
-
-    * Kernel#system and Kernel#exec do not close non-standard file descriptors
-      (The default of the +:close_others+ option is changed to +false+,
-      but we still set the +FD_CLOEXEC+ flag on descriptors we
-      create).  [Misc #14907]
-
-[KeyError]
-
-  [New options]
-
-    * KeyError#initialize accepts +:receiver+ and +:key+ options to
-      set receiver and key in Ruby code.  [Feature #14313]
-
-[Module]
-
-  [New methods]
-
-    * Module#method_defined?, Module#private_method_defined?, and
-      Module#protected_method_defined? now accept the second
-      parameter as optional. If it's +true+ (=default), checks ancestor
-      modules/classes, or checks only the class itself. [Feature #14944]
-
-[NameError]
-
-  [New options]
-
-    * NameError#initialize accepts +:receiver+ option to set receiver
-      in Ruby code.  [Feature #14313]
-
-[NoMethodError]
-
-  [New options]
-
-    * NoMethodError#initialize accepts +:receiver+ option to set receiver
-      in Ruby code.  [Feature #14313]
-
-[Numeric]
-
-  [Incompatible changes]
-
-    * Numeric#step now returns an instance of Enumerator::ArithmeticSequence
-      class rather than one of Enumerator class.
-
-[Proc]
-
-  [Incompatible changes]
-
-    * Proc#call doesn't change <code>$SAFE</code> any more.  [Feature #14250]
-
-[Random]
-
-  [New methods]
-
-    * added Random.bytes.  [Feature #4938]
-
-[Range]
-
-  [New methods]
-
-    * Added Range#% instance method.  [Feature #14697]
-
-  [Incompatible changes]
-
-    * Range#=== now uses +#cover?+ instead of +#include?+ method. [Feature #14575]
-    * Range#cover? now accepts Range object. [Feature #14473]
-    * Range#step now returns an instance of Enumerator::ArithmeticSequence
-      class rather than one of Enumerator class.
-
-[RubyVM::AbstractSyntaxTree]
-
-  [New methods]
-
-    * RubyVM::AbstractSyntaxTree.parse parses a given string and returns AST
-      nodes. [experimental]
-
-    * RubyVM::AbstractSyntaxTree.parse_file parses a given file and returns AST
-      nodes.  [experimental]
-
-    * RubyVM::AbstractSyntaxTree.of returns AST nodes of the given proc or method.
-      [experimental]
-
-[String]
-
-  [New features]
-
-    * String#split yields each substring to the block if given. [Feature #4780]
-
-[Struct]
-
-  [Modified methods]
-
-    * Struct#to_h now maps keys and values to new keys and values
-      by the block if given.  [Feature #15143]
-
-  [Aliased method]
-
-    * Struct#filter is a new alias for Struct#select [Feature #13784]
-
-[Time]
-
-  [New features]
-
-    * Time.new and Time#getlocal accept a timezone object as well as
-      UTC offset string. Time#+, Time#- and Time#succ also preserve
-      the timezone.  [Feature #14850]
-
-[TracePoint]
-
-  [New methods]
-
-    * TracePoint#parameters [Feature #14694]
-
-=== Stdlib updates (outstanding ones only)
-
-[Bundler]
-
-  * Add Bundler to Standard Library. [Feature #12733]
-
-  * Use 1.17.1. It's latest stable version.
-
-[Coverage]
-
-  A oneshot_lines mode is added.  [Feature #15022]
-  This mode checks "whether each line was executed at least once or not",
-  instead of "how many times each line was executed".
-  A hook for each line is fired at most once, and after it is fired
-  the hook flag is removed, i.e., it runs with zero overhead.
-
-  [New options]
-
-    * Add +:oneshot_lines+ keyword argument to Coverage.start.
-
-    * Add +:stop+ and +:clear+ keyword arguments to Coverage.result.
-      If +clear+ is true, it clears the counters to zero.
-      If +stop+ is true, it disables coverage measurement.
-
-  [New methods]
-
-    * Coverage.line_stub, which is a simple helper function that
-      creates the "stub" of line coverage from a given source code.
-
-[ERB]
-
-  [New options]
-
-    * Add +:trim_mode+ and +:eoutvar+ keyword arguments to ERB.new.
-      Now non-keyword arguments other than first one are softly deprecated
-      and will be removed when Ruby 2.5 becomes EOL. [Feature #14256]
-
-    * erb command's <tt>-S</tt> option is deprecated, which will be removed
-      in the next version.
-
-[FileUtils]
-
-  [New methods]
-
-    * FileUtils#cp_lr.  [Feature #4189]
-
-[Matrix]
-
-  [New methods]
-
-    * Matrix#antisymmetric? / #skew_symmetric?
-
-    * Matrix#map! / #collect! [Feature #14151]
-
-    * Matrix#[]=
-
-    * Vector#map! / #collect!
-
-    * Vector#[]=
-
-[Net]
-
-  [New options]
-
-    * Add +:write_timeout+ keyword argument to Net::HTTP.new. [Feature #13396]
-
-  [New methods]
-
-    * Add Net::HTTP#write_timeout and Net::HTTP#write_timeout=.  [Feature #13396]
-
-  [New constant]
-
-    * Add Net::HTTPClientException to deprecate Net::HTTPServerException,
-      whose name is misleading.  [Bug #14688]
-
-[REXML]
-
-  [Improved some XPath implementations]
-
-    * <code>concat()</code> function: Stringify all arguments before concatenating
-
-    * <code>string()</code> function: Support context node
-
-    * <code>string()</code> function: Support processing instruction node
-
-    * Support <code>"*:#{ELEMENT_NAME}"</code> syntax in XPath 2.0
-
-  [Fixed some XPath implementations]
-
-    * <code>"//#{ELEMENT_NAME}[#{POSITION}]"</code> case
-
-    * <code>string()</code> function: Fix <code>function(document)</code>
-      returns nodes that are out of root elements.
-
-    * <code>"/ #{ELEMENT_NAME} "</code> case
-
-    * <code>"/ #{ELEMENT_NAME} [ #{PREDICATE} ]"</code> case
-
-    * <code>"/ #{AXIS}::#{ELEMENT_NAME}"</code> case
-
-    * <code>"#{N}-#{M}"</code> case: One or more white spaces were required
-      before <code>"-"</code>
-
-    * <code>"/child::node()"</code> case
-
-    * <code>"#{FUNCTION}()/#{PATH}"</code> case
-
-    * <code>"@#{ATTRIBUTE}/parent::"</code> case
-
-    * <code>"name(#{NODE_SET})"</code> case
-
-[RSS]
-
-  [New options]
-
-    * RSS::Parser.parse: Accept options as Hash. +:validate+ ,
-      +:ignore_unknown_element+ , +:parser_class+ options are available.
-
-[Set]
-
-  [Aliased methods]
-
-    * Set#filter! is a new alias for Set#select!.  [Feature #13784]
-
-[URI]
-
-  [New constant]
-
-    * Add URI::File to handle file URI scheme.  [Feature #14035]
-
-=== Compatibility issues (excluding feature bug fixes)
-
-[Dir]
-
-  * Dir.glob with <code>'\0'</code>-separated pattern list will be deprecated,
-    and is now warned.  [Feature #14643]
-
-[File]
-
-  * File.read, File.binread, File.write, File.binwrite, File.foreach, and
-    File.readlines do not invoke external commands even if the path starts
-    with the pipe character <code>'|'</code>. [Feature #14245]
-
-=== Stdlib compatibility issues (excluding feature bug fixes)
-
-* These standard libraries have been promoted to default gems.
-
-  * e2mmap
-  * forwardable
-  * irb
-  * logger
-  * matrix
-  * mutex_m
-  * ostruct
-  * prime
-  * rexml
-  * rss
-  * shell
-  * sync
-  * thwait
-  * tracer
-
-=== C API updates
-
-=== Supported platform changes
-
-=== Implementation improvements
-
-* Speedup Proc#call because we don't need to care about <code>$SAFE</code>
-  any more. [Feature #14318]
-
-  With +lc_fizzbuzz+ benchmark which uses so many Proc#call we can
-  measure x1.4 improvements.  [Bug #10212]
-
-* Speedup block.call where +block+ is passed block parameter. [Feature #14330]
-
-  Ruby 2.5 improves block passing performance. [Feature #14045]
-
-  Additionally, Ruby 2.6 improves the performance of passed block calling.
-
-* Introduce an initial implementation of JIT (Just-in-time) compiler. [Feature #14235] [experimental]
-
-  * <tt>--jit</tt> command line option is added to enable JIT. <tt>--jit-verbose=1</tt>
-    is good for inspection.  See <tt>ruby --help</tt> for others.
-  * To generate machine code, this JIT compiler uses C compiler used for building
-    the interpreter. Currently GCC, Clang, and Microsoft Visual C++ are supported for it.
-  * <tt>--disable-mjit-support</tt> option is added to configure. This is added for JIT debugging,
-    but if you get an error on building a header file for JIT, you can use this option to skip
-    building it as a workaround.
-  * rb_waitpid reimplemented on Unix-like platforms to maintain
-    compatibility with processes created for JIT [Bug #14867]
-
-* VM generator script renewal; makes the generated VM more optimized. [GH-1779]
-
-* Thread cache enabled for pthreads platforms (for Thread.new and
-  Thread.start).  [Feature #14757]
-
-* timer thread is eliminated for platforms with POSIX timers [Misc #14937]
-
-* Transient Heap (theap) is supported. [Bug #14858] [Feature #14989]
-  theap is managed heap for short-living memory objects. For example,
-  making small and short-living Hash object is x2 faster. With rdoc benchmark,
-  we maesured 6-7% performance improvement.
-
-=== Miscellaneous changes
-
-* On macOS, shared libraries no longer include a full version number of Ruby
-  in their names.  This eliminates the burden of each teeny upgrade on the
-  platform that users need to rebuild every extension library.
-
-  [Before]
-    * libruby.2.6.0.dylib
-    * libruby.2.6.dylib -> libruby.2.6.0.dylib
-    * libruby.dylib -> libruby.2.6.0.dylib
-
-  [After]
-    * libruby.2.6.dylib
-    * libruby.dylib -> libruby.2.6.dylib
-
-=== Misc
-
-* Extracted misc/*.el files to https://github.com/ruby/elisp
diff --git a/NEWS.md b/NEWS.md
new file mode 100644
index 0000000000..2b021e7cdd
--- /dev/null
+++ b/NEWS.md
@@ -0,0 +1,87 @@
+# NEWS for Ruby 4.1.0
+
+This document is a list of user-visible feature changes
+since the **4.0.0** release, except for bug fixes.
+
+Note that each entry is kept to a minimum, see links for details.
+
+## Language changes
+
+## Core classes updates
+
+Note: We're only listing outstanding class updates.
+
+* Method
+
+    * `Method#source_location`, `Proc#source_location`, and
+      `UnboundMethod#source_location` now return extended location
+      information with 5 elements: `[path, start_line, start_column,
+      end_line, end_column]`. The previous 2-element format `[path,
+      line]` can still be obtained by calling `.take(2)` on the result.
+      [[Feature #6012]]
+
+* Set
+
+    * A deprecated behavior, `Set#to_set`, `Range#to_set`, and
+      `Enumerable#to_set` accepting arguments, was removed.  [[Feature #21390]]
+
+## Stdlib updates
+
+### The following bundled gems are added.
+
+
+We only list stdlib changes that are notable feature changes.
+
+Other changes are listed in the following sections. We also listed release
+history from the previous bundled version that is Ruby 3.4.0 if it has GitHub
+releases.
+
+### The following bundled gem is promoted from default gems.
+
+* tsort 0.2.0
+
+### The following default gem is added.
+
+### The following default gems are updated.
+
+* RubyGems 4.1.0.dev
+* bundler 4.1.0.dev
+* prism 1.8.0
+* stringio 3.2.1.dev
+* strscan 3.1.7.dev
+
+### The following bundled gems are updated.
+
+* minitest 6.0.1
+* test-unit 3.7.7
+* rss 0.3.2
+* net-imap 0.6.2
+* rbs 3.10.2
+* typeprof 0.31.1
+* debug 1.11.1
+* mutex_m 0.3.0
+* resolv-replace 0.2.0
+* rdoc 7.1.0
+
+### RubyGems and Bundler
+
+Ruby 4.0 bundled RubyGems and Bundler version 4. see the following links for details.
+
+## Supported platforms
+
+## Compatibility issues
+
+## Stdlib compatibility issues
+
+## C API updates
+
+## Implementation improvements
+
+### Ractor
+
+A lot of work has gone into making Ractors more stable, performant, and usable. These improvements bring Ractor implementation closer to leaving experimental status.
+
+## JIT
+
+[Feature #6012]: https://bugs.ruby-lang.org/issues/6012
+[Feature #21390]: https://bugs.ruby-lang.org/issues/21390
diff --git a/README.ja.md b/README.ja.md
index 353f9b14cc..9bbc3a83a5 100644
--- a/README.ja.md
+++ b/README.ja.md
@@ -1,5 +1,10 @@
-[![Build Status](https://travis-ci.org/ruby/ruby.svg)](https://travis-ci.org/ruby/ruby)
-[![Build status](https://ci.appveyor.com/api/projects/status/0sy8rrxut4o0k960/branch/trunk?svg=true)](https://ci.appveyor.com/project/ruby/ruby/branch/trunk)
+[![Actions Status: MinGW](https://github.com/ruby/ruby/workflows/MinGW/badge.svg)](https://github.com/ruby/ruby/actions?query=workflow%3A"MinGW")
+[![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)
+
+[English](rdoc-ref:README.md)
 
 # Rubyとは
 
@@ -13,7 +18,7 @@ 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
 
 *   シンプルな文法
 *   普通のオブジェクト指向機能(クラス，メソッドコールなど)
-*   特殊なオブジェクト指向機能(Mixin, 特異メソッドなど)
+*   特殊なオブジェクト指向機能(Mixin，特異メソッドなど)
 *   演算子オーバーロード
 *   例外処理機能
 *   イテレータとクロージャ
@@ -21,7 +26,7 @@ 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/trunk/doc/contributing.rdoc#platform-maintainers
+    https://docs.ruby-lang.org/en/master/maintainers_md.html#label-Platform+Maintainers
 
 
 ## 入手法
@@ -32,21 +37,22 @@ https://www.ruby-lang.org/ja/downloads/
 
 を参照してください．
 
-### Subversionで
-
-開発先端のソースコードは次のコマンドで取得できます．
-
-    $ svn co https://svn.ruby-lang.org/repos/ruby/trunk/ ruby
+### Git
 
-他に開発中のブランチの一覧は次のコマンドで見られます．
+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．
 
-    $ svn ls https://svn.ruby-lang.org/repos/ruby/branches/
+```console
+$ git clone https://github.com/ruby/ruby.git
+```
 
-### Gitで
+他のブランチの一覧は次のコマンドで見られます．
 
-Subversionのミラーを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．
+```console
+$ git ls-remote https://github.com/ruby/ruby.git
+```
 
-    $ git clone 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．
 
 ## ホームページ
 
@@ -58,38 +64,33 @@ 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
-
-mailto: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
-
-mailto: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．
+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@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@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
 
 以下の手順で行ってください．
 
-1.  もし `configure` ファイルが見つからない，もしくは `configure.ac` より古いようなら， `autoconf` を実行して
-    新しく `configure` を生成する
+1.  (Gitリポジトリから取得したソースをビルドする場合) `./autogen.sh` を実行して新しく `configure` を生成する
 
 2.  `configure` を実行して `Makefile` などを生成する
 
     環境によってはデフォルトのCコンパイラ用オプションが付きます． `configure` オプションで `optflags=..`
     `warnflags=..` 等で上書きできます．
 
-3.  (必要ならば)`defines.h` を編集する
+3.  (必要ならば)`include/ruby/defines.h` を編集する
 
     多分，必要無いと思います．
 
@@ -98,7 +99,8 @@ 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�
     `ext/Setup` に記述したモジュールは静的にリンクされます．
 
     ダイナミックローディングをサポートしていないアーキテクチャでは `Setup` の1行目の「`option nodynamic`」という行のコ
-    メントを外す必要があります．また，このアーキテクチャで拡張モジュールを利用するためには，あらかじめ静的にリンクをしておく必要があります．
+    メントを外す必要があります．
+    また，このアーキテクチャで拡張モジュールを利用するためには，あらかじめ静的にリンクをしておく必要があります．
 
 5.  `make` を実行してコンパイルする
 
@@ -154,21 +156,21 @@ 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
 
-Rubyに関する質問は Ruby-Talk（英語）や Ruby-List（日本語） (https://www.ruby-lang.org/ja/community/mailing-lists) や，
-stackoverflow (https://ja.stackoverflow.com/) などのWebサイトに投稿してください．
+Rubyに関する質問は [Ruby-Talk]（英語）や [Ruby-List]（日本語）や，
+[stackoverflow] などのWebサイトに投稿してください．
 
 バグ報告は https://bugs.ruby-lang.org で受け付けています．
 
+[Ruby-Talk]: https://www.ruby-lang.org/en/community/mailing-lists
+[Ruby-List]: https://www.ruby-lang.org/ja/community/mailing-lists
+[stackoverflow]: https://ja.stackoverflow.com/
 
 ## 著者
 
 Rubyのオリジナル版は，1995年にまつもとゆきひろ氏によって設計・開発されました．
 
 <mailto:matz@ruby-lang.org>
-
----
-created at: Thu Aug  3 11:57:36 JST 1995
diff --git a/README.md b/README.md
index 1e76fda4f0..02435b419e 100644
--- a/README.md
+++ b/README.md
@@ -1,28 +1,30 @@
-[![Build Status](https://travis-ci.org/ruby/ruby.svg?branch=trunk)](https://travis-ci.org/ruby/ruby)
-[![Build status](https://ci.appveyor.com/api/projects/status/0sy8rrxut4o0k960/branch/trunk?svg=true)](https://ci.appveyor.com/project/ruby/ruby/branch/trunk)
-[![wercker status](https://app.wercker.com/status/e5e7e1704f62b76525022aa424aef6ef/s/trunk "wercker status")](https://app.wercker.com/project/byKey/e5e7e1704f62b76525022aa424aef6ef)
+[![Actions Status: MinGW](https://github.com/ruby/ruby/workflows/MinGW/badge.svg)](https://github.com/ruby/ruby/actions?query=workflow%3A"MinGW")
+[![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")
+[![Travis Status](https://app.travis-ci.com/ruby/ruby.svg?branch=master)](https://app.travis-ci.com/ruby/ruby)
 
-# What's Ruby
+[日本語](rdoc-ref:README.ja.md)
 
-Ruby is the interpreted scripting language for quick and easy object-oriented
-programming. It has many features to process text files and to do system
-management tasks (as in Perl). It is simple, straight-forward, and
-extensible.
+# What is Ruby?
 
-## Features of Ruby
+Ruby is an interpreted object-oriented programming language often
+used for web development. It also offers many scripting features
+to process plain text and serialized files, or manage system tasks.
+It is simple, straightforward, and extensible.
 
-*   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, Haiku, etc.) cf.
-    https://github.com/ruby/ruby/blob/trunk/doc/contributing.rdoc#platform-maintainers
+## 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://docs.ruby-lang.org/en/master/maintainers_md.html#label-Platform+Maintainers
 
 ## How to get Ruby
 
@@ -31,142 +33,64 @@ like rvm, see:
 
 https://www.ruby-lang.org/en/downloads/
 
-The trunk of the Ruby source tree can be checked out with the following
-command:
+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/.
 
-    $ svn co https://svn.ruby-lang.org/repos/ruby/trunk/ ruby
+### Download with Git
 
-Or if you are using git then use the following command:
+The mirror of the Ruby source tree can be checked out with the following command:
 
     $ git clone https://github.com/ruby/ruby.git
 
 There are some other branches under development. Try the following command
 to see the list of branches:
 
-    $ svn ls https://svn.ruby-lang.org/repos/ruby/branches/
-
-Or if you are using git then use the following command:
-
     $ git ls-remote https://github.com/ruby/ruby.git
 
-## Ruby home page
-
-The URL of the Ruby home page is:
-
-https://www.ruby-lang.org/
-
-## Mailing list
-
-There is a mailing list to talk about 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>.
-
-## How to compile and install
-
-This is what you need to do to compile and install Ruby:
-
-1.  If you want to use Microsoft Visual C++ to compile Ruby, read
-    [win32/README.win32](win32/README.win32) instead of this document.
+You may also want to use https://git.ruby-lang.org/ruby.git (actual master of Ruby source)
+if you are a committer.
 
-2.  If `./configure` does not exist or is older than `configure.ac`, run
-    `autoconf` to (re)generate configure.
+## How to build
 
-3.  Run `./configure`, which will generate `config.h` and `Makefile`.
+See [Building Ruby](https://docs.ruby-lang.org/en/master/contributing/building_ruby_md.html)
 
-    Some C compiler flags may be added by default depending on your
-    environment. Specify `optflags=..` and `warnflags=..` as necessary to
-    override them.
-
-4.  Edit `defines.h` if you need. Usually this step will not be needed.
-
-5.  Remove comment mark(`#`) before the module names from `ext/Setup` (or add
-    module names if not present), if you want to link modules statically.
-
-    If you don't want to compile non static extension modules (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.  Optionally, run `make update-gems` and `make extract-gems`.
-
-    If you want to install bundled gems, run `make update-gems` and
-    `make extract-gems` before running `make install`.
-
-9.  Run '`make install`'.
-
-    This command will create the following directories and install files into
-    them.
+## Ruby home page
 
-    *   `${DESTDIR}${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`
+https://www.ruby-lang.org/
 
+## Documentation
 
-    If Ruby's API version is '*x.y.z*', the `${MAJOR}` is '*x*', the
-    `${MINOR}` is '*y*', and the `${TEENY}` is '*z*'.
+- [English](https://docs.ruby-lang.org/en/master/index.html)
+- [Japanese](https://docs.ruby-lang.org/ja/master/index.html)
 
-    **NOTE**: teeny of the API version may be different from one of Ruby's
-    program version
+## Mailing list
 
-    You may have to be a super user to install Ruby.
+There is a mailing list to discuss Ruby. To subscribe to this list, please
+send the following phrase:
 
+    join
 
-If you fail to compile Ruby, please send the detailed error report with the
-error log and machine/OS type, to help others.
+in the mail subject (not body) to the address [ruby-talk-request@ml.ruby-lang.org].
 
-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
 
-See the file [COPYING](COPYING).
+See the file [COPYING](rdoc-ref:COPYING).
 
 ## Feedback
 
-Questions about the Ruby language can be asked on the Ruby-Talk mailing list
-(https://www.ruby-lang.org/en/community/mailing-lists) or on websites like
-(https://stackoverflow.com).
+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.
 
-Bug reports should be filed at https://bugs.ruby-lang.org. Read [HowToReport] for more information.
-
-[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](CONTRIBUTING.md)
-
+See ["Contributing to Ruby"](https://docs.ruby-lang.org/en/master/contributing/contributing_md.html), which includes setup and build instructions.
 
 ## The Author
 
-Ruby was originally designed and developed by Yukihiro Matsumoto (Matz) in
-1995.
+Ruby was originally designed and developed by Yukihiro Matsumoto (Matz) in 1995.
 
 <matz@ruby-lang.org>
diff --git a/aclocal.m4 b/aclocal.m4
index b0fe3eb959..e69de29bb2 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -1,46 +0,0 @@
-# generated automatically by aclocal 1.16.1 -*- Autoconf -*-
-
-# Copyright (C) 1996-2018 Free Software Foundation, Inc.
-
-# This file is free software; the Free Software Foundation
-# gives unlimited permission to copy and/or distribute it,
-# with or without modifications, as long as this notice is preserved.
-
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY, to the extent permitted by law; without
-# even the implied warranty of MERCHANTABILITY or FITNESS FOR A
-# PARTICULAR PURPOSE.
-
-m4_ifndef([AC_CONFIG_MACRO_DIRS], [m4_defun([_AM_CONFIG_MACRO_DIRS], [])m4_defun([AC_CONFIG_MACRO_DIRS], [_AM_CONFIG_MACRO_DIRS($@)])])
-m4_include([tool/m4/_colorize_result_prepare.m4])
-m4_include([tool/m4/ac_msg_result.m4])
-m4_include([tool/m4/colorize_result.m4])
-m4_include([tool/m4/ruby_append_option.m4])
-m4_include([tool/m4/ruby_append_options.m4])
-m4_include([tool/m4/ruby_check_builtin_func.m4])
-m4_include([tool/m4/ruby_check_builtin_setjmp.m4])
-m4_include([tool/m4/ruby_check_printf_prefix.m4])
-m4_include([tool/m4/ruby_check_setjmp.m4])
-m4_include([tool/m4/ruby_check_signedness.m4])
-m4_include([tool/m4/ruby_check_sizeof.m4])
-m4_include([tool/m4/ruby_check_sysconf.m4])
-m4_include([tool/m4/ruby_cppoutfile.m4])
-m4_include([tool/m4/ruby_decl_attribute.m4])
-m4_include([tool/m4/ruby_default_arch.m4])
-m4_include([tool/m4/ruby_define_if.m4])
-m4_include([tool/m4/ruby_defint.m4])
-m4_include([tool/m4/ruby_dtrace_available.m4])
-m4_include([tool/m4/ruby_dtrace_postprocess.m4])
-m4_include([tool/m4/ruby_func_attribute.m4])
-m4_include([tool/m4/ruby_mingw32.m4])
-m4_include([tool/m4/ruby_prepend_option.m4])
-m4_include([tool/m4/ruby_prog_gnu_ld.m4])
-m4_include([tool/m4/ruby_replace_type.m4])
-m4_include([tool/m4/ruby_rm_recursive.m4])
-m4_include([tool/m4/ruby_setjmp_type.m4])
-m4_include([tool/m4/ruby_stack_grow_direction.m4])
-m4_include([tool/m4/ruby_try_cflags.m4])
-m4_include([tool/m4/ruby_try_ldflags.m4])
-m4_include([tool/m4/ruby_type_attribute.m4])
-m4_include([tool/m4/ruby_universal_arch.m4])
-m4_include([tool/m4/ruby_werror_flag.m4])
diff --git a/addr2line.c b/addr2line.c
index 485e9f6dc5..19a6a425c1 100644
--- a/addr2line.c
+++ b/addr2line.c
@@ -8,13 +8,16 @@
 
 **********************************************************************/
 
-#if defined(__clang__)
-#pragma clang diagnostic ignored "-Wpedantic"
-#elif defined(__GNUC__)
-#pragma GCC diagnostic ignored "-Wpedantic"
+#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/config.h"
+#include "ruby/internal/config.h"
 #include "ruby/defines.h"
 #include "ruby/missing.h"
 #include "addr2line.h"
@@ -22,12 +25,12 @@
 #include <stdio.h>
 #include <errno.h>
 
-#ifdef HAVE_STDBOOL_H
-#include <stdbool.h>
-#else
-#include "missing/stdbool.h"
+#ifdef HAVE_LIBPROC_H
+#include <libproc.h>
 #endif
 
+#include "ruby/internal/stdbool.h"
+
 #if defined(USE_ELF) || defined(HAVE_MACH_O_LOADER_H)
 
 #include <fcntl.h>
@@ -53,18 +56,33 @@
 #  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
 
 #ifdef HAVE_MACH_O_LOADER_H
+# include <crt_externs.h>
+# include <mach-o/fat.h>
 # include <mach-o/loader.h>
 # include <mach-o/nlist.h>
 # include <mach-o/stab.h>
@@ -126,7 +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;
@@ -158,11 +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 5
+#define DWARF_SECTION_COUNT 9
 
 static struct dwarf_section *
 obj_dwarf_section_at(obj_info_t *obj, int n)
@@ -172,10 +194,14 @@ obj_dwarf_section_at(obj_info_t *obj, int n)
         &obj->debug_info,
         &obj->debug_line,
         &obj->debug_ranges,
-        &obj->debug_str
+        &obj->debug_str_offsets,
+        &obj->debug_addr,
+        &obj->debug_rnglists,
+        &obj->debug_str,
+        &obj->debug_line_str
     };
     if (n < 0 || DWARF_SECTION_COUNT <= n) {
-        abort();
+        UNREACHABLE_RETURN(0);
     }
     return ary[n];
 }
@@ -186,110 +212,128 @@ struct debug_section_definition {
 };
 
 /* Avoid consuming stack as this module may be used from signal handler */
-static char binary_filename[PATH_MAX];
+static char binary_filename[PATH_MAX + 1];
 
 static unsigned long
-uleb128(char **p)
+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;
 }
 
 static long
-sleb128(char **p)
+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, 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, char *include_directories, 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;
-    char *p = filenames;
-    char *filename;
+    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) {
+#ifndef __APPLE__
+                /* Need to output binary file name? */
+                kprintf("Unexpected file number %d in %s at %tx\n",
+                        file, binary_filename, filenames - obj->mapped);
+#endif
+                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,
-	  char *include_directories, 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;
+        }
     }
 }
 
@@ -312,7 +356,7 @@ 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;
@@ -320,8 +364,8 @@ 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;
     }
 
@@ -329,7 +373,13 @@ 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;
@@ -350,20 +400,27 @@ 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;
 
@@ -371,8 +428,8 @@ parse_debug_line_header(const char **pp, struct LineNumberProgramHeader *header)
 }
 
 static int
-parse_debug_line_cu(int num_traces, void **traces, char **debug_line,
-		obj_info_t *obj, line_info_t *lines, int offset)
+parse_debug_line_cu(int num_traces, void **traces, const char **debug_line,
+                obj_info_t *obj, line_info_t *lines, int offset, FILE *errout)
 {
     const char *p = (const char *)*debug_line;
     struct LineNumberProgramHeader header;
@@ -389,106 +446,109 @@ parse_debug_line_cu(int num_traces, void **traces, 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,		    \
-                  (char *)header.include_directories,               \
-                  (char *)header.filenames,                         \
-		  obj, lines, offset);				    \
-	/*basic_block = prologue_end = epilogue_begin = 0;*/	    \
+#define FILL_LINE()                                                 \
+    do {                                                            \
+        fill_line(num_traces, traces, addr, file, line,             \
+                  header.format,                                    \
+                  header.version,                                   \
+                  header.include_directories,                       \
+                  header.filenames,                                 \
+                  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((char **)&p);
-	    addr += a;
-	    break;
-	case DW_LNS_advance_line: {
-	    long a = sleb128((char **)&p);
-	    line += a;
-	    break;
-	}
-	case DW_LNS_set_file:
-	    file = (unsigned int)uleb128((char **)&p);
-	    break;
-	case DW_LNS_set_column:
-	    /*column = (unsigned int)*/(void)uleb128((char **)&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 = ((255 - header.opcode_base) / header.line_range) *
-		header.minimum_instruction_length;
-	    addr += a;
-	    break;
-	case DW_LNS_fixed_advance_pc:
-	    a = *(unsigned char *)p++;
-	    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((char **)&p);
-	    break;
-	case 0:
-	    a = *(unsigned char *)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((char **)&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;
@@ -496,17 +556,17 @@ parse_debug_line_cu(int num_traces, void **traces, char **debug_line,
 
 static int
 parse_debug_line(int num_traces, void **traces,
-		 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)
 {
-    char *debug_line_end = debug_line + size;
+    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;
 }
@@ -514,7 +574,7 @@ 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)
@@ -525,13 +585,25 @@ append_obj(obj_info_t **objp)
 }
 
 #ifdef USE_ELF
+/* Ideally we should check 4 paths to follow gnu_debuglink:
+ *
+ *   - /usr/lib/debug/.build-id/ab/cdef1234.debug
+ *   - /usr/bin/ruby.debug
+ *   - /usr/bin/.debug/ruby.debug
+ *   - /usr/lib/debug/usr/bin/ruby.debug.
+ *
+ * but we handle only two cases for now as the two formats are
+ * used by some linux distributions.
+ *
+ * See GDB's info for detail.
+ * https://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html
+ */
+
+// 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)
 {
-    /* Ideally we should check 4 paths to follow gnu_debuglink,
-       but we handle only one case for now as this format is used
-       by some linux distributions. See GDB's info for detail. */
     static const char global_debug_dir[] = "/usr/lib/debug";
     const size_t global_debug_dir_len = sizeof(global_debug_dir) - 1;
     char *p;
@@ -540,13 +612,13 @@ 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;
@@ -556,7 +628,39 @@ 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, FILE *errout)
+{
+    static const char global_debug_dir[] = "/usr/lib/debug/.build-id/";
+    static const char debug_suffix[] = ".debug";
+    const size_t global_debug_dir_len = sizeof(global_debug_dir) - 1;
+    char *p;
+    obj_info_t *o1 = *objp, *o2;
+    size_t i;
+
+    if (PATH_MAX < global_debug_dir_len + build_id_size * 2 + sizeof(debug_suffix)) return;
+
+    memcpy(binary_filename, global_debug_dir, global_debug_dir_len);
+    p = binary_filename + global_debug_dir_len;
+    for (i = 0; i < build_id_size; i++) {
+        static const char tbl[] = "0123456789abcdef";
+        unsigned char n = build_id[i];
+        *p++ = tbl[n / 16];
+        *p++ = tbl[n % 16];
+        if (i == 0) *p++ = '/';
+    }
+    memcpy(p, debug_suffix, sizeof(debug_suffix));
+
+    append_obj(objp);
+    o2 = *objp;
+    o2->base_addr = o1->base_addr;
+    o2->path = o1->path;
+    fill_lines(num_traces, traces, 0, objp, lines, offset, errout);
 }
 #endif
 
@@ -760,7 +864,23 @@ 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 */
+enum {
+    DW_RLE_end_of_list = 0x00,
+    DW_RLE_base_addressx = 0x01,
+    DW_RLE_startx_endx = 0x02,
+    DW_RLE_startx_length = 0x03,
+    DW_RLE_offset_pair = 0x04,
+    DW_RLE_base_address = 0x05,
+    DW_RLE_start_end = 0x06,
+    DW_RLE_start_length = 0x07
 };
 
 enum {
@@ -768,27 +888,34 @@ 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;
-    char *file;
-    char *current_cu;
+    const char *file;
+    uint8_t current_version;
+    const char *current_cu;
     uint64_t current_low_pc;
-    char *debug_line_cu_end;
-    char *debug_line_files;
-    char *debug_line_directories;
-    char *p;
-    char *cu_end;
-    char *pend;
-    char *q0;
-    char *q;
-    int format; /* 4 or 8 */;
+    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;
+    const char *cu_end;
+    const char *pend;
+    const char *q0;
+    const char *q;
+    int format; // 4 or 8
     uint8_t address_size;
     int level;
-    char *abbrev_table[ABBREV_TABLE_SIZE];
+    const char *abbrev_table[ABBREV_TABLE_SIZE];
 } DebugInfoReader;
 
 typedef struct {
@@ -799,9 +926,10 @@ typedef struct {
 
 typedef struct {
     union {
-        char *ptr;
+        const char *ptr;
         uint64_t uint64;
         int64_t int64;
+        uint64_t addr_idx;
     } as;
     uint64_t off;
     uint64_t at;
@@ -810,8 +938,11 @@ 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)
@@ -832,39 +963,39 @@ get_uint64(const uint8_t *p)
 }
 
 static uint8_t
-read_uint8(char **ptr)
+read_uint8(const char **ptr)
 {
-    const unsigned char *p = (const unsigned char *)*ptr;
-    *ptr = (char *)(p + 1);
-    return *p;
+    const char *p = *ptr;
+    *ptr = (p + 1);
+    return (uint8_t)*p;
 }
 
 static uint16_t
-read_uint16(char **ptr)
+read_uint16(const char **ptr)
 {
-    const unsigned char *p = (const unsigned char *)*ptr;
-    *ptr = (char *)(p + 2);
-    return get_uint16(p);
+    const char *p = *ptr;
+    *ptr = (p + 2);
+    return get_uint16((const uint8_t *)p);
 }
 
 static uint32_t
-read_uint24(char **ptr)
+read_uint24(const char **ptr)
 {
-    const unsigned char *p = (const unsigned char *)*ptr;
-    *ptr = (char *)(p + 3);
-    return (*p << 16) | get_uint16(p+1);
+    const char *p = *ptr;
+    *ptr = (p + 3);
+    return ((uint8_t)*p << 16) | get_uint16((const uint8_t *)p+1);
 }
 
 static uint32_t
-read_uint32(char **ptr)
+read_uint32(const char **ptr)
 {
-    const unsigned char *p = (const unsigned char *)*ptr;
-    *ptr = (char *)(p + 4);
-    return get_uint32(p);
+    const char *p = *ptr;
+    *ptr = (p + 4);
+    return get_uint32((const uint8_t *)p);
 }
 
 static uint64_t
-read_uint64(char **ptr)
+read_uint64(const char **ptr)
 {
     const unsigned char *p = (const unsigned char *)*ptr;
     *ptr = (char *)(p + 8);
@@ -872,7 +1003,7 @@ read_uint64(char **ptr)
 }
 
 static uintptr_t
-read_uintptr(char **ptr)
+read_uintptr(const char **ptr)
 {
     const unsigned char *p = (const unsigned char *)*ptr;
     *ptr = (char *)(p + SIZEOF_VOIDP);
@@ -913,13 +1044,34 @@ debug_info_reader_init(DebugInfoReader *reader, obj_info_t *obj)
     reader->p = obj->debug_info.ptr;
     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
+di_skip_die_attributes(const char **p)
+{
+    for (;;) {
+        uint64_t at = uleb128(p);
+        uint64_t form = uleb128(p);
+        if (!at && !form) break;
+        switch (form) {
+          default:
+            break;
+          case DW_FORM_implicit_const:
+            sleb128(p);
+            break;
+        }
+    }
 }
 
 static void
 di_read_debug_abbrev_cu(DebugInfoReader *reader)
 {
     uint64_t prev = 0;
-    char *p = reader->q0;
+    const char *p = reader->q0;
     for (;;) {
         uint64_t abbrev_number = uleb128(&p);
         if (abbrev_number <= prev) break;
@@ -929,26 +1081,23 @@ di_read_debug_abbrev_cu(DebugInfoReader *reader)
         prev = abbrev_number;
         uleb128(&p); /* tag */
         p++; /* has_children */
-        /* skip content */
-        for (;;) {
-            uint64_t at = uleb128(&p);
-            uint64_t form = uleb128(&p);
-            if (!at && !form) break;
-        }
+        di_skip_die_attributes(&p);
     }
 }
 
 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;
 
@@ -956,6 +1105,13 @@ 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;
@@ -970,7 +1126,7 @@ set_int_value(DebugInfoValue *v, int64_t n)
 }
 
 static void
-set_cstr_value(DebugInfoValue *v, char *s)
+set_cstr_value(DebugInfoValue *v, const char *s)
 {
     v->as.ptr = s;
     v->off = 0;
@@ -978,7 +1134,7 @@ set_cstr_value(DebugInfoValue *v, char *s)
 }
 
 static void
-set_cstrp_value(DebugInfoValue *v, char *s, uint64_t off)
+set_cstrp_value(DebugInfoValue *v, const char *s, uint64_t off)
 {
     v->as.ptr = s;
     v->off = off;
@@ -986,7 +1142,7 @@ set_cstrp_value(DebugInfoValue *v, char *s, uint64_t off)
 }
 
 static void
-set_data_value(DebugInfoValue *v, char *s)
+set_data_value(DebugInfoValue *v, const char *s)
 {
     v->as.ptr = s;
     v->type = VAL_data;
@@ -1002,19 +1158,46 @@ 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);
@@ -1066,13 +1249,12 @@ 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->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));
+        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 address_size:%d", reader->address_size);
-            abort();
+            debug_info_reader_read_addr_value(reader, v, format);
         }
         break;
       case DW_FORM_ref1:
@@ -1091,7 +1273,7 @@ debug_info_reader_read_value(DebugInfoReader *reader, uint64_t form, DebugInfoVa
         set_uint_value(v, uleb128(&reader->p));
         break;
       case DW_FORM_indirect:
-        /* TODO: read the refered value */
+        /* TODO: read the referred value */
         set_uint_value(v, uleb128(&reader->p));
         break;
       case DW_FORM_sec_offset:
@@ -1114,11 +1296,10 @@ 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));
@@ -1133,8 +1314,7 @@ 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));
@@ -1152,45 +1332,53 @@ 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 char *
-di_find_abbrev(DebugInfoReader *reader, uint64_t abbrev_number)
+static const char *
+di_find_abbrev(DebugInfoReader *reader, uint64_t abbrev_number, FILE *errout)
 {
-    char *p;
+    const char *p;
     if (abbrev_number < ABBREV_TABLE_SIZE) {
         return reader->abbrev_table[abbrev_number];
     }
@@ -1198,77 +1386,67 @@ di_find_abbrev(DebugInfoReader *reader, uint64_t abbrev_number)
     /* skip 255th record */
     uleb128(&p); /* tag */
     p++; /* has_children */
-    /* skip content */
-    for (;;) {
-        uint64_t at = uleb128(&p);
-        uint64_t form = uleb128(&p);
-        if (!at && !form) break;
-    }
+    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 */
-        /* skip content */
-        for (;;) {
-            uint64_t at = uleb128(&p);
-            uint64_t form = uleb128(&p);
-            if (!at && !form) break;
-        }
+        di_skip_die_attributes(&p);
     }
     return p;
 }
 
 #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:%lx\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:%ld\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) {
@@ -1276,7 +1454,7 @@ 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 */
@@ -1288,29 +1466,111 @@ 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 {
     uint64_t low_pc;
     uint64_t high_pc;
@@ -1321,35 +1581,54 @@ 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, FILE *errout)
+{
+    const char *p = *ptr;
+    *ptr = p + reader->address_size;
+    if (reader->address_size == 4) {
+        return read_uint32(&p);
+    } else {
+        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;
@@ -1357,8 +1636,66 @@ ranges_include(DebugInfoReader *reader, ranges_t *ptr, uint64_t addr)
     }
     else if (ptr->ranges_set) {
         /* TODO: support base address selection entry */
-        char *p = reader->obj->debug_ranges.ptr + ptr->ranges;
+        const char *p;
         uint64_t base = ptr->low_pc_set ? ptr->low_pc : reader->current_low_pc;
+        bool base_valid = true;
+        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;
+                if (rle == DW_RLE_end_of_list) break;
+                switch (rle) {
+                  case DW_RLE_base_addressx:
+                    uleb128(&p);
+                    base_valid = false; /* not supported yet */
+                    break;
+                  case DW_RLE_startx_endx:
+                    uleb128(&p);
+                    uleb128(&p);
+                    break;
+                  case DW_RLE_startx_length:
+                    uleb128(&p);
+                    uleb128(&p);
+                    break;
+                  case DW_RLE_offset_pair:
+                    if (!base_valid) break;
+                    from = (uintptr_t)base + uleb128(&p);
+                    to = (uintptr_t)base + uleb128(&p);
+                    break;
+                  case DW_RLE_base_address:
+                    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, 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, errout);
+                    to = from + uleb128(&p);
+                    break;
+                }
+                if (from <= addr && addr < to) {
+                    return from;
+                }
+            }
+            return 0;
+        }
+        p = reader->obj->debug_ranges.ptr + ptr->ranges;
         for (;;) {
             uintptr_t from = read_uintptr(&p);
             uintptr_t to = read_uintptr(&p);
@@ -1368,7 +1705,7 @@ ranges_include(DebugInfoReader *reader, ranges_t *ptr, uint64_t addr)
                 base = to;
             }
             else if (base + from <= addr && addr < base + to) {
-                return from;
+                return (uintptr_t)base + from;
             }
         }
     }
@@ -1377,42 +1714,42 @@ 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;
@@ -1426,6 +1763,7 @@ 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;
     }
@@ -1438,56 +1776,102 @@ 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 abstract_origin, line_info_t *line)
+read_abstract_origin(DebugInfoReader *reader, uint64_t form, uint64_t abstract_origin, line_info_t *line, FILE *errout)
 {
-    char *p = reader->p;
-    char *q = reader->q;
+    const char *p = reader->p;
+    const char *q = reader->q;
     int level = reader->level;
     DIE die;
 
-    reader->p = reader->current_cu + abstract_origin;
-    if (!di_read_die(reader, &die)) goto finish;
+    switch (form) {
+      case DW_FORM_ref1:
+      case DW_FORM_ref2:
+      case DW_FORM_ref4:
+      case DW_FORM_ref8:
+      case DW_FORM_ref_udata:
+        reader->p = reader->current_cu + abstract_origin;
+        break;
+      case DW_FORM_ref_addr:
+        goto finish; /* not supported yet */
+      case DW_FORM_ref_sig8:
+        goto finish; /* not supported yet */
+      case DW_FORM_ref_sup4:
+      case DW_FORM_ref_sup8:
+        goto finish; /* not supported yet */
+      default:
+        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);
@@ -1501,36 +1885,44 @@ read_abstract_origin(DebugInfoReader *reader, uint64_t abstract_origin, line_inf
     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;
@@ -1538,7 +1930,7 @@ 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;
@@ -1546,18 +1938,19 @@ 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.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));
@@ -1574,32 +1967,86 @@ 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
 static unsigned long
 uncompress_debug_section(ElfW(Shdr) *shdr, char *file, char **ptr)
 {
+    *ptr = NULL;
 #ifdef SUPPORT_COMPRESSED_DEBUG_LINE
     ElfW(Chdr) *chdr = (ElfW(Chdr) *)(file + shdr->sh_offset);
     unsigned long destsize = chdr->ch_size;
     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;
 
 fail:
     free(*ptr);
+    *ptr = NULL;
 #endif
     return 0;
 }
@@ -1607,13 +2054,14 @@ 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;
     ElfW(Ehdr) *ehdr;
     ElfW(Shdr) *shdr, *shstr_shdr;
     ElfW(Shdr) *gnu_debuglink_shdr = NULL;
+    ElfW(Shdr) *note_gnu_build_id = NULL;
     int fd;
     off_t filesize;
     char *file;
@@ -1624,40 +2072,40 @@ 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;
@@ -1669,34 +2117,43 @@ 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;
-	  case SHT_PROGBITS:
-	    if (!strcmp(section_name, ".gnu_debuglink")) {
-		gnu_debuglink_shdr = shdr + i;
-	    }
+        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;
+            }
             else {
                 const char *debug_section_names[] = {
                     ".debug_abbrev",
                     ".debug_info",
                     ".debug_line",
                     ".debug_ranges",
-                    ".debug_str"
+                    ".debug_str_offsets",
+                    ".debug_addr",
+                    ".debug_rnglists",
+                    ".debug_str",
+                    ".debug_line_str"
                 };
 
                 for (j=0; j < DWARF_SECTION_COUNT; j++) {
@@ -1715,17 +2172,16 @@ 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)));
+    if (offset == 0) {
+        /* main executable */
+        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++) {
@@ -1742,14 +2198,14 @@ 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) {
@@ -1757,9 +2213,10 @@ 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 {
@@ -1794,20 +2251,27 @@ 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);
-	}
-	goto finish;
+        /* 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, errout);
+        }
+        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:
@@ -1819,7 +2283,7 @@ 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
@@ -1828,7 +2292,7 @@ fill_lines(int num_traces, void **traces, int check_debuglink,
 # endif
     int fd;
     off_t filesize;
-    char *file, *p;
+    char *file, *p = NULL;
     obj_info_t *obj = *objp;
     struct LP(mach_header) *header;
     uintptr_t dladdr_fbase = 0;
@@ -1889,20 +2353,53 @@ fill_lines(int num_traces, void **traces, int check_debuglink,
     obj->mapped_size = (size_t)filesize;
 
     header = (struct LP(mach_header) *)file;
-    if (header->magic != LP(MH_MAGIC)) {
-        /* TODO: universal binaries */
-        kprintf("'%s' is not a "
+    if (header->magic == LP(MH_MAGIC)) {
+        /* non universal binary */
+        p = file;
+    }
+    else if (header->magic == FAT_CIGAM) {
+        struct LP(mach_header) *mhp = _NSGetMachExecuteHeader();
+        struct fat_header *fat = (struct fat_header *)file;
+        char *q = file + sizeof(*fat);
+        uint32_t nfat_arch = __builtin_bswap32(fat->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);
+            /* 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;
+                file = p;
+                header = (struct LP(mach_header) *)p;
+                if (header->magic == LP(MH_MAGIC)) {
+                    goto found_mach_header;
+                }
+                break;
+            }
+            q += sizeof(*arch);
+        }
+        kprintf("'%s' is not a Mach-O universal binary file!\n",binary_filename);
+        close(fd);
+        goto fail;
+    }
+    else {
 # 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;
     }
+found_mach_header:
+    p += sizeof(*header);
 
-    p = file + sizeof(*header);
     for (uint32_t i = 0; i < (uint32_t)header->ncmds; i++) {
         struct load_command *lcmd = (struct load_command *)p;
         switch (lcmd->cmd) {
@@ -1913,7 +2410,11 @@ fill_lines(int num_traces, void **traces, int check_debuglink,
                     "__debug_info",
                     "__debug_line",
                     "__debug_ranges",
-                    "__debug_str"
+                    "__debug_str_offsets",
+                    "__debug_addr",
+                    "__debug_rnglists",
+                    "__debug_str",
+                    "__debug_line_str",
                 };
                 struct LP(segment_command) *scmd = (struct LP(segment_command) *)lcmd;
                 if (strcmp(scmd->segname, "__TEXT") == 0) {
@@ -1927,7 +2428,17 @@ fill_lines(int num_traces, void **traces, int check_debuglink,
                         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;
@@ -1947,20 +2458,21 @@ fill_lines(int num_traces, void **traces, int check_debuglink,
             {
                 struct symtab_command *cmd = (struct symtab_command *)lcmd;
                 struct LP(nlist) *nl = (struct LP(nlist) *)(file + cmd->symoff);
-                char *strtab = file + cmd->stroff, *sname;
+                char *strtab = file + cmd->stroff, *sname = 0;
                 uint32_t j;
-                uintptr_t saddr;
-                /* kprintf("[%2d]: %x/symtab %p\n", i, cmd->cmd, p); */
+                uintptr_t saddr = 0;
+                /* kprintf("[%2d]: %x/symtab %p\n", i, cmd->cmd, (void *)p); */
                 for (j = 0; j < cmd->nsyms; j++) {
                     uintptr_t symsize, d;
                     struct LP(nlist) *e = &nl[j];
+                        /* kprintf("[%2d][%4d]: %02x/%x/%x: %s %llx\n", i, j, e->n_type,e->n_sect,e->n_desc,strtab+e->n_un.n_strx,e->n_value); */
                     if (e->n_type != N_FUN) continue;
                     if (e->n_sect) {
                         saddr = (uintptr_t)e->n_value + obj->base_addr - obj->vmaddr;
                         sname = strtab + e->n_un.n_strx;
+                        /* kprintf("[%2d][%4d]: %02x/%x/%x: %s %llx\n", i, j, e->n_type,e->n_sect,e->n_desc,strtab+e->n_un.n_strx,e->n_value); */
                         continue;
                     }
-                    /* kprintf("[%2d][%4d]: %02x/%x/%x: %s %llx\n", i, j, e->n_type,e->n_sect,e->n_desc,strtab+e->n_un.n_strx,e->n_value); */
                     for (int k = offset; k < num_traces; k++) {
                         d = (uintptr_t)traces[k] - saddr;
                         symsize = e->n_value;
@@ -1983,15 +2495,16 @@ fill_lines(int num_traces, void **traces, int check_debuglink,
         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;
@@ -2001,44 +2514,58 @@ fail:
 #endif
 
 #define HAVE_MAIN_EXE_PATH
-#if defined(__FreeBSD__)
+#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).
  * it is NUL terminated.
  */
-#if defined(__linux__)
+#if defined(__linux__) || defined(__NetBSD__)
 static ssize_t
-main_exe_path(void)
+main_exe_path(FILE *errout)
 {
-# define PROC_SELF_EXE "/proc/self/exe"
+# if defined(__linux__)
+#  define PROC_SELF_EXE "/proc/self/exe"
+# elif defined(__NetBSD__)
+#  define PROC_SELF_EXE "/proc/curproc/exe"
+# endif
     ssize_t len = readlink(PROC_SELF_EXE, binary_filename, PATH_MAX);
+    if (len < 0) return 0;
     binary_filename[len] = 0;
     return len;
 }
-#elif defined(__FreeBSD__)
+#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(FILE *errout)
+{
+    int len = proc_pidpath(getpid(), binary_filename, PATH_MAX);
+    if (len == 0) return 0;
+    binary_filename[len] = 0;
+    return len;
+}
 #else
 #undef HAVE_MAIN_EXE_PATH
 #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;
@@ -2054,9 +2581,12 @@ 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);
@@ -2076,16 +2606,16 @@ 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 */
@@ -2093,79 +2623,84 @@ 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;
-	    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;
@@ -2179,435 +2714,8 @@ 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;
-}
+#undef kprintf
 
-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);
-}
-
-/*
- * 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 4f6cf179ef..ff8e476b92 100644
--- a/addr2line.h
+++ b/addr2line.h
@@ -1,3 +1,5 @@
+#ifndef RUBY_ADDR2LINE_H
+#define RUBY_ADDR2LINE_H
 /**********************************************************************
 
   addr2line.h -
@@ -8,13 +10,12 @@
 
 **********************************************************************/
 
-#ifndef RUBY_ADDR2LINE_H
-#define RUBY_ADDR2LINE_H
-
 #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/appveyor.yml b/appveyor.yml
deleted file mode 100644
index 90dc6ee246..0000000000
--- a/appveyor.yml
+++ /dev/null
@@ -1,142 +0,0 @@
----
-version: '{build}'
-shallow_clone: true
-platform:
-  - x64
-environment:
-  ruby_version: "24-%Platform%"
-  zlib_version: "1.2.11"
-  matrix:
-    # to reduce time for finishing all jobs, run the slowest msys2 build first.
-    - build: msys2
-      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
-    - build: vs
-      vs: 120
-      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2013
-    - build: vs
-      vs: 140
-      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
-notifications:
-  - provider: Webhook
-    url:
-      secure: iMINHMS0nZabaDsxN9omRDsekxzVvAAzEq5ev7lN6vZ6r9zNhl3/F/7POIVyahAwVFpRDeQT/iUugpAGWmOt3eGL/lZIdqiJFZ9DjPSkP68= # #alerts
-    method: POST
-    # "icon_url" is the url used by `provider: Slack`
-    body: >-
-      {{^isPullRequest}}
-        {
-          "attachments": [
-            {
-              "title": "Build {{projectName}} {{buildVersion}} {{status}}",
-              "fallback": "AppVeyor Build {{projectName}} {{buildVersion}} {{status}}",
-              "title_link": "{{buildUrl}}",
-              "text": "Commit <{{commitUrl}}|{{commitId}}> by {{commitAuthor}} on {{commitDate}}: _{{commitMessage}}_",
-              {{#passed}}
-                "color": "#44ee44"
-              {{/passed}}
-              {{#failed}}
-                "color": "#ee4444"
-              {{/failed}}
-            }
-          ],
-          "icon_url": "https://slack-files2.s3-us-west-2.amazonaws.com/bot_icons/2018-02-10/314363543719_48.png",
-          "username": "AppVeyor CI"
-        }
-      {{/isPullRequest}}
-    on_build_success: false
-    on_build_failure: true
-    on_build_status_changed: true
-for:
--
-  matrix:
-    only:
-      - build: vs
-  install:
-    - ver
-    - chcp
-    - SET BITS=%Platform:x86=32%
-    - SET BITS=%BITS:x=%
-    - SET OPENSSL_DIR=c:\OpenSSL-Win%BITS%
-    - 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% touch-unicode-files
-    - nmake %mflags% up incs UNICODE_FILES=.
-    - del Makefile
-    - mkdir \usr\local\bin
-    - mkdir \usr\local\include
-    - mkdir \usr\local\lib
-    - appveyor DownloadFile https://zlib.net/zlib%zlib_version:.=%.zip
-    - 7z x -o%APPVEYOR_BUILD_FOLDER%\ext\zlib zlib%zlib_version:.=%.zip
-    - for %%I in (%OPENSSL_DIR%\*.dll) do mklink /h \usr\local\bin\%%~nxI %%I
-    - mkdir %Platform%-mswin_%vs%
-    - ps: Get-ChildItem "win32" -Recurse | foreach {$_.Attributes = 'Readonly'}
-    - ps: Get-Item $env:Platform"-mswin_"$env:vs | foreach {$_.Attributes = 'Normal'}
-  build_script:
-    - cd %APPVEYOR_BUILD_FOLDER%
-    - cd %Platform%-mswin_%vs%
-    - ..\win32\configure.bat --without-ext=+,dbm,gdbm,readline --with-opt-dir=/usr/local --with-openssl-dir=%OPENSSL_DIR:\=/%
-    - nmake -l
-    - nmake install-nodoc
-    - \usr\bin\ruby -v -e "p :locale => Encoding.find('locale'), :filesystem => Encoding.find('filesystem')"
-  test_script:
-    - set /a JOBS=%NUMBER_OF_PROCESSORS%
-    - nmake -l "TESTOPTS=-v -q" btest
-    - nmake -l "TESTOPTS=-v -q" test-basic
-    - nmake -l "TESTOPTS=-q -j%JOBS% --subprocess-timeout-scale=3.0 --exclude win32ole --exclude test_syntax --exclude test_open-uri --exclude test_bundled_ca" test-all
-    # separately execute tests that may crash worker without -j.
-    - nmake -l "TESTOPTS=-v --subprocess-timeout-scale=3.0" test-all TESTS="../test/win32ole ../test/ruby/test_syntax.rb ../test/open-uri/test_open-uri.rb ../test/rubygems/test_bundled_ca.rb"
-    - nmake -l test-spec MSPECOPT=-fs # not using `-j` because sometimes `mspec -j` silently dies on Windows
--
-  matrix:
-    only:
-      - build: msys2
-  install:
-    - ver
-    - chcp
-    - set /a JOBS=%NUMBER_OF_PROCESSORS%
-    - set MSYS_NO_PATHCONV=1
-    - SET MSYSTEM=%Platform:x86=32%
-    - SET MSYSTEM=%MSYSTEM:x=MINGW%
-    - SET MSYS2_ARCH=%Platform:x86=i686%
-    - SET MSYS2_ARCH=%MSYS2_ARCH:x64=x86_64%
-    - set MSYSTEM_PREFIX=/mingw64
-    - set MINGW_CHOST=%MSYS2_ARCH%-w64-mingw32
-    - SET ruby_path=C:\Ruby%ruby_version:-x86=%
-    - cd ..
-    - mkdir build
-    - mkdir install
-    - SET PATH=%ruby_path%\bin;C:\msys64\%MSYSTEM%\bin;C:\msys64\usr\bin;%PATH%
-    - ruby --version
-  build_script:
-    # always update database
-    - pacman -Sy
-    - pacman -S --noconfirm --needed --noprogressbar mingw-w64-x86_64-toolchain
-    - pacman -S --noconfirm --needed --noprogressbar mingw-w64-x86_64-gdbm mingw-w64-x86_64-gmp mingw-w64-x86_64-libffi mingw-w64-x86_64-ncurses mingw-w64-x86_64-readline mingw-w64-x86_64-zlib
-    - cd %APPVEYOR_BUILD_FOLDER%
-    - set CFLAGS=-march=%MSYS2_ARCH:_=-% -mtune=generic -O3 -pipe
-    - set CXXFLAGS=%CFLAGS%
-    - set CPPFLAGS=-D_FORTIFY_SOURCE=2 -D__USE_MINGW_ANSI_STDIO=1 -DFD_SETSIZE=2048
-    - set LDFLAGS=-pipe
-    - sh -c "autoreconf -fi"
-    - cd ..\build
-    - sh ../ruby/configure --disable-install-doc --prefix=/. --build=%MINGW_CHOST% --host=%MINGW_CHOST% --target=%MINGW_CHOST%
-    - mingw32-make -j%JOBS% up
-    - mingw32-make -j%JOBS%
-    - mingw32-make DESTDIR=../install install-nodoc
-  test_script:
-    - mingw32-make test
-    - mingw32-make test-all TESTOPTS="--retry --job-status=normal --show-skip --subprocess-timeout-scale=1.5 -j %JOBS% --exclude win32ole --exclude test_open-uri"
-    # separately execute tests that may crash worker without -j.
-    - mingw32-make test-all TESTOPTS="--retry --job-status=normal --show-skip --subprocess-timeout-scale=1.5" TESTS="../ruby/test/win32ole ../ruby/test/open-uri/test_open-uri.rb"
-    - mingw32-make test-spec MSPECOPT=-fs # not using `-j` because sometimes `mspec -j` silently dies on Windows
diff --git a/array.c b/array.c
index 00061019b4..b471823876 100644
--- a/array.c
+++ b/array.c
@@ -11,22 +11,60 @@
 
 **********************************************************************/
 
-#include "ruby/encoding.h"
-#include "ruby/util.h"
-#include "ruby/st.h"
-#include "probes.h"
-#include "id.h"
 #include "debug_counter.h"
-#include "gc.h"
-#include "transient_heap.h"
+#include "id.h"
 #include "internal.h"
+#include "internal/array.h"
+#include "internal/compar.h"
+#include "internal/enum.h"
+#include "internal/gc.h"
+#include "internal/hash.h"
+#include "internal/numeric.h"
+#include "internal/object.h"
+#include "internal/proc.h"
+#include "internal/rational.h"
+#include "internal/vm.h"
+#include "probes.h"
+#include "ruby/encoding.h"
+#include "ruby/st.h"
+#include "ruby/thread.h"
+#include "ruby/util.h"
+#include "ruby/ractor.h"
+#include "vm_core.h"
+#include "builtin.h"
 
 #if !ARRAY_DEBUG
+# undef NDEBUG
 # define NDEBUG
 #endif
 #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
@@ -35,52 +73,56 @@ VALUE rb_cArray;
 #define ARY_MAX_SIZE (LONG_MAX / (int)sizeof(VALUE))
 #define SMALL_ARRAY_LEN 16
 
-# define ARY_SHARED_P(ary) \
-    (assert(!FL_TEST((ary), ELTS_SHARED) || !FL_TEST((ary), RARRAY_EMBED_FLAG)), \
-     FL_TEST((ary),ELTS_SHARED)!=0)
-# define ARY_EMBED_P(ary) \
-    (assert(!FL_TEST((ary), ELTS_SHARED) || !FL_TEST((ary), RARRAY_EMBED_FLAG)), \
-     FL_TEST((ary), RARRAY_EMBED_FLAG)!=0)
+RBIMPL_ATTR_MAYBE_UNUSED()
+static int
+should_be_T_ARRAY(VALUE ary)
+{
+    return RB_TYPE_P(ary, T_ARRAY);
+}
 
-#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)), RARRAY(a)->as.heap.aux.capa)
+#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_HEAP_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) (RUBY_ASSERT(should_be_T_ARRAY((VALUE)(a))), \
+                            !FL_TEST_RAW((a), RARRAY_SHARED_FLAG|RARRAY_EMBED_FLAG))
 
-#define ARY_OWNS_HEAP_P(a) (!FL_TEST((a), ELTS_SHARED|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_FORCE(ary, p) \
+    (RARRAY(ary)->as.heap.ptr = (p))
 #define ARY_SET_PTR(ary, p) do { \
-    assert(!ARY_EMBED_P(ary)); \
-    assert(!OBJ_FROZEN(ary)); \
-    RARRAY(ary)->as.heap.ptr = (p); \
+    RUBY_ASSERT(!ARY_EMBED_P(ary)); \
+    RUBY_ASSERT(!OBJ_FROZEN(ary)); \
+    ARY_SET_PTR_FORCE(ary, 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 { \
@@ -90,15 +132,15 @@ VALUE rb_cArray;
     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)); \
     } \
@@ -107,40 +149,92 @@ VALUE rb_cArray;
     } \
 } while (0)
 
-#define ARY_CAPA(ary) (ARY_EMBED_P(ary) ? RARRAY_EMBED_LEN_MAX : \
+#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_FORCE(ary, n) \
+    RARRAY(ary)->as.heap.aux.capa = (n);
 #define ARY_SET_CAPA(ary, n) do { \
-    assert(!ARY_EMBED_P(ary)); \
-    assert(!ARY_SHARED_P(ary)); \
-    assert(!OBJ_FROZEN(ary)); \
-    RARRAY(ary)->as.heap.aux.capa = (n); \
+    RUBY_ASSERT(!ARY_EMBED_P(ary)); \
+    RUBY_ASSERT(!ARY_SHARED_P(ary)); \
+    RUBY_ASSERT(!OBJ_FROZEN(ary)); \
+    ARY_SET_CAPA_FORCE(ary, n); \
 } while (0)
 
-#define ARY_SHARED(ary) (assert(ARY_SHARED_P(ary)), RARRAY(ary)->as.heap.aux.shared)
-#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, _value_); \
-} while (0)
-#define RARRAY_SHARED_ROOT_FLAG FL_USER5
-#define ARY_SHARED_ROOT_P(ary) (FL_TEST((ary), RARRAY_SHARED_ROOT_FLAG))
-#define ARY_SHARED_NUM(ary) \
-    (assert(ARY_SHARED_ROOT_P(ary)), RARRAY(ary)->as.heap.aux.capa)
-#define ARY_SHARED_OCCUPIED(ary) (ARY_SHARED_NUM(ary) == 1)
-#define ARY_SET_SHARED_NUM(ary, value) do { \
-    assert(ARY_SHARED_ROOT_P(ary)); \
+#define ARY_SHARED_ROOT_OCCUPIED(ary) (!OBJ_FROZEN(ary) && ARY_SHARED_ROOT_REFCNT(ary) == 1)
+#define ARY_SET_SHARED_ROOT_REFCNT(ary, value) do { \
+    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)
 
-#define ARY_SET(a, i, v) RARRAY_ASET((assert(!ARY_SHARED_P(a)), (a)), (i), (v))
+static inline void
+ARY_SET(VALUE a, long i, VALUE v)
+{
+    RUBY_ASSERT(!ARY_SHARED_P(a));
+    RUBY_ASSERT(!OBJ_FROZEN(a));
+
+    RARRAY_ASET(a, i, v);
+}
+#undef RARRAY_ASET
+
+static long
+ary_embed_capa(VALUE ary)
+{
+    size_t size = rb_gc_obj_slot_size(ary) - offsetof(struct RArray, as.ary);
+    RUBY_ASSERT(size % sizeof(VALUE) == 0);
+    return size / sizeof(VALUE);
+}
+
+static size_t
+ary_embed_size(long capa)
+{
+    size_t size = offsetof(struct RArray, as.ary) + (sizeof(VALUE) * capa);
+    if (size < sizeof(struct RArray)) size = sizeof(struct RArray);
+    return size;
+}
+
+static bool
+ary_embeddable_p(long capa)
+{
+    return rb_gc_size_allocatable_p(ary_embed_size(capa));
+}
+
+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;
+}
 
 
 #if ARRAY_DEBUG
@@ -149,25 +243,23 @@ VALUE rb_cArray;
 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;
+    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) <= RARRAY_EMBED_LEN_MAX);
+        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 */
@@ -175,22 +267,10 @@ ary_verify_(VALUE ary, const char *file, int line)
             v = ptr[i]; /* access check */
         }
         v = v;
-#endif
-    }
-
-    if (RARRAY_TRANSIENT_P(ary)) {
-        assert(rb_transient_heap_managed_ptr_p(RARRAY_CONST_PTR_TRANSIENT(ary)));
     }
 
-    rb_transient_heap_verify();
-
     return ary;
 }
-
-void
-rb_ary_verify(VALUE ary){
-    ary_verify(ary);
-}
 #else
 #define ary_verify(ary) ((void)0)
 #endif
@@ -201,7 +281,7 @@ 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
@@ -213,10 +293,10 @@ rb_ary_ptr_use_end(VALUE ary)
 }
 
 void
-rb_mem_clear(register VALUE *mem, register long size)
+rb_mem_clear(VALUE *mem, long size)
 {
     while (size--) {
-	*mem++ = Qnil;
+        *mem++ = Qnil;
     }
 }
 
@@ -224,7 +304,7 @@ static void
 ary_mem_clear(VALUE ary, long beg, long size)
 {
     RARRAY_PTR_USE(ary, ptr, {
-	rb_mem_clear(ptr + beg, size);
+        rb_mem_clear(ptr + beg, size);
     });
 }
 
@@ -232,7 +312,7 @@ static inline void
 memfill(register VALUE *mem, register long size, register VALUE val)
 {
     while (size--) {
-	*mem++ = val;
+        *mem++ = val;
     }
 }
 
@@ -240,15 +320,15 @@ static void
 ary_memfill(VALUE ary, long beg, long size, VALUE val)
 {
     RARRAY_PTR_USE(ary, ptr, {
-	memfill(ptr + beg, size, val);
-	RB_OBJ_WRITTEN(ary, Qundef, val);
+        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);
@@ -273,135 +353,62 @@ 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 void
+static size_t
 ary_heap_realloc(VALUE ary, size_t new_capa)
 {
-    size_t old_capa = ARY_HEAP_CAPA(ary);
-
-    if (RARRAY_TRANSIENT_P(ary)) {
-        if (new_capa <= old_capa) {
-            /* do nothing */
-        }
-        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 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 > RARRAY_EMBED_LEN_MAX) {
+    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);
@@ -409,9 +416,9 @@ ary_resize_capa(VALUE ary, long capacity)
             ARY_SET_HEAP_LEN(ary, len);
         }
         else {
-            ary_heap_realloc(ary, capacity);
+            new_capa = ary_heap_realloc(ary, capacity);
         }
-        ARY_SET_CAPA(ary, capacity);
+        ARY_SET_CAPA(ary, new_capa);
     }
     else {
         if (!ARY_EMBED_P(ary)) {
@@ -436,9 +443,12 @@ 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);
 }
@@ -449,10 +459,10 @@ 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);
@@ -461,103 +471,118 @@ ary_double_capa(VALUE ary, long min)
 }
 
 static void
-rb_ary_decrement_share(VALUE shared)
+rb_ary_decrement_share(VALUE shared_root)
 {
-    if (shared) {
-	long num = ARY_SHARED_NUM(shared) - 1;
-	if (num == 0) {
-	    rb_ary_free(shared);
-	    rb_gc_force_recycle(shared);
-	}
-	else if (num > 0) {
-	    ARY_SET_SHARED_NUM(shared, num);
-	}
+    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 = RARRAY(ary)->as.heap.aux.shared;
-    rb_ary_decrement_share(shared);
+    VALUE shared_root = ARY_SHARED_ROOT(ary);
+    rb_ary_decrement_share(shared_root);
     FL_UNSET_SHARED(ary);
 }
 
-static inline void
-rb_ary_unshare_safe(VALUE ary)
+static void
+rb_ary_reset(VALUE ary)
 {
-    if (ARY_SHARED_P(ary) && !ARY_EMBED_P(ary)) {
-	rb_ary_unshare(ary);
+    if (ARY_OWNS_HEAP_P(ary)) {
+        ary_heap_free(ary);
+    }
+    else if (ARY_SHARED_P(ary)) {
+        rb_ary_unshare(ary);
     }
+
+    FL_SET_EMBED(ary);
+    ARY_SET_EMBED_LEN(ary, 0);
 }
 
 static VALUE
-rb_ary_increment_share(VALUE shared)
+rb_ary_increment_share(VALUE shared_root)
 {
-    long num = ARY_SHARED_NUM(shared);
-    if (num >= 0) {
-	ARY_SET_SHARED_NUM(shared, 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;
+    return shared_root;
 }
 
 static void
-rb_ary_set_shared(VALUE ary, VALUE shared)
+rb_ary_set_shared(VALUE ary, VALUE shared_root)
 {
-    rb_ary_increment_share(shared);
+    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);
-    ARY_SET_SHARED(ary, shared);
+    RB_OBJ_WRITE(ary, &RARRAY(ary)->as.heap.aux.shared_root, shared_root);
+
+    RB_DEBUG_COUNTER_INC(obj_ary_shared_create);
 }
 
 static inline void
 rb_ary_modify_check(VALUE ary)
 {
+    RUBY_ASSERT(ruby_thread_has_gvl_p());
+
     rb_check_frozen(ary);
     ary_verify(ary);
 }
 
 void
-rb_ary_modify(VALUE ary)
+rb_ary_cancel_sharing(VALUE ary)
 {
-    rb_ary_modify_check(ary);
     if (ARY_SHARED_P(ary)) {
-	long shared_len, len = RARRAY_LEN(ary);
-	VALUE shared = ARY_SHARED(ary);
+        long shared_len, len = RARRAY_LEN(ary);
+        VALUE shared_root = ARY_SHARED_ROOT(ary);
 
-        ary_verify(shared);
+        ary_verify(shared_root);
 
-        if (len <= RARRAY_EMBED_LEN_MAX) {
-	    const VALUE *ptr = ARY_HEAP_PTR(ary);
+        if (len <= ary_embed_capa(ary)) {
+            const VALUE *ptr = ARY_HEAP_PTR(ary);
             FL_UNSET_SHARED(ary);
             FL_SET_EMBED(ary);
-	    MEMCPY((VALUE *)ARY_EMBED_PTR(ary), ptr, VALUE, len);
-            rb_ary_decrement_share(shared);
+            MEMCPY((VALUE *)ARY_EMBED_PTR(ary), ptr, VALUE, len);
+            rb_ary_decrement_share(shared_root);
             ARY_SET_EMBED_LEN(ary, len);
         }
-	else if (ARY_SHARED_OCCUPIED(shared) && len > ((shared_len = RARRAY_LEN(shared))>>1)) {
-            long shift = RARRAY_CONST_PTR_TRANSIENT(ary) - RARRAY_CONST_PTR_TRANSIENT(shared);
-	    FL_UNSET_SHARED(ary);
-            ARY_SET_PTR(ary, RARRAY_CONST_PTR_TRANSIENT(shared));
-	    ARY_SET_CAPA(ary, shared_len);
-	    RARRAY_PTR_USE(ary, ptr, {
-		MEMMOVE(ptr, ptr+shift, VALUE, len);
-	    });
-	    FL_SET_EMBED(shared);
-	    rb_ary_decrement_share(shared);
-	}
+        else if (ARY_SHARED_ROOT_OCCUPIED(shared_root) && len > ((shared_len = RARRAY_LEN(shared_root))>>1)) {
+            long shift = RARRAY_CONST_PTR(ary) - RARRAY_CONST_PTR(shared_root);
+            FL_UNSET_SHARED(ary);
+            ARY_SET_PTR(ary, RARRAY_CONST_PTR(shared_root));
+            ARY_SET_CAPA(ary, shared_len);
+            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);
-            ARY_SET_PTR(ary, ptr);
+            ARY_SET_CAPA_FORCE(ary, len);
+            ARY_SET_PTR_FORCE(ary, ptr);
         }
 
-	rb_gc_writebarrier_remember(ary);
+        rb_gc_writebarrier_remember(ary);
     }
     ary_verify(ary);
 }
 
+void
+rb_ary_modify(VALUE ary)
+{
+    rb_ary_modify_check(ary);
+    rb_ary_cancel_sharing(ary);
+}
+
 static VALUE
 ary_ensure_room_for_push(VALUE ary, long add_len)
 {
@@ -566,40 +591,40 @@ 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 > RARRAY_EMBED_LEN_MAX) {
-	    VALUE shared = ARY_SHARED(ary);
-	    if (ARY_SHARED_OCCUPIED(shared)) {
-                if (ARY_HEAP_PTR(ary) - RARRAY_CONST_PTR_TRANSIENT(shared) + new_len <= RARRAY_LEN(shared)) {
-		    rb_ary_modify_check(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(shared_root) + new_len <= RARRAY_LEN(shared_root)) {
+                    rb_ary_modify_check(ary);
 
                     ary_verify(ary);
-                    ary_verify(shared);
-                    return shared;
-		}
-		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(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);
+                    }
                     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);
@@ -608,17 +633,32 @@ ary_ensure_room_for_push(VALUE ary, long add_len)
 
 /*
  *  call-seq:
- *      ary.freeze -> ary
+ *    freeze -> self
+ *
+ *  Freezes +self+ (if not already frozen); returns +self+:
+ *
+ *    a = []
+ *    a.frozen? # => false
+ *    a.freeze
+ *    a.frozen? # => true
  *
- *  Calls Object#freeze on +ary+ to prevent any further
- *  modification. A RuntimeError will be raised if a modification
- *  attempt is made.
+ *  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);
 }
 
@@ -633,18 +673,22 @@ 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 == RARRAY(ary2)->as.heap.aux.shared &&
-	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;
 }
 
 static VALUE
-ary_alloc(VALUE klass)
+ary_alloc_embed(VALUE klass, long capa)
 {
-    NEWOBJ_OF(ary, struct RArray, klass, T_ARRAY | RARRAY_EMBED_FLAG | (RGENGC_WB_PROTECTED_ARRAY ? FL_WB_PROTECTED : 0));
+    size_t size = ary_embed_size(capa);
+    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, 0);
     /* Created array is:
      *   FL_SET_EMBED((VALUE)ary);
      *   ARY_SET_EMBED_LEN((VALUE)ary, 0);
@@ -653,32 +697,51 @@ ary_alloc(VALUE klass)
 }
 
 static VALUE
+ary_alloc_heap(VALUE klass)
+{
+    NEWOBJ_OF(ary, struct RArray, klass,
+                     T_ARRAY | (RGENGC_WB_PROTECTED_ARRAY ? FL_WB_PROTECTED : 0),
+                     sizeof(struct RArray), 0);
+
+    ary->as.heap.len = 0;
+    ary->as.heap.aux.capa = 0;
+    ary->as.heap.ptr = NULL;
+
+    return (VALUE)ary;
+}
+
+static VALUE
 empty_ary_alloc(VALUE klass)
 {
     RUBY_DTRACE_CREATE_HOOK(ARRAY, 0);
-    return ary_alloc(klass);
+    return ary_alloc_embed(klass, 0);
 }
 
 static VALUE
 ary_new(VALUE klass, long capa)
 {
-    VALUE ary,*ptr;
+    RUBY_ASSERT(ruby_thread_has_gvl_p());
+
+    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);
 
-    ary = ary_alloc(klass);
-    if (capa > RARRAY_EMBED_LEN_MAX) {
-        ptr = ary_heap_alloc(ary, capa);
-        FL_UNSET_EMBED(ary);
-        ARY_SET_PTR(ary, ptr);
+    if (ary_embeddable_p(capa)) {
+        ary = ary_alloc_embed(klass, capa);
+    }
+    else {
+        ary = ary_alloc_heap(klass);
         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);
     }
 
@@ -694,7 +757,7 @@ rb_ary_new_capa(long capa)
 VALUE
 rb_ary_new(void)
 {
-    return rb_ary_new2(RARRAY_EMBED_LEN_MAX);
+    return rb_ary_new_capa(0);
 }
 
 VALUE
@@ -708,7 +771,7 @@ 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);
 
@@ -716,15 +779,15 @@ 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;
@@ -736,21 +799,91 @@ rb_ary_new_from_values(long n, const VALUE *elts)
     return rb_ary_tmp_new_from_values(rb_cArray, n, elts);
 }
 
+static VALUE
+ec_ary_alloc_embed(rb_execution_context_t *ec, VALUE klass, long capa)
+{
+    size_t size = ary_embed_size(capa);
+    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);
+     */
+    return (VALUE)ary;
+}
+
+static VALUE
+ec_ary_alloc_heap(rb_execution_context_t *ec, VALUE klass)
+{
+    NEWOBJ_OF(ary, struct RArray, klass,
+            T_ARRAY | (RGENGC_WB_PROTECTED_ARRAY ? FL_WB_PROTECTED : 0),
+            sizeof(struct RArray), ec);
+
+    ary->as.heap.len = 0;
+    ary->as.heap.aux.capa = 0;
+    ary->as.heap.ptr = NULL;
+
+    return (VALUE)ary;
+}
+
+static VALUE
+ec_ary_new(rb_execution_context_t *ec, VALUE klass, long capa)
+{
+    VALUE ary;
+
+    if (capa < 0) {
+        rb_raise(rb_eArgError, "negative array size (or size too big)");
+    }
+    if (capa > ARY_MAX_SIZE) {
+        rb_raise(rb_eArgError, "array size too big");
+    }
+
+    RUBY_DTRACE_CREATE_HOOK(ARRAY, capa);
+
+    if (ary_embeddable_p(capa)) {
+        ary = ec_ary_alloc_embed(ec, klass, capa);
+    }
+    else {
+        ary = ec_ary_alloc_heap(ec, klass);
+        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);
+    }
+
+    return ary;
+}
+
 VALUE
-rb_ary_tmp_new(long capa)
+rb_ec_ary_new_from_values(rb_execution_context_t *ec, long n, const VALUE *elts)
 {
-    VALUE ary = ary_new(0, capa);
-    rb_ary_transient_heap_evacuate(ary, TRUE);
+    VALUE ary;
+
+    ary = ec_ary_new(ec, rb_cArray, n);
+    if (n > 0 && elts) {
+        ary_memcpy(ary, 0, n, elts);
+        ARY_SET_LEN(ary, n);
+    }
+
     return ary;
 }
 
 VALUE
-rb_ary_tmp_new_fill(long capa)
+rb_ary_hidden_new(long capa)
 {
     VALUE ary = ary_new(0, capa);
+    return ary;
+}
+
+VALUE
+rb_ary_hidden_new_fill(long 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;
 }
 
@@ -758,78 +891,107 @@ void
 rb_ary_free(VALUE ary)
 {
     if (ARY_OWNS_HEAP_P(ary)) {
-        if (RARRAY_TRANSIENT_P(ary)) {
-            RB_DEBUG_COUNTER_INC(obj_ary_transient);
-        }
-        else {
-            RB_DEBUG_COUNTER_INC(obj_ary_ptr);
-            ary_heap_free(ary);
+        if (USE_DEBUG_COUNTER &&
+            !ARY_SHARED_ROOT_P(ary) &&
+            ARY_HEAP_CAPA(ary) > RARRAY_LEN(ary)) {
+            RB_DEBUG_COUNTER_INC(obj_ary_extracapa);
         }
+
+        RB_DEBUG_COUNTER_INC(obj_ary_ptr);
+        ary_heap_free(ary);
     }
     else {
-	RB_DEBUG_COUNTER_INC(obj_ary_embed);
+        RB_DEBUG_COUNTER_INC(obj_ary_embed);
+    }
+
+    if (ARY_SHARED_P(ary)) {
+        RB_DEBUG_COUNTER_INC(obj_ary_shared);
+    }
+    if (ARY_SHARED_ROOT_P(ary) && ARY_SHARED_ROOT_OCCUPIED(ary)) {
+        RB_DEBUG_COUNTER_INC(obj_ary_shared_root_occupied);
     }
 }
 
-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(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_NUM(ary, 1);
-	return ary;
+        return ary;
     }
     else {
-	long capa = ARY_CAPA(ary), len = RARRAY_LEN(ary);
-        const VALUE *ptr;
-	NEWOBJ_OF(shared, struct RArray, 0, T_ARRAY | (RGENGC_WB_PROTECTED_ARRAY ? FL_WB_PROTECTED : 0));
-
-        rb_ary_transient_heap_evacuate(ary, TRUE);
-        ptr = ARY_HEAP_PTR(ary);
-
-        FL_UNSET_EMBED(shared);
-	ARY_SET_LEN((VALUE)shared, capa);
-        ARY_SET_PTR((VALUE)shared, ptr);
-        ary_mem_clear((VALUE)shared, len, capa - len);
-	FL_SET_SHARED_ROOT(shared);
-	ARY_SET_SHARED_NUM((VALUE)shared, 1);
-	FL_SET_SHARED(ary);
-	ARY_SET_SHARED(ary, (VALUE)shared);
-	OBJ_FREEZE(shared);
-
-        ary_verify((VALUE)shared);
+        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);
+        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 (VALUE)shared;
+
+        return shared;
     }
 }
 
@@ -838,9 +1000,11 @@ ary_make_substitution(VALUE ary)
 {
     long len = RARRAY_LEN(ary);
 
-    if (len <= RARRAY_EMBED_LEN_MAX) {
-	VALUE subst = rb_ary_new2(len);
-        ary_memcpy(subst, 0, len, RARRAY_CONST_PTR_TRANSIENT(ary));
+    if (ary_embeddable_p(len)) {
+        VALUE subst = rb_ary_new_capa(len);
+        RUBY_ASSERT(ARY_EMBED_P(subst));
+
+        ary_memcpy(subst, 0, len, RARRAY_CONST_PTR(ary));
         ARY_SET_EMBED_LEN(subst, len);
         return subst;
     }
@@ -868,29 +1032,34 @@ 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);
 }
 
+VALUE
+rb_to_array(VALUE ary)
+{
+    return rb_convert_type_with_id(ary, T_ARRAY, "Array", idTo_a);
+}
+
 /*
  *  call-seq:
- *     Array.try_convert(obj) -> array or nil
+ *    Array.try_convert(object) -> object, new_array, or nil
+ *
+ *  Attempts to return an array, based on the given +object+.
  *
- *  Tries to convert +obj+ into an array, using +to_ary+ method.  Returns the
- *  converted array or +nil+ if +obj+ cannot be converted for any reason.
- *  This method can be used to check if an argument is an array.
+ *  If +object+ is an array, returns +object+.
  *
- *     Array.try_convert([1])   #=> [1]
- *     Array.try_convert("1")   #=> nil
+ *  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.
  *
- *     if tmp = Array.try_convert(arg)
- *       # the argument is an array
- *     elsif tmp = String.try_convert(arg)
- *       # the argument is a string
- *     end
+ *  Otherwise returns +nil+.
  *
+ *  Related: see {Methods for Creating an Array}[rdoc-ref:Array@Methods+for+Creating+an+Array].
  */
 
 static VALUE
@@ -899,60 +1068,79 @@ rb_ary_s_try_convert(VALUE dummy, VALUE ary)
     return rb_check_array_type(ary);
 }
 
+/* :nodoc: */
+static VALUE
+rb_ary_s_new(int argc, VALUE *argv, VALUE klass)
+{
+    VALUE ary;
+
+    if (klass == rb_cArray) {
+        long size = 0;
+        if (argc > 0 && FIXNUM_P(argv[0])) {
+            size = FIX2LONG(argv[0]);
+            if (size < 0) size = 0;
+        }
+
+        ary = ary_new(klass, size);
+
+        rb_obj_call_init_kw(ary, argc, argv, RB_PASS_CALLED_KEYWORDS);
+    }
+    else {
+        ary = rb_class_new_instance_pass_kw(argc, argv, klass);
+    }
+
+    return ary;
+}
+
 /*
  *  call-seq:
- *     Array.new(size=0, default=nil)
- *     Array.new(array)
- *     Array.new(size) {|index| block }
+ *    Array.new -> new_empty_array
+ *    Array.new(array) -> new_array
+ *    Array.new(size, default_value = nil) -> new_array
+ *    Array.new(size = 0) {|index| ... } -> new_array
  *
  *  Returns a new array.
  *
- *  In the first form, if no arguments are sent, the new array will be empty.
- *  When a +size+ and an optional +default+ are sent, an array is created with
- *  +size+ copies of +default+.  Take notice that all elements will reference the
- *  same object +default+.
- *
- *  The second form creates a copy of the array passed as a parameter (the
- *  array is generated by calling to_ary on the parameter).
- *
- *    first_array = ["Matz", "Guido"]
+ *  With no block and no argument given, returns a new empty array:
  *
- *    second_array = Array.new(first_array) #=> ["Matz", "Guido"]
+ *    Array.new # => []
  *
- *    first_array.equal? second_array       #=> false
+ *  With no block and array argument given, returns a new array with the same elements:
  *
- *  In the last form, an array of the given size is created.  Each element in
- *  this array is created by passing the element's index to the given block
- *  and storing the return value.
+ *    Array.new([:foo, 'bar', 2]) # => [:foo, "bar", 2]
  *
- *    Array.new(3) {|index| index ** 2}
- *    # => [0, 1, 4]
+ *  With no block and integer argument given, returns a new array containing
+ *  that many instances of the given +default_value+:
  *
- *  == Common gotchas
+ *    Array.new(0)    # => []
+ *    Array.new(3)    # => [nil, nil, nil]
+ *    Array.new(2, 3) # => [3, 3]
  *
- *  When sending the second parameter, the same object will be used as the
- *  value for all the array elements:
+ *  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:
  *
- *     a = Array.new(2, Hash.new)
- *     # => [{}, {}]
+ *    Array.new(3)  {|index| "Element #{index}" } # => ["Element 0", "Element 1", "Element 2"]
  *
- *     a[0]['cat'] = 'feline'
- *     a # => [{"cat"=>"feline"}, {"cat"=>"feline"}]
+ *  A common pitfall for new Rubyists is providing an expression as +default_value+:
  *
- *     a[1]['cat'] = 'Felix'
- *     a # => [{"cat"=>"Felix"}, {"cat"=>"Felix"}]
+ *    array = Array.new(2, {})
+ *    array # => [{}, {}]
+ *    array[0][:a] = 1
+ *    array # => [{a: 1}, {a: 1}], as array[0] and array[1] are same object
  *
- *  Since all the Array elements store the same hash, changes to one of them
- *  will affect them all.
+ *  If you want the elements of the array to be distinct, you should pass a block:
  *
- *  If multiple copies are what you want, you should use the block
- *  version which uses the result of that block each time an element
- *  of the array needs to be initialized:
+ *    array = Array.new(2) { {} }
+ *    array # => [{}, {}]
+ *    array[0][:a] = 1
+ *    array # => [{a: 1}, {}], as array[0] and array[1] are different objects
  *
- *     a = Array.new(2) {Hash.new}
- *     a[0]['cat'] = 'feline'
- *     a # => [{"cat"=>"feline"}, {}]
+ *  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
@@ -963,61 +1151,60 @@ rb_ary_initialize(int argc, VALUE *argv, VALUE ary)
 
     rb_ary_modify(ary);
     if (argc == 0) {
-        if (ARY_OWNS_HEAP_P(ary) && ARY_HEAP_PTR(ary) != NULL) {
-            ary_heap_free(ary);
-	}
-        rb_ary_unshare_safe(ary);
-        FL_SET_EMBED(ary);
-	ARY_SET_EMBED_LEN(ary, 0);
-	if (rb_block_given_p()) {
-	    rb_warning("given block not used");
-	}
-	return ary;
+        rb_ary_reset(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
@@ -1038,26 +1225,26 @@ 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);
 }
@@ -1065,22 +1252,26 @@ 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 (len <= RARRAY_EMBED_LEN_MAX) {
-        VALUE result = ary_alloc(klass);
-        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(klass);
+        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);
 
@@ -1088,15 +1279,71 @@ ary_make_partial(VALUE ary, VALUE klass, long offset, long len)
         ARY_SET_LEN(result, len);
 
         ary_verify(shared);
-        ary_verify(result);
+    }
+
+    ary_verify(result);
+    return result;
+}
+
+static VALUE
+ary_make_partial_step(VALUE ary, VALUE klass, long offset, long len, long step)
+{
+    RUBY_ASSERT(offset >= 0);
+    RUBY_ASSERT(len >= 0);
+    RUBY_ASSERT(offset+len <= RARRAY_LEN(ary));
+    RUBY_ASSERT(step != 0);
+
+    const long orig_len = 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 = roomof(len, ustep);
+
+    long i;
+    long j = offset + ((step > 0) ? 0 : (orig_len - 1));
+
+    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;
+        }
+        ARY_SET_EMBED_LEN(result, len);
+    }
+    else {
+        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;
+            }
+        });
+        ARY_SET_LEN(result, len);
+    }
+
+    return result;
 }
 
 static VALUE
 ary_make_shared_copy(VALUE ary)
 {
-    return ary_make_partial(ary, rb_obj_class(ary), 0, RARRAY_LEN(ary));
+    return ary_make_partial(ary, rb_cArray, 0, RARRAY_LEN(ary));
 }
 
 enum ary_take_pos_flags
@@ -1106,42 +1353,47 @@ 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)
 {
-    VALUE nv;
-    long n;
-    long len;
+    long len = RARRAY_LEN(ary);
     long offset = 0;
 
-    rb_scan_args(argc, argv, "1", &nv);
-    n = NUM2LONG(nv);
-    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:
- *     ary << obj            -> ary
+ *    self << object -> self
+ *
+ *  Appends +object+ as the last element in +self+; returns +self+:
+ *
+ *    [:foo, 'bar', 2] << :baz # => [:foo, "bar", 2, :baz]
  *
- *  Append---Pushes the given object on to the end of this array. This
- *  expression returns the array itself, so several appends
- *  may be chained together.
+ *  Appends +object+ as a single element, even if it is another array:
  *
- *     a = [ 1, 2 ]
- *     a << "c" << "d" << [ 3, 4 ]
- *             #=>  [ 1, 2, "c", "d", [ 3, 4 ] ]
- *     a
- *             #=>  [ 1, 2, "c", "d", [ 3, 4 ] ]
+ *    [:foo, 'bar', 2] << [3, 4] # => [:foo, "bar", 2, [3, 4]]
  *
+ *  Related: see {Methods for Assigning}[rdoc-ref:Array@Methods+for+Assigning].
  */
 
 VALUE
@@ -1150,7 +1402,7 @@ 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(ary, ptr, {
-	RB_OBJ_WRITE(target_ary, &ptr[idx], item);
+        RB_OBJ_WRITE(target_ary, &ptr[idx], item);
     });
     ARY_SET_LEN(ary, idx + 1);
     ary_verify(ary);
@@ -1169,19 +1421,20 @@ rb_ary_cat(VALUE ary, const VALUE *argv, long len)
 
 /*
  *  call-seq:
- *     ary.push(obj, ...)    -> ary
- *     ary.append(obj, ...)  -> ary
- *
- *  Append --- Pushes the given object(s) on to the end of this array. This
- *  expression returns the array itself, so several appends
- *  may be chained together. See also Array#pop for the opposite
- *  effect.
- *
- *     a = [ "a", "b", "c" ]
- *     a.push("d", "e", "f")
- *             #=> ["a", "b", "c", "d", "e", "f"]
- *     [1, 2, 3].push(4).push(5)
- *             #=> [1, 2, 3, 4, 5]
+ *    push(*objects) -> self
+ *    append(*objects) -> self
+ *
+ *  Appends each argument in +objects+ to +self+; returns +self+:
+ *
+ *    a = [:foo, 'bar', 2] # => [:foo, "bar", 2]
+ *    a.push(:baz, :bat)   # => [:foo, "bar", 2, :baz, :bat]
+ *
+ *  Appends each argument as a single element, even if it is another array:
+ *
+ *    a = [:foo, 'bar', 2]               # => [:foo, "bar", 2]
+      a.push([:baz, :bat], [:bam, :bad]) # => [:foo, "bar", 2, [:baz, :bat], [:bam, :bad]]
+ *
+ *  Related: see {Methods for Assigning}[rdoc-ref:Array@Methods+for+Assigning].
  */
 
 static VALUE
@@ -1198,33 +1451,47 @@ 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);
+
+    VALUE obj = RARRAY_AREF(ary, n - 1);
+
+    ARY_SET_LEN(ary, n - 1);
     ary_verify(ary);
-    return RARRAY_AREF(ary, n);
+    return obj;
 }
 
 /*
  *  call-seq:
- *     ary.pop    -> obj or nil
- *     ary.pop(n) -> new_ary
+ *    pop -> object or nil
+ *    pop(count) -> new_array
+ *
+ *  Removes and returns trailing elements of +self+.
  *
- *  Removes the last element from +self+ and returns it, or
- *  +nil+ if the array is empty.
+ *  With no argument given, removes and returns the last element, if available;
+ *  otherwise returns +nil+:
  *
- *  If a number +n+ is given, returns an array of the last +n+ elements
- *  (or less) just like <code>array.slice!(-n, n)</code> does. See also
- *  Array#push for the opposite effect.
+ *    a = [:foo, 'bar', 2]
+ *    a.pop  # => 2
+ *    a      # => [:foo, "bar"]
+ *    [].pop # => nil
  *
- *     a = [ "a", "b", "c", "d" ]
- *     a.pop     #=> "d"
- *     a.pop(2)  #=> ["b", "c"]
- *     a         #=> ["a"]
+ *  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.pop(2) # => ["bar", 2]
+ *    a        # => [:foo]
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.pop(50) # => [:foo, "bar", 2]
+ *    a         # => []
+ *
+ *  Related: Array#push;
+ *  see also {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
 
 static VALUE
@@ -1233,7 +1500,7 @@ 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);
@@ -1249,55 +1516,54 @@ rb_ary_shift(VALUE ary)
     VALUE top;
     long len = RARRAY_LEN(ary);
 
-    rb_ary_modify_check(ary);
-    if (len == 0) return Qnil;
-    top = RARRAY_AREF(ary, 0);
-    if (!ARY_SHARED_P(ary)) {
-	if (len < ARY_DEFAULT_SIZE) {
-	    RARRAY_PTR_USE(ary, ptr, {
-		MEMMOVE(ptr, ptr+1, VALUE, len-1);
-	    }); /* WB: no new reference */
-            ARY_INCREASE_LEN(ary, -1);
-            ary_verify(ary);
-	    return top;
-	}
-        assert(!ARY_EMBED_P(ary)); /* ARY_EMBED_LEN_MAX < ARY_DEFAULT_SIZE */
-
-	ARY_SET(ary, 0, Qnil);
-	ary_make_shared(ary);
-    }
-    else if (ARY_SHARED_OCCUPIED(ARY_SHARED(ary))) {
-	RARRAY_PTR_USE(ary, ptr, ptr[0] = Qnil);
+    if (len == 0) {
+        rb_ary_modify_check(ary);
+        return Qnil;
     }
-    ARY_INCREASE_PTR(ary, 1);		/* shift ptr */
-    ARY_INCREASE_LEN(ary, -1);
 
-    ary_verify(ary);
+    top = RARRAY_AREF(ary, 0);
+
+    rb_ary_behead(ary, 1);
 
     return top;
 }
 
 /*
  *  call-seq:
- *     ary.shift    -> obj or nil
- *     ary.shift(n) -> new_ary
+ *    shift -> object or nil
+ *    shift(count) -> new_array or nil
+ *
+ *  Removes and returns leading elements from +self+.
+ *
+ *  With no argument, removes and returns one element, if available,
+ *  or +nil+ otherwise:
+ *
+ *    a = [0, 1, 2, 3]
+ *    a.shift  # => 0
+ *    a        # => [1, 2, 3]
+ *    [].shift # => nil
+ *
+ *  With non-negative numeric argument +count+ given,
+ *  removes and returns the first +count+ elements:
  *
- *  Removes the first element of +self+ and returns it (shifting all
- *  other elements down by one). Returns +nil+ if the array
- *  is empty.
+ *    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 a number +n+ is given, returns an array of the first +n+ elements
- *  (or less) just like <code>array.slice!(0, n)</code> does. With +ary+
- *  containing only the remainder elements, not including what was shifted to
- *  +new_ary+. See also Array#unshift for the opposite effect.
+ *  If +count+ is large,
+ *  removes and returns all elements:
  *
- *     args = [ "-m", "-q", "filename" ]
- *     args.shift     #=> "-m"
- *     args           #=> ["-q", "filename"]
+ *    a = [0, 1, 2, 3]
+ *    a.shift(50) # => [0, 1, 2, 3]
+ *    a           # => []
  *
- *     args = [ "-m", "-q", "filename" ]
- *     args.shift(2)  #=> ["-m", "-q"]
- *     args           #=> ["filename"]
+ *  If +self+ is empty, returns a new empty array.
+ *
+ *  Related: see {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
 
 static VALUE
@@ -1307,7 +1573,7 @@ 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);
@@ -1318,122 +1584,147 @@ 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) return ary;
+    if (n <= 0) {
+        return ary;
+    }
 
     rb_ary_modify_check(ary);
-    if (ARY_SHARED_P(ary)) {
-	if (ARY_SHARED_OCCUPIED(ARY_SHARED(ary))) {
-	  setup_occupied_shared:
-	    ary_mem_clear(ary, 0, n);
-	}
-        ARY_INCREASE_PTR(ary, n);
+
+    if (!ARY_SHARED_P(ary)) {
+        if (ARY_EMBED_P(ary) || RARRAY_LEN(ary) < ARY_DEFAULT_SIZE) {
+            RARRAY_PTR_USE(ary, ptr, {
+                MEMMOVE(ptr, ptr + n, VALUE, RARRAY_LEN(ary) - n);
+            }); /* WB: no new reference */
+            ARY_INCREASE_LEN(ary, -n);
+            ary_verify(ary);
+            return ary;
+        }
+
+        ary_mem_clear(ary, 0, n);
+        ary_make_shared(ary);
     }
-    else {
-	if (RARRAY_LEN(ary) < ARY_DEFAULT_SIZE) {
-	    RARRAY_PTR_USE(ary, ptr, {
-		MEMMOVE(ptr, ptr+n, VALUE, RARRAY_LEN(ary)-n);
-	    }); /* WB: no new reference */
-	}
-	else {
-	    ary_make_shared(ary);
-	    goto setup_occupied_shared;
-	}
+    else if (ARY_SHARED_ROOT_OCCUPIED(ARY_SHARED_ROOT(ary))) {
+        ary_mem_clear(ary, 0, n);
     }
-    ARY_INCREASE_LEN(ary, -n);
 
+    ARY_INCREASE_PTR(ary, n);
+    ARY_INCREASE_LEN(ary, -n);
     ary_verify(ary);
+
     return ary;
 }
 
 static VALUE
-ary_ensure_room_for_unshift(VALUE ary, int argc)
+make_room_for_unshift(VALUE ary, const VALUE *head, VALUE *sharedp, int argc, long capa, long len)
+{
+    if (head - sharedp < argc) {
+        long room = capa - len - argc;
+
+        room -= room >> 4;
+        MEMMOVE((VALUE *)sharedp + argc + room, head, VALUE, len);
+        head = sharedp + argc + room;
+    }
+    ARY_SET_PTR(ary, head - argc);
+    RUBY_ASSERT(ARY_SHARED_ROOT_OCCUPIED(ARY_SHARED_ROOT(ary)));
+
+    ary_verify(ary);
+    return ARY_SHARED_ROOT(ary);
+}
+
+static VALUE
+ary_modify_for_unshift(VALUE ary, int argc)
 {
     long len = RARRAY_LEN(ary);
     long new_len = len + argc;
     long capa;
     const VALUE *head, *sharedp;
 
-    if (len > ARY_MAX_SIZE - argc) {
-	rb_raise(rb_eIndexError, "index %ld too big", new_len);
-    }
-
-    if (ARY_SHARED_P(ary)) {
-	VALUE shared = ARY_SHARED(ary);
-	capa = RARRAY_LEN(shared);
-	if (ARY_SHARED_OCCUPIED(shared) && capa > new_len) {
-            head = RARRAY_CONST_PTR_TRANSIENT(ary);
-            sharedp = RARRAY_CONST_PTR_TRANSIENT(shared);
-	    goto makeroom_if_need;
-	}
-    }
-
     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" */
-    if (new_len > ARY_DEFAULT_SIZE * 4) {
+    if (new_len > ARY_DEFAULT_SIZE * 4 && !ARY_EMBED_P(ary)) {
         ary_verify(ary);
 
         /* make a room for unshifted items */
-	capa = ARY_CAPA(ary);
-	ary_make_shared(ary);
-
-        head = sharedp = RARRAY_CONST_PTR_TRANSIENT(ary);
-	goto makeroom;
-      makeroom_if_need:
-	if (head - sharedp < argc) {
-	    long room;
-	  makeroom:
-	    room = capa - new_len;
-	    room -= room >> 4;
-	    MEMMOVE((VALUE *)sharedp + argc + room, head, VALUE, len);
-	    head = sharedp + argc + room;
-	}
-	ARY_SET_PTR(ary, head - argc);
-	assert(ARY_SHARED_OCCUPIED(ARY_SHARED(ary)));
+        capa = ARY_CAPA(ary);
+        ary_make_shared(ary);
 
-        ary_verify(ary);
-	return ARY_SHARED(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(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;
+    }
+}
+
+static VALUE
+ary_ensure_room_for_unshift(VALUE ary, int argc)
+{
+    long len = RARRAY_LEN(ary);
+    long new_len = len + argc;
+
+    if (len > ARY_MAX_SIZE - argc) {
+        rb_raise(rb_eIndexError, "index %ld too big", new_len);
+    }
+    else if (! ARY_SHARED_P(ary)) {
+        return ary_modify_for_unshift(ary, argc);
+    }
+    else {
+        VALUE shared_root = ARY_SHARED_ROOT(ary);
+        long capa = RARRAY_LEN(shared_root);
+
+        if (! ARY_SHARED_ROOT_OCCUPIED(shared_root)) {
+            return ary_modify_for_unshift(ary, argc);
+        }
+        else if (new_len > capa) {
+            return ary_modify_for_unshift(ary, argc);
+        }
+        else {
+            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);
+        }
     }
 }
 
 /*
  *  call-seq:
- *     ary.unshift(obj, ...)  -> ary
- *     ary.prepend(obj, ...)  -> ary
+ *    unshift(*objects) -> self
+ *    prepend(*objects) -> self
+ *
+ *  Prepends the given +objects+ to +self+:
  *
- *  Prepends objects to the front of +self+, moving other elements upwards.
- *  See also Array#shift for the opposite effect.
+ *    a = [:foo, 'bar', 2]
+ *    a.unshift(:bam, :bat) # => [:bam, :bat, :foo, "bar", 2]
  *
- *     a = [ "b", "c", "d" ]
- *     a.unshift("a")   #=> ["a", "b", "c", "d"]
- *     a.unshift(1, 2)  #=> [ 1, 2, "a", "b", "c", "d"]
+ *  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);
@@ -1445,7 +1736,7 @@ 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 */
@@ -1455,7 +1746,7 @@ 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);
 }
@@ -1467,7 +1758,7 @@ rb_ary_entry(VALUE ary, long offset)
 }
 
 VALUE
-rb_ary_subseq(VALUE ary, long beg, long len)
+rb_ary_subseq_step(VALUE ary, long beg, long len, long step)
 {
     VALUE klass;
     long alen = RARRAY_LEN(ary);
@@ -1476,48 +1767,142 @@ rb_ary_subseq(VALUE ary, long beg, long len)
     if (beg < 0 || len < 0) return Qnil;
 
     if (alen < len || alen < beg + len) {
-	len = alen - beg;
+        len = alen - beg;
     }
-    klass = rb_obj_class(ary);
+    klass = rb_cArray;
     if (len == 0) return ary_new(klass, 0);
+    if (step == 0)
+        rb_raise(rb_eArgError, "slice step cannot be zero");
+    if (step == 1)
+        return ary_make_partial(ary, klass, beg, len);
+    else
+        return ary_make_partial_step(ary, klass, beg, len, step);
+}
 
-    return ary_make_partial(ary, klass, beg, len);
+VALUE
+rb_ary_subseq(VALUE ary, long beg, long len)
+{
+    return rb_ary_subseq_step(ary, beg, len, 1);
 }
 
+static VALUE rb_ary_aref2(VALUE ary, VALUE b, VALUE e);
+
 /*
  *  call-seq:
- *     ary[index]                -> obj     or nil
- *     ary[start, length]        -> new_ary or nil
- *     ary[range]                -> new_ary or nil
- *     ary.slice(index)          -> obj     or nil
- *     ary.slice(start, length)  -> new_ary or nil
- *     ary.slice(range)          -> new_ary or nil
- *
- *  Element Reference --- Returns the element at +index+, or returns a
- *  subarray starting at the +start+ index and continuing for +length+
- *  elements, or returns a subarray specified by +range+ of indices.
- *
- *  Negative indices count backward from the end of the array (-1 is the last
- *  element).  For +start+ and +range+ cases the starting index is just before
- *  an element.  Additionally, an empty array is returned when the starting
- *  index for an element range is at the end of the array.
- *
- *  Returns +nil+ if the index (or starting index) are out of range.
- *
- *     a = [ "a", "b", "c", "d", "e" ]
- *     a[2] +  a[0] + a[1]    #=> "cab"
- *     a[6]                   #=> nil
- *     a[1, 2]                #=> [ "b", "c" ]
- *     a[1..3]                #=> [ "b", "c", "d" ]
- *     a[4..7]                #=> [ "e" ]
- *     a[6..10]               #=> nil
- *     a[-3, 3]               #=> [ "c", "d", "e" ]
- *     # special cases
- *     a[5]                   #=> nil
- *     a[6, 1]                #=> nil
- *     a[5, 1]                #=> []
- *     a[5..10]               #=> []
+ *    self[offset] -> object or nil
+ *    self[offset, size] -> object or nil
+ *    self[range] -> object or nil
+ *    self[aseq] -> object or nil
+ *
+ *  Returns elements from +self+; does not modify +self+.
+ *
+ *  In brief:
  *
+ *    a = [:foo, 'bar', 2]
+ *
+ *    # Single argument offset: returns one element.
+ *    a[0]     # => :foo          # Zero-based index.
+ *    a[-1]    # => 2             # Negative index counts backwards from end.
+ *
+ *    # Arguments offset and size: returns an array.
+ *    a[1, 2]  # => ["bar", 2]
+ *    a[-2, 2] # => ["bar", 2]    # Negative offset 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 +offset+ is given, returns the element at offset +offset+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[0] # => :foo
+ *    a[2] # => 2
+ *    a # => [:foo, "bar", 2]
+ *
+ *  If +offset+ 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 +offset+ and +size+ are given,
+ *  returns a new array of size +size+ containing successive elements beginning at offset +offset+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[0, 2] # => [:foo, "bar"]
+ *    a[1, 2] # => ["bar", 2]
+ *
+ *  If <tt>offset + size</tt> is greater than <tt>self.size</tt>,
+ *  returns all elements from offset +offset+ to the end:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[0, 4] # => [:foo, "bar", 2]
+ *    a[1, 3] # => ["bar", 2]
+ *    a[2, 2] # => [2]
+ *
+ *  If <tt>offset == self.size</tt> and <tt>size >= 0</tt>,
+ *  returns a new empty array.
+ *
+ *  If +size+ is negative, returns +nil+.
+ *
+ *  When a single Range argument +range+ is given,
+ *  treats <tt>range.min</tt> as +offset+ above
+ *  and <tt>range.size</tt> as +size+ 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.
+ *
+ *  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
+ *  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)
+ *    a[(7..).step(2)]
+ *    # RangeError (((7..).step(2)) out of range)
+ *
+ *  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]
+ *
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 VALUE
@@ -1525,54 +1910,66 @@ 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]);
 }
 
-VALUE
+static VALUE
 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;
+    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 */
-    switch (rb_range_beg_len(arg, &beg, &len, RARRAY_LEN(ary), 0)) {
+    /* check if idx is Range or ArithmeticSequence */
+    switch (rb_arithmetic_sequence_beg_len_step(arg, &beg, &len, &step, RARRAY_LEN(ary), 0)) {
       case Qfalse:
-	break;
+        break;
       case Qnil:
-	return Qnil;
+        return Qnil;
       default:
-	return rb_ary_subseq(ary, beg, len);
+        return rb_ary_subseq_step(ary, beg, len, step);
     }
+
     return rb_ary_entry(ary, NUM2LONG(arg));
 }
 
 /*
  *  call-seq:
- *     ary.at(index)   ->   obj  or nil
+ *    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 +index+. A negative index counts from the end of
- *  +self+. Returns +nil+ if the index is out of range. See also
- *  Array#[].
+ *    a = [:foo, 'bar', 2]
+ *    a.at(0)   # => :foo
+ *    a.at(2)   # => 2
+ *    a.at(2.0) # => 2
  *
- *     a = [ "a", "b", "c", "d", "e" ]
- *     a.at(0)     #=> "a"
- *     a.at(-1)    #=> "e"
+ *  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
@@ -1581,83 +1978,82 @@ rb_ary_at(VALUE ary, VALUE pos)
     return rb_ary_entry(ary, NUM2LONG(pos));
 }
 
-/*
- *  call-seq:
- *     ary.first     ->   obj or nil
- *     ary.first(n)  ->   new_ary
- *
- *  Returns the first element, or the first +n+ elements, of the array.
- *  If the array is empty, the first form returns +nil+, and the
- *  second form returns an empty array. See also Array#last for
- *  the opposite effect.
- *
- *     a = [ "q", "r", "s", "t" ]
- *     a.first     #=> "q"
- *     a.first(2)  #=> ["q", "r"]
- */
-
+#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:
- *     ary.last     ->  obj or nil
- *     ary.last(n)  ->  new_ary
- *
- *  Returns the last element(s) of +self+. If the array is empty,
- *  the first form returns +nil+.
- *
- *  See also Array#first for the opposite effect.
- *
- *     a = [ "w", "x", "y", "z" ]
- *     a.last     #=> "z"
- *     a.last(2)  #=> ["y", "z"]
- */
+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:
- *     ary.fetch(index)                    -> obj
- *     ary.fetch(index, default)           -> obj
- *     ary.fetch(index) {|index| block}    -> obj
- *
- *  Tries to return the element at position +index+, but throws an IndexError
- *  exception if the referenced +index+ lies outside of the array bounds.  This
- *  error can be prevented by supplying a second argument, which will act as a
- *  +default+ value.
- *
- *  Alternatively, if a block is given it will only be executed when an
- *  invalid +index+ is referenced.
- *
- *  Negative values of +index+ count from the end of the array.
- *
- *     a = [ 11, 22, 33, 44 ]
- *     a.fetch(1)               #=> 22
- *     a.fetch(-1)              #=> 44
- *     a.fetch(4, 'cat')        #=> "cat"
- *     a.fetch(100) {|i| puts "#{i} is out of bounds"}
- *                              #=> "100 is out of bounds"
+ *    fetch(index) -> element
+ *    fetch(index, default_value) -> element or default_value
+ *    fetch(index) {|index| ... } -> element or block_return_value
+ *
+ *  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 argument +index+ and no block,
+ *  returns the element at offset +index+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    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+ (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(3, :foo) # => :foo
+ *
+ *  With argument +index+ and a block,
+ *  returns the element at offset +index+ if index is in range
+ *  (and the block is not called); otherwise calls the block with index and returns its return value:
+ *
+ *    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
@@ -1670,48 +2066,145 @@ 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:
+ *   find(if_none_proc = nil) {|element| ... } -> object or nil
+ *   find(if_none_proc = nil) -> enumerator
+ *
+ * Returns the first element for which the block returns a truthy value.
+ *
+ * With a block given, calls the block with successive elements of the array;
+ * returns the first element for which the block returns a truthy value:
+ *
+ *   [1, 3, 5].find {|element| element > 2}                # => 3
+ *
+ * If no such element is found, calls +if_none_proc+ and returns its return value.
+ *
+ *   [1, 3, 5].find(proc {-1}) {|element| element > 12} # => -1
+ *
+ * With no block given, returns an Enumerator.
+ *
+ */
+
+static VALUE
+rb_ary_find(int argc, VALUE *argv, VALUE ary)
+{
+    VALUE if_none;
+    long idx;
+
+    RETURN_ENUMERATOR(ary, argc, argv);
+    if_none = rb_check_arity(argc, 0, 1) ? argv[0] : Qnil;
+
+    for (idx = 0; idx < RARRAY_LEN(ary); idx++) {
+        VALUE elem = RARRAY_AREF(ary, idx);
+        if (RTEST(rb_yield(elem))) {
+            return elem;
+        }
+    }
+
+    if (!NIL_P(if_none)) {
+        return rb_funcallv(if_none, idCall, 0, 0);
+    }
+    return Qnil;
+}
+
+/*
+ * call-seq:
+ *   rfind(if_none_proc = nil) {|element| ... } -> object or nil
+ *   rfind(if_none_proc = nil) -> enumerator
+ *
+ * Returns the last element for which the block returns a truthy value.
+ *
+ * With a block given, calls the block with successive elements of the array in
+ * reverse order; returns the first element for which the block returns a truthy
+ * value:
+ *
+ *   [1, 2, 3, 4, 5, 6].rfind {|element| element < 5}       # => 4
+ *
+ * If no such element is found, calls +if_none_proc+ and returns its return value.
+ *
+ *   [1, 2, 3, 4].rfind(proc {0}) {|element| element < -2}  # => 0
+ *
+ * With no block given, returns an Enumerator.
+ *
+ */
+
+static VALUE
+rb_ary_rfind(int argc, VALUE *argv, VALUE ary)
+{
+    VALUE if_none;
+    long len, idx;
+
+    RETURN_ENUMERATOR(ary, argc, argv);
+    if_none = rb_check_arity(argc, 0, 1) ? argv[0] : Qnil;
+
+    idx = RARRAY_LEN(ary);
+    while (idx--) {
+        VALUE elem = RARRAY_AREF(ary, idx);
+        if (RTEST(rb_yield(elem))) {
+            return elem;
+        }
+
+        len = RARRAY_LEN(ary);
+        idx = (idx >= len) ? len : idx;
+    }
+
+    if (!NIL_P(if_none)) {
+        return rb_funcallv(if_none, idCall, 0, 0);
+    }
+    return Qnil;
+}
+
+/*
  *  call-seq:
- *     ary.find_index(obj)             ->  int or nil
- *     ary.find_index {|item| block}  ->  int or nil
- *     ary.find_index                  ->  Enumerator
- *     ary.index(obj)             ->  int or nil
- *     ary.index {|item| block}   ->  int or nil
- *     ary.index                  ->  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 zero-based integer index of a specified element, or +nil+.
+ *
+ *  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 the _index_ of the first object in +ary+ such that the object is
- *  <code>==</code> to +obj+.
+ *  Returns +nil+ if no such element found.
  *
- *  If a block is given instead of an argument, returns the _index_ of the
- *  first object for which the block returns +true+.  Returns +nil+ if no
- *  match is found.
+ *  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:
  *
- *  See also Array#rindex.
+ *    a = [:foo, 'bar', 2, 'bar']
+ *    a.index {|element| element == 'bar' } # => 1
  *
- *  An Enumerator is returned if neither a block nor argument is given.
+ *  Returns +nil+ if the block never returns a truthy value.
  *
- *     a = [ "a", "b", "c" ]
- *     a.index("b")              #=> 1
- *     a.index("z")              #=> nil
- *     a.index {|x| x == "b"}    #=> 1
+ *  With neither an argument nor a block given, returns a new Enumerator.
+ *
+ *  Related: see {Methods for Querying}[rdoc-ref:Array@Methods+for+Querying].
  */
 
 static VALUE
@@ -1721,49 +2214,53 @@ 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:
- *     ary.rindex(obj)             ->  int or nil
- *     ary.rindex {|item| block}   ->  int or nil
- *     ary.rindex                  ->  Enumerator
+ *    rindex(object) -> integer or nil
+ *    rindex {|element| ... } -> integer or nil
+ *    rindex -> new_enumerator
  *
- *  Returns the _index_ of the last object in +self+ <code>==</code> to +obj+.
+ *  Returns the index of the last element for which <tt>object == element</tt>.
  *
- *  If a block is given instead of an argument, returns the _index_ of the
- *  first object for which the block returns +true+, starting from the last
- *  object.
+ *  With argument +object+ given, returns the index of the last such element found:
  *
- *  Returns +nil+ if no match is found.
+ *    a = [:foo, 'bar', 2, 'bar']
+ *    a.rindex('bar') # => 3
  *
- *  See also Array#index.
+ *  Returns +nil+ if no such object found.
  *
- *  If neither block nor argument is given, an Enumerator is returned instead.
+ *  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 = [ "a", "b", "b", "b", "c" ]
- *     a.rindex("b")             #=> 3
- *     a.rindex("z")             #=> nil
- *     a.rindex {|x| x == "b"}   #=> 3
+ *    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.
+ *
+ *  Related: see {Methods for Querying}[rdoc-ref:Array@Methods+for+Querying].
  */
 
 static VALUE
@@ -1773,25 +2270,28 @@ 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;
+        }
     }
     return Qnil;
 }
@@ -1814,58 +2314,69 @@ 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(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 */
-	    MEMMOVE(RARRAY_PTR(ary) + beg, rptr, VALUE, rlen);
-	}
+        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) {
+                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(ary, ptr,
+                                     MEMMOVE(ptr + beg, rptr, VALUE, rlen));
+        }
     }
 }
 
@@ -1876,22 +2387,14 @@ 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);
 }
 
-/*!
- * expands or shrinks \a ary to \a len elements.
- * expanded region will be filled with Qnil.
- * \param ary  an array
- * \param len  new size
- * \return     \a ary
- * \post       the size of \a ary is \a len.
- */
 VALUE
 rb_ary_resize(VALUE ary, long len)
 {
@@ -1901,118 +2404,260 @@ 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);
     }
-    else if (len <= RARRAY_EMBED_LEN_MAX) {
-	VALUE tmp[RARRAY_EMBED_LEN_MAX];
-	MEMCPY(tmp, ARY_HEAP_PTR(ary), VALUE, len);
-	ary_discard(ary);
-	MEMCPY((VALUE *)ARY_EMBED_PTR(ary), tmp, VALUE, len); /* WB: no new reference */
+    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);
+
+        FL_SET_EMBED(ary);
+
+        MEMCPY((VALUE *)ARY_EMBED_PTR(ary), ptr, VALUE, len); /* WB: no new reference */
         ARY_SET_EMBED_LEN(ary, len);
+
+        if (is_malloc_ptr) ruby_sized_xfree((void *)ptr, ptr_capa);
     }
     else {
-	if (olen > len + ARY_DEFAULT_SIZE) {
-            ary_heap_realloc(ary, len);
-	    ARY_SET_CAPA(ary, len);
-	}
-	ARY_SET_HEAP_LEN(ary, len);
+        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_verify(ary);
     return ary;
 }
 
+static VALUE
+ary_aset_by_rb_ary_store(VALUE ary, long key, VALUE val)
+{
+    rb_ary_store(ary, key, val);
+    return val;
+}
+
+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(rpl), RARRAY_LEN(rpl));
+    RB_GC_GUARD(rpl);
+    return val;
+}
+
 /*
  *  call-seq:
- *     ary[index]         = obj                      ->  obj
- *     ary[start, length] = obj or other_ary or nil  ->  obj or other_ary or nil
- *     ary[range]         = obj or other_ary or nil  ->  obj or other_ary or nil
- *
- *  Element Assignment --- Sets the element at +index+, or replaces a subarray
- *  from the +start+ index for +length+ elements, or replaces a subarray
- *  specified by the +range+ of indices.
- *
- *  If indices are greater than the current capacity of the array, the array
- *  grows automatically.  Elements are inserted into the array at +start+ if
- *  +length+ is zero.
- *
- *  Negative indices will count backward from the end of the array.  For
- *  +start+ and +range+ cases the starting index is just before an element.
- *
- *  An IndexError is raised if a negative index points past the beginning of
- *  the array.
- *
- *  See also Array#push, and Array#unshift.
- *
- *     a = Array.new
- *     a[4] = "4";                 #=> [nil, nil, nil, nil, "4"]
- *     a[0, 3] = [ 'a', 'b', 'c' ] #=> ["a", "b", "c", nil, "4"]
- *     a[1..2] = [ 1, 2 ]          #=> ["a", 1, 2, nil, "4"]
- *     a[0, 2] = "?"               #=> ["?", 2, nil, "4"]
- *     a[0..2] = "A"               #=> ["A", "4"]
- *     a[-1]   = "Z"               #=> ["A", "Z"]
- *     a[1..-1] = nil              #=> ["A", nil]
- *     a[1..-1] = []               #=> ["A"]
- *     a[0, 0] = [ 1, 2 ]          #=> [1, 2, "A"]
- *     a[3, 0] = "B"               #=> [1, 2, "A", "B"]
+ *    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,
+ *  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"]
+ *
+ *  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 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>,
+ *  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"]
+ *    a = [:foo, 'bar', 2]
+ *    a[1..-2] = 'foo' # => "foo"
+ *    a # => [:foo, "foo", 2]
+ *    a = [:foo, 'bar', 2]
+ *    a[1..-3] = 'foo' # => "foo"
+ *    a # => [:foo, "foo", "bar", 2]
+ *    a = [:foo, 'bar', 2]
+ *
+ *  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
 rb_ary_aset(int argc, VALUE *argv, VALUE ary)
 {
     long offset, beg, len;
-    VALUE rpl;
 
+    rb_check_arity(argc, 2, 3);
+    rb_ary_modify_check(ary);
     if (argc == 3) {
-	rb_ary_modify_check(ary);
-	beg = NUM2LONG(argv[0]);
-	len = NUM2LONG(argv[1]);
-	goto range;
+        beg = NUM2LONG(argv[0]);
+        len = NUM2LONG(argv[1]);
+        return ary_aset_by_rb_ary_splice(ary, beg, len, argv[2]);
     }
-    rb_check_arity(argc, 2, 2);
-    rb_ary_modify_check(ary);
     if (FIXNUM_P(argv[0])) {
-	offset = FIX2LONG(argv[0]);
-	goto fixnum;
+        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 */
-      range:
-	rpl = rb_ary_to_ary(argv[argc-1]);
-        rb_ary_splice(ary, beg, len, RARRAY_CONST_PTR_TRANSIENT(rpl), RARRAY_LEN(rpl));
-	RB_GC_GUARD(rpl);
-	return argv[argc-1];
+        /* check if idx is Range */
+        return ary_aset_by_rb_ary_splice(ary, beg, len, argv[1]);
     }
 
     offset = NUM2LONG(argv[0]);
-fixnum:
-    rb_ary_store(ary, offset, argv[1]);
-    return argv[1];
+    return ary_aset_by_rb_ary_store(ary, offset, argv[1]);
 }
 
 /*
  *  call-seq:
- *     ary.insert(index, obj...)  -> ary
+ *    insert(index, *objects) -> self
+ *
+ *  Inserts the given +objects+ as elements of +self+;
+ *  returns +self+.
+ *
+ *  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 = ['a', 'b', 'c']     # => ["a", "b", "c"]
+ *    a.insert(5, :x, :y, :z) # => ["a", "b", "c", nil, nil, :x, :y, :z]
  *
- *  Inserts the given values before the element with the given +index+.
+ *  When +index+ is negative, inserts +objects+
+ *  _after_ the element at offset <tt>index + self.size</tt>:
  *
- *  Negative indices count backwards from the end of the array, where +-1+ is
- *  the last element. If a negative index is used, the given values will be
- *  inserted after that element, so using an index of +-1+ will insert the
- *  values at the end of the array.
+ *    a = ['a', 'b', 'c']      # => ["a", "b", "c"]
+ *    a.insert(-2, :x, :y, :z) # => ["a", "b", :x, :y, :z, "c"]
  *
- *     a = %w{ a b c d }
- *     a.insert(2, 99)         #=> ["a", "b", 99, "c", "d"]
- *     a.insert(-2, 1, 2, 3)   #=> ["a", "b", 99, "c", 1, 2, 3, "d"]
+ *  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
@@ -2025,15 +2670,15 @@ 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;
@@ -2048,22 +2693,51 @@ 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:
- *     ary.each {|item| block}    -> ary
- *     ary.each                   -> Enumerator
+ *    each {|element| ... } -> self
+ *    each -> new_enumerator
+ *
+ *  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:
  *
- *  Calls the given block once for each element in +self+, passing that element
- *  as a parameter.  Returns the array itself.
+ *    Symbol foo
+ *    String bar
+ *    Integer 2
  *
- *  If no block is given, an Enumerator is returned.
+ *  Allows the array to be modified during iteration:
  *
- *     a = [ "a", "b", "c" ]
- *     a.each {|x| print x, " -- " }
+ *    a = [:foo, 'bar', 2]
+ *    a.each {|element| puts element; a.clear if element.to_s.start_with?('b') }
  *
- *  produces:
+ *  Output:
  *
- *     a -- b -- c --
+ *    foo
+ *    bar
+ *
+ *  With no block given, returns a new Enumerator.
+ *
+ *  Related: see {Methods for Iterating}[rdoc-ref:Array@Methods+for+Iterating].
  */
 
 VALUE
@@ -2073,27 +2747,43 @@ 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:
- *     ary.each_index {|index| block}    -> ary
- *     ary.each_index                    -> Enumerator
+ *    each_index {|index| ... } -> self
+ *    each_index -> new_enumerator
+ *
+ *  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
  *
- *  Same as Array#each, but passes the +index+ of the element instead of the
- *  element itself.
+ *  Allows the array to be modified during iteration:
  *
- *  An Enumerator is returned if no block is given.
+ *    a = [:foo, 'bar', 2]
+ *    a.each_index {|index| puts index; a.clear if index > 0 }
+ *    a # => []
  *
- *     a = [ "a", "b", "c" ]
- *     a.each_index {|x| print x, " -- " }
+ *  Output:
  *
- *  produces:
+ *    0
+ *    1
  *
- *     0 -- 1 -- 2 --
+ *  With no block given, returns a new Enumerator.
+ *
+ *  Related: see {Methods for Iterating}[rdoc-ref:Array@Methods+for+Iterating].
  */
 
 static VALUE
@@ -2103,24 +2793,33 @@ 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:
- *     ary.reverse_each {|item| block}    -> ary
- *     ary.reverse_each                   -> Enumerator
+ *    reverse_each {|element| ... } -> self
+ *    reverse_each -> Enumerator
+ *
+ *  When a block given, iterates backwards over the elements of +self+,
+ *  passing, in reverse order, each element to the block;
+ *  returns +self+:
  *
- *  Same as Array#each, but traverses +self+ in reverse order.
+ *    a = []
+ *    [0, 1, 2].reverse_each {|element| a.push(element) }
+ *    a # => [2, 1, 0]
  *
- *     a = [ "a", "b", "c" ]
- *     a.reverse_each {|x| print x, " " }
+ *  Allows the array to be modified during iteration:
  *
- *  produces:
+ *    a = ['a', 'b', 'c']
+ *    a.reverse_each {|element| a.clear if element.start_with?('b') }
+ *    a # => []
  *
- *     c b a
+ *  When no block given, returns a new Enumerator.
+ *
+ *  Related: see {Methods for Iterating}[rdoc-ref:Array@Methods+for+Iterating].
  */
 
 static VALUE
@@ -2131,24 +2830,27 @@ 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:
- *     ary.length -> int
+ *    length -> integer
+ *    size -> integer
  *
- *  Returns the number of elements in +self+. May be zero.
+ *  Returns the count of elements in +self+:
  *
- *     [ 1, 2, 3, 4, 5 ].length   #=> 5
- *     [].length                  #=> 0
+ *    [0, 1, 2].length # => 3
+ *    [].length        # => 0
+ *
+ *  Related: see {Methods for Querying}[rdoc-ref:Array@Methods+for+Querying].
  */
 
 static VALUE
@@ -2160,19 +2862,18 @@ rb_ary_length(VALUE ary)
 
 /*
  *  call-seq:
- *     ary.empty?   -> true or false
+ *    empty?  -> true or false
  *
- *  Returns +true+ if +self+ contains no elements.
+ *  Returns +true+ if the count of elements in +self+ is zero,
+ *  +false+ otherwise.
  *
- *     [].empty?   #=> true
+ *  Related: see {Methods for Querying}[rdoc-ref:Array@Methods+for+Querying].
  */
 
 static VALUE
 rb_ary_empty_p(VALUE ary)
 {
-    if (RARRAY_LEN(ary) == 0)
-	return Qtrue;
-    return Qfalse;
+    return RBOOL(RARRAY_LEN(ary) == 0);
 }
 
 VALUE
@@ -2180,7 +2881,7 @@ 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);
@@ -2191,7 +2892,7 @@ rb_ary_dup(VALUE ary)
 VALUE
 rb_ary_resurrect(VALUE ary)
 {
-    return rb_ary_new4(RARRAY_LEN(ary), RARRAY_CONST_PTR_TRANSIENT(ary));
+    return ary_make_partial(ary, rb_cArray, 0, RARRAY_LEN(ary));
 }
 
 extern VALUE rb_output_fs;
@@ -2208,15 +2909,15 @@ 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;
 }
 
-static void
+static long
 ary_join_0(VALUE ary, VALUE sep, long max, VALUE result)
 {
     long i;
@@ -2224,11 +2925,40 @@ 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);
-	if (i > 0 && !NIL_P(sep))
-	    rb_str_buf_append(result, sep);
-	rb_str_buf_append(result, val);
-	if (OBJ_TAINTED(val)) OBJ_TAINT(result);
+        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);
+    }
+    return i;
+}
+
+static void
+ary_join_1_str(VALUE dst, VALUE src, int *first)
+{
+    rb_str_buf_append(dst, src);
+    if (*first) {
+        rb_enc_copy(dst, src);
+        *first = FALSE;
+    }
+}
+
+static void
+ary_join_1_ary(VALUE obj, VALUE ary, VALUE sep, VALUE result, VALUE val, int *first)
+{
+    if (val == ary) {
+        rb_raise(rb_eArgError, "recursive array join");
+    }
+    else {
+        VALUE args[4];
+
+        *first = FALSE;
+        args[0] = val;
+        args[1] = sep;
+        args[2] = result;
+        args[3] = (VALUE)first;
+        rb_exec_recursive(recursive_join, obj, (VALUE)args);
     }
 }
 
@@ -2238,50 +2968,25 @@ 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);
-
-	val = RARRAY_AREF(ary, i);
-	if (RB_TYPE_P(val, T_STRING)) {
-	  str_join:
-	    rb_str_buf_append(result, val);
-	    if (*first) {
-		rb_enc_copy(result, val);
-		*first = FALSE;
-	    }
-	}
-	else if (RB_TYPE_P(val, T_ARRAY)) {
-	    obj = val;
-	  ary_join:
-	    if (val == ary) {
-		rb_raise(rb_eArgError, "recursive array join");
-	    }
-	    else {
-		VALUE args[4];
-
-		*first = FALSE;
-		args[0] = val;
-		args[1] = sep;
-		args[2] = result;
-		args[3] = (VALUE)first;
-		rb_exec_recursive(recursive_join, obj, (VALUE)args);
-	    }
-	}
-	else {
-	    tmp = rb_check_string_type(val);
-	    if (!NIL_P(tmp)) {
-		val = tmp;
-		goto str_join;
-	    }
-	    tmp = rb_check_array_type(val);
-	    if (!NIL_P(tmp)) {
-		obj = val;
-		val = tmp;
-		goto ary_join;
-	    }
-	    val = rb_obj_as_string(val);
-	    goto str_join;
-	}
+        if (i > 0 && !NIL_P(sep))
+            rb_str_buf_append(result, sep);
+
+        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)) {
+            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);
+        }
+        else if (!NIL_P(tmp = rb_check_array_type(val))) {
+            ary_join_1_ary(val, ary, sep, result, tmp, first);
+        }
+        else {
+            ary_join_1_str(result, rb_obj_as_string(val), first);
+        }
     }
 }
 
@@ -2289,36 +2994,41 @@ VALUE
 rb_ary_join(VALUE ary, VALUE sep)
 {
     long len = 1, i;
-    int taint = FALSE;
     VALUE val, tmp, result;
 
     if (RARRAY_LEN(ary) == 0) return rb_usascii_str_new(0, 0);
-    if (OBJ_TAINTED(ary)) taint = TRUE;
 
     if (!NIL_P(sep)) {
-	StringValue(sep);
-	len += RSTRING_LEN(sep) * (RARRAY_LEN(ary) - 1);
+        StringValue(sep);
+        len += RSTRING_LEN(sep) * (RARRAY_LEN(ary) - 1);
+    }
+    long len_memo = RARRAY_LEN(ary);
+    for (i=0; i < len_memo; i++) {
+        val = RARRAY_AREF(ary, i);
+        if (RB_UNLIKELY(!RB_TYPE_P(val, T_STRING))) {
+            tmp = rb_check_string_type(val);
+            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());
+                i = ary_join_0(ary, sep, i, result);
+                first = i == 0;
+                ary_join_1(ary, ary, sep, i, result, &first);
+                return result;
+            }
+            len += RSTRING_LEN(tmp);
+            len_memo = RARRAY_LEN(ary);
+        }
+        else {
+            len += RSTRING_LEN(val);
+        }
     }
-    for (i=0; i<RARRAY_LEN(ary); i++) {
-	val = RARRAY_AREF(ary, i);
-	tmp = rb_check_string_type(val);
-
-	if (NIL_P(tmp) || tmp != val) {
-	    int first;
-	    result = rb_str_buf_new(len + (RARRAY_LEN(ary)-i)*10);
-	    rb_enc_associate(result, rb_usascii_encoding());
-	    if (taint) OBJ_TAINT(result);
-	    ary_join_0(ary, sep, i, result);
-	    first = i == 0;
-	    ary_join_1(ary, ary, sep, i, result, &first);
-	    return result;
-	}
 
-	len += RSTRING_LEN(tmp);
-    }
+    result = rb_str_new(0, len);
+    rb_str_set_len(result, 0);
 
-    result = rb_str_buf_new(len);
-    if (taint) OBJ_TAINT(result);
     ary_join_0(ary, sep, RARRAY_LEN(ary), result);
 
     return result;
@@ -2326,29 +3036,44 @@ rb_ary_join(VALUE ary, VALUE sep)
 
 /*
  *  call-seq:
- *     ary.join(separator=$,)    -> str
+ *    join(separator = $,) -> new_string
+ *
+ *  Returns the new string formed by joining the converted elements of +self+;
+ *  for each element +element+:
+ *
+ *  - Converts recursively using <tt>element.join(separator)</tt>
+ *    if +element+ is a <tt>kind_of?(Array)</tt>.
+ *  - Otherwise, converts using <tt>element.to_s</tt>.
+ *
+ *  With no argument given, joins using the output field separator, <tt>$,</tt>:
  *
- *  Returns a string created by converting each element of the array to
- *  a string, separated by the given +separator+.
- *  If the +separator+ is +nil+, it uses current <code>$,</code>.
- *  If both the +separator+ and <code>$,</code> are +nil+,
- *  it uses an empty string.
+ *    a = [:foo, 'bar', 2]
+ *    $, # => nil
+ *    a.join # => "foobar2"
  *
- *     [ "a", "b", "c" ].join        #=> "abc"
- *     [ "a", "b", "c" ].join("-")   #=> "a-b-c"
+ *  With string argument +separator+ given, joins using that separator:
  *
- *  For nested arrays, join is applied recursively:
+ *    a = [:foo, 'bar', 2]
+ *    a.join("\n") # => "foo\nbar\n2"
  *
- *     [ "a", [1, 2, [:x, :y]], "b" ].join("-")   #=> "a-1-2-x-y-b"
+ *  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)
 {
     VALUE sep;
 
-    rb_scan_args(argc, argv, "01", &sep);
-    if (NIL_P(sep)) sep = rb_output_fs;
+    if (rb_check_arity(argc, 0, 1) == 0 || NIL_P(sep = argv[0])) {
+        sep = rb_output_fs;
+        if (!NIL_P(sep)) {
+            rb_category_warn(RB_WARN_CATEGORY_DEPRECATED, "$, is set to non-nil value");
+        }
+    }
 
     return rb_ary_join(ary, sep);
 }
@@ -2356,32 +3081,33 @@ rb_ary_join_m(int argc, VALUE *argv, VALUE ary)
 static VALUE
 inspect_ary(VALUE ary, VALUE dummy, int recur)
 {
-    int tainted = OBJ_TAINTED(ary);
     long i;
     VALUE s, str;
 
     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 (OBJ_TAINTED(s)) tainted = TRUE;
-	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, "]");
-    if (tainted) OBJ_TAINT(str);
     return str;
 }
 
 /*
  *  call-seq:
- *     ary.inspect  -> string
- *     ary.to_s     -> string
+ *    inspect -> new_string
+ *    to_s -> new_string
+ *
+ *  Returns the new string formed by calling method <tt>#inspect</tt>
+ *  on each array element:
  *
- *  Creates a string representation of +self+.
+ *    a = [:foo, 'bar', 2]
+ *    a.inspect # => "[:foo, \"bar\", 2]"
  *
- *     [ "a", "b", "c" ].to_s     #=> "[\"a\", \"b\", \"c\"]"
+ *  Related: see {Methods for Converting}[rdoc-ref:Array@Methods+for+Converting].
  */
 
 static VALUE
@@ -2399,40 +3125,55 @@ rb_ary_to_s(VALUE ary)
 
 /*
  *  call-seq:
- *     ary.to_a     -> ary
+ *    to_a -> self or new_array
  *
- *  Returns +self+.
+ *  When +self+ is an instance of \Array, returns +self+.
+ *
+ *  Otherwise, returns a new array containing the elements of +self+:
+ *
+ *    class MyArray < Array; end
+ *    my_a = MyArray.new(['foo', 'bar', 'two'])
+ *    a = my_a.to_a
+ *    a # => ["foo", "bar", "two"]
+ *    a.class # => Array # Not MyArray.
  *
- *  If called on a subclass of Array, converts the receiver to an Array object.
+ *  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:
- *     ary.to_h            -> hash
- *     ary.to_h { block }  -> hash
+ *    to_h -> new_hash
+ *    to_h {|element| ... } -> new_hash
  *
- *  Returns the result of interpreting <i>ary</i> as an array of
- *  <tt>[key, value]</tt> pairs.
+ *  Returns a new hash formed from +self+.
  *
- *     [[:foo, :bar], [1, 2]].to_h
- *       # => {:foo => :bar, 1 => 2}
+ *  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:
  *
- *  If a block is given, the results of the block on each element of
- *  the array will be used as pairs.
+ *    a = [['foo', 'zero'], ['bar', 'one'], ['baz', 'two']]
+ *    a.to_h # => {"foo"=>"zero", "bar"=>"one", "baz"=>"two"}
+ *    [].to_h # => {}
  *
- *     ["foo", "bar"].to_h {|s| [s.ord, s]}
- *       # => {102=>"foo", 98=>"bar"}
+ *  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
@@ -2443,25 +3184,25 @@ 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;
 }
 
 /*
  *  call-seq:
- *     ary.to_ary -> ary
+ *    to_ary -> self
  *
  *  Returns +self+.
  */
@@ -2476,9 +3217,9 @@ 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;
     }
 }
 
@@ -2490,23 +3231,26 @@ rb_ary_reverse(VALUE ary)
 
     rb_ary_modify(ary);
     if (len > 1) {
-	RARRAY_PTR_USE(ary, p1, {
-	    p2 = p1 + len - 1;	/* points last item */
-	    ary_reverse(p1, p2);
-	}); /* WB: no new reference */
+        RARRAY_PTR_USE(ary, p1, {
+            p2 = p1 + len - 1;	/* points last item */
+            ary_reverse(p1, p2);
+        }); /* WB: no new reference */
     }
     return ary;
 }
 
 /*
  *  call-seq:
- *     ary.reverse!   -> ary
+ *    reverse! -> self
+ *
+ *  Reverses the order of the elements of +self+;
+ *  returns +self+:
  *
- *  Reverses +self+ in place.
+ *    a = [0, 1, 2]
+ *    a.reverse! # => [2, 1, 0]
+ *    a          # => [2, 1, 0]
  *
- *     a = [ "a", "b", "c" ]
- *     a.reverse!       #=> ["c", "b", "a"]
- *     a                #=> ["c", "b", "a"]
+ *  Related: see {Methods for Assigning}[rdoc-ref:Array@Methods+for+Assigning].
  */
 
 static VALUE
@@ -2517,12 +3261,13 @@ rb_ary_reverse_bang(VALUE ary)
 
 /*
  *  call-seq:
- *     ary.reverse    -> new_ary
+ *    reverse -> new_array
  *
- *  Returns a new array containing +self+'s elements in reverse order.
+ *  Returns a new array containing the elements of +self+ in reverse order:
  *
- *     [ "a", "b", "c" ].reverse   #=> ["c", "b", "a"]
- *     [ 1 ].reverse               #=> [1]
+ *    [0, 1, 2].reverse # => [2, 1, 0]
+ *
+ *  Related: see {Methods for Combining}[rdoc-ref:Array@Methods+for+Combining].
  */
 
 static VALUE
@@ -2532,9 +3277,9 @@ 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;
@@ -2549,10 +3294,22 @@ rotate_count(long cnt, long len)
 static void
 ary_rotate_ptr(VALUE *ptr, long len, long cnt)
 {
-    --len;
-    if (cnt < len) ary_reverse(ptr + cnt, ptr + len);
-    if (--cnt > 0) ary_reverse(ptr, ptr + cnt);
-    if (len > 0) ary_reverse(ptr, ptr + len);
+    if (cnt == 1) {
+        VALUE tmp = *ptr;
+        memmove(ptr, ptr + 1, sizeof(VALUE)*(len - 1));
+        *(ptr + len - 1) = tmp;
+    }
+    else if (cnt == len - 1) {
+        VALUE tmp = *(ptr + len - 1);
+        memmove(ptr + 1, ptr, sizeof(VALUE)*(len - 1));
+        *ptr = tmp;
+    }
+    else {
+        --len;
+        if (cnt < len) ary_reverse(ptr + cnt, ptr + len);
+        if (--cnt > 0) ary_reverse(ptr, ptr + cnt);
+        if (len > 0) ary_reverse(ptr, ptr + len);
+    }
 }
 
 VALUE
@@ -2562,7 +3319,7 @@ rb_ary_rotate(VALUE ary, long cnt)
 
     if (cnt != 0) {
         long len = RARRAY_LEN(ary);
-        if (len > 0 && (cnt = rotate_count(cnt, len)) > 0) {
+        if (len > 1 && (cnt = rotate_count(cnt, len)) > 0) {
             RARRAY_PTR_USE(ary, ptr, ary_rotate_ptr(ptr, len, cnt));
             return ary;
         }
@@ -2572,50 +3329,75 @@ rb_ary_rotate(VALUE ary, long cnt)
 
 /*
  *  call-seq:
- *     ary.rotate!(count=1)   -> ary
+ *    rotate!(count = 1) -> self
  *
- *  Rotates +self+ in place so that the element at +count+ comes first, and
- *  returns +self+.
+ *  Rotates +self+ in place by moving elements from one end to the other; returns +self+.
+ *
+ *  With non-negative numeric +count+,
+ *  rotates +count+ elements from the beginning to the end:
+ *
+ *    [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:
+ *
+ *    [0, 1, 2, 3].rotate!(21) # => [1, 2, 3, 0]
+ *
+ *  If +count+ is zero, rotates no elements:
  *
- *  If +count+ is negative then it rotates in the opposite direction, starting
- *  from the end of the array where +-1+ is the last element.
+ *    [0, 1, 2, 3].rotate!(0) # => [0, 1, 2, 3]
  *
- *     a = [ "a", "b", "c", "d" ]
- *     a.rotate!        #=> ["b", "c", "d", "a"]
- *     a                #=> ["b", "c", "d", "a"]
- *     a.rotate!(2)     #=> ["d", "a", "b", "c"]
- *     a.rotate!(-3)    #=> ["a", "b", "c", "d"]
+ *  With a negative numeric +count+, rotates in the opposite direction,
+ *  from end to 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:
+ *
+ *    [0, 1, 2, 3].rotate!(-21) # => [3, 0, 1, 2]
+ *
+ *  Related: see {Methods for Assigning}[rdoc-ref:Array@Methods+for+Assigning].
  */
 
 static VALUE
 rb_ary_rotate_bang(int argc, VALUE *argv, VALUE ary)
 {
-    long n = 1;
-
-    switch (argc) {
-      case 1: n = NUM2LONG(argv[0]);
-      case 0: break;
-      default: rb_scan_args(argc, argv, "01", NULL);
-    }
+    long n = (rb_check_arity(argc, 0, 1) ? NUM2LONG(argv[0]) : 1);
     rb_ary_rotate(ary, n);
     return ary;
 }
 
 /*
  *  call-seq:
- *     ary.rotate(count=1)    -> new_ary
+ *    rotate(count = 1) -> new_array
+ *
+ *  Returns a new array formed from +self+ with elements
+ *  rotated from one end to the other.
+ *
+ *  With non-negative numeric +count+,
+ *  rotates elements from the beginning to the end:
+ *
+ *    [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:
+ *
+ *    [0, 1, 2, 3].rotate(22) # => [2, 3, 0, 1]
  *
- *  Returns a new array by rotating +self+ so that the element at +count+ is
- *  the first element of the new array.
+ *  With a +count+ of zero, rotates no elements:
  *
- *  If +count+ is negative then it rotates in the opposite direction, starting
- *  from the end of +self+ where +-1+ is the last element.
+ *    [0, 1, 2, 3].rotate(0) # => [0, 1, 2, 3]
  *
- *     a = [ "a", "b", "c", "d" ]
- *     a.rotate         #=> ["b", "c", "d", "a"]
- *     a                #=> ["a", "b", "c", "d"]
- *     a.rotate(2)      #=> ["c", "d", "a", "b"]
- *     a.rotate(-3)     #=> ["b", "c", "d", "a"]
+ *  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:
+ *
+ *    [0, 1, 2, 3].rotate(-21) # => [3, 0, 1, 2]
+ *
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 static VALUE
@@ -2623,22 +3405,17 @@ rb_ary_rotate_m(int argc, VALUE *argv, VALUE ary)
 {
     VALUE rotated;
     const VALUE *ptr;
-    long len, cnt = 1;
-
-    switch (argc) {
-      case 1: cnt = NUM2LONG(argv[0]);
-      case 0: break;
-      default: rb_scan_args(argc, argv, "01", NULL);
-    }
+    long len;
+    long cnt = (rb_check_arity(argc, 0, 1) ? NUM2LONG(argv[0]) : 1);
 
     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;
@@ -2646,18 +3423,27 @@ rb_ary_rotate_m(int argc, VALUE *argv, VALUE ary)
 
 struct ary_sort_data {
     VALUE ary;
-    struct cmp_opt_data cmp_opt;
+    VALUE receiver;
 };
 
 static VALUE
 sort_reentered(VALUE ary)
 {
     if (RBASIC(ary)->klass) {
-	rb_raise(rb_eRuntimeError, "sort reentered");
+        rb_raise(rb_eRuntimeError, "sort reentered");
     }
     return Qnil;
 }
 
+static void
+sort_returned(struct ary_sort_data *data)
+{
+    if (rb_obj_frozen_p(data->receiver)) {
+        rb_raise(rb_eFrozenError, "array frozen during sort");
+    }
+    sort_reentered(data->ary);
+}
+
 static int
 sort_1(const void *ap, const void *bp, void *dummy)
 {
@@ -2671,7 +3457,7 @@ sort_1(const void *ap, const void *bp, void *dummy)
     args[1] = b;
     retval = rb_yield_values2(2, args);
     n = rb_cmpint(retval, a, b);
-    sort_reentered(data->ary);
+    sort_returned(data);
     return n;
 }
 
@@ -2683,73 +3469,61 @@ 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, Fixnum)) {
-	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);
     n = rb_cmpint(retval, a, b);
-    sort_reentered(data->ary);
+    sort_returned(data);
 
     return n;
 }
 
 /*
  *  call-seq:
- *     ary.sort!                   -> ary
- *     ary.sort! {|a, b| block}    -> ary
- *
- *  Sorts +self+ in place.
- *
- *  Comparisons for the sort will be done using the <code><=></code> operator
- *  or using an optional code block.
- *
- *  The block must implement a comparison between +a+ and +b+ and return
- *  an integer less than 0 when +b+ follows +a+, +0+ when +a+ and +b+
- *  are equivalent, or an integer greater than 0 when +a+ follows +b+.
- *
- *  The result is not guaranteed to be stable.  When the comparison of two
- *  elements returns +0+, the order of the elements is unpredictable.
+ *    sort! -> self
+ *    sort! {|a, b| ... } -> self
  *
- *     ary = [ "d", "a", "e", "c", "b" ]
- *     ary.sort!                     #=> ["a", "b", "c", "d", "e"]
- *     ary.sort! {|a, b| b <=> a}    #=> ["e", "d", "c", "b", "a"]
+ *  Like Array#sort, but returns +self+ with its elements sorted in place.
  *
- *  See also Enumerable#sort_by.
+ *  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;
-	data.cmp_opt.opt_methods = 0;
-	data.cmp_opt.opt_inited = 0;
-	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);
+        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;
+        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);
         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);
+            }
+            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_memcpy(ary, 0, ARY_EMBED_LEN(tmp), ARY_EMBED_PTR(tmp));
             ARY_SET_LEN(ary, ARY_EMBED_LEN(tmp));
         }
         else {
@@ -2758,7 +3532,7 @@ 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);
                 }
@@ -2774,10 +3548,9 @@ rb_ary_sort_bang(VALUE ary)
                 ARY_SET_CAPA(ary, ARY_HEAP_LEN(tmp));
             }
             /* tmp was lost ownership for the ptr */
-            FL_UNSET(tmp, FL_FREEZE);
             FL_SET_EMBED(tmp);
             ARY_SET_EMBED_LEN(tmp, 0);
-            FL_SET(tmp, FL_FREEZE);
+            OBJ_FREEZE(tmp);
         }
         /* tmp will be GC'ed. */
         RBASIC_SET_CLASS_RAW(tmp, rb_cArray); /* rb_cArray must be marked */
@@ -2788,26 +3561,36 @@ rb_ary_sort_bang(VALUE ary)
 
 /*
  *  call-seq:
- *     ary.sort                   -> new_ary
- *     ary.sort {|a, b| block}    -> new_ary
+ *    sort -> new_array
+ *    sort {|a, b| ... } -> new_array
+ *
+ *  Returns a new array containing the elements of +self+, sorted.
+ *
+ *  With no block given, compares elements using operator <tt>#<=></tt>
+ *  (see Object#<=>):
+ *
+ *    [0, 2, 3, 1].sort # => [0, 1, 2, 3]
  *
- *  Returns a new array created by sorting +self+.
+ *  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:
  *
- *  Comparisons for the sort will be done using the <code><=></code> operator
- *  or using an optional code block.
+ *  - Negative when +b+ is to follow +a+.
+ *  - Zero when +a+ and +b+ are equivalent.
+ *  - Positive when +a+ is to follow +b+.
  *
- *  The block must implement a comparison between +a+ and +b+ and return
- *  an integer less than 0 when +b+ follows +a+, +0+ when +a+ and +b+
- *  are equivalent, or an integer greater than 0 when +a+ follows +b+.
+ *  Example:
  *
- *  The result is not guaranteed to be stable.  When the comparison of two
- *  elements returns +0+, the order of the elements is unpredictable.
+ *    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]
  *
- *     ary = [ "d", "a", "e", "c", "b" ]
- *     ary.sort                     #=> ["a", "b", "c", "d", "e"]
- *     ary.sort {|a, b| b <=> a}    #=> ["e", "d", "c", "b", "a"]
+ *  When the block returns zero, the order for +a+ and +b+ is indeterminate,
+ *  and may be unstable.
  *
- *  See also Enumerable#sort_by.
+ *  See an example in Numeric#nonzero? for the idiom to sort more
+ *  complex structure.
+ *
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 VALUE
@@ -2822,55 +3605,15 @@ static VALUE rb_ary_bsearch_index(VALUE ary);
 
 /*
  *  call-seq:
- *     ary.bsearch {|x| block }  -> elem
- *
- *  By using binary search, finds a value from this array which meets
- *  the given condition in O(log n) where n is the size of the array.
- *
- *  You can use this method in two modes: a find-minimum mode and
- *  a find-any mode.  In either case, the elements of the array must be
- *  monotone (or sorted) with respect to the block.
- *
- *  In find-minimum mode (this is a good choice for typical use cases),
- *  the block must always return true or false, and there must be an index i
- *  (0 <= i <= ary.size) so that:
- *
- *  - the block returns false for any element whose index is less than
- *    i, and
- *  - the block returns true for any element whose index is greater
- *    than or equal to i.
- *
- *  This method returns the i-th element.  If i is equal to ary.size,
- *  it returns nil.
- *
- *     ary = [0, 4, 7, 10, 12]
- *     ary.bsearch {|x| x >=   4 } #=> 4
- *     ary.bsearch {|x| x >=   6 } #=> 7
- *     ary.bsearch {|x| x >=  -1 } #=> 0
- *     ary.bsearch {|x| x >= 100 } #=> nil
- *
- *  In find-any mode (this behaves like libc's bsearch(3)), the block
- *  must always return a number, and there must be two indices i and j
- *  (0 <= i <= j <= ary.size) so that:
- *
- *  - the block returns a positive number for ary[k] if 0 <= k < i,
- *  - the block returns zero for ary[k] if i <= k < j, and
- *  - the block returns a negative number for ary[k] if
- *    j <= k < ary.size.
- *
- *  Under this condition, this method returns any element whose index
- *  is within i...j.  If i is equal to j (i.e., there is no element
- *  that satisfies the block), this method returns nil.
- *
- *     ary = [0, 4, 7, 10, 12]
- *     # try to find v such that 4 <= v < 8
- *     ary.bsearch {|x| 1 - x / 4 } #=> 4 or 7
- *     # try to find v such that 8 <= v < 10
- *     ary.bsearch {|x| 4 - x / 2 } #=> nil
- *
- *  You must not mix the two modes at a time; the block must always
- *  return either true/false, or always return a number.  It is
- *  undefined which value is actually picked up at each iteration.
+ *    bsearch {|element| ... } -> found_element or nil
+ *    bsearch -> new_enumerator
+ *
+ *  Returns the element from +self+ found by a binary search,
+ *  or +nil+ if the search found no suitable element.
+ *
+ *  See {Binary Searching}[rdoc-ref:language/bsearch.rdoc].
+ *
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 static VALUE
@@ -2879,22 +3622,22 @@ 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:
- *     ary.bsearch_index {|x| block }  -> int or nil
+ *    bsearch_index {|element| ... } -> integer or nil
+ *    bsearch_index -> new_enumerator
  *
- *  By using binary search, finds an index of a value from this array which
- *  meets the given condition in O(log n) where n is the size of the array.
+ *  Returns the integer index of the element from +self+ found by a binary search,
+ *  or +nil+ if the search found no suitable element.
  *
- *  It supports two modes, depending on the nature of the block. They are
- *  exactly the same as in the case of the #bsearch method, with the only difference
- *  being that this method returns the index of the element instead of the
- *  element itself. For more details consult the documentation for #bsearch.
+ *  See {Binary Searching}[rdoc-ref:language/bsearch.rdoc].
+ *
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 static VALUE
@@ -2906,39 +3649,39 @@ 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 (v == Qfalse || v == Qnil) {
-	    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);
@@ -2953,18 +3696,24 @@ sort_by_i(RB_BLOCK_CALL_FUNC_ARGLIST(i, dummy))
 
 /*
  *  call-seq:
- *     ary.sort_by! {|obj| block}      -> ary
- *     ary.sort_by!                    -> Enumerator
+ *    sort_by! {|element| ... } -> self
+ *    sort_by! -> new_enumerator
+ *
+ *  With a block given, sorts the elements of +self+ in place;
+ *  returns self.
  *
- *  Sorts +self+ in place using a set of keys generated by mapping the
- *  values in +self+ through the given block.
+ *  Calls the block with each successive element;
+ *  sorts elements based on the values returned from the block:
  *
- *  The result is not guaranteed to be stable.  When two keys are equal,
- *  the order of the corresponding elements is unpredictable.
+ *    a = ['aaaa', 'bbb', 'cc', 'd']
+ *    a.sort_by! {|element| element.size }
+ *    a # => ["d", "cc", "bbb", "aaaa"]
  *
- *  If no block is given, an Enumerator is returned instead.
+ *  For duplicate values returned by the block, the ordering is indeterminate, and may be unstable.
  *
- *  See also Enumerable#sort_by.
+ *  With no block given, returns a new Enumerator.
+ *
+ *  Related: see {Methods for Assigning}[rdoc-ref:Array@Methods+for+Assigning].
  */
 
 static VALUE
@@ -2974,31 +3723,32 @@ rb_ary_sort_by_bang(VALUE ary)
 
     RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
     rb_ary_modify(ary);
-    sorted = rb_block_call(ary, rb_intern("sort_by"), 0, 0, sort_by_i, 0);
-    rb_ary_replace(ary, sorted);
+    if (RARRAY_LEN(ary) > 1) {
+        sorted = rb_block_call(ary, rb_intern("sort_by"), 0, 0, sort_by_i, 0);
+        rb_ary_replace(ary, sorted);
+    }
     return ary;
 }
 
 
 /*
  *  call-seq:
- *     ary.collect {|item| block}    -> new_ary
- *     ary.map     {|item| block}    -> new_ary
- *     ary.collect                   -> Enumerator
- *     ary.map                       -> Enumerator
+ *    collect {|element| ... } -> new_array
+ *    collect -> new_enumerator
+ *    map {|element| ... } -> new_array
+ *    map -> new_enumerator
  *
- *  Invokes the given block once for each element of +self+.
+ *  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:
  *
- *  Creates a new array containing the values returned by the block.
+ *    a = [:foo, 'bar', 2]
+ *    a1 = a.map {|element| element.class }
+ *    a1 # => [Symbol, String, Integer]
  *
- *  See also Enumerable#collect.
+ *  With no block given, returns a new Enumerator.
  *
- *  If no block is given, an Enumerator is returned instead.
- *
- *     a = [ "a", "b", "c", "d" ]
- *     a.collect {|x| x + "!"}           #=> ["a!", "b!", "c!", "d!"]
- *     a.map.with_index {|x, i| x * i}   #=> ["", "b", "cc", "ddd"]
- *     a                                 #=> ["a", "b", "c", "d"]
+ *  Related: #collect!;
+ *  see also {Methods for Converting}[rdoc-ref:Array@Methods+for+Converting].
  */
 
 static VALUE
@@ -3010,7 +3760,7 @@ rb_ary_collect(VALUE ary)
     RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
     collect = rb_ary_new2(RARRAY_LEN(ary));
     for (i = 0; i < RARRAY_LEN(ary); i++) {
-	rb_ary_push(collect, rb_yield_force_blockarg(RARRAY_AREF(ary, i)));
+        rb_ary_push(collect, rb_yield(RARRAY_AREF(ary, i)));
     }
     return collect;
 }
@@ -3018,23 +3768,22 @@ rb_ary_collect(VALUE ary)
 
 /*
  *  call-seq:
- *     ary.collect! {|item| block }   -> ary
- *     ary.map!     {|item| block }   -> ary
- *     ary.collect!                   -> Enumerator
- *     ary.map!                       -> Enumerator
+ *    collect! {|element| ... } -> self
+ *    collect! -> new_enumerator
+ *    map! {|element| ... } -> self
+ *    map! -> new_enumerator
  *
- *  Invokes the given block once for each element of +self+, replacing the
- *  element with the value returned by the block.
+ *  With a block given, calls the block with each element of +self+
+ *  and replaces the element with the block's return value;
+ *  returns +self+:
  *
- *  See also Enumerable#collect.
+ *    a = [:foo, 'bar', 2]
+ *    a.map! { |element| element.class } # => [Symbol, String, Integer]
  *
- *  If no block is given, an Enumerator is returned instead.
+ *  With no block given, returns a new Enumerator.
  *
- *     a = [ "a", "b", "c", "d" ]
- *     a.map! {|x| x + "!" }
- *     a #=>  [ "a!", "b!", "c!", "d!" ]
- *     a.collect!.with_index {|x, i| x[0...i] }
- *     a #=>  ["", "b", "c!", "d!"]
+ *  Related: #collect;
+ *  see also {Methods for Converting}[rdoc-ref:Array@Methods+for+Converting].
  */
 
 static VALUE
@@ -3045,7 +3794,7 @@ 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;
 }
@@ -3057,21 +3806,21 @@ 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;
 }
@@ -3081,45 +3830,133 @@ 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:
- *     ary.values_at(selector, ...)  -> new_ary
+ *    values_at(*specifiers) -> new_array
+ *
+ *  Returns elements from +self+ in a new array; does not modify +self+.
+ *
+ *  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.
+ *
+ *  In brief:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *
+ *    # 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.
+ *
+ *    # 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.
+ *
+ *    a.values_at(-3..3)  # => ["b", "c", "d"]     # Negative range.begin counts backwards.
+ *    a.values_at(-50..3)                          # Raises RangeError.
+ *
+ *    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"]
  *
- *  Returns an array containing the elements in +self+ corresponding to the
- *  given +selector+(s).
+ *  - 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+:
  *
- *  The selectors may be either integer indices or ranges.
+ *      a.values_at(-2..3) # => ["c", "d"]
  *
- *  See also Array#select.
+ *  - If <tt>range.begin</tt> is negative and out-of-range, raises an exception:
  *
- *     a = %w{ a b c d e f }
- *     a.values_at(1, 3, 5)          # => ["b", "d", "f"]
- *     a.values_at(1, 3, 5, 7)       # => ["b", "d", "f", nil]
- *     a.values_at(-1, -2, -2, -7)   # => ["f", "e", "e", nil]
- *     a.values_at(4..6, 3...6)      # => ["e", "f", nil, "d", "e", "f"]
+ *      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
@@ -3128,7 +3965,7 @@ 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;
@@ -3137,24 +3974,22 @@ rb_ary_values_at(int argc, VALUE *argv, VALUE ary)
 
 /*
  *  call-seq:
- *     ary.select {|item| block}   -> new_ary
- *     ary.select                  -> Enumerator
- *     ary.filter {|item| block}   -> new_ary
- *     ary.filter                  -> Enumerator
- *
- *  Returns a new array containing all elements of +ary+
- *  for which the given +block+ returns a true value.
- *
- *  If no block is given, an Enumerator is returned instead.
+ *    select {|element| ... } -> new_array
+ *    select -> new_enumerator
+ *    filter {|element| ... } -> new_array
+ *    filter -> new_enumerator
  *
- *     [1,2,3,4,5].select {|num| num.even? }     #=> [2, 4]
+ *  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 = %w[ a b c d e f ]
- *     a.select {|v| v =~ /[aeiou]/ }    #=> ["a", "e"]
+ *    a = [:foo, 'bar', 2, :bam]
+ *    a.select {|element| element.to_s.start_with?('b') }
+ *    # => ["bar", :bam]
  *
- *  See also Enumerable#select.
+ *  With no block given, returns a new Enumerator.
  *
- *  Array#filter is an alias for Array#select.
+ *  Related: see {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 static VALUE
@@ -3166,9 +4001,9 @@ 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;
 }
@@ -3186,12 +4021,12 @@ 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;
 }
@@ -3205,37 +4040,39 @@ select_bang_ensure(VALUE a)
     long i1 = arg->len[0], i2 = arg->len[1];
 
     if (i2 < len && i2 < i1) {
-	long tail = 0;
-	if (i1 < len) {
-	    tail = len - i1;
-	    RARRAY_PTR_USE(ary, ptr, {
-		    MEMMOVE(ptr + i2, ptr + i1, VALUE, tail);
-		});
-	}
-	ARY_SET_LEN(ary, i2 + tail);
+        long tail = 0;
+        rb_ary_modify(ary);
+        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:
- *     ary.select! {|item| block } -> ary or nil
- *     ary.select!                 -> Enumerator
- *     ary.filter! {|item| block } -> ary or nil
- *     ary.filter!                 -> Enumerator
+ *    select! {|element| ... } -> self or nil
+ *    select! -> new_enumerator
+ *    filter! {|element| ... } -> self or nil
+ *    filter! -> new_enumerator
  *
- *  Invokes the given block passing in successive elements from +self+,
- *  deleting elements for which the block returns a +false+ value.
+ *  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+.
  *
- *  The array may not be changed instantly every time the block is called.
+ *  Returns +self+ if any elements were removed:
  *
- *  If changes were made, it will return +self+, otherwise it returns +nil+.
+ *    a = [:foo, 'bar', 2, :bam]
+ *    a.select! {|element| element.to_s.start_with?('b') } # => ["bar", :bam]
  *
- *  If no block is given, an Enumerator is returned instead.
+ *  Returns +nil+ if no elements were removed.
  *
- *  See also Array#keep_if.
+ *  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
@@ -3253,19 +4090,18 @@ rb_ary_select_bang(VALUE ary)
 
 /*
  *  call-seq:
- *     ary.keep_if {|item| block}   -> ary
- *     ary.keep_if                  -> Enumerator
+ *    keep_if {|element| ... } -> self
+ *    keep_if -> new_enumerator
  *
- *  Deletes every element of +self+ for which the given block evaluates to
- *  +false+, and returns +self+.
+ *  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:
  *
- *  If no block is given, an Enumerator is returned instead.
+ *    a = [:foo, 'bar', 2, :bam]
+ *    a.keep_if {|element| element.to_s.start_with?('b') } # => ["bar", :bam]
  *
- *     a = %w[ a b c d e f ]
- *     a.keep_if {|v| v =~ /[aeiou]/ }    #=> ["a", "e"]
- *     a                                  #=> ["a", "e"]
+ *  With no block given, returns a new Enumerator.
  *
- *  See also Array#select!.
+ *  Related: see {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
 
 static VALUE
@@ -3281,32 +4117,49 @@ 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:
- *     ary.delete(obj)            -> item or nil
- *     ary.delete(obj) {block}    -> item or result of block
+ *    delete(object) -> last_removed_object
+ *    delete(object) {|element| ... } -> last_removed_object or block_return
+ *
+ *  Removes zero or more elements from +self+.
+ *
+ *  With no block given,
+ *  removes from +self+ each element +ele+ such that <tt>ele == object</tt>;
+ *  returns the last removed element:
+ *
+ *    a = [0, 1, 2, 2.0]
+ *    a.delete(2) # => 2.0
+ *    a           # => [0, 1]
+ *
+ *  Returns +nil+ if no elements removed:
+ *
+ *    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 removed element:
  *
- *  Deletes all items from +self+ that are equal to +obj+.
+ *    a = [0, 1, 2, 2.0]
+ *    a.delete(2) {|element| fail 'Cannot happen' } # => 2.0
+ *    a                                             # => [0, 1]
  *
- *  Returns the last deleted item, or +nil+ if no matching item is found.
+ *  If no such element is found, returns the block's return value:
  *
- *  If the optional code block is given, the result of the block is returned if
- *  the item is not found.  (To remove +nil+ elements and get an informative
- *  return value, use Array#compact!)
+ *    a.delete(2) {|element| "Element #{element} not found." }
+ *    # => "Element 2 not found."
  *
- *     a = [ "a", "b", "b", "b", "c" ]
- *     a.delete("b")                   #=> "b"
- *     a                               #=> ["a", "c"]
- *     a.delete("z")                   #=> nil
- *     a.delete("z") {"not found"}     #=> "not found"
+ *  Related: see {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
 
 VALUE
@@ -3316,22 +4169,22 @@ 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);
@@ -3346,18 +4199,18 @@ 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);
@@ -3371,14 +4224,14 @@ 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(ary, ptr, {
-	MEMMOVE(ptr+pos, ptr+pos+1, VALUE, len-pos-1);
+        MEMMOVE(ptr+pos, ptr+pos+1, VALUE, len-pos-1);
     });
     ARY_INCREASE_LEN(ary, -1);
     ary_verify(ary);
@@ -3387,17 +4240,30 @@ rb_ary_delete_at(VALUE ary, long pos)
 
 /*
  *  call-seq:
- *     ary.delete_at(index)  -> obj or nil
+ *    delete_at(index) -> removed_object or nil
  *
- *  Deletes the element at the specified +index+, returning that element, or
- *  +nil+ if the +index+ is out of range.
+ *  Removes the element of +self+ at the given +index+, which must be an
+ *  {integer-convertible object}[rdoc-ref:implicit_conversion.rdoc@Integer-Convertible+Objects].
  *
- *  See also Array#slice!
+ *  When +index+ is non-negative, deletes the element at offset +index+:
  *
- *     a = ["ant", "bat", "cat", "dog"]
- *     a.delete_at(2)    #=> "cat"
- *     a                 #=> ["ant", "bat", "dog"]
- *     a.delete_at(99)   #=> nil
+ *    a = [:foo, 'bar', 2]
+ *    a.delete_at(1) # => "bar"
+ *    a # => [:foo, 2]
+ *
+ *  When +index+ is negative, counts backward from the end of the array:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.delete_at(-2) # => "bar"
+ *    a # => [:foo, 2]
+ *
+ *  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
@@ -3406,73 +4272,156 @@ rb_ary_delete_at_m(VALUE ary, VALUE pos)
     return rb_ary_delete_at(ary, NUM2LONG(pos));
 }
 
+static VALUE
+ary_slice_bang_by_rb_ary_splice(VALUE ary, long pos, long len)
+{
+    const long orig_len = RARRAY_LEN(ary);
+
+    if (len < 0) {
+        return Qnil;
+    }
+    else if (pos < -orig_len) {
+        return Qnil;
+    }
+    else if (pos < 0) {
+        pos += orig_len;
+    }
+    else if (orig_len < pos) {
+        return Qnil;
+    }
+    if (orig_len < pos + len) {
+        len = orig_len - pos;
+    }
+    if (len == 0) {
+        return rb_ary_new2(0);
+    }
+    else {
+        VALUE arg2 = rb_ary_new4(len, RARRAY_CONST_PTR(ary)+pos);
+        rb_ary_splice(ary, pos, len, 0, 0);
+        return arg2;
+    }
+}
+
 /*
  *  call-seq:
- *     ary.slice!(index)         -> obj or nil
- *     ary.slice!(start, length) -> new_ary or nil
- *     ary.slice!(range)         -> new_ary or nil
- *
- *  Deletes the element(s) given by an +index+ (optionally up to +length+
- *  elements) or by a +range+.
- *
- *  Returns the deleted object (or objects), or +nil+ if the +index+ is out of
- *  range.
- *
- *     a = [ "a", "b", "c" ]
- *     a.slice!(1)     #=> "b"
- *     a               #=> ["a", "c"]
- *     a.slice!(-1)    #=> "c"
- *     a               #=> ["a"]
- *     a.slice!(100)   #=> nil
- *     a               #=> ["a"]
+ *    slice!(index) -> object or nil
+ *    slice!(start, length) -> new_array or nil
+ *    slice!(range) -> new_array or nil
+ *
+ *  Removes and returns elements from +self+.
+ *
+ *  With numeric argument +index+ given,
+ *  removes and returns the element at offset +index+:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.slice!(2)   # => "c"
+ *    a             # => ["a", "b", "d"]
+ *    a.slice!(2.1) # => "d"
+ *    a             # => ["a", "b"]
+ *
+ *  If +index+ is negative, counts backwards from the end of +self+:
+ *
+ *    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 = ['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.
+ *
+ *  If +length+ is negative, returns +nil+.
+ *
+ *  With Range argument +range+ given,
+ *  treats <tt>range.min</tt> as +start+ (as above)
+ *  and <tt>range.size</tt> as +length+ (as above):
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.slice!(1..2) # => ["b", "c"]
+ *    a              # => ["a", "d"]
+ *
+ *  If <tt>range.start == a.size</tt>, returns a new empty array:
+ *
+ *    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 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
 rb_ary_slice_bang(int argc, VALUE *argv, VALUE ary)
 {
-    VALUE arg1, arg2;
-    long pos, len, orig_len;
+    VALUE arg1;
+    long pos, len;
 
     rb_ary_modify_check(ary);
+    rb_check_arity(argc, 1, 2);
+    arg1 = argv[0];
+
     if (argc == 2) {
-	pos = NUM2LONG(argv[0]);
-	len = NUM2LONG(argv[1]);
-      delete_pos_len:
-	if (len < 0) return Qnil;
-	orig_len = RARRAY_LEN(ary);
-	if (pos < 0) {
-	    pos += orig_len;
-	    if (pos < 0) return Qnil;
-	}
-	else if (orig_len < pos) return Qnil;
-	if (orig_len < pos + len) {
-	    len = orig_len - pos;
-	}
-	if (len == 0) return rb_ary_new2(0);
-        arg2 = rb_ary_new4(len, RARRAY_CONST_PTR_TRANSIENT(ary)+pos);
-	RBASIC_SET_CLASS(arg2, rb_obj_class(ary));
-	rb_ary_splice(ary, pos, len, 0, 0);
-	return arg2;
-    }
-
-    if (argc != 1) {
-	/* error report */
-	rb_scan_args(argc, argv, "11", NULL, NULL);
+        pos = NUM2LONG(argv[0]);
+        len = NUM2LONG(argv[1]);
+        return ary_slice_bang_by_rb_ary_splice(ary, pos, len);
     }
-    arg1 = argv[0];
 
     if (!FIXNUM_P(arg1)) {
-	switch (rb_range_beg_len(arg1, &pos, &len, RARRAY_LEN(ary), 0)) {
-	  case Qtrue:
-	    /* valid range */
-	    goto delete_pos_len;
-	  case Qnil:
-	    /* invalid range */
-	    return Qnil;
-	  default:
-	    /* not a range */
-	    break;
-	}
+        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;
+        }
     }
 
     return rb_ary_delete_at(ary, NUM2LONG(arg1));
@@ -3484,11 +4433,11 @@ 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;
 }
@@ -3501,12 +4450,12 @@ 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;
 }
@@ -3523,37 +4472,47 @@ ary_reject_bang(VALUE ary)
 
 /*
  *  call-seq:
- *     ary.reject! {|item| block}    -> ary or nil
- *     ary.reject!                   -> Enumerator
+ *    reject! {|element| ... } -> self or nil
+ *    reject! -> new_enumerator
+ *
+ *  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:
  *
- *  Deletes every element of +self+ for which the block evaluates to +true+,
- *  if no changes were made returns +nil+.
+ *    a = [:foo, 'bar', 2, 'bat']
+ *    a.reject! {|element| element.to_s.start_with?('b') } # => [:foo, 2]
  *
- *  The array may not be changed instantly every time the block is called.
+ *  Returns +nil+ if no elements removed.
  *
- *  See also Enumerable#reject and Array#delete_if.
+ *  With no block given, returns a new Enumerator.
  *
- *  If no block is given, an Enumerator is returned instead.
+ *  Related: see {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
 
 static VALUE
 rb_ary_reject_bang(VALUE ary)
 {
     RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
+    rb_ary_modify(ary);
     return ary_reject_bang(ary);
 }
 
 /*
  *  call-seq:
- *     ary.reject  {|item| block }  -> new_ary
- *     ary.reject                   -> Enumerator
+ *    reject {|element| ... } -> new_array
+ *    reject -> new_enumerator
+ *
+ *  With a block given, returns a new array whose elements are all those from +self+
+ *  for which the block returns +false+ or +nil+:
  *
- *  Returns a new array containing the items in +self+ for which the given
- *  block is not +true+. The ordering of non-rejected elements is maintained.
+ *    a = [:foo, 'bar', 2, 'bat']
+ *    a1 = a.reject {|element| element.to_s.start_with?('b') }
+ *    a1 # => [:foo, 2]
  *
- *  See also Array#delete_if
+ *  With no block given, returns a new Enumerator.
  *
- *  If no block is given, an Enumerator is returned instead.
+ *  Related: {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 static VALUE
@@ -3569,20 +4528,19 @@ rb_ary_reject(VALUE ary)
 
 /*
  *  call-seq:
- *     ary.delete_if {|item| block}    -> ary
- *     ary.delete_if                   -> Enumerator
- *
- *  Deletes every element of +self+ for which block evaluates to +true+.
+ *    delete_if {|element| ... } -> self
+ *    delete_if -> new_numerator
  *
- *  The array is changed instantly every time the block is called, not after
- *  the iteration is over.
+ *  With a block given, calls the block with each element of +self+;
+ *  removes the element if the block returns a truthy value;
+ *  returns +self+:
  *
- *  See also Array#reject!
+ *    a = [:foo, 'bar', 2, 'bat']
+ *    a.delete_if {|element| element.to_s.start_with?('b') } # => [:foo, 2]
  *
- *  If no block is given, an Enumerator is returned instead.
+ *  With no block given, returns a new Enumerator.
  *
- *     scores = [ 97, 42, 75 ]
- *     scores.delete_if {|score| score < 80 }   #=> [97]
+ *  Related: see {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
 
 static VALUE
@@ -3598,9 +4556,9 @@ static VALUE
 take_i(RB_BLOCK_CALL_FUNC_ARGLIST(val, cbarg))
 {
     VALUE *args = (VALUE *)cbarg;
-    if (args[1]-- == 0) rb_iter_break();
     if (argc > 1) val = rb_ary_new4(argc, argv);
     rb_ary_push(args[0], val);
+    if (--args[1] == 0) rb_iter_break();
     return Qnil;
 }
 
@@ -3610,38 +4568,108 @@ take_items(VALUE obj, long n)
     VALUE result = rb_check_array_type(obj);
     VALUE args[2];
 
+    if (n == 0) return result;
     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:
- *     ary.zip(arg, ...)                  -> new_ary
- *     ary.zip(arg, ...) {|arr| block}    -> nil
- *
- *  Converts any arguments to arrays, then merges elements of +self+ with
- *  corresponding elements from each argument.
- *
- *  This generates a sequence of <code>ary.size</code> _n_-element arrays,
- *  where _n_ is one more than the count of arguments.
- *
- *  If the size of any argument is less than the size of the initial array,
- *  +nil+ values are supplied.
- *
- *  If a block is given, it is invoked for each output +array+, otherwise an
- *  array of arrays is returned.
- *
- *     a = [ 4, 5, 6 ]
- *     b = [ 7, 8, 9 ]
- *     [1, 2, 3].zip(a, b)   #=> [[1, 4, 7], [2, 5, 8], [3, 6, 9]]
- *     [1, 2].zip(a, b)      #=> [[1, 4, 7], [2, 5, 8]]
- *     a.zip([1, 2], [8])    #=> [[4, 1, 8], [5, 2, nil], [6, nil, 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]]
+ *
+ *  Returned:
+ *
+ *  - 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:
+ *
+ *    a = [:a0, :a1, :a2, :a3]
+ *    b = [:b0, :b1, :b2, :b3]
+ *    c = [:c0, :c1, :c2, :c3]
+ *    d = a.zip(b, c)
+ *    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:
+ *
+ *    a = [:a0, :a1, :a2, :a3]
+ *    b = [:b0, :b1, :b2]
+ *    c = [:c0, :c1]
+ *    d = a.zip(b, c)
+ *    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:
+ *
+ *    a = [:a0, :a1, :a2, :a3]
+ *    b = [:b0, :b1, :b2, :b3, :b4]
+ *    c = [:c0, :c1, :c2, :c3, :c4, :c5]
+ *    d = a.zip(b, c)
+ *    pp d
+ *    # =>
+ *    [[:a0, :b0, :c0],
+ *     [:a1, :b1, :c1],
+ *     [:a2, :b2, :c2],
+ *     [:a3, :b3, :c3]]
+ *
+ *  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| 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 "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
@@ -3652,51 +4680,51 @@ 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;
@@ -3704,15 +4732,17 @@ rb_ary_zip(int argc, VALUE *argv, VALUE ary)
 
 /*
  *  call-seq:
- *     ary.transpose -> new_ary
+ *    transpose -> new_array
+ *
+ *  Returns a new array that is +self+
+ *  as a {transposed matrix}[https://en.wikipedia.org/wiki/Transpose]:
  *
- *  Assumes that +self+ is an array of arrays and transposes the rows and
- *  columns.
+ *    a = [[:a0, :a1], [:b0, :b1], [:c0, :c1]]
+ *    a.transpose # => [[:a0, :b0, :c0], [:a1, :b1, :c1]]
  *
- *     a = [[1,2], [3,4], [5,6]]
- *     a.transpose   #=> [[1, 3, 5], [2, 4, 6]]
+ *  The elements of +self+ must all be the same size.
  *
- *  If the length of the subarrays don't match, an IndexError is raised.
+ *  Related: see {Methods for Converting}[rdoc-ref:Array@Methods+for+Converting].
  */
 
 static VALUE
@@ -3724,36 +4754,38 @@ 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:
- *     ary.replace(other_ary)  -> ary
- *     ary.initialize_copy(other_ary)	-> ary
+ *    initialize_copy(other_array) -> self
+ *    replace(other_array) -> self
  *
- *  Replaces the contents of +self+ with the contents of +other_ary+,
- *  truncating or expanding if necessary.
+ *  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", "d", "e" ]
- *     a.replace([ "x", "y", "z" ])   #=> ["x", "y", "z"]
- *     a                              #=> ["x", "y", "z"]
+ *    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
@@ -3763,35 +4795,39 @@ rb_ary_replace(VALUE copy, VALUE orig)
     orig = to_ary(orig);
     if (copy == orig) return copy;
 
-    if (RARRAY_LEN(orig) <= RARRAY_EMBED_LEN_MAX) {
-        VALUE shared = 0;
+    rb_ary_reset(copy);
 
-        if (ARY_OWNS_HEAP_P(copy)) {
-            ary_heap_free(copy);
-	}
-        else if (ARY_SHARED_P(copy)) {
-            shared = ARY_SHARED(copy);
-            FL_UNSET_SHARED(copy);
-        }
-        FL_SET_EMBED(copy);
-        ary_memcpy(copy, 0, RARRAY_LEN(orig), RARRAY_CONST_PTR_TRANSIENT(orig));
-        if (shared) {
-            rb_ary_decrement_share(shared);
-        }
-        ARY_SET_LEN(copy, RARRAY_LEN(orig));
+    /* orig has enough space to embed the contents of orig. */
+    if (RARRAY_LEN(orig) <= ary_embed_capa(copy)) {
+        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));
+    }
+    /* 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_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));
     }
+    /* Otherwise, orig is on heap and copy does not have enough space to embed
+     * the contents of orig. */
     else {
-        VALUE shared = ary_make_shared(orig);
-        if (ARY_OWNS_HEAP_P(copy)) {
-            ary_heap_free(copy);
-        }
-        else {
-            rb_ary_unshare_safe(copy);
-        }
+        VALUE shared_root = ary_make_shared(orig);
         FL_UNSET_EMBED(copy);
         ARY_SET_PTR(copy, ARY_HEAP_PTR(orig));
         ARY_SET_LEN(copy, ARY_HEAP_LEN(orig));
-        rb_ary_set_shared(copy, shared);
+        rb_ary_set_shared(copy, shared_root);
+
+        RUBY_ASSERT(RB_OBJ_SHAREABLE_P(copy) ? RB_OBJ_SHAREABLE_P(shared_root) : 1);
     }
     ary_verify(copy);
     return copy;
@@ -3799,12 +4835,14 @@ rb_ary_replace(VALUE copy, VALUE orig)
 
 /*
  *  call-seq:
- *     ary.clear    -> ary
+ *    clear -> self
+ *
+ *  Removes all elements from +self+; returns +self+:
  *
- *  Removes all elements from +self+.
+ *    a = [:foo, 'bar', 2]
+ *    a.clear # => []
  *
- *     a = [ "a", "b", "c", "d", "e" ]
- *     a.clear    #=> [ ]
+ *  Related: see {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
 
 VALUE
@@ -3812,11 +4850,9 @@ 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);
@@ -3830,32 +4866,182 @@ rb_ary_clear(VALUE ary)
 
 /*
  *  call-seq:
- *     ary.fill(obj)                                 -> ary
- *     ary.fill(obj, start [, length])               -> ary
- *     ary.fill(obj, range)                          -> ary
- *     ary.fill {|index| block}                      -> ary
- *     ary.fill(start [, length]) {|index| block}    -> ary
- *     ary.fill(range) {|index| block}               -> ary
+ *    fill(object, start = nil, count = nil) -> self
+ *    fill(object, range) -> self
+ *    fill(start = nil, count = nil) {|element| ... } -> self
+ *    fill(range) {|element| ... } -> self
+ *
+ *  Replaces selected elements in +self+;
+ *  may add elements to +self+;
+ *  always returns +self+ (never a new array).
+ *
+ *  In brief:
+ *
+ *    # 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"]
+ *
+ *    # 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"]
+ *
+ *    # 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"]
+ *
+ *    # 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"]
+ *
+ *    # 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"]
+ *
+ *  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+):
+ *
+ *  - +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."
+ *
+ *  With argument +object+ given,
+ *  that one object is used for all replacements:
+ *
+ *    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"]
+ *
+ *  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:
+ *
+ *    a = ['a', 'b', 'c', 'd']               # => ["a", "b", "c", "d"]
+ *    a.fill(1, 2) {|element| element.to_s } # => ["a", "1", "2", "d"]
+ *
+ *  For arguments +start+ and +count+:
+ *
+ *  - If +start+ is non-negative,
+ *    replaces +count+ elements beginning at offset +start+:
+ *
+ *      ['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", "-", "-"]
+ *
+ *      ['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"]
+ *
+ *    Extends +self+ if necessary:
+ *
+ *      ['a', 'b', 'c', 'd'].fill('-', 3, 2) # => ["a", "b", "c", "-", "-"]
+ *      ['a', 'b', 'c', 'd'].fill('-', 4, 2) # => ["a", "b", "c", "d", "-", "-"]
+ *
+ *      ['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"]
+ *
+ *    Fills with +nil+ if necessary:
+ *
+ *      ['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, "-", "-"]
+ *
+ *      ['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"]
+ *
+ *    Does nothing if +count+ is non-positive:
+ *
+ *      ['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"]
+ *
+ *      ['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"]
+ *
+ *  - If +start+ is negative, counts backwards from the end of +self+:
+ *
+ *      ['a', 'b', 'c', 'd'].fill('-', -4, 3) # => ["-", "-", "-", "d"]
+ *      ['a', 'b', 'c', 'd'].fill('-', -3, 3) # => ["a", "-", "-", "-"]
+ *
+ *      ['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"]
+ *
+ *    Extends +self+ if necessary:
+ *
+ *      ['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+:
  *
- *  The first three forms set the selected elements of +self+ (which
- *  may be the entire array) to +obj+.
+ *      ['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 +start+ of +nil+ is equivalent to zero.
+ *      ['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"]
  *
- *  A +length+ of +nil+ is equivalent to the length of the array.
+ *  - If the +end+ value is excluded (see Range#exclude_end?), omits the last replacement:
  *
- *  The last three forms fill the array with the value of the given block,
- *  which is passed the absolute index of each element to be filled.
+ *      ['a', 'b', 'c', 'd'].fill('-', 1...2)  # => ["a", "-", "c", "d"]
+ *      ['a', 'b', 'c', 'd'].fill('-', 1...-2) # => ["a", "-", "c", "d"]
  *
- *  Negative values of +start+ count from the end of the array, where +-1+ is
- *  the last element.
+ *      ['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"]
  *
- *     a = [ "a", "b", "c", "d" ]
- *     a.fill("x")              #=> ["x", "x", "x", "x"]
- *     a.fill("z", 2, 2)        #=> ["x", "x", "z", "z"]
- *     a.fill("y", 0..1)        #=> ["y", "y", "z", "z"]
- *     a.fill {|i| i*i}         #=> [0, 1, 4, 9]
- *     a.fill(-2) {|i| i*i*i}   #=> [0, 1, 8, 27]
+ *  - 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
@@ -3865,84 +5051,74 @@ 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:
- *     ary + other_ary   -> new_ary
- *
- *  Concatenation --- Returns a new array built by concatenating the
- *  two arrays together to produce a third array.
+ *    self + other_array -> new_array
  *
- *     [ 1, 2, 3 ] + [ 4, 5 ]    #=> [ 1, 2, 3, 4, 5 ]
- *     a = [ "a", "b", "c" ]
- *     c = a + [ "d", "e", "f" ]
- *     c                         #=> [ "a", "b", "c", "d", "e", "f" ]
- *     a                         #=> [ "a", "b", "c" ]
+ *  Returns a new array containing all elements of +self+
+ *  followed by all elements of +other_array+:
  *
- *  Note that
- *     x += y
- *  is the same as
- *     x = x + y
- *  This means that it produces a new array. As a consequence,
- *  repeated use of <code>+=</code> on arrays can be quite inefficient.
+ *    a = [0, 1] + [2, 3]
+ *    a # => [0, 1, 2, 3]
  *
- *  See also Array#concat.
+ *  Related: see {Methods for Combining}[rdoc-ref:Array@Methods+for+Combining].
  */
 
 VALUE
@@ -3957,8 +5133,8 @@ 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;
 }
@@ -3968,29 +5144,23 @@ 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;
 }
 
 /*
  *  call-seq:
- *     ary.concat(other_ary1, other_ary2, ...)   -> ary
- *
- *  Appends the elements of <code>other_ary</code>s to +self+.
+ *    concat(*other_arrays) -> self
  *
- *     [ "a", "b" ].concat( ["c", "d"])   #=> [ "a", "b", "c", "d" ]
- *     [ "a" ].concat( ["b"], ["c", "d"]) #=> [ "a", "b", "c", "d" ]
- *     [ "a" ].concat #=> [ "a" ]
+ *  Adds to +self+ all elements from each array in +other_arrays+; returns +self+:
  *
- *     a = [ 1, 2, 3 ]
- *     a.concat( [ 4, 5 ])
- *     a                                 #=> [ 1, 2, 3, 4, 5 ]
+ *    a = [0, 1]
+ *    a.concat(['two', 'three'], [:four, :five], a)
+ *    # => [0, 1, "two", "three", :four, :five, 0, 1]
  *
- *     a = [ 1, 2 ]
- *     a.concat(a, a)                    #=> [1, 2, 1, 2, 1, 2]
- *
- *  See also Array#+.
+ *  Related: see {Methods for Assigning}[rdoc-ref:Array@Methods+for+Assigning].
  */
 
 static VALUE
@@ -3999,15 +5169,15 @@ 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);
@@ -4022,18 +5192,19 @@ rb_ary_concat(VALUE x, VALUE y)
 
 /*
  *  call-seq:
- *     ary * int     -> new_ary
- *     ary * str     -> new_string
+ *    self * n -> new_array
+ *    self * string_separator -> new_string
  *
- *  Repetition --- With a String argument, equivalent to
- *  <code>ary.join(str)</code>.
+ *  When non-negative integer argument +n+ is given,
+ *  returns a new array built by concatenating +n+ copies of +self+:
  *
- *  Otherwise, returns a new array built by concatenating the +int+ copies of
- *  +self+.
+ *    a = ['x', 'y']
+ *    a * 3 # => ["x", "y", "x", "y", "x", "y"]
  *
+ *  When string argument +string_separator+ is given,
+ *  equivalent to <tt>self.join(string_separator)</tt>:
  *
- *     [ 1, 2, 3 ] * 3    #=> [ 1, 2, 3, 1, 2, 3, 1, 2, 3 ]
- *     [ 1, 2, 3 ] * ","  #=> "1,2,3"
+ *    [0, [0, 1], {foo: 0}] * ', ' # => "0, 0, 1, {foo: 0}"
  *
  */
 
@@ -4046,61 +5217,55 @@ 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_obj_class(ary), 0);
-	goto out;
+        ary2 = ary_new(rb_cArray, 0);
+        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_obj_class(ary), len);
+    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:
-    OBJ_INFECT(ary2, ary);
-
     return ary2;
 }
 
 /*
  *  call-seq:
- *     ary.assoc(obj)   -> element_ary  or  nil
+ *    assoc(object) -> found_array or nil
  *
- *  Searches through an array whose elements are also arrays comparing +obj+
- *  with the first element of each contained array using <code>obj.==</code>.
+ *  Returns the first element +ele+ in +self+ such that +ele+ is an array
+ *  and <tt>ele[0] == object</tt>:
  *
- *  Returns the first contained array that matches (that is, the first
- *  associated array), or +nil+ if no match is found.
+ *    a = [{foo: 0}, [2, 4], [4, 5, 6], [4, 5]]
+ *    a.assoc(4) # => [4, 5, 6]
  *
- *  See also Array#rassoc
+ *  Returns +nil+ if no such element is found.
  *
- *     s1 = [ "colors", "red", "blue", "green" ]
- *     s2 = [ "letters", "a", "b", "c" ]
- *     s3 = "foo"
- *     a  = [ s1, s2, s3 ]
- *     a.assoc("letters")  #=> [ "letters", "a", "b", "c" ]
- *     a.assoc("foo")      #=> nil
+ *  Related: Array#rassoc;
+ *  see also {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 VALUE
@@ -4110,30 +5275,29 @@ 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:
- *     ary.rassoc(obj) -> element_ary or nil
- *
- *  Searches through the array whose elements are also arrays.
+ *    rassoc(object) -> found_array or nil
  *
- *  Compares +obj+ with the second element of each contained array using
- *  <code>obj.==</code>.
+ *  Returns the first element +ele+ in +self+ such that +ele+ is an array
+ *  and <tt>ele[1] == object</tt>:
  *
- *  Returns the first contained array that matches +obj+.
+ *    a = [{foo: 0}, [2, 4], [4, 5, 6], [4, 5]]
+ *    a.rassoc(4) # => [2, 4]
+ *    a.rassoc(5) # => [4, 5, 6]
  *
- *  See also Array#assoc.
+ *  Returns +nil+ if no such element is found.
  *
- *     a = [ [ 1, "one"], [2, "two"], [3, "three"], ["ii", "two"] ]
- *     a.rassoc("two")    #=> [2, "two"]
- *     a.rassoc("four")   #=> nil
+ *  Related: Array#assoc;
+ *  see also {Methods for Fetching}[rdoc-ref:Array@Methods+for+Fetching].
  */
 
 VALUE
@@ -4143,11 +5307,11 @@ 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;
 }
@@ -4166,38 +5330,48 @@ 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:
- *     ary == other_ary   ->   bool
+ *    self == other_array -> true or false
  *
- *  Equality --- Two arrays are equal if they contain the same number of
- *  elements and if each element is equal to (according to Object#==) the
- *  corresponding element in +other_ary+.
+ *  Returns whether both:
  *
- *     [ "a", "c" ]    == [ "a", "c", 7 ]     #=> false
- *     [ "a", "c", 7 ] == [ "a", "c", 7 ]     #=> true
- *     [ "a", "c", 7 ] == [ "a", "d", "f" ]   #=> 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
@@ -4205,13 +5379,13 @@ 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);
 }
 
@@ -4222,18 +5396,29 @@ 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:
- *     ary.eql?(other)  -> 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>:
+ *
+ *    a0 = [:foo, 'bar', 2]
+ *    a1 = [:foo, 'bar', 2]
+ *    a1.eql?(a0) # => true
  *
- *  Returns +true+ if +self+ and +other+ are the same object,
- *  or are both arrays with the same content (according to Object#eql?).
+ *  Otherwise, returns +false+.
+ *
+ *  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
@@ -4242,49 +5427,71 @@ 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);
 }
 
+static VALUE
+ary_hash_values(long len, const VALUE *elements, const VALUE ary)
+{
+    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));
+        if (ary) {
+            len = RARRAY_LEN(ary);
+            elements = RARRAY_CONST_PTR(ary);
+        }
+    }
+    h = rb_hash_end(h);
+    return ST2FIX(h);
+}
+
+VALUE
+rb_ary_hash_values(long len, const VALUE *elements)
+{
+    return ary_hash_values(len, elements, 0);
+}
+
 /*
  *  call-seq:
- *     ary.hash   -> integer
+ *    hash -> integer
  *
- *  Compute a hash-code for this array.
+ *  Returns the integer hash value for +self+.
  *
- *  Two arrays with the same content will have the same hash code (and will
- *  compare using #eql?).
+ *  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
  *
- *  See also Object#hash.
  */
 
 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);
+    RBIMPL_ASSERT_OR_ASSUME(ary);
+    return ary_hash_values(RARRAY_LEN(ary), RARRAY_CONST_PTR(ary), ary);
 }
 
 /*
  *  call-seq:
- *     ary.include?(object)   -> true or false
+ *    include?(object) -> true or false
+ *
+ *  Returns whether for some element +element+ in +self+,
+ *  <tt>object == element</tt>:
  *
- *  Returns +true+ if the given +object+ is present in +self+ (that is, if any
- *  element <code>==</code> +object+), otherwise returns +false+.
+ *    [0, 1, 2].include?(2)   # => true
+ *    [0, 1, 2].include?(2.0) # => true
+ *    [0, 1, 2].include?(2.1) # => false
  *
- *     a = [ "a", "b", "c" ]
- *     a.include?("b")   #=> true
- *     a.include?("z")   #=> false
+ *  Related: see {Methods for Querying}[rdoc-ref:Array@Methods+for+Querying].
  */
 
 VALUE
@@ -4294,10 +5501,10 @@ 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;
 }
@@ -4309,10 +5516,10 @@ 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;
 }
@@ -4325,46 +5532,54 @@ 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:
- *     ary <=> other_ary   ->  -1, 0, +1 or nil
+ *    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
  *
- *  Comparison --- Returns an integer (+-1+, +0+, or <code>+1</code>) if this
- *  array is less than, equal to, or greater than +other_ary+.
+ *  - Immediately returns -1 if <tt>result[i]</tt> is -1:
  *
- *  Each object in each array is compared (using the <=> operator).
+ *      [0, 1, 2] <=> [0, 2, 2] # => -1
  *
- *  Arrays are compared in an "element-wise" manner; the first element of +ary+
- *  is compared with the first one of +other_ary+ using the <=> operator, then
- *  each of the second elements, etc...
- *  As soon as the result of any such comparison is non zero (i.e. the two
- *  corresponding elements are not equal), that result is returned for the
- *  whole array comparison.
+ *  - Continues if <tt>result[i]</tt> is 0.
  *
- *  If all the elements are equal, then the result is based on a comparison of
- *  the array lengths. Thus, two arrays are "equal" according to Array#<=> if,
- *  and only if, they have the same length and the value of each element is
- *  equal to the value of the corresponding element in the other array.
+ *  When every +result+ is 0,
+ *  returns <tt>self.size <=> other_array.size</tt>
+ *  (see Integer#<=>):
  *
- *  +nil+ is returned if the +other_ary+ is not an array or if the comparison
- *  of two elements returned +nil+.
+ *    [0, 1, 2] <=> [0, 1]        # => 1
+ *    [0, 1, 2] <=> [0, 1, 2]     # => 0
+ *    [0, 1, 2] <=> [0, 1, 2, 3]  # => -1
  *
- *     [ "a", "a", "c" ]    <=> [ "a", "b", "c" ]   #=> -1
- *     [ 1, 2, 3, 4, 5, 6 ] <=> [ 1, 2 ]            #=> +1
- *     [ 1, 2 ]             <=> [ 1, :two ]         #=> nil
+ *  Note that when +other_array+ is larger than +self+,
+ *  its trailing elements do not affect the result:
  *
+ *    [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
@@ -4377,7 +5592,7 @@ 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);
@@ -4390,8 +5605,8 @@ 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;
 }
@@ -4419,8 +5634,8 @@ 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;
 }
@@ -4432,37 +5647,25 @@ 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_TABLE_P(hash)) {
-        st_table *tbl = RHASH_ST_TABLE(hash);
-	st_free_table(tbl);
-        RHASH_CLEAR(hash);
-    }
-}
-
 /*
  *  call-seq:
- *     ary - other_ary    -> new_ary
- *
- *  Array Difference
+ *    self - other_array -> new_array
  *
- *  Returns a new array that is a copy of the original array, removing any
- *  items that also appear in +other_ary+. The order is preserved from the
- *  original array.
+ *  Returns a new array containing only those elements of +self+
+ *  that are not found in +other_array+;
+ *  the order from +self+ is preserved:
  *
- *  It compares elements using their #hash and #eql? methods for efficiency.
+ *    [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]
  *
- *     [ 1, 1, 2, 2, 3, 3, 4, 5 ] - [ 1, 2, 4 ]  #=>  [ 3, 3, 5 ]
+ *  Element are compared using method <tt>#eql?</tt>
+ *  (as defined in each element of +self+).
  *
- *  If you need set-like behavior, see the library class Set.
- *
- *  See also Array#difference.
+ *  Related: see {Methods for Combining}[rdoc-ref:Array@Methods+for+Combining].
  */
 
-static VALUE
+VALUE
 rb_ary_diff(VALUE ary1, VALUE ary2)
 {
     VALUE ary3;
@@ -4470,44 +5673,44 @@ rb_ary_diff(VALUE ary1, VALUE ary2)
     long i;
 
     ary2 = to_ary(ary2);
+    if (RARRAY_LEN(ary2) == 0) { return ary_make_shared_copy(ary1); }
     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:
- *     ary.difference(other_ary1, other_ary2, ...)   -> ary
- *
- *  Array Difference
+ *    difference(*other_arrays = []) -> new_array
  *
- *  Returns a new array that is a copy of the receiver, removing any items
- *  that also appear in any of the arrays given as arguments.
- *  The order is preserved from the original array.
+ *  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:
  *
- *  It compares elements using their #hash and #eql? methods for efficiency.
+ *    [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].difference                        # => [0, 1, 2]
  *
- *     [ 1, 1, 2, 2, 3, 3, 4, 5 ].difference([ 1, 2, 4 ])     #=> [ 3, 3, 5 ]
- *     [ 1, 'c', :s, 'yep' ].difference([ 1 ], [ 'a', 'c' ])  #=> [ :s, "yep" ]
+ *  Returns a copy of +self+ if no arguments are given.
  *
- *  If you need set-like behavior, see the library class Set.
- *
- *  See also Array#-.
+ *  Related: Array#-;
+ *  see also {Methods for Combining}[rdoc-ref:Array@Methods+for+Combining].
  */
 
 static VALUE
@@ -4529,9 +5732,9 @@ rb_ary_difference_multi(int argc, VALUE *argv, VALUE ary)
     for (i = 0; i < RARRAY_LEN(ary); i++) {
         int j;
         VALUE elt = rb_ary_elt(ary, i);
-        for (j = 0; j < argc; j++){
+        for (j = 0; j < argc; j++) {
             if (is_hash[j]) {
-                if (rb_hash_stlike_lookup(argv[j], RARRAY_AREF(ary, i), NULL))
+                if (rb_hash_stlike_lookup(argv[j], elt, NULL))
                     break;
             }
             else {
@@ -4549,17 +5752,25 @@ rb_ary_difference_multi(int argc, VALUE *argv, VALUE ary)
 
 /*
  *  call-seq:
- *     ary & other_ary      -> new_ary
+ *    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+:
+ *
+ *    [0, 1, 2, 3] & [1, 2] # => [1, 2]
+ *
+ *  Omits duplicates:
  *
- *  Set Intersection --- Returns a new array containing unique elements common to the
- *  two arrays. The order is preserved from the original array.
+ *    [0, 1, 1, 0] & [0, 1] # => [0, 1]
  *
- *  It compares elements using their #hash and #eql? methods for efficiency.
+ *  Preserves order from +self+:
  *
- *     [ 1, 1, 3, 5 ] & [ 3, 2, 1 ]                 #=> [ 1, 3 ]
- *     [ 'a', 'b', 'b', 'z' ] & [ 'a', 'b', 'c' ]   #=> [ 'a', 'b' ]
+ *    [0, 1, 2] & [3, 2, 1, 0] # => [0, 1, 2]
  *
- *  See also Array#uniq.
+ *  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].
  */
 
 
@@ -4575,29 +5786,62 @@ 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:
+ *    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:
+ *
+ *    [0, 0, 1, 1, 2, 3].intersection([0, 1, 2], [0, 1, 3]) # => [0, 1]
+ *
+ *  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 are given.
+ *
+ *  Related: see {Methods for Combining}[rdoc-ref:Array@Methods+for+Combining].
+ */
+
+static VALUE
+rb_ary_intersection_multi(int argc, VALUE *argv, VALUE ary)
+{
+    VALUE result = rb_ary_dup(ary);
+    int i;
+
+    for (i = 0; i < argc; i++) {
+        result = rb_ary_and(result, argv[i]);
+    }
+
+    return result;
+}
+
 static int
 ary_hash_orset(st_data_t *key, st_data_t *value, st_data_t arg, int existing)
 {
@@ -4631,54 +5875,59 @@ rb_ary_union_hash(VALUE hash, VALUE ary2)
 
 /*
  *  call-seq:
- *     ary | other_ary     -> new_ary
- *
- *  Set Union --- Returns a new array by joining +ary+ with +other_ary+,
- *  excluding any duplicates and preserving the order from the given arrays.
+ *    self | other_array -> new_array
  *
- *  It compares elements using their #hash and #eql? methods for efficiency.
+ *  Returns the union of +self+ and +other_array+;
+ *  duplicates are removed; order is preserved;
+ *  items are compared using <tt>eql?</tt>:
  *
- *     [ "a", "b", "c" ] | [ "c", "d", "a" ]    #=> [ "a", "b", "c", "d" ]
- *     [ "c", "d", "a" ] | [ "a", "b", "c" ]    #=> [ "c", "d", "a", "b" ]
+ *    [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]
  *
- *  See also 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:
- *     ary.union(other_ary1, other_ary2, ...)   -> ary
+ *    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>:
  *
- *  Set Union --- Returns a new array by joining <code>other_ary</code>s with +self+,
- *  excluding any duplicates and preserving the order from the given arrays.
+ *    [0, 1, 2, 3].union([4, 5], [6, 7]) # => [0, 1, 2, 3, 4, 5, 6, 7]
  *
- *  It compares elements using their #hash and #eql? methods for efficiency.
+ *  Removes duplicates (preserving the first found):
  *
- *     [ "a", "b", "c" ].union( [ "c", "d", "a" ] )    #=> [ "a", "b", "c", "d" ]
- *     [ "a" ].union( ["e", "b"], ["a", "c", "b"] )    #=> [ "a", "e", "b", "c" ]
- *     [ "a" ].union #=> [ "a" ]
+ *    [0, 1, 1].union([2, 1], [3, 1]) # => [0, 1, 2, 3]
  *
- *  See also Array#|.
+ *  Preserves order (preserving the position of the first found):
+ *
+ *    [3, 2, 1, 0].union([5, 3], [4, 2]) # => [3, 2, 1, 0, 5, 4]
+ *
+ *  With no arguments given, returns a copy of +self+.
+ *
+ *  Related: see {Methods for Combining}[rdoc-ref:Array@Methods+for+Combining].
  */
 
 static VALUE
@@ -4686,16 +5935,16 @@ 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++){
+    for (i = 0; i < argc; i++) {
         argv[i] = to_ary(argv[i]);
         sum += RARRAY_LEN(argv[i]);
     }
 
     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]);
@@ -4706,121 +5955,448 @@ 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:
+ *    intersect?(other_array) -> true or false
+ *
+ *  Returns whether +other_array+ has at least one element that is +#eql?+ to some element of +self+:
+ *
+ *    [1, 2, 3].intersect?([3, 4, 5]) # => true
+ *    [1, 2, 3].intersect?([4, 5, 6]) # => false
+ *
+ *  Each element must correctly implement method <tt>#hash</tt>.
+ *
+ *  Related: see {Methods for Querying}[rdoc-ref:Array@Methods+for+Querying].
+ */
+
+static VALUE
+rb_ary_intersect_p(VALUE ary1, VALUE ary2)
+{
+    VALUE hash, v, result, shorter, longer;
+    st_data_t vv;
+    long i;
+
+    ary2 = to_ary(ary2);
+    if (RARRAY_LEN(ary1) == 0 || RARRAY_LEN(ary2) == 0) return Qfalse;
+
+    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)) return Qtrue;
+        }
+        return Qfalse;
+    }
+
+    shorter = ary1;
+    longer = ary2;
+    if (RARRAY_LEN(ary1) > RARRAY_LEN(ary2)) {
+        longer = ary1;
+        shorter = ary2;
+    }
+
+    hash = ary_make_hash(shorter);
+    result = Qfalse;
+
+    for (i=0; i<RARRAY_LEN(longer); i++) {
+        v = RARRAY_AREF(longer, i);
+        vv = (st_data_t)v;
+        if (rb_hash_stlike_lookup(hash, vv, 0)) {
+            result = Qtrue;
+            break;
+        }
+    }
+
+    return result;
+}
+
+static VALUE
+ary_max_generic(VALUE ary, long i, VALUE vmax)
+{
+    RUBY_ASSERT(i > 0 && i < RARRAY_LEN(ary));
+
+    VALUE v;
+    for (; i < RARRAY_LEN(ary); ++i) {
+        v = RARRAY_AREF(ary, i);
+
+        if (rb_cmpint(rb_funcallv(vmax, id_cmp, 1, &v), vmax, v) < 0) {
+            vmax = v;
+        }
+    }
+
+    return vmax;
+}
+
+static VALUE
+ary_max_opt_fixnum(VALUE ary, long i, VALUE vmax)
+{
+    const long n = RARRAY_LEN(ary);
+    RUBY_ASSERT(i > 0 && i < n);
+    RUBY_ASSERT(FIXNUM_P(vmax));
+
+    VALUE v;
+    for (; i < n; ++i) {
+        v = RARRAY_AREF(ary, i);
+
+        if (FIXNUM_P(v)) {
+            if ((long)vmax < (long)v) {
+                vmax = v;
+            }
+        }
+        else {
+            return ary_max_generic(ary, i, vmax);
+        }
+    }
+
+    return vmax;
+}
+
+static VALUE
+ary_max_opt_float(VALUE ary, long i, VALUE vmax)
+{
+    const long n = RARRAY_LEN(ary);
+    RUBY_ASSERT(i > 0 && i < n);
+    RUBY_ASSERT(RB_FLOAT_TYPE_P(vmax));
+
+    VALUE v;
+    for (; i < n; ++i) {
+        v = RARRAY_AREF(ary, i);
+
+        if (RB_FLOAT_TYPE_P(v)) {
+            if (rb_float_cmp(vmax, v) < 0) {
+                vmax = v;
+            }
+        }
+        else {
+            return ary_max_generic(ary, i, vmax);
+        }
+    }
+
+    return vmax;
+}
+
+static VALUE
+ary_max_opt_string(VALUE ary, long i, VALUE vmax)
+{
+    const long n = RARRAY_LEN(ary);
+    RUBY_ASSERT(i > 0 && i < n);
+    RUBY_ASSERT(STRING_P(vmax));
+
+    VALUE v;
+    for (; i < n; ++i) {
+        v = RARRAY_AREF(ary, i);
+
+        if (STRING_P(v)) {
+            if (rb_str_cmp(vmax, v) < 0) {
+                vmax = v;
+            }
+        }
+        else {
+            return ary_max_generic(ary, i, vmax);
+        }
+    }
+
+    return vmax;
 }
 
 /*
  *  call-seq:
- *     ary.max                     -> obj
- *     ary.max {|a, b| block}      -> obj
- *     ary.max(n)                  -> array
- *     ary.max(n) {|a, b| block}   -> array
+ *    max -> element
+ *    max(count) -> new_array
+ *    max {|a, b| ... } -> element
+ *    max(count) {|a, b| ... } -> new_array
  *
- *  Returns the object in _ary_ with the maximum value. The
- *  first form assumes all objects implement <code>Comparable</code>;
- *  the second uses the block to return <em>a <=> b</em>.
+ *  Returns one of the following:
  *
- *     ary = %w(albatross dog horse)
- *     ary.max                                   #=> "horse"
- *     ary.max {|a, b| a.length <=> b.length}    #=> "albatross"
+ *  - The maximum-valued element from +self+.
+ *  - A new array of maximum-valued elements from +self+.
  *
- *  If the +n+ argument is given, maximum +n+ elements are returned
- *  as an array.
+ *  Does not modify +self+.
  *
- *     ary = %w[albatross dog horse]
- *     ary.max(2)                                  #=> ["horse", "dog"]
- *     ary.max(2) {|a, b| a.length <=> b.length }  #=> ["albatross", "horse"]
+ *  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>:
+ *
+ *    [1, 0, 3, 2].max # => 3
+ *
+ *  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>:
+ *
+ *    [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 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', '', '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;
 
-    rb_scan_args(argc, argv, "01", &num);
-
-    if (!NIL_P(num))
+    if (rb_check_arity(argc, 0, 1) && !NIL_P(num = argv[0]))
        return rb_nmin_run(ary, num, 0, 1, 1);
 
+    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 {
-	for (i = 0; i < RARRAY_LEN(ary); i++) {
-	   v = RARRAY_AREF(ary, i);
-	   if (result == Qundef || OPTIMIZED_CMP(v, result, cmp_opt) > 0) {
-	       result = v;
-	   }
-	}
-    }
-    if (result == Qundef) return Qnil;
+    else if (n > 0) {
+        result = RARRAY_AREF(ary, 0);
+        if (n > 1) {
+            if (FIXNUM_P(result) && CMP_OPTIMIZABLE(INTEGER)) {
+                return ary_max_opt_fixnum(ary, 1, result);
+            }
+            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(FLOAT)) {
+                return ary_max_opt_float(ary, 1, result);
+            }
+            else {
+                return ary_max_generic(ary, 1, result);
+            }
+        }
+    }
+    if (UNDEF_P(result)) return Qnil;
     return result;
 }
 
+static VALUE
+ary_min_generic(VALUE ary, long i, VALUE vmin)
+{
+    RUBY_ASSERT(i > 0 && i < RARRAY_LEN(ary));
+
+    VALUE v;
+    for (; i < RARRAY_LEN(ary); ++i) {
+        v = RARRAY_AREF(ary, i);
+
+        if (rb_cmpint(rb_funcallv(vmin, id_cmp, 1, &v), vmin, v) > 0) {
+            vmin = v;
+        }
+    }
+
+    return vmin;
+}
+
+static VALUE
+ary_min_opt_fixnum(VALUE ary, long i, VALUE vmin)
+{
+    const long n = RARRAY_LEN(ary);
+    RUBY_ASSERT(i > 0 && i < n);
+    RUBY_ASSERT(FIXNUM_P(vmin));
+
+    VALUE a;
+    for (; i < n; ++i) {
+        a = RARRAY_AREF(ary, i);
+
+        if (FIXNUM_P(a)) {
+            if ((long)vmin > (long)a) {
+                vmin = a;
+            }
+        }
+        else {
+            return ary_min_generic(ary, i, vmin);
+        }
+    }
+
+    return vmin;
+}
+
+static VALUE
+ary_min_opt_float(VALUE ary, long i, VALUE vmin)
+{
+    const long n = RARRAY_LEN(ary);
+    RUBY_ASSERT(i > 0 && i < n);
+    RUBY_ASSERT(RB_FLOAT_TYPE_P(vmin));
+
+    VALUE a;
+    for (; i < n; ++i) {
+        a = RARRAY_AREF(ary, i);
+
+        if (RB_FLOAT_TYPE_P(a)) {
+            if (rb_float_cmp(vmin, a) > 0) {
+                vmin = a;
+            }
+        }
+        else {
+            return ary_min_generic(ary, i, vmin);
+        }
+    }
+
+    return vmin;
+}
+
+static VALUE
+ary_min_opt_string(VALUE ary, long i, VALUE vmin)
+{
+    const long n = RARRAY_LEN(ary);
+    RUBY_ASSERT(i > 0 && i < n);
+    RUBY_ASSERT(STRING_P(vmin));
+
+    VALUE a;
+    for (; i < n; ++i) {
+        a = RARRAY_AREF(ary, i);
+
+        if (STRING_P(a)) {
+            if (rb_str_cmp(vmin, a) > 0) {
+                vmin = a;
+            }
+        }
+        else {
+            return ary_min_generic(ary, i, vmin);
+        }
+    }
+
+    return vmin;
+}
+
 /*
  *  call-seq:
- *     ary.min                     -> obj
- *     ary.min {| a,b | block }    -> obj
- *     ary.min(n)                  -> array
- *     ary.min(n) {| a,b | block } -> 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 from +self+.
+ *
+ *  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 minimum value per method <tt>#<=></tt>:
+ *
+ *    [1, 0, 3, 2].min # => 0
+ *
+ *  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>:
+ *
+ *    [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.
  *
- *  Returns the object in _ary_ with the minimum value. The
- *  first form assumes all objects implement <code>Comparable</code>;
- *  the second uses the block to return <em>a <=> b</em>.
+ *  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:
  *
- *     ary = %w(albatross dog horse)
- *     ary.min                                   #=> "albatross"
- *     ary.min {|a, b| a.length <=> b.length}    #=> "dog"
+ *    ['0', '', '000', '00'].min {|a, b| a.size <=> b.size }
+ *    # => ""
  *
- *  If the +n+ argument is given, minimum +n+ elements are returned
- *  as an array.
+ *  With non-negative numeric argument +count+ and a block,
+ *  returns a new array with at most +count+ elements,
+ *  in ascending order, per the block:
  *
- *     ary = %w[albatross dog horse]
- *     ary.min(2)                                  #=> ["albatross", "dog"]
- *     ary.min(2) {|a, b| a.length <=> b.length }  #=> ["dog", "horse"]
+ *    ['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;
 
-    rb_scan_args(argc, argv, "01", &num);
-
-    if (!NIL_P(num))
+    if (rb_check_arity(argc, 0, 1) && !NIL_P(num = argv[0]))
        return rb_nmin_run(ary, num, 0, 0, 1);
 
+    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 {
-	for (i = 0; i < RARRAY_LEN(ary); i++) {
-	   v = RARRAY_AREF(ary, i);
-	   if (result == Qundef || OPTIMIZED_CMP(v, result, cmp_opt) < 0) {
-	       result = v;
-	   }
-	}
-    }
-    if (result == Qundef) return Qnil;
+    else if (n > 0) {
+        result = RARRAY_AREF(ary, 0);
+        if (n > 1) {
+            if (FIXNUM_P(result) && CMP_OPTIMIZABLE(INTEGER)) {
+                return ary_min_opt_fixnum(ary, 1, result);
+            }
+            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(FLOAT)) {
+                return ary_min_opt_float(ary, 1, result);
+            }
+            else {
+                return ary_min_generic(ary, 1, result);
+            }
+        }
+    }
+    if (UNDEF_P(result)) return Qnil;
     return result;
 }
 
+/*
+ *  call-seq:
+ *    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)
+{
+    if (rb_block_given_p()) {
+        return rb_call_super(0, NULL);
+    }
+    return rb_assoc_new(rb_ary_min(0, 0, ary), rb_ary_max(0, 0, ary));
+}
+
 static int
 push_value(st_data_t key, st_data_t val, st_data_t ary)
 {
@@ -4830,31 +6406,31 @@ push_value(st_data_t key, st_data_t val, st_data_t ary)
 
 /*
  *  call-seq:
- *     ary.uniq!                -> ary or nil
- *     ary.uniq! {|item| ...}   -> ary or nil
+ *    uniq! -> self or nil
+ *    uniq! {|element| ... } -> self or nil
  *
- *  Removes duplicate elements from +self+.
+ *  Removes duplicate elements from +self+, the first occurrence always being retained;
+ *  returns +self+ if any elements removed, +nil+ otherwise.
  *
- *  If a block is given, it will use the return value of the block for
- *  comparison.
+ *  With no block given, identifies and removes elements using method <tt>eql?</tt>
+ *  to compare elements:
  *
- *  It compares values using their #hash and #eql? methods for efficiency.
+ *    a = [0, 0, 1, 1, 2, 2]
+ *    a.uniq! # => [0, 1, 2]
+ *    a.uniq! # => nil
  *
- *  +self+ is traversed in order, and the first occurrence is kept.
+ *  With a block given, calls the block for each element;
+ *  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 +nil+ if no changes are made (that is, no duplicates are found).
- *
- *     a = [ "a", "a", "b", "b", "c" ]
- *     a.uniq!   # => ["a", "b", "c"]
- *
- *     b = [ "a", "b", "c" ]
- *     b.uniq!   # => nil
- *
- *     c = [["student","sam"], ["student","george"], ["teacher","matz"]]
- *     c.uniq! {|s| s.first}   # => [["student", "sam"], ["teacher", "matz"]]
+ *    a = ['a', 'aa', 'aaa', 'b', 'bb', 'bbb']
+ *    a.uniq! {|element| element.size } # => ["a", "aa", "aaa"]
+ *    a.uniq! {|element| element.size } # => nil
  *
+ *  Related: see {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
-
 static VALUE
 rb_ary_uniq_bang(VALUE ary)
 {
@@ -4865,46 +6441,50 @@ 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:
- *     ary.uniq                -> new_ary
- *     ary.uniq {|item| ...}   -> new_ary
- *
- *  Returns a new array by removing duplicate values in +self+.
+ *    uniq -> new_array
+ *    uniq {|element| ... } -> new_array
  *
- *  If a block is given, it will use the return value of the block for comparison.
+ *  Returns a new array containing those elements from +self+ that are not duplicates,
+ *  the first occurrence always being retained.
  *
- *  It compares values using their #hash and #eql? methods for efficiency.
+ *  With no block given, identifies and omits duplicate elements using method <tt>eql?</tt>
+ *  to compare elements:
  *
- *  +self+ is traversed in order, and the first occurrence is kept.
+ *    a = [0, 0, 1, 1, 2, 2]
+ *    a.uniq # => [0, 1, 2]
  *
- *     a = [ "a", "a", "b", "b", "c" ]
- *     a.uniq   # => ["a", "b", "c"]
+ *  With a block given, calls the block for each element;
+ *  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:
  *
- *     b = [["student","sam"], ["student","george"], ["teacher","matz"]]
- *     b.uniq {|s| s.first}   # => [["student", "sam"], ["teacher", "matz"]]
+ *    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
@@ -4912,32 +6492,36 @@ rb_ary_uniq(VALUE ary)
 {
     VALUE hash, uniq;
 
-    if (RARRAY_LEN(ary) <= 1)
-        return rb_ary_dup(ary);
-    if (rb_block_given_p()) {
-	hash = ary_make_hash_by(ary);
-	uniq = rb_hash_values(hash);
+    if (RARRAY_LEN(ary) <= 1) {
+        hash = 0;
+        uniq = rb_ary_dup(ary);
+    }
+    else if (rb_block_given_p()) {
+        hash = ary_make_hash_by(ary);
+        uniq = rb_hash_values(hash);
     }
     else {
-	hash = ary_make_hash(ary);
-	uniq = rb_hash_values(hash);
+        hash = ary_make_hash(ary);
+        uniq = rb_hash_values(hash);
     }
-    RBASIC_SET_CLASS(uniq, rb_obj_class(ary));
-    ary_recycle_hash(hash);
 
     return uniq;
 }
 
 /*
  *  call-seq:
- *     ary.compact!    -> ary  or  nil
+ *    compact! -> self or nil
  *
- *  Removes +nil+ elements from the array.
+ *  Removes all +nil+ elements from +self+;
+ *  Returns +self+ if any elements are removed, +nil+ otherwise:
  *
- *  Returns +nil+ if no changes were made, otherwise returns the array.
+ *    a = [nil, 0, nil, false, nil, '', nil, [], nil, {}]
+ *    a.compact! # => [0, false, "", [], {}]
+ *    a          # => [0, false, "", [], {}]
+ *    a.compact! # => nil
  *
- *     [ "a", nil, "b", nil, "c" ].compact! #=> [ "a", "b", "c" ]
- *     [ "a", "b", "c" ].compact!           #=> nil
+ *  Related: Array#compact;
+ *  see also {Methods for Deleting}[rdoc-ref:Array@Methods+for+Deleting].
  */
 
 static VALUE
@@ -4947,16 +6531,16 @@ 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);
 
@@ -4965,12 +6549,16 @@ rb_ary_compact_bang(VALUE ary)
 
 /*
  *  call-seq:
- *     ary.compact     -> new_ary
+ *    compact -> new_array
  *
- *  Returns a copy of +self+ with all +nil+ elements removed.
+ *  Returns a new array containing only the non-+nil+ elements from +self+;
+ *  element order is preserved:
  *
- *     [ "a", nil, "b", nil, "c", nil ].compact
- *                       #=> [ "a", "b", "c" ]
+ *    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
@@ -4983,23 +6571,29 @@ rb_ary_compact(VALUE ary)
 
 /*
  *  call-seq:
- *     ary.count                   -> int
- *     ary.count(obj)              -> int
- *     ary.count {|item| block}    -> int
+ *    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, :one, 'two', 3, 3.0].count # => 5
  *
- *  Returns the number of elements.
+ *  With argument +object+ given, returns the count of elements <tt>==</tt> to +object+:
  *
- *  If an argument is given, counts the number of elements which equal +obj+
- *  using <code>==</code>.
+ *    [0, :one, 'two', 3, 3.0].count(3) # => 2
  *
- *  If a block is given, counts the number of elements for which the block
- *  returns a true value.
+ *  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:
  *
- *     ary = [1, 2, 4, 2]
- *     ary.count                  #=> 4
- *     ary.count(2)               #=> 2
- *     ary.count {|x| x%2 == 0}   #=> 3
+ *    [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
@@ -5007,108 +6601,149 @@ rb_ary_count(int argc, VALUE *argv, VALUE ary)
 {
     long i, n = 0;
 
-    if (argc == 0) {
-	VALUE v;
+    if (rb_check_arity(argc, 0, 1) == 0) {
+        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;
+        VALUE obj = argv[0];
 
-	rb_scan_args(argc, argv, "1", &obj);
-	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);
 }
 
 static VALUE
-flatten(VALUE ary, int level, int *modified)
+flatten(VALUE ary, int level)
 {
-    long i = 0;
-    VALUE stack, result, tmp, elt;
-    st_table *memo;
-    st_data_t id;
+    long i;
+    VALUE stack, result, tmp = 0, elt;
+    VALUE memo = Qfalse;
+
+    for (i = 0; i < RARRAY_LEN(ary); i++) {
+        elt = RARRAY_AREF(ary, i);
+        tmp = rb_check_array_type(elt);
+        if (!NIL_P(tmp)) {
+            break;
+        }
+    }
+    if (i == RARRAY_LEN(ary)) {
+        return ary;
+    }
 
-    stack = ary_new(0, ARY_DEFAULT_SIZE);
     result = ary_new(0, RARRAY_LEN(ary));
-    memo = st_init_numtable();
-    st_insert(memo, (st_data_t)ary, (st_data_t)Qtrue);
-    *modified = 0;
+    ary_memcpy(result, 0, i, RARRAY_CONST_PTR(ary));
+    ARY_SET_LEN(result, i);
+
+    stack = ary_new(0, ARY_DEFAULT_SIZE);
+    rb_ary_push(stack, ary);
+    rb_ary_push(stack, LONG2NUM(i + 1));
+
+    if (level < 0) {
+        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) {
-		rb_raise(rb_eRuntimeError, "flatten reentered");
-	    }
-	    if (NIL_P(tmp)) {
-		rb_ary_push(result, elt);
-	    }
-	    else {
-		*modified = 1;
-		id = (st_data_t)tmp;
-		if (st_lookup(memo, id, 0)) {
-		    st_free_table(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;
-	}
-	id = (st_data_t)ary;
-	st_delete(memo, &id, 0);
-	tmp = rb_ary_pop(stack);
-	i = NUM2LONG(tmp);
-	ary = rb_ary_pop(stack);
-    }
-
-    st_free_table(memo);
-
-    RBASIC_SET_CLASS(result, rb_obj_class(ary));
+        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) {
+        rb_hash_clear(memo);
+    }
+
+    RBASIC_SET_CLASS(result, rb_cArray);
     return result;
 }
 
 /*
  *  call-seq:
- *     ary.flatten!        -> ary or nil
- *     ary.flatten!(level) -> ary or 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+).
  *
- *  Flattens +self+ in place.
+ *  Returns +nil+ if no elements were flattened.
  *
- *  Returns +nil+ if no modifications were made (i.e., the array contains no
- *  subarrays.)
+ *  With non-negative integer argument +depth+, flattens recursively through +depth+ levels:
  *
- *  The optional +level+ argument determines the level of recursion to flatten.
+ *    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}>]
  *
- *     a = [ 1, 2, [3, [4, 5] ] ]
- *     a.flatten!   #=> [1, 2, 3, 4, 5]
- *     a.flatten!   #=> nil
- *     a            #=> [1, 2, 3, 4, 5]
- *     a = [ 1, 2, [3, [4, 5] ] ]
- *     a.flatten!(1) #=> [1, 2, 3, [4, 5]]
+ *  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
@@ -5117,17 +6752,16 @@ rb_ary_flatten_bang(int argc, VALUE *argv, VALUE ary)
     int mod = 0, level = -1;
     VALUE result, lv;
 
-    rb_scan_args(argc, argv, "01", &lv);
+    lv = (rb_check_arity(argc, 0, 1) ? argv[0] : Qnil);
     rb_ary_modify_check(ary);
     if (!NIL_P(lv)) level = NUM2INT(lv);
     if (level == 0) return Qnil;
 
-    result = flatten(ary, level, &mod);
-    if (mod == 0) {
-	ary_discard(result);
-	return Qnil;
+    result = flatten(ary, level);
+    if (result == ary) {
+        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);
 
@@ -5136,287 +6770,221 @@ rb_ary_flatten_bang(int argc, VALUE *argv, VALUE ary)
 
 /*
  *  call-seq:
- *     ary.flatten -> new_ary
- *     ary.flatten(level) -> new_ary
+ *    flatten(depth = nil) -> new_array
  *
- *  Returns a new array that is a one-dimensional flattening of +self+
- *  (recursively).
+ *  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:
  *
- *  That is, for every element that is an array, extract its elements into
- *  the new array.
+ *  - 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+).
  *
- *  The optional +level+ argument determines the level of recursion to
- *  flatten.
+ *  With non-negative integer argument +depth+, flattens recursively through +depth+ levels:
  *
- *     s = [ 1, 2, 3 ]           #=> [1, 2, 3]
- *     t = [ 4, 5, 6, [7, 8] ]   #=> [4, 5, 6, [7, 8]]
- *     a = [ s, t, 9, 10 ]       #=> [[1, 2, 3], [4, 5, 6, [7, 8]], 9, 10]
- *     a.flatten                 #=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
- *     a = [ 1, 2, [3, [4, 5] ] ]
- *     a.flatten(1)              #=> [1, 2, 3, [4, 5]]
+ *    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
 rb_ary_flatten(int argc, VALUE *argv, VALUE ary)
 {
-    int mod = 0, level = -1;
-    VALUE result, lv;
+    int level = -1;
+    VALUE result;
 
-    rb_scan_args(argc, argv, "01", &lv);
-    if (!NIL_P(lv)) level = NUM2INT(lv);
-    if (level == 0) return ary_make_shared_copy(ary);
+    if (rb_check_arity(argc, 0, 1) && !NIL_P(argv[0])) {
+        level = NUM2INT(argv[0]);
+        if (level == 0) return ary_make_shared_copy(ary);
+    }
 
-    result = flatten(ary, level, &mod);
-    OBJ_INFECT(result, ary);
+    result = flatten(ary, level);
+    if (result == ary) {
+        result = ary_make_shared_copy(ary);
+    }
 
     return result;
 }
 
-#define OPTHASH_GIVEN_P(opts) \
-    (argc > 0 && !NIL_P((opts) = rb_check_hash_type(argv[argc-1])) && (--argc, 1))
-static ID id_random;
-
 #define RAND_UPTO(max) (long)rb_random_ulong_limited((randgen), (max)-1)
 
-/*
- *  call-seq:
- *     ary.shuffle!              -> ary
- *     ary.shuffle!(random: rng) -> ary
- *
- *  Shuffles elements in +self+ in place.
- *
- *     a = [ 1, 2, 3 ]           #=> [1, 2, 3]
- *     a.shuffle!                #=> [2, 3, 1]
- *     a                         #=> [2, 3, 1]
- *
- *  The optional +rng+ argument will be used as the random number generator.
- *
- *     a.shuffle!(random: Random.new(1))  #=> [1, 3, 2]
- */
-
 static VALUE
-rb_ary_shuffle_bang(int argc, VALUE *argv, VALUE ary)
+rb_ary_shuffle_bang(rb_execution_context_t *ec, VALUE ary, VALUE randgen)
 {
-    VALUE opts, randgen = rb_cRandom;
     long i, len;
 
-    if (OPTHASH_GIVEN_P(opts)) {
-	VALUE rnd;
-	ID keyword_ids[1];
-
-	keyword_ids[0] = id_random;
-	rb_get_kwargs(opts, keyword_ids, 0, 1, &rnd);
-	if (rnd != Qundef) {
-	    randgen = rnd;
-	}
-    }
-    rb_check_arity(argc, 0, 0);
     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 > 1) {
+            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;
 }
 
-
-/*
- *  call-seq:
- *     ary.shuffle              -> new_ary
- *     ary.shuffle(random: rng) -> new_ary
- *
- *  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]
- *
- *  The optional +rng+ argument will be used as the random number generator.
- *
- *     a.shuffle(random: Random.new(1))  #=> [1, 3, 2]
- */
-
 static VALUE
-rb_ary_shuffle(int argc, VALUE *argv, VALUE ary)
+rb_ary_shuffle(rb_execution_context_t *ec, VALUE ary, VALUE randgen)
 {
     ary = rb_ary_dup(ary);
-    rb_ary_shuffle_bang(argc, argv, ary);
+    rb_ary_shuffle_bang(ec, ary, randgen);
     return ary;
 }
 
-
-/*
- *  call-seq:
- *     ary.sample                  -> obj
- *     ary.sample(random: rng)     -> obj
- *     ary.sample(n)               -> new_ary
- *     ary.sample(n, random: rng)  -> new_ary
- *
- *  Choose a random element or +n+ random elements from the array.
- *
- *  The elements are chosen by using random and unique indices into the array
- *  in order to ensure that an element doesn't repeat itself unless the array
- *  already contained duplicate elements.
- *
- *  If the array is empty the first form returns +nil+ and the second form
- *  returns an empty array.
- *
- *     a = [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ]
- *     a.sample         #=> 7
- *     a.sample(4)      #=> [6, 4, 2, 5]
- *
- *  The optional +rng+ argument will be used as the random number generator.
- *
- *     a.sample(random: Random.new(1))     #=> 6
- *     a.sample(4, random: Random.new(1))  #=> [6, 10, 9, 2]
- */
-
+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
-rb_ary_sample(int argc, VALUE *argv, VALUE ary)
+ary_sample(rb_execution_context_t *ec, VALUE ary, VALUE randgen, VALUE nv, VALUE to_array)
 {
-    VALUE nv, result;
-    VALUE opts, randgen = rb_cRandom;
+    VALUE result;
     long n, len, i, j, k, idx[10];
     long rnds[numberof(idx)];
     long memo_threshold;
 
-    if (OPTHASH_GIVEN_P(opts)) {
-	VALUE rnd;
-	ID keyword_ids[1];
-
-	keyword_ids[0] = id_random;
-	rb_get_kwargs(opts, keyword_ids, 0, 1, &rnd);
-	if (rnd != Qundef) {
-	    randgen = rnd;
-	}
-    }
     len = RARRAY_LEN(ary);
-    if (argc == 0) {
-	if (len < 2)
-	    i = 0;
-	else
-	    i = RAND_UPTO(len);
+    if (!to_array) {
+        if (len < 2)
+            i = 0;
+        else
+            i = RAND_UPTO(len);
 
-	return rb_ary_elt(ary, i);
+        return rb_ary_elt(ary, i);
     }
-    rb_scan_args(argc, argv, "1", &nv);
     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_values(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(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(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);
 
@@ -5424,15 +6992,27 @@ rb_ary_sample(int argc, VALUE *argv, VALUE ary)
 }
 
 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);
+}
+
+static VALUE
 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 (n == Qnil) return DBL2NUM(HUGE_VAL);
+    if (NIL_P(n)) return DBL2NUM(HUGE_VAL);
     mul = NUM2LONG(n);
     if (mul <= 0) return INT2FIX(0);
     n = LONG2FIX(mul);
@@ -5441,38 +7021,50 @@ rb_ary_cycle_size(VALUE self, VALUE args, VALUE eobj)
 
 /*
  *  call-seq:
- *     ary.cycle(n=nil) {|obj| block}    -> nil
- *     ary.cycle(n=nil)                  -> 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 +count+ is positive,
+ *  calls the block with each element, then does so repeatedly,
+ *  until it has done so +count+ times; returns +nil+:
  *
- *  Calls the given block for each element +n+ times or forever if +nil+ is
- *  given.
+ *    output = []
+ *    [0, 1].cycle(2) {|element| output.push(element) } # => nil
+ *    output # => [0, 1, 0, 1]
  *
- *  Does nothing if a non-positive number is given or the array is empty.
+ *  When +count+ is zero or negative, does not call the block:
  *
- *  Returns +nil+ if the loop has finished without getting interrupted.
+ *    [0, 1].cycle(0) {|element| fail 'Cannot happen' }  # => nil
+ *    [0, 1].cycle(-1) {|element| fail 'Cannot happen' } # => nil
  *
- *  If no block is given, an Enumerator is returned instead.
+ *  When +count+ is +nil+, cycles forever:
  *
- *     a = ["a", "b", "c"]
- *     a.cycle {|x| puts x}       # print, a, b, c, a, b, c,.. forever.
- *     a.cycle(2) {|x| puts x}    # print, a, b, c, a, b, c.
+ *    # Prints 0 and 1 forever.
+ *    [0, 1].cycle {|element| puts element }
+ *    [0, 1].cycle(nil) {|element| puts element }
  *
+ *  With no block given, returns a new Enumerator.
+ *
+ *  Related: see {Methods for Iterating}[rdoc-ref:Array@Methods+for+Iterating].
  */
-
 static VALUE
 rb_ary_cycle(int argc, VALUE *argv, VALUE ary)
 {
     long n, i;
-    VALUE nv = Qnil;
 
-    rb_scan_args(argc, argv, "01", &nv);
+    rb_check_arity(argc, 0, 1);
 
     RETURN_SIZED_ENUMERATOR(ary, argc, argv, rb_ary_cycle_size);
-    if (NIL_P(nv)) {
+    if (argc == 0 || NIL_P(argv[0])) {
         n = -1;
     }
     else {
-        n = NUM2LONG(nv);
+        n = NUM2LONG(argv[0]);
         if (n <= 0) return Qnil;
     }
 
@@ -5484,9 +7076,6 @@ 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.
@@ -5498,7 +7087,7 @@ yield_indexed_values(const VALUE values, const long r, const long *const p)
     const VALUE result = rb_ary_new2(r);
     long i;
 
-    for (i = 0; i < r; i++) RARRAY_ASET(result, i, RARRAY_AREF(values, p[i]));
+    for (i = 0; i < r; i++) ARY_SET(result, i, RARRAY_AREF(values, p[i]));
     ARY_SET_LEN(result, r);
     rb_yield(result);
     return !RBASIC(values)->klass;
@@ -5522,52 +7111,52 @@ 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;
+        }
     }
 }
 
 /*
  * Returns the product of from, from-1, ..., from - how_many + 1.
- * http://en.wikipedia.org/wiki/Pochhammer_symbol
+ * https://en.wikipedia.org/wiki/Pochhammer_symbol
  */
 static VALUE
 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;
 }
@@ -5578,18 +7167,18 @@ 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;
 }
@@ -5605,66 +7194,80 @@ rb_ary_permutation_size(VALUE ary, VALUE args, VALUE eobj)
 
 /*
  *  call-seq:
- *     ary.permutation {|p| block}            -> ary
- *     ary.permutation                        -> Enumerator
- *     ary.permutation(n) {|p| block}         -> ary
- *     ary.permutation(n)                     -> Enumerator
+ *    permutation(count = self.size) {|permutation| ... } -> self
+ *    permutation(count = self.size) -> new_enumerator
  *
- * When invoked with a block, yield all permutations of length +n+ of the
- * elements of the array, then return the array itself.
+ *  Iterates over permutations of the elements of +self+;
+ *  the order of permutations is indeterminate.
  *
- * If +n+ is not specified, yield all permutations of all elements.
+ *  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+:
  *
author	nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>	2012-05-23 07:13:21 +0000
committer	nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>	2012-05-23 07:13:21 +0000
commit	b0dd250dc95ea0fae89c3201967039d582fbf156 (patch)
tree	fb9483ca974a305e496eb87e960dcfecf7b9115f /include/ruby/ruby.h
parent	87c8c5edf43a7f7d33d5fe75f51ef410a03b93b1 (diff)