Update to ruby/spec@1d9d5c6

51 files changed, 1142 insertions, 259 deletions

diff --git a/spec/ruby/.rubocop.yml b/spec/ruby/.rubocop.yml
index 1200e9d7ce..3a16fc43f8 100644
--- a/spec/ruby/.rubocop.yml
+++ b/spec/ruby/.rubocop.yml
@@ -161,6 +161,9 @@ Lint/Debugger:
 Lint/Loop:
   Enabled: false
 
+Style/BlockComments:
+  Enabled: true
+
 Style/Lambda:
   Enabled: true
   EnforcedStyle: literal
diff --git a/spec/ruby/core/basicobject/instance_eval_spec.rb b/spec/ruby/core/basicobject/instance_eval_spec.rb
index b6a146095d..350b08a30e 100644
--- a/spec/ruby/core/basicobject/instance_eval_spec.rb
+++ b/spec/ruby/core/basicobject/instance_eval_spec.rb
@@ -20,12 +20,18 @@ describe "BasicObject#instance_eval" do
     a.instance_eval('self').equal?(a).should be_true
   end
 
-  it "expects a block with no arguments" do
-    -> { "hola".instance_eval }.should raise_error(ArgumentError)
+  it "raises an ArgumentError when no arguments and no block are given" do
+    -> { "hola".instance_eval }.should raise_error(ArgumentError, "wrong number of arguments (given 0, expected 1..3)")
   end
 
-  it "takes no arguments with a block" do
-    -> { "hola".instance_eval(4, 5) {|a,b| a + b } }.should raise_error(ArgumentError)
+  it "raises an ArgumentError when a block and normal arguments are given" do
+    -> { "hola".instance_eval(4, 5) {|a,b| a + b } }.should raise_error(ArgumentError, "wrong number of arguments (given 2, expected 0)")
+  end
+
+  it "raises an ArgumentError when more than 3 arguments are given" do
+    -> {
+      "hola".instance_eval("1 + 1", "some file", 0, "bogus")
+    }.should raise_error(ArgumentError, "wrong number of arguments (given 4, expected 1..3)")
   end
 
   it "yields the object to the block" do
@@ -185,4 +191,58 @@ end
 
     x.should == :value
   end
+
+  it "converts string argument with #to_str method" do
+    source_code = Object.new
+    def source_code.to_str() "1" end
+
+    a = BasicObject.new
+    a.instance_eval(source_code).should == 1
+  end
+
+  it "raises ArgumentError if returned value is not String" do
+    source_code = Object.new
+    def source_code.to_str() :symbol end
+
+    a = BasicObject.new
+    -> { a.instance_eval(source_code) }.should raise_error(TypeError, /can't convert Object to String/)
+  end
+
+  it "converts filename argument with #to_str method" do
+    filename = Object.new
+    def filename.to_str() "file.rb" end
+
+    err = begin
+            Object.new.instance_eval("raise", filename)
+          rescue => e
+            e
+          end
+    err.backtrace.first.split(":")[0].should == "file.rb"
+  end
+
+  it "raises ArgumentError if returned value is not String" do
+    filename = Object.new
+    def filename.to_str() :symbol end
+
+    -> { Object.new.instance_eval("raise", filename) }.should raise_error(TypeError, /can't convert Object to String/)
+  end
+
+  it "converts lineno argument with #to_int method" do
+    lineno = Object.new
+    def lineno.to_int() 15 end
+
+    err = begin
+            Object.new.instance_eval("raise", "file.rb", lineno)
+          rescue => e
+            e
+          end
+    err.backtrace.first.split(":")[1].should == "15"
+  end
+
+  it "raises ArgumentError if returned value is not Integer" do
+    lineno = Object.new
+    def lineno.to_int() :symbol end
+
+    -> { Object.new.instance_eval("raise", "file.rb", lineno) }.should raise_error(TypeError, /can't convert Object to Integer/)
+  end
 end
diff --git a/spec/ruby/core/enumerable/sum_spec.rb b/spec/ruby/core/enumerable/sum_spec.rb
index 4a978794e5..fc173e4173 100644
--- a/spec/ruby/core/enumerable/sum_spec.rb
+++ b/spec/ruby/core/enumerable/sum_spec.rb
@@ -22,8 +22,21 @@ describe 'Enumerable#sum' do
     @enum.sum.should == 5/3r
   end
 
-  it 'takes a block to transform the elements' do
-    @enum.sum { |element| element * 2 }.should == 10/3r
+  context 'with a block' do
+    it 'transforms the elements' do
+      @enum.sum { |element| element * 2 }.should == 10/3r
+    end
+
+    it 'does not destructure array elements' do
+      class << @enum
+        def each
+          yield [1,2]
+          yield [3]
+        end
+      end
+
+      @enum.sum(&:last).should == 5
+    end
   end
 
   # https://bugs.ruby-lang.org/issues/12217
diff --git a/spec/ruby/core/io/gets_spec.rb b/spec/ruby/core/io/gets_spec.rb
index b9f82f8133..07be99f400 100644
--- a/spec/ruby/core/io/gets_spec.rb
+++ b/spec/ruby/core/io/gets_spec.rb
@@ -213,6 +213,8 @@ describe "IO#gets" do
 
   it "returns empty string when 0 passed as a limit" do
     @io.gets(0).should == ""
+    @io.gets(nil, 0).should == ""
+    @io.gets("", 0).should == ""
   end
 end
 
diff --git a/spec/ruby/core/io/print_spec.rb b/spec/ruby/core/io/print_spec.rb
index 04e971ef6d..085852024c 100644
--- a/spec/ruby/core/io/print_spec.rb
+++ b/spec/ruby/core/io/print_spec.rb
@@ -3,16 +3,27 @@ require_relative 'fixtures/classes'
 
 describe "IO#print" do
   before :each do
-    @old_separator = $\
-    suppress_warning {$\ = '->'}
+    @old_record_separator = $\
+    @old_field_separator = $,
+    suppress_warning {
+      $\ = '->'
+      $, = '^^'
+    }
     @name = tmp("io_print")
   end
 
   after :each do
-    suppress_warning {$\ = @old_separator}
+    suppress_warning {
+      $\ = @old_record_separator
+      $, = @old_field_separator
+    }
     rm_r @name
   end
 
+  it "returns nil" do
+    touch(@name) { |f| f.print.should be_nil }
+  end
+
   it "writes $_.to_s followed by $\\ (if any) to the stream if no arguments given" do
     o = mock('o')
     o.should_receive(:to_s).and_return("mockmockmock")
@@ -38,13 +49,15 @@ describe "IO#print" do
     IO.read(@name).should == "hello#{$\}"
   end
 
-  it "writes each obj.to_s to the stream and appends $\\ (if any) given multiple objects" do
+  it "writes each obj.to_s to the stream separated by $, (if any) and appends $\\ (if any) given multiple objects" do
     o, o2 = Object.new, Object.new
     def o.to_s(); 'o'; end
     def o2.to_s(); 'o2'; end
 
-    touch(@name) { |f| f.print(o, o2) }
-    IO.read(@name).should == "#{o.to_s}#{o2.to_s}#{$\}"
+    suppress_warning {
+      touch(@name) { |f| f.print(o, o2) }
+    }
+    IO.read(@name).should == "#{o.to_s}#{$,}#{o2.to_s}#{$\}"
   end
 
   it "raises IOError on closed stream" do
diff --git a/spec/ruby/core/io/read_nonblock_spec.rb b/spec/ruby/core/io/read_nonblock_spec.rb
index e50531d336..a62b75274c 100644
--- a/spec/ruby/core/io/read_nonblock_spec.rb
+++ b/spec/ruby/core/io/read_nonblock_spec.rb
@@ -55,6 +55,27 @@ describe "IO#read_nonblock" do
     @read.read_nonblock(4).should == "hell"
   end
 
+  it "reads after ungetc with data in the buffer" do
+    @write.write("foobar")
+    @read.set_encoding(
+      'utf-8', universal_newline: false
+    )
+    c = @read.getc
+    @read.ungetc(c)
+    @read.read_nonblock(3).should == "foo"
+    @read.read_nonblock(3).should == "bar"
+  end
+
+  it "raises an exception after ungetc with data in the buffer and character conversion enabled" do
+    @write.write("foobar")
+    @read.set_encoding(
+      'utf-8', universal_newline: true
+    )
+    c = @read.getc
+    @read.ungetc(c)
+    -> { @read.read_nonblock(3).should == "foo" }.should raise_error(IOError)
+  end
+
   it "returns less data if that is all that is available" do
     @write << "hello"
     @read.read_nonblock(10).should == "hello"
@@ -70,6 +91,10 @@ describe "IO#read_nonblock" do
     @read.read_nonblock(1).should == "1"
   end
 
+  it "raises ArgumentError when length is less than 0" do
+    -> { @read.read_nonblock(-1) }.should raise_error(ArgumentError)
+  end
+
   it "reads into the passed buffer" do
     buffer = ""
     @write.write("1")
@@ -84,6 +109,21 @@ describe "IO#read_nonblock" do
     output.should equal(buffer)
   end
 
+  it "discards the existing buffer content upon successful read" do
+    buffer = "existing content"
+    @write.write("hello world")
+    @write.close
+    @read.read_nonblock(11, buffer)
+    buffer.should == "hello world"
+  end
+
+  it "discards the existing buffer content upon error" do
+    buffer = "existing content"
+    @write.close
+    -> { @read.read_nonblock(1, buffer) }.should raise_error(EOFError)
+    buffer.should be_empty
+  end
+
   it "raises IOError on closed stream" do
     -> { IOSpecs.closed_io.read_nonblock(5) }.should raise_error(IOError)
   end
@@ -96,4 +136,13 @@ describe "IO#read_nonblock" do
 
     -> { @read.read_nonblock(5) }.should raise_error(EOFError)
   end
+
+  it "preserves the encoding of the given buffer" do
+    buffer = ''.encode(Encoding::ISO_8859_1)
+    @write.write("abc")
+    @write.close
+    @read.read_nonblock(10, buffer)
+
+    buffer.encoding.should == Encoding::ISO_8859_1
+  end
 end
diff --git a/spec/ruby/core/io/read_spec.rb b/spec/ruby/core/io/read_spec.rb
index 28cab13340..d34f7bd0eb 100644
--- a/spec/ruby/core/io/read_spec.rb
+++ b/spec/ruby/core/io/read_spec.rb
@@ -270,6 +270,13 @@ describe "IO#read" do
     @io.read(nil, buf).should equal buf
   end
 
+  it "returns the given buffer when there is nothing to read" do
+    buf = ""
+
+    @io.read
+    @io.read(nil, buf).should equal buf
+  end
+
   it "coerces the second argument to string and uses it as a buffer" do
     buf = "ABCDE"
     obj = mock("buff")
@@ -312,6 +319,9 @@ describe "IO#read" do
     -> { IOSpecs.closed_io.read }.should raise_error(IOError)
   end
 
+  it "raises ArgumentError when length is less than 0" do
+    -> { @io.read(-1) }.should raise_error(ArgumentError)
+  end
 
   platform_is_not :windows do
     it "raises IOError when stream is closed by another thread" do
diff --git a/spec/ruby/core/io/readchar_spec.rb b/spec/ruby/core/io/readchar_spec.rb
index b5f762a846..a66773851a 100644
--- a/spec/ruby/core/io/readchar_spec.rb
+++ b/spec/ruby/core/io/readchar_spec.rb
@@ -1,6 +1,16 @@
 require_relative '../../spec_helper'
 require_relative 'fixtures/classes'
 
+describe :io_readchar_internal_encoding, shared: true do
+  it "returns a transcoded String" do
+    @io.readchar.should == "あ"
+  end
+
+  it "sets the String encoding to the internal encoding" do
+    @io.readchar.encoding.should equal(Encoding::UTF_8)
+  end
+end
+
 describe "IO#readchar" do
   before :each do
     @io = IOSpecs.io_fixture "lines.txt"
@@ -29,6 +39,62 @@ describe "IO#readchar" do
   end
 end
 
+describe "IO#readchar with internal encoding" do
+  after :each do
+    @io.close if @io
+  end
+
+  describe "not specified" do
+    before :each do
+      @io = IOSpecs.io_fixture "read_euc_jp.txt", "r:euc-jp"
+    end
+
+    it "does not transcode the String" do
+      @io.readchar.should == ("あ").encode(Encoding::EUC_JP)
+    end
+
+    it "sets the String encoding to the external encoding" do
+      @io.readchar.encoding.should equal(Encoding::EUC_JP)
+    end
+  end
+
+  describe "specified by open mode" do
+    before :each do
+      @io = IOSpecs.io_fixture "read_euc_jp.txt", "r:euc-jp:utf-8"
+    end
+
+    it_behaves_like :io_readchar_internal_encoding, nil
+  end
+
+  describe "specified by mode: option" do
+    before :each do
+      @io = IOSpecs.io_fixture "read_euc_jp.txt", mode: "r:euc-jp:utf-8"
+    end
+
+    it_behaves_like :io_readchar_internal_encoding, nil
+  end
+
+  describe "specified by internal_encoding: option" do
+    before :each do
+      options = { mode: "r",
+                  internal_encoding: "utf-8",
+                  external_encoding: "euc-jp" }
+      @io = IOSpecs.io_fixture "read_euc_jp.txt", options
+    end
+
+    it_behaves_like :io_readchar_internal_encoding, nil
+  end
+
+  describe "specified by encoding: option" do
+    before :each do
+      options = { mode: "r", encoding: "euc-jp:utf-8" }
+      @io = IOSpecs.io_fixture "read_euc_jp.txt", options
+    end
+
+    it_behaves_like :io_readchar_internal_encoding, nil
+  end
+end
+
 describe "IO#readchar" do
   before :each do
     @io = IOSpecs.io_fixture "empty.txt"
diff --git a/spec/ruby/core/io/readpartial_spec.rb b/spec/ruby/core/io/readpartial_spec.rb
index 2b33a0d5b1..324ae0b6e6 100644
--- a/spec/ruby/core/io/readpartial_spec.rb
+++ b/spec/ruby/core/io/readpartial_spec.rb
@@ -59,7 +59,7 @@ describe "IO#readpartial" do
   end
 
   it "discards the existing buffer content upon successful read" do
-    buffer = "existing"
+    buffer = "existing content"
     @wr.write("hello world")
     @wr.close
     @rd.readpartial(11, buffer)
@@ -93,4 +93,17 @@ describe "IO#readpartial" do
     @rd.readpartial(0).should == ""
   end
 
+  it "clears and returns the given buffer if the length argument is 0" do
+    buffer = "existing content"
+    @rd.readpartial(0, buffer).should == buffer
+    buffer.should == ""
+  end
+
+  it "preserves the encoding of the given buffer" do
+    buffer = ''.encode(Encoding::ISO_8859_1)
+    @wr.write("abc")
+    @wr.close
+    @rd.readpartial(10, buffer)
+    buffer.encoding.should == Encoding::ISO_8859_1
+  end
 end
diff --git a/spec/ruby/core/io/rewind_spec.rb b/spec/ruby/core/io/rewind_spec.rb
index 649041afaf..5579cbd988 100644
--- a/spec/ruby/core/io/rewind_spec.rb
+++ b/spec/ruby/core/io/rewind_spec.rb
@@ -18,6 +18,17 @@ describe "IO#rewind" do
     @io.readline.should == "Voici la ligne une.\n"
   end
 
+  it "positions the instance to the beginning of output for write-only IO" do
+    name = tmp("io_rewind_spec")
+    io = File.open(name, "w")
+    io.write("Voici la ligne une.\n")
+    io.rewind
+    io.pos.should == 0
+  ensure
+    io.close
+    rm_r name
+  end
+
   it "positions the instance to the beginning of input and clears EOF" do
     value = @io.read
     @io.rewind
@@ -32,6 +43,10 @@ describe "IO#rewind" do
     @io.lineno.should == 0
   end
 
+  it "returns 0" do
+    @io.rewind.should == 0
+  end
+
   it "raises IOError on closed stream" do
     -> { IOSpecs.closed_io.rewind }.should raise_error(IOError)
   end
diff --git a/spec/ruby/core/io/set_encoding_by_bom_spec.rb b/spec/ruby/core/io/set_encoding_by_bom_spec.rb
index b52d3a943a..92433d6640 100644
--- a/spec/ruby/core/io/set_encoding_by_bom_spec.rb
+++ b/spec/ruby/core/io/set_encoding_by_bom_spec.rb
@@ -12,45 +12,232 @@ describe "IO#set_encoding_by_bom" do
     rm_r @name
   end
 
+  it "returns nil if not readable" do
+    not_readable_io = new_io(@name, 'wb')
+
+    not_readable_io.set_encoding_by_bom.should be_nil
+    not_readable_io.external_encoding.should == Encoding::ASCII_8BIT
+  ensure
+    not_readable_io.close
+  end
+
   it "returns the result encoding if found BOM UTF-8 sequence" do
+    File.binwrite(@name, "\u{FEFF}")
+
+    @io.set_encoding_by_bom.should == Encoding::UTF_8
+    @io.external_encoding.should == Encoding::UTF_8
+    @io.read.b.should == "".b
+    @io.rewind
+    @io.set_encoding(Encoding::ASCII_8BIT)
+
     File.binwrite(@name, "\u{FEFF}abc")
 
     @io.set_encoding_by_bom.should == Encoding::UTF_8
     @io.external_encoding.should == Encoding::UTF_8
+    @io.read.b.should == "abc".b
   end
 
   it "returns the result encoding if found BOM UTF_16LE sequence" do
+    File.binwrite(@name, "\xFF\xFE")
+
+    @io.set_encoding_by_bom.should == Encoding::UTF_16LE
+    @io.external_encoding.should == Encoding::UTF_16LE
+    @io.read.b.should == "".b
+    @io.rewind
+    @io.set_encoding(Encoding::ASCII_8BIT)
+
     File.binwrite(@name, "\xFF\xFEabc")
 
     @io.set_encoding_by_bom.should == Encoding::UTF_16LE
     @io.external_encoding.should == Encoding::UTF_16LE
+    @io.read.b.should == "abc".b
   end
 
   it "returns the result encoding if found BOM UTF_16BE sequence" do
+    File.binwrite(@name, "\xFE\xFF")
+
+    @io.set_encoding_by_bom.should == Encoding::UTF_16BE
+    @io.external_encoding.should == Encoding::UTF_16BE
+    @io.read.b.should == "".b
+    @io.rewind
+    @io.set_encoding(Encoding::ASCII_8BIT)
+
     File.binwrite(@name, "\xFE\xFFabc")
 
     @io.set_encoding_by_bom.should == Encoding::UTF_16BE
     @io.external_encoding.should == Encoding::UTF_16BE
+    @io.read.b.should == "abc".b
   end
 
   it "returns the result encoding if found BOM UTF_32LE sequence" do
+    File.binwrite(@name, "\xFF\xFE\x00\x00")
+
+    @io.set_encoding_by_bom.should == Encoding::UTF_32LE
+    @io.external_encoding.should == Encoding::UTF_32LE
+    @io.read.b.should == "".b
+    @io.rewind
+    @io.set_encoding(Encoding::ASCII_8BIT)
+
     File.binwrite(@name, "\xFF\xFE\x00\x00abc")
 
     @io.set_encoding_by_bom.should == Encoding::UTF_32LE
     @io.external_encoding.should == Encoding::UTF_32LE
+    @io.read.b.should == "abc".b
   end
 
   it "returns the result encoding if found BOM UTF_32BE sequence" do
+    File.binwrite(@name, "\x00\x00\xFE\xFF")
+
+    @io.set_encoding_by_bom.should == Encoding::UTF_32BE
+    @io.external_encoding.should == Encoding::UTF_32BE
+    @io.read.b.should == "".b
+    @io.rewind
+    @io.set_encoding(Encoding::ASCII_8BIT)
+
     File.binwrite(@name, "\x00\x00\xFE\xFFabc")
 
     @io.set_encoding_by_bom.should == Encoding::UTF_32BE
     @io.external_encoding.should == Encoding::UTF_32BE
+    @io.read.b.should == "abc".b
+  end
+
+  it "returns nil if io is empty" do
+    @io.set_encoding_by_bom.should be_nil
+    @io.external_encoding.should == Encoding::ASCII_8BIT
+  end
+
+  it "returns nil if UTF-8 BOM sequence is incomplete" do
+    File.write(@name, "\xEF")
+
+    @io.set_encoding_by_bom.should == nil
+    @io.external_encoding.should == Encoding::ASCII_8BIT
+    @io.read.b.should == "\xEF".b
+    @io.rewind
+
+    File.write(@name, "\xEFa")
+
+    @io.set_encoding_by_bom.should == nil
+    @io.external_encoding.should == Encoding::ASCII_8BIT
+    @io.read.b.should == "\xEFa".b
+    @io.rewind
+
+    File.write(@name, "\xEF\xBB")
+
+    @io.set_encoding_by_bom.should == nil
+    @io.external_encoding.should == Encoding::ASCII_8BIT
+    @io.read.b.should == "\xEF\xBB".b
+    @io.rewind
+
+    File.write(@name, "\xEF\xBBa")
+
+    @io.set_encoding_by_bom.should == nil
+    @io.external_encoding.should == Encoding::ASCII_8BIT
+    @io.read.b.should == "\xEF\xBBa".b
+  end
+
+  it "returns nil if UTF-16BE BOM sequence is incomplete" do
+    File.write(@name, "\xFE")
+
+    @io.set_encoding_by_bom.should == nil
+    @io.external_encoding.should == Encoding::ASCII_8BIT
+    @io.read.b.should == "\xFE".b
+    @io.rewind
+
+    File.write(@name, "\xFEa")
+
+    @io.set_encoding_by_bom.should == nil
+    @io.external_encoding.should == Encoding::ASCII_8BIT
+    @io.read.b.should == "\xFEa".b
+  end
+
+  it "returns nil if UTF-16LE/UTF-32LE BOM sequence is incomplete" do
+    File.write(@name, "\xFF")
+
+    @io.set_encoding_by_bom.should == nil
+    @io.external_encoding.should == Encoding::ASCII_8BIT
+    @io.read.b.should == "\xFF".b
+    @io.rewind
+
+    File.write(@name, "\xFFa")
+
+    @io.set_encoding_by_bom.should == nil
+    @io.external_encoding.should == Encoding::ASCII_8BIT
+    @io.read.b.should == "\xFFa".b
+  end
+
+  it "returns UTF-16LE if UTF-32LE BOM sequence is incomplete" do
+    File.write(@name, "\xFF\xFE")
+
+    @io.set_encoding_by_bom.should == Encoding::UTF_16LE
+    @io.external_encoding.should == Encoding::UTF_16LE
+    @io.read.b.should == "".b
+    @io.rewind
+    @io.set_encoding(Encoding::ASCII_8BIT)
+
+    File.write(@name, "\xFF\xFE\x00")
+
+    @io.set_encoding_by_bom.should == Encoding::UTF_16LE
+    @io.external_encoding.should == Encoding::UTF_16LE
+    @io.read.b.should == "\x00".b
+    @io.rewind
+    @io.set_encoding(Encoding::ASCII_8BIT)
+
+    File.write(@name, "\xFF\xFE\x00a")
+
+    @io.set_encoding_by_bom.should == Encoding::UTF_16LE
+    @io.external_encoding.should == Encoding::UTF_16LE
+    @io.read.b.should == "\x00a".b
+  end
+
+  it "returns nil if UTF-32BE BOM sequence is incomplete" do
+    File.write(@name, "\x00")
+
+    @io.set_encoding_by_bom.should == nil
+    @io.external_encoding.should == Encoding::ASCII_8BIT
+    @io.read.b.should == "\x00".b
+    @io.rewind
+
+    File.write(@name, "\x00a")
+
+    @io.set_encoding_by_bom.should == nil
+    @io.external_encoding.should == Encoding::ASCII_8BIT
+    @io.read.b.should == "\x00a".b
+    @io.rewind
+
+    File.write(@name, "\x00\x00")
+
+    @io.set_encoding_by_bom.should == nil
+    @io.external_encoding.should == Encoding::ASCII_8BIT
+    @io.read.b.should == "\x00\x00".b
+    @io.rewind
+
+    File.write(@name, "\x00\x00a")
+
+    @io.set_encoding_by_bom.should == nil
+    @io.external_encoding.should == Encoding::ASCII_8BIT
+    @io.read.b.should == "\x00\x00a".b
+    @io.rewind
+
+    File.write(@name, "\x00\x00\xFE")
+
+    @io.set_encoding_by_bom.should == nil
+    @io.external_encoding.should == Encoding::ASCII_8BIT
+    @io.read.b.should == "\x00\x00\xFE".b
+    @io.rewind
+
+    File.write(@name, "\x00\x00\xFEa")
+
+    @io.set_encoding_by_bom.should == nil
+    @io.external_encoding.should == Encoding::ASCII_8BIT
+    @io.read.b.should == "\x00\x00\xFEa".b
   end
 
   it "returns nil if found BOM sequence not provided" do
     File.write(@name, "abc")
 
     @io.set_encoding_by_bom.should == nil
+    @io.external_encoding.should == Encoding::ASCII_8BIT
+    @io.read(3).should == "abc".b
   end
 
   it 'returns exception if io not in binary mode' do
diff --git a/spec/ruby/core/io/set_encoding_spec.rb b/spec/ruby/core/io/set_encoding_spec.rb
index 5aec6a96c3..bc448acfce 100644
--- a/spec/ruby/core/io/set_encoding_spec.rb
+++ b/spec/ruby/core/io/set_encoding_spec.rb
@@ -188,4 +188,21 @@ describe "IO#set_encoding" do
     @io.external_encoding.should == Encoding::UTF_8
     @io.internal_encoding.should == Encoding::UTF_16BE
   end
+
+  it "saves encoding options passed as a hash in the last argument" do
+    File.write(@name, "\xff")
+    io = File.open(@name)
+    io.set_encoding(Encoding::EUC_JP, Encoding::SHIFT_JIS, invalid: :replace, replace: ".")
+    io.read.should == "."
+  ensure
+    io.close
+  end
+
+  it "raises ArgumentError when no arguments are given" do
+    -> { @io.set_encoding() }.should raise_error(ArgumentError)
+  end
+
+  it "raises ArgumentError when too many arguments are given" do
+    -> { @io.set_encoding(1, 2, 3) }.should raise_error(ArgumentError)
+  end
 end
diff --git a/spec/ruby/core/io/shared/each.rb b/spec/ruby/core/io/shared/each.rb
index 607e7de03e..1b8abce5ff 100644
--- a/spec/ruby/core/io/shared/each.rb
+++ b/spec/ruby/core/io/shared/each.rb
@@ -113,6 +113,13 @@ describe :io_each, shared: true do
       @io.send(@method, "") { |s| ScratchPad << s }
       ScratchPad.recorded.should == IOSpecs.paragraphs
     end
+
+    it "discards leading newlines" do
+      @io.readline
+      @io.readline
+      @io.send(@method, "") { |s| ScratchPad << s }
+      ScratchPad.recorded.should == IOSpecs.paragraphs[1..-1]
+    end
   end
 
   describe "with both separator and limit" do
@@ -152,6 +159,13 @@ describe :io_each, shared: true do
           @io.send(@method, "", 1024) { |s| ScratchPad << s }
           ScratchPad.recorded.should == IOSpecs.paragraphs
         end
+
+        it "discards leading newlines" do
+          @io.readline
+          @io.readline
+          @io.send(@method, "", 1024) { |s| ScratchPad << s }
+          ScratchPad.recorded.should == IOSpecs.paragraphs[1..-1]
+        end
       end
     end
   end
@@ -220,6 +234,14 @@ describe :io_each, shared: true do
       ]
     end
   end
+
+  describe "when passed too many arguments" do
+    it "raises ArgumentError" do
+      -> {
+        @io.send(@method, "", 1, "excess argument", chomp: true) {}
+      }.should raise_error(ArgumentError)
+    end
+  end
 end
 
 describe :io_each_default_separator, shared: true do
diff --git a/spec/ruby/core/io/shared/write.rb b/spec/ruby/core/io/shared/write.rb
index 270b84ac39..9503f94212 100644
--- a/spec/ruby/core/io/shared/write.rb
+++ b/spec/ruby/core/io/shared/write.rb
@@ -69,16 +69,6 @@ describe :io_write, shared: true do
     -> { IOSpecs.closed_io.send(@method, "hello") }.should raise_error(IOError)
   end
 
-  it "does not modify the passed argument" do
-    File.open(@filename, "w") do |f|
-      f.set_encoding(Encoding::IBM437)
-      # A character whose codepoint differs between UTF-8 and IBM437
-      f.write "ƒ".freeze
-    end
-
-    File.binread(@filename).bytes.should == [159]
-  end
-
   describe "on a pipe" do
     before :each do
       @r, @w = IO.pipe
diff --git a/spec/ruby/core/io/sysread_spec.rb b/spec/ruby/core/io/sysread_spec.rb
index 8201ad47ca..e7f63cefec 100644
--- a/spec/ruby/core/io/sysread_spec.rb
+++ b/spec/ruby/core/io/sysread_spec.rb
@@ -6,7 +6,7 @@ describe "IO#sysread on a file" do
     @file_name = tmp("IO_sysread_file") + $$.to_s
     File.open(@file_name, "w") do |f|
       # write some stuff
-      f.write("012345678901234567890123456789")
+      f.write("012345678901234567890123456789\nabcdef")
     end
     @file = File.open(@file_name, "r+")
   end
@@ -84,6 +84,29 @@ describe "IO#sysread on a file" do
   it "raises IOError on closed stream" do
     -> { IOSpecs.closed_io.sysread(5) }.should raise_error(IOError)
   end
+
+  it "immediately returns an empty string if the length argument is 0" do
+    @file.sysread(0).should == ""
+  end
+
+  it "immediately returns the given buffer if the length argument is 0" do
+    buffer = "existing content"
+    @file.sysread(0, buffer).should == buffer
+    buffer.should == "existing content"
+  end
+
+  it "discards the existing buffer content upon successful read" do
+    buffer = "existing content"
+    @file.sysread(11, buffer)
+    buffer.should == "01234567890"
+  end
+
+  it "discards the existing buffer content upon error" do
+    buffer = "existing content"
+    @file.seek(0, :END)
+    -> { @file.sysread(1, buffer) }.should raise_error(EOFError)
+    buffer.should be_empty
+  end
 end
 
 describe "IO#sysread" do
@@ -100,4 +123,10 @@ describe "IO#sysread" do
     @write.syswrite "ab"
     @read.sysread(3).should == "ab"
   end
+
+  guard_not -> { platform_is :windows and ruby_version_is ""..."3.2" } do # https://bugs.ruby-lang.org/issues/18880
+    it "raises ArgumentError when length is less than 0" do
+      -> { @read.sysread(-1) }.should raise_error(ArgumentError)
+    end
+  end
 end
diff --git a/spec/ruby/core/io/syswrite_spec.rb b/spec/ruby/core/io/syswrite_spec.rb
index a28cc62174..eeb8d302a7 100644
--- a/spec/ruby/core/io/syswrite_spec.rb
+++ b/spec/ruby/core/io/syswrite_spec.rb
@@ -29,6 +29,16 @@ describe "IO#syswrite on a file" do
     end
   end
 
+  it "does not modify the passed argument" do
+    File.open(@filename, "w") do |f|
+      f.set_encoding(Encoding::IBM437)
+      # A character whose codepoint differs between UTF-8 and IBM437
+      f.syswrite("ƒ".freeze)
+    end
+
+    File.binread(@filename).bytes.should == [198, 146]
+  end
+
   it "warns if called immediately after a buffered IO#write" do
     @file.write("abcde")
     -> { @file.syswrite("fghij") }.should complain(/syswrite/)
diff --git a/spec/ruby/core/io/write_nonblock_spec.rb b/spec/ruby/core/io/write_nonblock_spec.rb
index a8b9ce0a36..5532556d8a 100644
--- a/spec/ruby/core/io/write_nonblock_spec.rb
+++ b/spec/ruby/core/io/write_nonblock_spec.rb
@@ -31,6 +31,16 @@ platform_is_not :windows do
       end
     end
 
+    it "does not modify the passed argument" do
+      File.open(@filename, "w") do |f|
+        f.set_encoding(Encoding::IBM437)
+        # A character whose codepoint differs between UTF-8 and IBM437
+        f.write_nonblock("ƒ".freeze)
+      end
+
+      File.binread(@filename).bytes.should == [198, 146]
+    end
+
     it "checks if the file is writable if writing zero bytes" do
       -> {
          @readonly_file.write_nonblock("")
diff --git a/spec/ruby/core/io/write_spec.rb b/spec/ruby/core/io/write_spec.rb
index f29fdf3a01..bcc0582d9e 100644
--- a/spec/ruby/core/io/write_spec.rb
+++ b/spec/ruby/core/io/write_spec.rb
@@ -44,6 +44,16 @@ describe "IO#write on a file" do
     @file.write("hellø").should == 6
   end
 
+  it "does not modify the passed argument" do
+    File.open(@filename, "w") do |f|
+      f.set_encoding(Encoding::IBM437)
+      # A character whose codepoint differs between UTF-8 and IBM437
+      f.write("ƒ".freeze)
+    end
+
+    File.binread(@filename).bytes.should == [159]
+  end
+
   it "uses the encoding from the given option for non-ascii encoding" do
     File.open(@filename, "w", encoding: Encoding::UTF_32LE) do |file|
       file.write("hi").should == 8
diff --git a/spec/ruby/core/kernel/p_spec.rb b/spec/ruby/core/kernel/p_spec.rb
index 1bdd1740ca..eae191aa54 100644
--- a/spec/ruby/core/kernel/p_spec.rb
+++ b/spec/ruby/core/kernel/p_spec.rb
@@ -76,10 +76,8 @@ describe "Kernel#p" do
     -> { p(*[]) }.should output("")
   end
 
-=begin Not sure how to spec this, but wanted to note the behavior here
-  it "does not flush if receiver is not a TTY or a File" do
-  end
-=end
+  # Not sure how to spec this, but wanted to note the behavior here
+  it "does not flush if receiver is not a TTY or a File"
 end
 
 describe "Kernel.p" do
diff --git a/spec/ruby/core/method/fixtures/classes.rb b/spec/ruby/core/method/fixtures/classes.rb
index be96f65e25..50daa773e1 100644
--- a/spec/ruby/core/method/fixtures/classes.rb
+++ b/spec/ruby/core/method/fixtures/classes.rb
@@ -213,4 +213,28 @@ module MethodSpecs
       n * m
     end
   end
+
+  module InheritedMethods
+    module A
+      private
+      def derp(message)
+        'A'
+      end
+    end
+
+    module B
+      private
+      def derp
+        'B' + super('superclass')
+      end
+    end
+
+    class C
+      include A
+      include B
+
+      public :derp
+      alias_method :meow, :derp
+    end
+  end
 end
diff --git a/spec/ruby/core/method/super_method_spec.rb b/spec/ruby/core/method/super_method_spec.rb
index e5d8b87a06..dc8764f6c7 100644
--- a/spec/ruby/core/method/super_method_spec.rb
+++ b/spec/ruby/core/method/super_method_spec.rb
@@ -42,4 +42,32 @@ describe "Method#super_method" do
 
     method.super_method.should == nil
   end
+
+  # https://github.com/jruby/jruby/issues/7240
+  context "after changing an inherited methods visibility" do
+    it "calls the proper super method" do
+      MethodSpecs::InheritedMethods::C.new.derp.should == 'BA'
+    end
+
+    ruby_version_is ""..."3.2" do
+      it "returns the expected super_method" do
+        method = MethodSpecs::InheritedMethods::C.new.method(:derp)
+        method.super_method.owner.should == MethodSpecs::InheritedMethods::A
+      end
+    end
+
+    ruby_version_is "3.2" do
+      it "returns the expected super_method" do
+        method = MethodSpecs::InheritedMethods::C.new.method(:derp)
+        method.super_method.owner.should == MethodSpecs::InheritedMethods::B
+      end
+    end
+  end
+
+  context "after aliasing an inherited method" do
+    it "returns the expected super_method" do
+      method = MethodSpecs::InheritedMethods::C.new.method(:meow)
+      method.super_method.owner.should == MethodSpecs::InheritedMethods::A
+    end
+  end
 end
diff --git a/spec/ruby/core/module/const_defined_spec.rb b/spec/ruby/core/module/const_defined_spec.rb
index 75730395e8..0c15629c08 100644
--- a/spec/ruby/core/module/const_defined_spec.rb
+++ b/spec/ruby/core/module/const_defined_spec.rb
@@ -17,11 +17,16 @@ describe "Module#const_defined?" do
     ConstantSpecs::ContainerA::ChildA.const_defined?(:CS_CONST4).should be_true
   end
 
-  it "returns true if the constant is defined in a mixed-in module of the receiver" do
+  it "returns true if the constant is defined in a mixed-in module of the receiver's parent" do
     # CS_CONST10 is defined in a module included by ChildA
     ConstantSpecs::ContainerA::ChildA.const_defined?(:CS_CONST10).should be_true
   end
 
+  it "returns true if the constant is defined in a mixed-in module (with prepends) of the receiver" do
+    # CS_CONST11 is defined in the module included by ContainerPrepend
+    ConstantSpecs::ContainerPrepend.const_defined?(:CS_CONST11).should be_true
+  end
+
   it "returns true if the constant is defined in Object and the receiver is a module" do
     # CS_CONST1 is defined in Object
     ConstantSpecs::ModuleA.const_defined?(:CS_CONST1).should be_true
diff --git a/spec/ruby/core/module/define_method_spec.rb b/spec/ruby/core/module/define_method_spec.rb
index c65b30de24..ce94436bfd 100644
--- a/spec/ruby/core/module/define_method_spec.rb
+++ b/spec/ruby/core/module/define_method_spec.rb
@@ -219,18 +219,55 @@ describe "Module#define_method" do
     o.block_test2.should == o
   end
 
+  it "raises TypeError if name cannot converted to String" do
+    -> {
+      Class.new { define_method(1001, -> {}) }
+    }.should raise_error(TypeError, /is not a symbol nor a string/)
+
+    -> {
+      Class.new { define_method([], -> {}) }
+    }.should raise_error(TypeError, /is not a symbol nor a string/)
+  end
+
+  it "converts non-String name to String with #to_str" do
+    obj = Object.new
+    def obj.to_str() "foo" end
+
+    new_class = Class.new { define_method(obj, -> { :called }) }
+    new_class.new.foo.should == :called
+  end
+
+  it "raises TypeError when #to_str called on non-String name returns non-String value" do
+    obj = Object.new
+    def obj.to_str() [] end
+
+    -> {
+      Class.new { define_method(obj, -> {}) }
+    }.should raise_error(TypeError, /can't convert Object to String/)
+  end
+
   it "raises a TypeError when the given method is no Method/Proc" do
     -> {
       Class.new { define_method(:test, "self") }
-    }.should raise_error(TypeError)
+    }.should raise_error(TypeError, "wrong argument type String (expected Proc/Method/UnboundMethod)")
 
     -> {
       Class.new { define_method(:test, 1234) }
-    }.should raise_error(TypeError)
+    }.should raise_error(TypeError, "wrong argument type Integer (expected Proc/Method/UnboundMethod)")
 
     -> {
       Class.new { define_method(:test, nil) }
-    }.should raise_error(TypeError)
+    }.should raise_error(TypeError, "wrong argument type NilClass (expected Proc/Method/UnboundMethod)")
+  end
+
+  it "uses provided Method/Proc even if block is specified" do
+    new_class = Class.new do
+      define_method(:test, -> { :method_is_called }) do
+        :block_is_called
+      end
+    end
+
+    new_class.new.test.should == :method_is_called
   end
 
   it "raises an ArgumentError when no block is given" do
diff --git a/spec/ruby/core/module/fixtures/classes.rb b/spec/ruby/core/module/fixtures/classes.rb
index a64f672b2f..2b47ff112e 100644
--- a/spec/ruby/core/module/fixtures/classes.rb
+++ b/spec/ruby/core/module/fixtures/classes.rb
@@ -42,6 +42,14 @@ module ModuleSpecs
   class LookupChild < Lookup
   end
 
+  module ModuleWithPrepend
+    prepend LookupMod
+  end
+
+  class WithPrependedModule
+    include ModuleWithPrepend
+  end
+
   class Parent
     # For private_class_method spec
     def self.private_method; end
diff --git a/spec/ruby/core/module/included_modules_spec.rb b/spec/ruby/core/module/included_modules_spec.rb
index 40e20953f4..ce94ed1285 100644
--- a/spec/ruby/core/module/included_modules_spec.rb
+++ b/spec/ruby/core/module/included_modules_spec.rb
@@ -4,9 +4,11 @@ require_relative 'fixtures/classes'
 describe "Module#included_modules" do
   it "returns a list of modules included in self" do
     ModuleSpecs.included_modules.should == []
+
     ModuleSpecs::Child.included_modules.should include(ModuleSpecs::Super, ModuleSpecs::Basic, Kernel)
     ModuleSpecs::Parent.included_modules.should include(Kernel)
     ModuleSpecs::Basic.included_modules.should == []
     ModuleSpecs::Super.included_modules.should include(ModuleSpecs::Basic)
+    ModuleSpecs::WithPrependedModule.included_modules.should include(ModuleSpecs::ModuleWithPrepend)
   end
 end
diff --git a/spec/ruby/core/module/instance_method_spec.rb b/spec/ruby/core/module/instance_method_spec.rb
index b4d6a0d8c8..30e27bb180 100644
--- a/spec/ruby/core/module/instance_method_spec.rb
+++ b/spec/ruby/core/module/instance_method_spec.rb
@@ -51,14 +51,36 @@ describe "Module#instance_method" do
     @mod_um.inspect.should =~ /\bModuleSpecs::InstanceMethChild\b/
   end
 
-  it "raises a TypeError if not passed a symbol" do
-    -> { Object.instance_method([]) }.should raise_error(TypeError)
-    -> { Object.instance_method(0)  }.should raise_error(TypeError)
+  it "raises a TypeError if the given name is not a String/Symbol" do
+    -> { Object.instance_method([]) }.should raise_error(TypeError, /is not a symbol nor a string/)
+    -> { Object.instance_method(0) }.should raise_error(TypeError, /is not a symbol nor a string/)
+    -> { Object.instance_method(nil) }.should raise_error(TypeError, /is not a symbol nor a string/)
+    -> { Object.instance_method(mock('x')) }.should raise_error(TypeError, /is not a symbol nor a string/)
   end
 
-  it "raises a TypeError if the given name is not a string/symbol" do
-    -> { Object.instance_method(nil)       }.should raise_error(TypeError)
-    -> { Object.instance_method(mock('x')) }.should raise_error(TypeError)
+  it "accepts String name argument" do
+    method = ModuleSpecs::InstanceMeth.instance_method(:foo)
+    method.should be_kind_of(UnboundMethod)
+  end
+
+  it "accepts Symbol name argument"  do
+    method = ModuleSpecs::InstanceMeth.instance_method("foo")
+    method.should be_kind_of(UnboundMethod)
+  end
+
+  it "converts non-String name by calling #to_str method" do
+    obj = Object.new
+    def obj.to_str() "foo" end
+
+    method = ModuleSpecs::InstanceMeth.instance_method(obj)
+    method.should be_kind_of(UnboundMethod)
+  end
+
+  it "raises TypeError when passed non-String name and #to_str returns non-String value" do
+    obj = Object.new
+    def obj.to_str() [] end
+
+    -> { ModuleSpecs::InstanceMeth.instance_method(obj) }.should raise_error(TypeError, /can't convert Object to String/)
   end
 
   it "raises a NameError if the method has been undefined" do
diff --git a/spec/ruby/core/module/shared/class_eval.rb b/spec/ruby/core/module/shared/class_eval.rb
index 224078ae54..9ef7b5be44 100644
--- a/spec/ruby/core/module/shared/class_eval.rb
+++ b/spec/ruby/core/module/shared/class_eval.rb
@@ -55,40 +55,49 @@ describe :module_class_eval, shared: true do
   it "converts a non-string filename to a string using to_str" do
     (file = mock(__FILE__)).should_receive(:to_str).and_return(__FILE__)
     ModuleSpecs.send(@method, "1+1", file)
+
+    (file = mock(__FILE__)).should_receive(:to_str).and_return(__FILE__)
+    ModuleSpecs.send(@method, "1+1", file, 15)
   end
 
   it "raises a TypeError when the given filename can't be converted to string using to_str" do
     (file = mock('123')).should_receive(:to_str).and_return(123)
-    -> { ModuleSpecs.send(@method, "1+1", file) }.should raise_error(TypeError)
+    -> { ModuleSpecs.send(@method, "1+1", file) }.should raise_error(TypeError, /can't convert MockObject to String/)
   end
 
   it "converts non string eval-string to string using to_str" do
     (o = mock('1 + 1')).should_receive(:to_str).and_return("1 + 1")
     ModuleSpecs.send(@method, o).should == 2
+
+    (o = mock('1 + 1')).should_receive(:to_str).and_return("1 + 1")
+    ModuleSpecs.send(@method, o, "file.rb").should == 2
+
+    (o = mock('1 + 1')).should_receive(:to_str).and_return("1 + 1")
+    ModuleSpecs.send(@method, o, "file.rb", 15).should == 2
   end
 
   it "raises a TypeError when the given eval-string can't be converted to string using to_str" do
     o = mock('x')
-    -> { ModuleSpecs.send(@method, o) }.should raise_error(TypeError)
+    -> { ModuleSpecs.send(@method, o) }.should raise_error(TypeError, "no implicit conversion of MockObject into String")
 
     (o = mock('123')).should_receive(:to_str).and_return(123)
-    -> { ModuleSpecs.send(@method, o) }.should raise_error(TypeError)
+    -> { ModuleSpecs.send(@method, o) }.should raise_error(TypeError, /can't convert MockObject to String/)
   end
 
   it "raises an ArgumentError when no arguments and no block are given" do
-    -> { ModuleSpecs.send(@method) }.should raise_error(ArgumentError)
+    -> { ModuleSpecs.send(@method) }.should raise_error(ArgumentError, "wrong number of arguments (given 0, expected 1..3)")
   end
 
   it "raises an ArgumentError when more than 3 arguments are given" do
     -> {
       ModuleSpecs.send(@method, "1 + 1", "some file", 0, "bogus")
-    }.should raise_error(ArgumentError)
+    }.should raise_error(ArgumentError, "wrong number of arguments (given 4, expected 1..3)")
   end
 
   it "raises an ArgumentError when a block and normal arguments are given" do
     -> {
       ModuleSpecs.send(@method, "1 + 1") { 1 + 1 }
-    }.should raise_error(ArgumentError)
+    }.should raise_error(ArgumentError, "wrong number of arguments (given 1, expected 0)")
   end
 
   # This case was found because Rubinius was caching the compiled
diff --git a/spec/ruby/core/string/split_spec.rb b/spec/ruby/core/string/split_spec.rb
index b57f660816..0417486692 100644
--- a/spec/ruby/core/string/split_spec.rb
+++ b/spec/ruby/core/string/split_spec.rb
@@ -29,9 +29,35 @@ describe "String#split with String" do
     "1,2,,3,4,,".split(',').should == ["1", "2", "", "3", "4"]
     "1,2,,3,4,,".split(',', 0).should == ["1", "2", "", "3", "4"]
     "  a  b  c\nd  ".split("  ").should == ["", "a", "b", "c\nd"]
+    "  a  あ  c\nd  ".split("  ").should == ["", "a", "あ", "c\nd"]
     "hai".split("hai").should == []
     ",".split(",").should == []
     ",".split(",", 0).should == []
+    "あ".split("あ").should == []
+    "あ".split("あ", 0).should == []
+  end
+
+  it "does not suppress trailing empty fields when a positive limit is given" do
+    " 1 2 ".split(" ", 2).should == ["1", "2 "]
+    " 1 2 ".split(" ", 3).should == ["1", "2", ""]
+    " 1 2 ".split(" ", 4).should == ["1", "2", ""]
+    " 1 あ ".split(" ", 2).should == ["1", "あ "]
+    " 1 あ ".split(" ", 3).should == ["1", "あ", ""]
+    " 1 あ ".split(" ", 4).should == ["1", "あ", ""]
+
+    "1,2,".split(',', 2).should == ["1", "2,"]
+    "1,2,".split(',', 3).should == ["1", "2", ""]
+    "1,2,".split(',', 4).should == ["1", "2", ""]
+    "1,あ,".split(',', 2).should == ["1", "あ,"]
+    "1,あ,".split(',', 3).should == ["1", "あ", ""]
+    "1,あ,".split(',', 4).should == ["1", "あ", ""]
+
+    "1 2 ".split(/ /, 2).should == ["1", "2 "]
+    "1 2 ".split(/ /, 3).should == ["1", "2", ""]
+    "1 2 ".split(/ /, 4).should == ["1", "2", ""]
+    "1 あ ".split(/ /, 2).should == ["1", "あ "]
+    "1 あ ".split(/ /, 3).should == ["1", "あ", ""]
+    "1 あ ".split(/ /, 4).should == ["1", "あ", ""]
   end
 
   it "returns an array with one entry if limit is 1: the original string" do
diff --git a/spec/ruby/core/thread/backtrace/location/absolute_path_spec.rb b/spec/ruby/core/thread/backtrace/location/absolute_path_spec.rb
index 4136f09348..e35e1fc0b4 100644
--- a/spec/ruby/core/thread/backtrace/location/absolute_path_spec.rb
+++ b/spec/ruby/core/thread/backtrace/location/absolute_path_spec.rb
@@ -17,6 +17,15 @@ describe 'Thread::Backtrace::Location#absolute_path' do
     end
   end
 
+  it 'returns the correct absolute path when using a relative main script path and changing CWD' do
+    script = fixture(__FILE__, 'subdir/absolute_path_main_chdir.rb')
+    sibling = fixture(__FILE__, 'subdir/sibling.rb')
+    subdir = File.dirname script
+    Dir.chdir(fixture(__FILE__)) do
+      ruby_exe('subdir/absolute_path_main_chdir.rb').should == "subdir/absolute_path_main_chdir.rb\n#{subdir}\n#{subdir}\n#{script}\n#{sibling}\n"
+    end
+  end
+
   context "when used in eval with a given filename" do
     code = "caller_locations(0)[0].absolute_path"
 
diff --git a/spec/ruby/core/thread/backtrace/location/fixtures/subdir/absolute_path_main_chdir.rb b/spec/ruby/core/thread/backtrace/location/fixtures/subdir/absolute_path_main_chdir.rb
new file mode 100644
index 0000000000..33c8fb36ef
--- /dev/null
+++ b/spec/ruby/core/thread/backtrace/location/fixtures/subdir/absolute_path_main_chdir.rb
@@ -0,0 +1,11 @@
+puts __FILE__
+puts __dir__
+Dir.chdir __dir__
+
+# Check __dir__ is still correct after chdir
+puts __dir__
+
+puts caller_locations(0)[0].absolute_path
+
+# require_relative also needs to know the absolute path of the current file so we test it here too
+require_relative 'sibling'
diff --git a/spec/ruby/core/thread/backtrace/location/fixtures/subdir/sibling.rb b/spec/ruby/core/thread/backtrace/location/fixtures/subdir/sibling.rb
new file mode 100644
index 0000000000..2a854ddccd
--- /dev/null
+++ b/spec/ruby/core/thread/backtrace/location/fixtures/subdir/sibling.rb
@@ -0,0 +1 @@
+puts __FILE__
diff --git a/spec/ruby/core/unboundmethod/fixtures/classes.rb b/spec/ruby/core/unboundmethod/fixtures/classes.rb
index 46b1c51669..1f466e39d8 100644
--- a/spec/ruby/core/unboundmethod/fixtures/classes.rb
+++ b/spec/ruby/core/unboundmethod/fixtures/classes.rb
@@ -84,4 +84,14 @@ module UnboundMethodSpecs
   class C < B
     def overridden; end
   end
+
+  module HashSpecs
+    class SuperClass
+      def foo
+      end
+    end
+
+    class SubClass < SuperClass
+    end
+  end
 end
diff --git a/spec/ruby/core/unboundmethod/hash_spec.rb b/spec/ruby/core/unboundmethod/hash_spec.rb
index 12dce0020f..6888675bc1 100644
--- a/spec/ruby/core/unboundmethod/hash_spec.rb
+++ b/spec/ruby/core/unboundmethod/hash_spec.rb
@@ -12,4 +12,11 @@ describe "UnboundMethod#hash" do
     to_s, inspect = Array.instance_method(:to_s), Array.instance_method(:inspect)
     to_s.hash.should == inspect.hash
   end
+
+  it "equals a hash of the same method in the superclass" do
+    foo_in_superclass = UnboundMethodSpecs::HashSpecs::SuperClass.instance_method(:foo)
+    foo = UnboundMethodSpecs::HashSpecs::SubClass.instance_method(:foo)
+
+    foo.hash.should == foo_in_superclass.hash
+  end
 end
diff --git a/spec/ruby/core/unboundmethod/super_method_spec.rb b/spec/ruby/core/unboundmethod/super_method_spec.rb
index c9fa1ec533..5cf96e6fa9 100644
--- a/spec/ruby/core/unboundmethod/super_method_spec.rb
+++ b/spec/ruby/core/unboundmethod/super_method_spec.rb
@@ -1,5 +1,6 @@
 require_relative '../../spec_helper'
 require_relative 'fixtures/classes'
+require_relative '../method/fixtures/classes'
 
 describe "UnboundMethod#super_method" do
   it "returns the method that would be called by super in the method" do
@@ -25,4 +26,28 @@ describe "UnboundMethod#super_method" do
 
     method.super_method.should == nil
   end
+
+  # https://github.com/jruby/jruby/issues/7240
+  context "after changing an inherited methods visibility" do
+    ruby_version_is ""..."3.2" do
+      it "returns the expected super_method" do
+        method = MethodSpecs::InheritedMethods::C.instance_method(:derp)
+        method.super_method.owner.should == MethodSpecs::InheritedMethods::A
+      end
+    end
+
+    ruby_version_is "3.2" do
+      it "returns the expected super_method" do
+        method = MethodSpecs::InheritedMethods::C.instance_method(:derp)
+        method.super_method.owner.should == MethodSpecs::InheritedMethods::B
+      end
+    end
+  end
+
+  context "after aliasing an inherited method" do
+    it "returns the expected super_method" do
+      method = MethodSpecs::InheritedMethods::C.instance_method(:meow)
+      method.super_method.owner.should == MethodSpecs::InheritedMethods::A
+    end
+  end
 end
diff --git a/spec/ruby/fixtures/constants.rb b/spec/ruby/fixtures/constants.rb
index 4c456dae89..47a8e87e56 100644
--- a/spec/ruby/fixtures/constants.rb
+++ b/spec/ruby/fixtures/constants.rb
@@ -75,6 +75,13 @@ module ConstantSpecs
     CS_CONST10 = :const10_8
   end
 
+  # Included in ContainerA
+  module ModuleIncludePrepended
+    prepend ModuleD
+
+    CS_CONST11 = :const11_8
+  end
+
   # The following classes/modules have all the constants set "statically".
   # Contrast with the classes below where the constants are set as the specs
   # are run.
@@ -169,6 +176,10 @@ module ConstantSpecs
     def const10; CS_CONST10; end
   end
 
+  class ContainerPrepend
+    include ModuleIncludePrepended
+  end
+
   class ContainerA::ChildA
     def self.const23; CS_CONST23; end
   end
diff --git a/spec/ruby/language/precedence_spec.rb b/spec/ruby/language/precedence_spec.rb
index 5a3c2861ce..c5adcca2c0 100644
--- a/spec/ruby/language/precedence_spec.rb
+++ b/spec/ruby/language/precedence_spec.rb
@@ -14,46 +14,44 @@ require_relative 'fixtures/precedence'
 # the level below (as well as showing associativity within
 # the precedence level).
 
-=begin
-Excerpted from 'Programming Ruby: The Pragmatic Programmer's Guide'
-Second Edition by Dave Thomas, Chad Fowler, and Andy Hunt, page 324
-
-Table 22.4. Ruby operators (high to low precedence)
-Method   Operator                  Description
------------------------------------------------------------------------
-         :: .
- x*      [ ] [ ]=                  Element reference, element set
- x       **                        Exponentiation
- x       ! ~ + -                   Not, complement, unary plus and minus
-                                   (method names for the last two are +@ and -@)
- x       * / %                     Multiply, divide, and modulo
- x       + -                       Plus and minus
- x       >> <<                     Right and left shift
- x       &                         “And” (bitwise for integers)
- x       ^ |                       Exclusive “or” and regular “or” (bitwise for integers)
- x       <= < > >=                 Comparison operators
- x       <=> == === != =~ !~       Equality and pattern match operators (!=
-                                   and !~ may not be defined as methods)
-         &&                        Logical “and”
-         ||                        Logical “or”
-         .. ...                    Range (inclusive and exclusive)
-         ? :                       Ternary if-then-else
-         = %= /= -= += |= &=       Assignment
-         >>= <<= *= &&= ||= **=
-         defined?                  Check if symbol defined
-         not                       Logical negation
-         or and                    Logical composition
-         if unless while until     Expression modifiers
-         begin/end                 Block expression
------------------------------------------------------------------------
-
-* Operators marked with 'x' in the Method column are implemented as methods
-and can be overridden (except != and !~ as noted). (But see the specs
-below for implementations that define != and !~ as methods.)
-
-** These are not included in the excerpted table but are shown here for
-completeness.
-=end
+# Excerpted from 'Programming Ruby: The Pragmatic Programmer's Guide'
+# Second Edition by Dave Thomas, Chad Fowler, and Andy Hunt, page 324
+#
+# Table 22.4. Ruby operators (high to low precedence)
+# Method   Operator                  Description
+# -----------------------------------------------------------------------
+#          :: .
+#  x*      [ ] [ ]=                  Element reference, element set
+#  x       **                        Exponentiation
+#  x       ! ~ + -                   Not, complement, unary plus and minus
+#                                    (method names for the last two are +@ and -@)
+#  x       * / %                     Multiply, divide, and modulo
+#  x       + -                       Plus and minus
+#  x       >> <<                     Right and left shift
+#  x       &                         “And” (bitwise for integers)
+#  x       ^ |                       Exclusive “or” and regular “or” (bitwise for integers)
+#  x       <= < > >=                 Comparison operators
+#  x       <=> == === != =~ !~       Equality and pattern match operators (!=
+#                                    and !~ may not be defined as methods)
+#          &&                        Logical “and”
+#          ||                        Logical “or”
+#          .. ...                    Range (inclusive and exclusive)
+#          ? :                       Ternary if-then-else
+#          = %= /= -= += |= &=       Assignment
+#          >>= <<= *= &&= ||= **=
+#          defined?                  Check if symbol defined
+#          not                       Logical negation
+#          or and                    Logical composition
+#          if unless while until     Expression modifiers
+#          begin/end                 Block expression
+# -----------------------------------------------------------------------
+#
+# * Operators marked with 'x' in the Method column are implemented as methods
+# and can be overridden (except != and !~ as noted). (But see the specs
+# below for implementations that define != and !~ as methods.)
+#
+# ** These are not included in the excerpted table but are shown here for
+# completeness.
 
 # -----------------------------------------------------------------------
 # It seems that this table is not correct anymore
diff --git a/spec/ruby/language/predefined_spec.rb b/spec/ruby/language/predefined_spec.rb
index 87385a29e5..d1cda25918 100644
--- a/spec/ruby/language/predefined_spec.rb
+++ b/spec/ruby/language/predefined_spec.rb
@@ -7,37 +7,33 @@ require 'stringio'
 # Entries marked [r/o] are read-only and an error will be raised of the program attempts to
 # modify them. Entries marked [thread] are thread local.
 
-=begin
-Exception Information
----------------------------------------------------------------------------------------------------
-
-$!               Exception       The exception object passed to raise. [thread]
-$@               Array           The stack backtrace generated by the last exception. [thread]
-=end
-
-=begin
-Pattern Matching Variables
----------------------------------------------------------------------------------------------------
-
-These variables are set to nil after an unsuccessful pattern match.
-
-$&               String          The string matched (following a successful pattern match). This variable is
-                                 local to the current scope. [r/o, thread]
-$+               String          The contents of the highest-numbered group matched following a successful
-                                 pattern match. Thus, in "cat" =~/(c|a)(t|z)/, $+ will be set to “t”. This
-                                 variable is local to the current scope. [r/o, thread]
-$`               String          The string preceding the match in a successful pattern match. This variable
-                                 is local to the current scope. [r/o, thread]
-$'               String          The string following the match in a successful pattern match. This variable
-                                 is local to the current scope. [r/o, thread]
-$1 to $<N>       String          The contents of successive groups matched in a successful pattern match. In
-                                 "cat" =~/(c|a)(t|z)/, $1 will be set to “a” and $2 to “t”. This variable
-                                 is local to the current scope. [r/o, thread]
-$~               MatchData       An object that encapsulates the results of a successful pattern match. The
-                                 variables $&, $`, $', and $1 to $<N> are all derived from $~. Assigning to $~
-                                 changes the values of these derived variables. This variable is local to the
-                                 current scope. [thread]
-=end
+# Exception Information
+# ---------------------------------------------------------------------------------------------------
+#
+# $!               Exception       The exception object passed to raise. [thread]
+# $@               Array           The stack backtrace generated by the last exception. [thread]
+
+# Pattern Matching Variables
+# ---------------------------------------------------------------------------------------------------
+#
+# These variables are set to nil after an unsuccessful pattern match.
+#
+# $&               String          The string matched (following a successful pattern match). This variable is
+#                                  local to the current scope. [r/o, thread]
+# $+               String          The contents of the highest-numbered group matched following a successful
+#                                  pattern match. Thus, in "cat" =~/(c|a)(t|z)/, $+ will be set to “t”. This
+#                                  variable is local to the current scope. [r/o, thread]
+# $`               String          The string preceding the match in a successful pattern match. This variable
+#                                  is local to the current scope. [r/o, thread]
+# $'               String          The string following the match in a successful pattern match. This variable
+#                                  is local to the current scope. [r/o, thread]
+# $1 to $<N>       String          The contents of successive groups matched in a successful pattern match. In
+#                                  "cat" =~/(c|a)(t|z)/, $1 will be set to “a” and $2 to “t”. This variable
+#                                  is local to the current scope. [r/o, thread]
+# $~               MatchData       An object that encapsulates the results of a successful pattern match. The
+#                                  variables $&, $`, $', and $1 to $<N> are all derived from $~. Assigning to $~
+#                                  changes the values of these derived variables. This variable is local to the
+#                                  current scope. [thread]
 
 
 describe "Predefined global $~" do
@@ -506,41 +502,39 @@ describe "Predefined global $!" do
   end
 end
 
-=begin
-Input/Output Variables
----------------------------------------------------------------------------------------------------
-
-$/               String          The input record separator (newline by default). This is the value that rou-
-                                 tines such as Kernel#gets use to determine record boundaries. If set to
-                                 nil, gets will read the entire file.
-$-0              String          Synonym for $/.
-$\               String          The string appended to the output of every call to methods such as
-                                 Kernel#print and IO#write. The default value is nil.
-$,               String          The separator string output between the parameters to methods such as
-                                 Kernel#print and Array#join. Defaults to nil, which adds no text.
-$.               Integer          The number of the last line read from the current input file.
-$;               String          The default separator pattern used by String#split. May be set from the
-                                 command line using the -F flag.
-$<               Object          An object that provides access to the concatenation of the contents of all
-                                 the files given as command-line arguments or $stdin (in the case where
-                                 there are no arguments). $< supports methods similar to a File object:
-                                 binmode, close, closed?, each, each_byte, each_line, eof, eof?,
-                                 file, filename, fileno, getc, gets, lineno, lineno=, path, pos, pos=,
-                                 read, readchar, readline, readlines, rewind, seek, skip, tell, to_a,
-                                 to_i, to_io, to_s, along with the methods in Enumerable. The method
-                                 file returns a File object for the file currently being read. This may change
-                                 as $< reads through the files on the command line. [r/o]
-$>               IO              The destination of output for Kernel#print and Kernel#printf. The
-                                 default value is $stdout.
-$_               String          The last line read by Kernel#gets or Kernel#readline. Many string-
-                                 related functions in the Kernel module operate on $_ by default. The vari-
-                                 able is local to the current scope. [thread]
-$-F              String          Synonym for $;.
-$stderr          IO              The current standard error output.
-$stdin           IO              The current standard input.
-$stdout          IO              The current standard output. Assignment to $stdout is deprecated: use
-                                 $stdout.reopen instead.
-=end
+# Input/Output Variables
+# ---------------------------------------------------------------------------------------------------
+#
+# $/               String          The input record separator (newline by default). This is the value that rou-
+#                                  tines such as Kernel#gets use to determine record boundaries. If set to
+#                                  nil, gets will read the entire file.
+# $-0              String          Synonym for $/.
+# $\               String          The string appended to the output of every call to methods such as
+#                                  Kernel#print and IO#write. The default value is nil.
+# $,               String          The separator string output between the parameters to methods such as
+#                                  Kernel#print and Array#join. Defaults to nil, which adds no text.
+# $.               Integer          The number of the last line read from the current input file.
+# $;               String          The default separator pattern used by String#split. May be set from the
+#                                  command line using the -F flag.
+# $<               Object          An object that provides access to the concatenation of the contents of all
+#                                  the files given as command-line arguments or $stdin (in the case where
+#                                  there are no arguments). $< supports methods similar to a File object:
+#                                  binmode, close, closed?, each, each_byte, each_line, eof, eof?,
+#                                  file, filename, fileno, getc, gets, lineno, lineno=, path, pos, pos=,
+#                                  read, readchar, readline, readlines, rewind, seek, skip, tell, to_a,
+#                                  to_i, to_io, to_s, along with the methods in Enumerable. The method
+#                                  file returns a File object for the file currently being read. This may change
+#                                  as $< reads through the files on the command line. [r/o]
+# $>               IO              The destination of output for Kernel#print and Kernel#printf. The
+#                                  default value is $stdout.
+# $_               String          The last line read by Kernel#gets or Kernel#readline. Many string-
+#                                  related functions in the Kernel module operate on $_ by default. The vari-
+#                                  able is local to the current scope. [thread]
+# $-F              String          Synonym for $;.
+# $stderr          IO              The current standard error output.
+# $stdin           IO              The current standard input.
+# $stdout          IO              The current standard output. Assignment to $stdout is deprecated: use
+#                                  $stdout.reopen instead.
 
 describe "Predefined global $/" do
   before :each do
@@ -803,54 +797,52 @@ describe "Predefined global $_" do
   end
 end
 
-=begin
-Execution Environment Variables
----------------------------------------------------------------------------------------------------
-
-$0               String          The name of the top-level Ruby program being executed. Typically this will
-                                 be the program’s filename. On some operating systems, assigning to this
-                                 variable will change the name of the process reported (for example) by the
-                                 ps(1) command.
-$*               Array           An array of strings containing the command-line options from the invoca-
-                                 tion of the program. Options used by the Ruby interpreter will have been
-                                 removed. [r/o]
-$"               Array           An array containing the filenames of modules loaded by require. [r/o]
-$$               Integer          The process number of the program being executed. [r/o]
-$?               Process::Status The exit status of the last child process to terminate. [r/o, thread]
-$:               Array           An array of strings, where each string specifies a directory to be searched for
-                                 Ruby scripts and binary extensions used by the load and require methods.
-                                 The initial value is the value of the arguments passed via the -I command-
-                                 line option, followed by an installation-defined standard library location, fol-
-                                 lowed by the current directory (“.”). This variable may be set from within a
-                                 program to alter the default search path; typically, programs use $: << dir
-                                 to append dir to the path. [r/o]
-$-a              Object          True if the -a option is specified on the command line. [r/o]
-$-d              Object          Synonym for $DEBUG.
-$DEBUG           Object          Set to true if the -d command-line option is specified.
-__FILE__         String          The name of the current source file. [r/o]
-$F               Array           The array that receives the split input line if the -a command-line option is
-                                 used.
-$FILENAME        String          The name of the current input file. Equivalent to $<.filename. [r/o]
-$-i              String          If in-place edit mode is enabled (perhaps using the -i command-line
-                                 option), $-i holds the extension used when creating the backup file. If you
-                                 set a value into $-i, enables in-place edit mode.
-$-I              Array           Synonym for $:. [r/o]
-$-K              String          Sets the multibyte coding system for strings and regular expressions. Equiv-
-                                 alent to the -K command-line option.
-$-l              Object          Set to true if the -l option (which enables line-end processing) is present
-                                 on the command line. [r/o]
-__LINE__         String          The current line number in the source file. [r/o]
-$LOAD_PATH       Array           A synonym for $:. [r/o]
-$-p              Object          Set to true if the -p option (which puts an implicit while gets . . . end
-                                 loop around your program) is present on the command line. [r/o]
-$VERBOSE         Object          Set to true if the -v, --version, -W, or -w option is specified on the com-
-                                 mand line. Set to false if no option, or -W1 is given. Set to nil if -W0
-                                 was specified. Setting this option to true causes the interpreter and some
-                                 library routines to report additional information. Setting to nil suppresses
-                                 all warnings (including the output of Kernel.warn).
-$-v              Object          Synonym for $VERBOSE.
-$-w              Object          Synonym for $VERBOSE.
-=end
+# Execution Environment Variables
+# ---------------------------------------------------------------------------------------------------
+#
+# $0               String          The name of the top-level Ruby program being executed. Typically this will
+#                                  be the program’s filename. On some operating systems, assigning to this
+#                                  variable will change the name of the process reported (for example) by the
+#                                  ps(1) command.
+# $*               Array           An array of strings containing the command-line options from the invoca-
+#                                  tion of the program. Options used by the Ruby interpreter will have been
+#                                  removed. [r/o]
+# $"               Array           An array containing the filenames of modules loaded by require. [r/o]
+# $$               Integer          The process number of the program being executed. [r/o]
+# $?               Process::Status The exit status of the last child process to terminate. [r/o, thread]
+# $:               Array           An array of strings, where each string specifies a directory to be searched for
+#                                  Ruby scripts and binary extensions used by the load and require methods.
+#                                  The initial value is the value of the arguments passed via the -I command-
+#                                  line option, followed by an installation-defined standard library location, fol-
+#                                  lowed by the current directory (“.”). This variable may be set from within a
+#                                  program to alter the default search path; typically, programs use $: << dir
+#                                  to append dir to the path. [r/o]
+# $-a              Object          True if the -a option is specified on the command line. [r/o]
+# $-d              Object          Synonym for $DEBUG.
+# $DEBUG           Object          Set to true if the -d command-line option is specified.
+# __FILE__         String          The name of the current source file. [r/o]
+# $F               Array           The array that receives the split input line if the -a command-line option is
+#                                  used.
+# $FILENAME        String          The name of the current input file. Equivalent to $<.filename. [r/o]
+# $-i              String          If in-place edit mode is enabled (perhaps using the -i command-line
+#                                  option), $-i holds the extension used when creating the backup file. If you
+#                                  set a value into $-i, enables in-place edit mode.
+# $-I              Array           Synonym for $:. [r/o]
+# $-K              String          Sets the multibyte coding system for strings and regular expressions. Equiv-
+#                                  alent to the -K command-line option.
+# $-l              Object          Set to true if the -l option (which enables line-end processing) is present
+#                                  on the command line. [r/o]
+# __LINE__         String          The current line number in the source file. [r/o]
+# $LOAD_PATH       Array           A synonym for $:. [r/o]
+# $-p              Object          Set to true if the -p option (which puts an implicit while gets . . . end
+#                                  loop around your program) is present on the command line. [r/o]
+# $VERBOSE         Object          Set to true if the -v, --version, -W, or -w option is specified on the com-
+#                                  mand line. Set to false if no option, or -W1 is given. Set to nil if -W0
+#                                  was specified. Setting this option to true causes the interpreter and some
+#                                  library routines to report additional information. Setting to nil suppresses
+#                                  all warnings (including the output of Kernel.warn).
+# $-v              Object          Synonym for $VERBOSE.
+# $-w              Object          Synonym for $VERBOSE.
 describe "Execution variable $:" do
   it "is initialized to an array of strings" do
     $:.is_a?(Array).should == true
@@ -1068,22 +1060,20 @@ describe "Global variable $0" do
   end
 end
 
-=begin
-Standard Objects
----------------------------------------------------------------------------------------------------
-
-ARGF             Object          A synonym for $<.
-ARGV             Array           A synonym for $*.
-ENV              Object          A hash-like object containing the program’s environment variables. An
-                                 instance of class Object, ENV implements the full set of Hash methods. Used
-                                 to query and set the value of an environment variable, as in ENV["PATH"]
-                                 and ENV["term"]="ansi".
-false            FalseClass      Singleton instance of class FalseClass. [r/o]
-nil              NilClass        The singleton instance of class NilClass. The value of uninitialized
-                                 instance and global variables. [r/o]
-self             Object          The receiver (object) of the current method. [r/o]
-true             TrueClass       Singleton instance of class TrueClass. [r/o]
-=end
+# Standard Objects
+# ---------------------------------------------------------------------------------------------------
+#
+# ARGF             Object          A synonym for $<.
+# ARGV             Array           A synonym for $*.
+# ENV              Object          A hash-like object containing the program’s environment variables. An
+#                                  instance of class Object, ENV implements the full set of Hash methods. Used
+#                                  to query and set the value of an environment variable, as in ENV["PATH"]
+#                                  and ENV["term"]="ansi".
+# false            FalseClass      Singleton instance of class FalseClass. [r/o]
+# nil              NilClass        The singleton instance of class NilClass. The value of uninitialized
+#                                  instance and global variables. [r/o]
+# self             Object          The receiver (object) of the current method. [r/o]
+# true             TrueClass       Singleton instance of class TrueClass. [r/o]
 
 describe "The predefined standard objects" do
   it "includes ARGF" do
@@ -1136,36 +1126,34 @@ describe "The self pseudo-variable" do
   end
 end
 
-=begin
-Global Constants
----------------------------------------------------------------------------------------------------
-
-The following constants are defined by the Ruby interpreter.
-
-DATA                 IO          If the main program file contains the directive __END__, then
-                                 the constant DATA will be initialized so that reading from it will
-                                 return lines following __END__ from the source file.
-FALSE                FalseClass  Synonym for false (deprecated, removed in Ruby 3).
-NIL                  NilClass    Synonym for nil (deprecated, removed in Ruby 3).
-RUBY_PLATFORM        String      The identifier of the platform running this program. This string
-                                 is in the same form as the platform identifier used by the GNU
-                                 configure utility (which is not a coincidence).
-RUBY_RELEASE_DATE    String      The date of this release.
-RUBY_VERSION         String      The version number of the interpreter.
-STDERR               IO          The actual standard error stream for the program. The initial
-                                 value of $stderr.
-STDIN                IO          The actual standard input stream for the program. The initial
-                                 value of $stdin.
-STDOUT               IO          The actual standard output stream for the program. The initial
-                                 value of $stdout.
-SCRIPT_LINES__       Hash        If a constant SCRIPT_LINES__ is defined and references a Hash,
-                                 Ruby will store an entry containing the contents of each file it
-                                 parses, with the file’s name as the key and an array of strings as
-                                 the value.
-TOPLEVEL_BINDING     Binding     A Binding object representing the binding at Ruby’s top level—
-                                 the level where programs are initially executed.
-TRUE                 TrueClass   Synonym for true (deprecated, removed in Ruby 3).
-=end
+# Global Constants
+# ---------------------------------------------------------------------------------------------------
+#
+# The following constants are defined by the Ruby interpreter.
+#
+# DATA                 IO          If the main program file contains the directive __END__, then
+#                                  the constant DATA will be initialized so that reading from it will
+#                                  return lines following __END__ from the source file.
+# FALSE                FalseClass  Synonym for false (deprecated, removed in Ruby 3).
+# NIL                  NilClass    Synonym for nil (deprecated, removed in Ruby 3).
+# RUBY_PLATFORM        String      The identifier of the platform running this program. This string
+#                                  is in the same form as the platform identifier used by the GNU
+#                                  configure utility (which is not a coincidence).
+# RUBY_RELEASE_DATE    String      The date of this release.
+# RUBY_VERSION         String      The version number of the interpreter.
+# STDERR               IO          The actual standard error stream for the program. The initial
+#                                  value of $stderr.
+# STDIN                IO          The actual standard input stream for the program. The initial
+#                                  value of $stdin.
+# STDOUT               IO          The actual standard output stream for the program. The initial
+#                                  value of $stdout.
+# SCRIPT_LINES__       Hash        If a constant SCRIPT_LINES__ is defined and references a Hash,
+#                                  Ruby will store an entry containing the contents of each file it
+#                                  parses, with the file’s name as the key and an array of strings as
+#                                  the value.
+# TOPLEVEL_BINDING     Binding     A Binding object representing the binding at Ruby’s top level—
+#                                  the level where programs are initially executed.
+# TRUE                 TrueClass   Synonym for true (deprecated, removed in Ruby 3).
 
 describe "The predefined global constants" do
   describe "TRUE" do
diff --git a/spec/ruby/library/bigdecimal/exponent_spec.rb b/spec/ruby/library/bigdecimal/exponent_spec.rb
index f63c4e5798..8877147955 100644
--- a/spec/ruby/library/bigdecimal/exponent_spec.rb
+++ b/spec/ruby/library/bigdecimal/exponent_spec.rb
@@ -18,17 +18,6 @@ describe "BigDecimal#exponent" do
     BigDecimal("1234567E10").exponent.should == 17
   end
 
-# commenting this spec out after discussion with Defiler, since it seems to be an MRI bug, not a real feature
-=begin
-  platform_is wordsize: 32 do
-    # TODO: write specs for both 32 and 64 bit
-    it "returns 0 if exponent can't be represented as Integer" do
-      BigDecimal("2E1000000000000000").exponent.should == 0
-      BigDecimal("-5E-999999999999999").exponent.should == 0
-    end
-  end
-=end
-
   it "returns 0 if self is 0" do
     BigDecimal("0").exponent.should == 0
     BigDecimal("+0").exponent.should == 0
diff --git a/spec/ruby/library/fiddle/handle/initialize_spec.rb b/spec/ruby/library/fiddle/handle/initialize_spec.rb
new file mode 100644
index 0000000000..51c2470efd
--- /dev/null
+++ b/spec/ruby/library/fiddle/handle/initialize_spec.rb
@@ -0,0 +1,10 @@
+require_relative '../../../spec_helper'
+require 'fiddle'
+
+describe "Fiddle::Handle#initialize" do
+  it "raises Fiddle::DLError if the library cannot be found" do
+    -> {
+      Fiddle::Handle.new("doesnotexist.doesnotexist")
+    }.should raise_error(Fiddle::DLError)
+  end
+end
diff --git a/spec/ruby/library/io-wait/wait_readable_spec.rb b/spec/ruby/library/io-wait/wait_readable_spec.rb
new file mode 100644
index 0000000000..48e0b4ef7d
--- /dev/null
+++ b/spec/ruby/library/io-wait/wait_readable_spec.rb
@@ -0,0 +1,25 @@
+require_relative '../../spec_helper'
+
+require 'io/wait'
+
+describe "IO#wait_readable" do
+  before :each do
+    @io = File.new(__FILE__ )
+  end
+
+  after :each do
+    @io.close
+  end
+
+  it "waits for the IO to become readable with no timeout" do
+    @io.wait_readable.should == @io
+  end
+
+  it "waits for the IO to become readable with the given timeout" do
+    @io.wait_readable(1).should == @io
+  end
+
+  it "waits for the IO to become readable with the given large timeout" do
+    @io.wait_readable(365 * 24 * 60 * 60).should == @io
+  end
+end
diff --git a/spec/ruby/library/io-wait/wait_writable_spec.rb b/spec/ruby/library/io-wait/wait_writable_spec.rb
new file mode 100644
index 0000000000..5900a0c566
--- /dev/null
+++ b/spec/ruby/library/io-wait/wait_writable_spec.rb
@@ -0,0 +1,18 @@
+require_relative '../../spec_helper'
+
+require 'io/wait'
+
+describe "IO#wait_writable" do
+  it "waits for the IO to become writable with no timeout" do
+    STDOUT.wait_writable.should == STDOUT
+  end
+
+  it "waits for the IO to become writable with the given timeout" do
+    STDOUT.wait_writable(1).should == STDOUT
+  end
+
+  it "waits for the IO to become writable with the given large timeout" do
+    # Represents one year and is larger than a 32-bit int
+    STDOUT.wait_writable(365 * 24 * 60 * 60).should == STDOUT
+  end
+end
diff --git a/spec/ruby/library/socket/addrinfo/initialize_spec.rb b/spec/ruby/library/socket/addrinfo/initialize_spec.rb
index 00250439fd..83b204b575 100644
--- a/spec/ruby/library/socket/addrinfo/initialize_spec.rb
+++ b/spec/ruby/library/socket/addrinfo/initialize_spec.rb
@@ -91,7 +91,7 @@ describe "Addrinfo#initialize" do
         @addrinfo.afamily.should == Socket::AF_INET6
       end
 
-      it "returns the 0 socket type" do
+      it "returns the specified socket type" do
         @addrinfo.socktype.should == Socket::SOCK_STREAM
       end
 
diff --git a/spec/ruby/library/socket/shared/pack_sockaddr.rb b/spec/ruby/library/socket/shared/pack_sockaddr.rb
index 2df09027c9..ca823742cb 100644
--- a/spec/ruby/library/socket/shared/pack_sockaddr.rb
+++ b/spec/ruby/library/socket/shared/pack_sockaddr.rb
@@ -19,6 +19,11 @@ describe :socket_pack_sockaddr_in, shared: true do
     Socket.unpack_sockaddr_in(sockaddr_in).should == [0, '127.0.0.1']
   end
 
+  it 'resolves the service name to a port' do
+    sockaddr_in = Socket.public_send(@method, 'http', '127.0.0.1')
+    Socket.unpack_sockaddr_in(sockaddr_in).should == [80, '127.0.0.1']
+  end
+
   describe 'using an IPv4 address' do
     it 'returns a String of 16 bytes' do
       str = Socket.public_send(@method, 80, '127.0.0.1')
diff --git a/spec/ruby/optional/capi/class_spec.rb b/spec/ruby/optional/capi/class_spec.rb
index 8e678c9111..abeba0f741 100644
--- a/spec/ruby/optional/capi/class_spec.rb
+++ b/spec/ruby/optional/capi/class_spec.rb
@@ -204,6 +204,10 @@ describe "C-API Class function" do
     it "returns a string for an anonymous class" do
       @s.rb_class2name(Class.new).should be_kind_of(String)
     end
+
+    it "returns a string beginning with # for an anonymous class" do
+      @s.rb_class2name(Struct.new(:x, :y).new(1, 2).class).should.start_with?('#')
+    end
   end
 
   describe "rb_class_path" do
diff --git a/spec/ruby/optional/capi/ext/kernel_spec.c b/spec/ruby/optional/capi/ext/kernel_spec.c
index 46af8696a5..e194ba8fde 100644
--- a/spec/ruby/optional/capi/ext/kernel_spec.c
+++ b/spec/ruby/optional/capi/ext/kernel_spec.c
@@ -112,6 +112,10 @@ VALUE kernel_spec_rb_eval_string(VALUE self, VALUE str) {
   return rb_eval_string(RSTRING_PTR(str));
 }
 
+VALUE kernel_spec_rb_eval_cmd_kw(VALUE self, VALUE cmd, VALUE args, VALUE kw_splat) {
+  return rb_eval_cmd_kw(cmd, args, NUM2INT(kw_splat));
+}
+
 VALUE kernel_spec_rb_raise(VALUE self, VALUE hash) {
   rb_hash_aset(hash, ID2SYM(rb_intern("stage")), ID2SYM(rb_intern("before")));
   if (self != Qundef)
@@ -361,6 +365,7 @@ void Init_kernel_spec(void) {
   rb_define_method(cls, "rb_frame_this_func_test_again", kernel_spec_rb_frame_this_func, 0);
   rb_define_method(cls, "rb_ensure", kernel_spec_rb_ensure, 4);
   rb_define_method(cls, "rb_eval_string", kernel_spec_rb_eval_string, 1);
+  rb_define_method(cls, "rb_eval_cmd_kw", kernel_spec_rb_eval_cmd_kw, 3);
   rb_define_method(cls, "rb_raise", kernel_spec_rb_raise, 1);
   rb_define_method(cls, "rb_throw", kernel_spec_rb_throw, 1);
   rb_define_method(cls, "rb_throw_obj", kernel_spec_rb_throw_obj, 2);
diff --git a/spec/ruby/optional/capi/ext/object_spec.c b/spec/ruby/optional/capi/ext/object_spec.c
index 967b355c4a..30ac44cf1f 100644
--- a/spec/ruby/optional/capi/ext/object_spec.c
+++ b/spec/ruby/optional/capi/ext/object_spec.c
@@ -393,6 +393,18 @@ static VALUE object_spec_rb_class_inherited_p(VALUE self, VALUE mod, VALUE arg)
   return rb_class_inherited_p(mod, arg);
 }
 
+static int foreach_f(ID key, VALUE val, VALUE ary) {
+  rb_ary_push(ary, ID2SYM(key));
+  rb_ary_push(ary, val);
+  return ST_CONTINUE;
+}
+
+static VALUE object_spec_rb_ivar_foreach(VALUE self, VALUE obj) {
+  VALUE ary = rb_ary_new();
+  rb_ivar_foreach(obj, foreach_f, ary);
+  return ary;
+}
+
 static VALUE speced_allocator(VALUE klass) {
   VALUE flags = 0;
   VALUE instance;
@@ -508,6 +520,7 @@ void Init_object_spec(void) {
   rb_define_method(cls, "speced_allocator?", speced_allocator_p, 1);
   rb_define_method(cls, "custom_alloc_func?", custom_alloc_func_p, 1);
   rb_define_method(cls, "not_implemented_method", rb_f_notimplement, -1);
+  rb_define_method(cls, "rb_ivar_foreach", object_spec_rb_ivar_foreach, 1);
 }
 
 #ifdef __cplusplus
diff --git a/spec/ruby/optional/capi/fixtures/object.rb b/spec/ruby/optional/capi/fixtures/object.rb
new file mode 100644
index 0000000000..a59f2309d8
--- /dev/null
+++ b/spec/ruby/optional/capi/fixtures/object.rb
@@ -0,0 +1,29 @@
+class CApiObjectSpecs
+  class IVars
+    def initialize
+      @a = 3
+      @b = 7
+      @c = 4
+    end
+
+    def self.set_class_variables
+      @@foo = :a
+      @@bar = :b
+      @@baz = :c
+    end
+  end
+
+  module MVars
+    @@mvar = :foo
+    @@mvar2 = :bar
+
+    @ivar = :baz
+  end
+
+  module CVars
+    @@cvar = :foo
+    @@cvar2 = :bar
+
+    @ivar = :baz
+  end
+end
diff --git a/spec/ruby/optional/capi/kernel_spec.rb b/spec/ruby/optional/capi/kernel_spec.rb
index d1e3e03582..54d8d8a8d3 100644
--- a/spec/ruby/optional/capi/kernel_spec.rb
+++ b/spec/ruby/optional/capi/kernel_spec.rb
@@ -504,6 +504,25 @@ describe "C-API Kernel function" do
     end
   end
 
+  describe "rb_eval_cmd_kw" do
+    it "evaluates a string of ruby code" do
+      @s.rb_eval_cmd_kw("1+1", [], 0).should == 2
+    end
+
+    it "calls a proc with the supplied arguments" do
+      @s.rb_eval_cmd_kw(-> *x { x.map { |i| i + 1 } }, [1, 3, 7], 0).should == [2, 4, 8]
+    end
+
+    it "calls a proc with keyword arguments if kw_splat is non zero" do
+      a_proc = -> *x, **y {
+        res = x.map { |i| i + 1 }
+        y.each { |k, v| res << k; res << v }
+        res
+      }
+      @s.rb_eval_cmd_kw(a_proc, [1, 3, 7, {a: 1, b: 2, c: 3}], 1).should == [2, 4, 8, :a, 1, :b, 2, :c, 3]
+    end
+  end
+
   describe "rb_block_proc" do
     it "converts the implicit block into a proc" do
       proc = @s.rb_block_proc { 1+1 }
diff --git a/spec/ruby/optional/capi/object_spec.rb b/spec/ruby/optional/capi/object_spec.rb
index b0f8a1f891..25a43d8908 100644
--- a/spec/ruby/optional/capi/object_spec.rb
+++ b/spec/ruby/optional/capi/object_spec.rb
@@ -1,4 +1,5 @@
 require_relative 'spec_helper'
+require_relative 'fixtures/object'
 
 load_extension("object")
 
@@ -983,5 +984,24 @@ describe "CApiObject" do
         @o.speced_allocator?(parent).should == true
       end
     end
+
+    describe "rb_ivar_foreach" do
+      it "calls the callback function for each instance variable on an object" do
+        o = CApiObjectSpecs::IVars.new
+        ary = @o.rb_ivar_foreach(o)
+        ary.should == [:@a, 3, :@b, 7, :@c, 4]
+      end
+
+      it "calls the callback function for each cvar and ivar on a class" do
+        ary = @o.rb_ivar_foreach(CApiObjectSpecs::CVars)
+        ary.should == [:__classpath__, 'CApiObjectSpecs::CVars', :@@cvar, :foo, :@@cvar2, :bar, :@ivar, :baz]
+      end
+
+      it "calls the callback function for each cvar and ivar on a module" do
+        ary = @o.rb_ivar_foreach(CApiObjectSpecs::MVars)
+        ary.should == [:__classpath__, 'CApiObjectSpecs::MVars', :@@mvar, :foo, :@@mvar2, :bar, :@ivar, :baz]
+      end
+
+    end
   end
 end
diff --git a/spec/ruby/optional/capi/shared/rbasic.rb b/spec/ruby/optional/capi/shared/rbasic.rb
index 105408ec3d..99c2044bd7 100644
--- a/spec/ruby/optional/capi/shared/rbasic.rb
+++ b/spec/ruby/optional/capi/shared/rbasic.rb
@@ -8,9 +8,16 @@ describe :rbasic, shared: true do
 
   it "reports the appropriate FREEZE flag for the object when reading" do
     obj, _ = @data.call
-    (@specs.get_flags(obj) & @freeze).should == 0
+    initial = @specs.get_flags(obj)
     obj.freeze
-    (@specs.get_flags(obj) & @freeze).should == @freeze
+    @specs.get_flags(obj).should == @freeze | initial
+  end
+
+  it "supports setting the FREEZE flag" do
+    obj, _ = @data.call
+    initial = @specs.get_flags(obj)
+    @specs.set_flags(obj, @freeze | initial).should == @freeze | initial
+    obj.should.frozen?
   end
 
   it "supports retrieving the (meta)class" do
diff --git a/spec/ruby/spec_helper.rb b/spec/ruby/spec_helper.rb
index f92d316c2a..3404521c03 100644
--- a/spec/ruby/spec_helper.rb
+++ b/spec/ruby/spec_helper.rb
@@ -27,7 +27,8 @@ unless ENV['MSPEC_RUNNER'] # Running directly with ruby some_spec.rb
   end
 end
 
-ruby_version_is ""..."2.7" do
+# Compare with SpecVersion directly here so it works even with --unguarded
+if VersionGuard::FULL_RUBY_VERSION < SpecVersion.new('2.7')
   abort "This version of ruby/spec requires Ruby 2.7+"
 end