Update to ruby/spec@37e52e5

32 files changed, 467 insertions, 39 deletions

diff --git a/spec/ruby/core/array/drop_spec.rb b/spec/ruby/core/array/drop_spec.rb
index 84ea86b04c..f911fd9018 100644
--- a/spec/ruby/core/array/drop_spec.rb
+++ b/spec/ruby/core/array/drop_spec.rb
@@ -1,4 +1,5 @@
 require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
 
 describe "Array#drop" do
   it "removes the specified number of elements from the start of the array" do
@@ -48,4 +49,16 @@ describe "Array#drop" do
 
     -> { [1, 2].drop(obj) }.should raise_error(TypeError)
   end
+
+  ruby_version_is ''...'3.0' do
+    it 'returns a subclass instance for Array subclasses' do
+      ArraySpecs::MyArray[1, 2, 3, 4, 5].drop(1).should be_an_instance_of(ArraySpecs::MyArray)
+    end
+  end
+
+  ruby_version_is '3.0' do
+    it 'returns a Array instance for Array subclasses' do
+      ArraySpecs::MyArray[1, 2, 3, 4, 5].drop(1).should be_an_instance_of(Array)
+    end
+  end
 end
diff --git a/spec/ruby/core/array/drop_while_spec.rb b/spec/ruby/core/array/drop_while_spec.rb
index cfb6b1e267..bb783d22a5 100644
--- a/spec/ruby/core/array/drop_while_spec.rb
+++ b/spec/ruby/core/array/drop_while_spec.rb
@@ -1,4 +1,5 @@
 require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
 
 describe "Array#drop_while" do
   it "removes elements from the start of the array while the block evaluates to true" do
@@ -12,4 +13,16 @@ describe "Array#drop_while" do
   it "removes elements from the start of the array until the block returns false" do
     [1, 2, 3, false, 5].drop_while { |n| n }.should == [false, 5]
   end
+
+  ruby_version_is ''...'3.0' do
+    it 'returns a subclass instance for Array subclasses' do
+      ArraySpecs::MyArray[1, 2, 3, 4, 5].drop_while { |n| n < 4 }.should be_an_instance_of(ArraySpecs::MyArray)
+    end
+  end
+
+  ruby_version_is '3.0' do
+    it 'returns a Array instance for Array subclasses' do
+      ArraySpecs::MyArray[1, 2, 3, 4, 5].drop_while { |n| n < 4 }.should be_an_instance_of(Array)
+    end
+  end
 end
diff --git a/spec/ruby/core/array/slice_spec.rb b/spec/ruby/core/array/slice_spec.rb
index f416d8d0ce..2f98df9488 100644
--- a/spec/ruby/core/array/slice_spec.rb
+++ b/spec/ruby/core/array/slice_spec.rb
@@ -185,6 +185,64 @@ describe "Array#slice!" do
       a.should == [3, 4]
     end
   end
+
+  describe "with a subclass of Array" do
+    before :each do
+      @array = ArraySpecs::MyArray[1, 2, 3, 4, 5]
+    end
+
+    ruby_version_is ''...'3.0' do
+      it "returns a subclass instance with [n, m]" do
+        @array.slice!(0, 2).should be_an_instance_of(ArraySpecs::MyArray)
+      end
+
+      it "returns a subclass instance with [-n, m]" do
+        @array.slice!(-3, 2).should be_an_instance_of(ArraySpecs::MyArray)
+      end
+
+      it "returns a subclass instance with [n..m]" do
+        @array.slice!(1..3).should be_an_instance_of(ArraySpecs::MyArray)
+      end
+
+      it "returns a subclass instance with [n...m]" do
+        @array.slice!(1...3).should be_an_instance_of(ArraySpecs::MyArray)
+      end
+
+      it "returns a subclass instance with [-n..-m]" do
+        @array.slice!(-3..-1).should be_an_instance_of(ArraySpecs::MyArray)
+      end
+
+      it "returns a subclass instance with [-n...-m]" do
+        @array.slice!(-3...-1).should be_an_instance_of(ArraySpecs::MyArray)
+      end
+    end
+
+    ruby_version_is '3.0' do
+      it "returns a Array instance with [n, m]" do
+        @array.slice!(0, 2).should be_an_instance_of(Array)
+      end
+
+      it "returns a Array instance with [-n, m]" do
+        @array.slice!(-3, 2).should be_an_instance_of(Array)
+      end
+
+      it "returns a Array instance with [n..m]" do
+        @array.slice!(1..3).should be_an_instance_of(Array)
+      end
+
+      it "returns a Array instance with [n...m]" do
+        @array.slice!(1...3).should be_an_instance_of(Array)
+      end
+
+      it "returns a Array instance with [-n..-m]" do
+        @array.slice!(-3..-1).should be_an_instance_of(Array)
+      end
+
+      it "returns a Array instance with [-n...-m]" do
+        @array.slice!(-3...-1).should be_an_instance_of(Array)
+      end
+    end
+  end
 end
 
 describe "Array#slice" do
diff --git a/spec/ruby/core/array/take_spec.rb b/spec/ruby/core/array/take_spec.rb
index 0de99b0a7e..4fb6f0ce75 100644
--- a/spec/ruby/core/array/take_spec.rb
+++ b/spec/ruby/core/array/take_spec.rb
@@ -1,4 +1,5 @@
 require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
 
 describe "Array#take" do
   it "returns the first specified number of elements" do
@@ -24,4 +25,16 @@ describe "Array#take" do
   it "raises an ArgumentError when the argument is negative" do
     ->{ [1].take(-3) }.should raise_error(ArgumentError)
   end
+
+  ruby_version_is ''...'3.0' do
+    it 'returns a subclass instance for Array subclasses' do
+      ArraySpecs::MyArray[1, 2, 3, 4, 5].take(1).should be_an_instance_of(ArraySpecs::MyArray)
+    end
+  end
+
+  ruby_version_is '3.0' do
+    it 'returns a Array instance for Array subclasses' do
+      ArraySpecs::MyArray[1, 2, 3, 4, 5].take(1).should be_an_instance_of(Array)
+    end
+  end
 end
diff --git a/spec/ruby/core/array/take_while_spec.rb b/spec/ruby/core/array/take_while_spec.rb
index f159e6f251..363419b265 100644
--- a/spec/ruby/core/array/take_while_spec.rb
+++ b/spec/ruby/core/array/take_while_spec.rb
@@ -1,4 +1,5 @@
 require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
 
 describe "Array#take_while" do
   it "returns all elements until the block returns false" do
@@ -12,4 +13,16 @@ describe "Array#take_while" do
   it "returns all elements until the block returns false" do
     [1, 2, false, 4].take_while{ |element| element }.should == [1, 2]
   end
+
+  ruby_version_is ''...'3.0' do
+    it 'returns a subclass instance for Array subclasses' do
+      ArraySpecs::MyArray[1, 2, 3, 4, 5].take_while { |n| n < 4 }.should be_an_instance_of(ArraySpecs::MyArray)
+    end
+  end
+
+  ruby_version_is '3.0' do
+    it 'returns a Array instance for Array subclasses' do
+      ArraySpecs::MyArray[1, 2, 3, 4, 5].take_while { |n| n < 4 }.should be_an_instance_of(Array)
+    end
+  end
 end
diff --git a/spec/ruby/core/basicobject/singleton_method_added_spec.rb b/spec/ruby/core/basicobject/singleton_method_added_spec.rb
index 8d256e22db..ab6b2a2d10 100644
--- a/spec/ruby/core/basicobject/singleton_method_added_spec.rb
+++ b/spec/ruby/core/basicobject/singleton_method_added_spec.rb
@@ -83,4 +83,63 @@ describe "BasicObject#singleton_method_added" do
     end
     ScratchPad.recorded.should == [:singleton_method_added, :new_method_with_define_method]
   end
+
+  describe "when singleton_method_added is undefined" do
+    it "raises NoMethodError for a metaclass" do
+      class BasicObjectSpecs::NoSingletonMethodAdded
+        class << self
+          undef_method :singleton_method_added
+        end
+
+        -> {
+          def self.foo
+          end
+        }.should raise_error(NoMethodError, /undefined method `singleton_method_added' for/)
+      end
+    end
+
+    it "raises NoMethodError for a singleton instance" do
+      object = Object.new
+      class << object
+        undef_method :singleton_method_added
+
+        -> {
+          def foo
+          end
+        }.should raise_error(NoMethodError, /undefined method `singleton_method_added' for #<Object:/)
+
+        -> {
+          define_method(:bar) {}
+        }.should raise_error(NoMethodError, /undefined method `singleton_method_added' for #<Object:/)
+      end
+
+      -> {
+        object.define_singleton_method(:baz) {}
+      }.should raise_error(NoMethodError, /undefined method `singleton_method_added' for #<Object:/)
+    end
+
+    it "calls #method_missing" do
+      ScratchPad.record []
+      object = Object.new
+      class << object
+        def method_missing(*args)
+          ScratchPad << args
+        end
+
+        undef_method :singleton_method_added
+
+        def foo
+        end
+
+        define_method(:bar) {}
+      end
+      object.define_singleton_method(:baz) {}
+
+      ScratchPad.recorded.should == [
+        [:singleton_method_added, :foo],
+        [:singleton_method_added, :bar],
+        [:singleton_method_added, :baz],
+      ]
+    end
+  end
 end
diff --git a/spec/ruby/core/dir/children_spec.rb b/spec/ruby/core/dir/children_spec.rb
index e0325a24b8..f890f54eb4 100644
--- a/spec/ruby/core/dir/children_spec.rb
+++ b/spec/ruby/core/dir/children_spec.rb
@@ -100,10 +100,18 @@ ruby_version_is "2.6" do
       a.should == %w|.dotfile.ext directory|
     end
 
-    it "accepts an options Hash" do
+    it "accepts an encoding keyword for the encoding of the entries" do
       @dir = Dir.new("#{DirSpecs.mock_dir}/deeply/nested", encoding: "utf-8")
-      a = @dir.children.sort
-      a.should == %w|.dotfile.ext directory|
+      dirs = @dir.to_a.sort
+      dirs.each { |d| d.encoding.should == Encoding::UTF_8 }
+    end
+
+    ruby_version_is ""..."2.7" do
+      it "accepts nil options" do
+        @dir = Dir.new("#{DirSpecs.mock_dir}/deeply/nested", nil)
+        dirs = @dir.to_a.sort
+        dirs.each { |d| d.encoding.should == Encoding.find("filesystem") }
+      end
     end
 
     it "returns children encoded with the filesystem encoding by default" do
diff --git a/spec/ruby/core/dir/each_child_spec.rb b/spec/ruby/core/dir/each_child_spec.rb
index 93b4a1aec1..684f42acc0 100644
--- a/spec/ruby/core/dir/each_child_spec.rb
+++ b/spec/ruby/core/dir/each_child_spec.rb
@@ -10,6 +10,18 @@ describe "Dir.each_child" do
     DirSpecs.delete_mock_dirs
   end
 
+  it "accepts an encoding keyword for the encoding of the entries" do
+    dirs = Dir.each_child("#{DirSpecs.mock_dir}/deeply/nested", encoding: "utf-8").to_a.sort
+    dirs.each {|dir| dir.encoding.should == Encoding::UTF_8}
+  end
+
+  ruby_version_is ""..."2.7" do
+    it "accepts nil options" do
+      dirs = Dir.each_child("#{DirSpecs.mock_dir}/deeply/nested", nil).to_a.sort
+      dirs.each {|dir| dir.encoding.should == Encoding.find("filesystem")}
+    end
+  end
+
   it "yields all names in an existing directory to the provided block" do
     a, b = [], []
 
diff --git a/spec/ruby/core/dir/entries_spec.rb b/spec/ruby/core/dir/entries_spec.rb
index 33568b6fc4..9aa58657db 100644
--- a/spec/ruby/core/dir/entries_spec.rb
+++ b/spec/ruby/core/dir/entries_spec.rb
@@ -35,9 +35,16 @@ describe "Dir.entries" do
     Dir.entries(p)
   end
 
-  it "accepts an options Hash" do
-    a = Dir.entries("#{DirSpecs.mock_dir}/deeply/nested", encoding: "utf-8").sort
-    a.should == %w|. .. .dotfile.ext directory|
+  it "accepts an encoding keyword for the encoding of the entries" do
+    dirs = Dir.entries("#{DirSpecs.mock_dir}/deeply/nested", encoding: "utf-8").to_a.sort
+    dirs.each {|dir| dir.encoding.should == Encoding::UTF_8}
+  end
+
+  ruby_version_is ""..."2.7" do
+    it "accepts nil options" do
+      dirs = Dir.entries("#{DirSpecs.mock_dir}/deeply/nested", nil).to_a.sort
+      dirs.each {|dir| dir.encoding.should == Encoding.find("filesystem")}
+    end
   end
 
   it "returns entries encoded with the filesystem encoding by default" do
diff --git a/spec/ruby/core/dir/foreach_spec.rb b/spec/ruby/core/dir/foreach_spec.rb
index 1560b85f8a..c3ddb27a84 100644
--- a/spec/ruby/core/dir/foreach_spec.rb
+++ b/spec/ruby/core/dir/foreach_spec.rb
@@ -39,6 +39,18 @@ describe "Dir.foreach" do
     Dir.foreach(DirSpecs.mock_dir).to_a.sort.should == DirSpecs.expected_paths
   end
 
+  it "accepts an encoding keyword for the encoding of the entries" do
+    dirs = Dir.foreach("#{DirSpecs.mock_dir}/deeply/nested", encoding: "utf-8").to_a.sort
+    dirs.each {|dir| dir.encoding.should == Encoding::UTF_8}
+  end
+
+  ruby_version_is ""..."2.7" do
+    it "accepts nil options" do
+      dirs = Dir.foreach("#{DirSpecs.mock_dir}/deeply/nested", nil).to_a.sort
+      dirs.each {|dir| dir.encoding.should == Encoding.find("filesystem")}
+    end
+  end
+
   describe "when no block is given" do
     it "returns an Enumerator" do
       Dir.foreach(DirSpecs.mock_dir).should be_an_instance_of(Enumerator)
diff --git a/spec/ruby/core/enumerator/lazy/chunk_while_spec.rb b/spec/ruby/core/enumerator/lazy/chunk_while_spec.rb
index d555089872..772bd42de9 100644
--- a/spec/ruby/core/enumerator/lazy/chunk_while_spec.rb
+++ b/spec/ruby/core/enumerator/lazy/chunk_while_spec.rb
@@ -6,4 +6,9 @@ describe "Enumerator::Lazy#chunk_while" do
     s.lazy.chunk_while { |a, b| false }.first(100).should ==
       s.first(100).chunk_while { |a, b| false }.to_a
   end
+
+  it "should return a lazy enumerator" do
+    s = 0..Float::INFINITY
+    s.lazy.chunk_while { |a, b| false }.should be_kind_of(Enumerator::Lazy)
+  end
 end
diff --git a/spec/ruby/core/enumerator/lazy/slice_after_spec.rb b/spec/ruby/core/enumerator/lazy/slice_after_spec.rb
index 438df8d550..8b08a1ecfd 100644
--- a/spec/ruby/core/enumerator/lazy/slice_after_spec.rb
+++ b/spec/ruby/core/enumerator/lazy/slice_after_spec.rb
@@ -6,4 +6,9 @@ describe "Enumerator::Lazy#slice_after" do
     s.lazy.slice_after { |n| true }.first(100).should ==
       s.first(100).slice_after { |n| true }.to_a
   end
+
+  it "should return a lazy enumerator" do
+    s = 0..Float::INFINITY
+    s.lazy.slice_after { |n| true }.should be_kind_of(Enumerator::Lazy)
+  end
 end
diff --git a/spec/ruby/core/enumerator/lazy/slice_before_spec.rb b/spec/ruby/core/enumerator/lazy/slice_before_spec.rb
index 6c8660c1a1..9c1ec9ba4a 100644
--- a/spec/ruby/core/enumerator/lazy/slice_before_spec.rb
+++ b/spec/ruby/core/enumerator/lazy/slice_before_spec.rb
@@ -6,4 +6,9 @@ describe "Enumerator::Lazy#slice_before" do
     s.lazy.slice_before { |n| true }.first(100).should ==
       s.first(100).slice_before { |n| true }.to_a
   end
+
+  it "should return a lazy enumerator" do
+    s = 0..Float::INFINITY
+    s.lazy.slice_before { |n| true }.should be_kind_of(Enumerator::Lazy)
+  end
 end
diff --git a/spec/ruby/core/enumerator/lazy/slice_when_spec.rb b/spec/ruby/core/enumerator/lazy/slice_when_spec.rb
index e7673def47..f83403425d 100644
--- a/spec/ruby/core/enumerator/lazy/slice_when_spec.rb
+++ b/spec/ruby/core/enumerator/lazy/slice_when_spec.rb
@@ -6,4 +6,9 @@ describe "Enumerator::Lazy#slice_when" do
     s.lazy.slice_when { |a, b| true }.first(100).should ==
       s.first(100).slice_when { |a, b| true }.to_a
   end
+
+  it "should return a lazy enumerator" do
+    s = 0..Float::INFINITY
+    s.lazy.slice_when { |a, b| true }.should be_kind_of(Enumerator::Lazy)
+  end
 end
diff --git a/spec/ruby/core/env/except_spec.rb b/spec/ruby/core/env/except_spec.rb
new file mode 100644
index 0000000000..cfe5865abe
--- /dev/null
+++ b/spec/ruby/core/env/except_spec.rb
@@ -0,0 +1,36 @@
+require_relative 'spec_helper'
+require_relative 'shared/to_hash'
+
+ruby_version_is "3.0" do
+  describe "ENV.except" do
+    before do
+      @orig_hash = ENV.to_hash
+    end
+
+    after do
+      ENV.replace @orig_hash
+    end
+
+    # Testing the method without arguments is covered via
+    it_behaves_like :env_to_hash, :except
+
+    it "returns a hash without the requested subset" do
+      ENV.clear
+
+      ENV['one'] = '1'
+      ENV['two'] = '2'
+      ENV['three'] = '3'
+
+      ENV.except('one', 'three').should == { 'two' => '2' }
+    end
+
+    it "ignores keys not present in the original hash" do
+      ENV.clear
+
+      ENV['one'] = '1'
+      ENV['two'] = '2'
+
+      ENV.except('one', 'three').should == { 'two' => '2' }
+    end
+  end
+end
diff --git a/spec/ruby/core/io/close_spec.rb b/spec/ruby/core/io/close_spec.rb
index dda82b34de..eb560eaf67 100644
--- a/spec/ruby/core/io/close_spec.rb
+++ b/spec/ruby/core/io/close_spec.rb
@@ -45,19 +45,36 @@ describe "IO#close" do
   end
 
   it 'raises an IOError with a clear message' do
-    read_io, write_io = IO.pipe
-    going_to_read = false
-    thread = Thread.new do
-      -> do
-        going_to_read = true
-        read_io.read
-      end.should raise_error(IOError, 'stream closed in another thread')
-    end
-
-    Thread.pass until going_to_read && thread.stop?
-    read_io.close
-    thread.join
-    write_io.close
+    matching_exception = nil
+
+    -> do
+      IOSpecs::THREAD_CLOSE_RETRIES.times do
+        read_io, write_io = IO.pipe
+        going_to_read = false
+
+        thread = Thread.new do
+          begin
+            going_to_read = true
+            read_io.read
+          rescue IOError => ioe
+            if ioe.message == IOSpecs::THREAD_CLOSE_ERROR_MESSAGE
+              matching_exception = ioe
+            end
+            # try again
+          end
+        end
+
+        # best attempt to ensure the thread is actually blocked on read
+        Thread.pass until going_to_read && thread.stop?
+        sleep(0.001)
+
+        read_io.close
+        thread.join
+        write_io.close
+
+        matching_exception&.tap {|ex| raise ex}
+      end
+    end.should raise_error(IOError, IOSpecs::THREAD_CLOSE_ERROR_MESSAGE)
   end
 end
 
diff --git a/spec/ruby/core/io/fixtures/classes.rb b/spec/ruby/core/io/fixtures/classes.rb
index 5cc42c9b44..5d81d5fcd9 100644
--- a/spec/ruby/core/io/fixtures/classes.rb
+++ b/spec/ruby/core/io/fixtures/classes.rb
@@ -1,6 +1,9 @@
 # -*- encoding: utf-8 -*-
 
 module IOSpecs
+  THREAD_CLOSE_RETRIES = 10
+  THREAD_CLOSE_ERROR_MESSAGE = 'stream closed in another thread'
+
   class SubIO < IO
   end
 
diff --git a/spec/ruby/core/kernel/fixtures/classes.rb b/spec/ruby/core/kernel/fixtures/classes.rb
index 8702c925c8..1bf5715c50 100644
--- a/spec/ruby/core/kernel/fixtures/classes.rb
+++ b/spec/ruby/core/kernel/fixtures/classes.rb
@@ -362,18 +362,19 @@ module KernelSpecs
   class RespondViaMissing
     def respond_to_missing?(method, priv=false)
       case method
-        when :handled_publicly
-          true
-        when :handled_privately
-          priv
-        when :not_handled
-          false
-        else
-          raise "Typo in method name"
+      when :handled_publicly
+        true
+      when :handled_privately
+        priv
+      when :not_handled
+        false
+      else
+        raise "Typo in method name: #{method.inspect}"
       end
     end
 
     def method_missing(method, *args)
+      raise "the method name should be a Symbol" unless Symbol === method
       "Done #{method}(#{args})"
     end
   end
diff --git a/spec/ruby/core/kernel/public_send_spec.rb b/spec/ruby/core/kernel/public_send_spec.rb
index 6b942a2e4b..4dae419ff9 100644
--- a/spec/ruby/core/kernel/public_send_spec.rb
+++ b/spec/ruby/core/kernel/public_send_spec.rb
@@ -104,5 +104,13 @@ describe "Kernel#public_send" do
     }.should raise_error(NoMethodError)
   end
 
+  it "includes `public_send` in the backtrace when passed not enough arguments" do
+    -> { public_send() }.should raise_error(ArgumentError) { |e| e.backtrace[0].should.include?("`public_send'") }
+  end
+
+  it "includes `public_send` in the backtrace when passed a single incorrect argument" do
+    -> { public_send(Object.new) }.should raise_error(TypeError) { |e| e.backtrace[0].should.include?("`public_send'") }
+  end
+
   it_behaves_like :basicobject_send, :public_send
 end
diff --git a/spec/ruby/core/kernel/shared/method.rb b/spec/ruby/core/kernel/shared/method.rb
index 3418966b1b..8b6ab23fd3 100644
--- a/spec/ruby/core/kernel/shared/method.rb
+++ b/spec/ruby/core/kernel/shared/method.rb
@@ -15,12 +15,18 @@ describe :kernel_method, shared: true do
     m.call.should == 'class done'
   end
 
-  it "returns a method object if we repond_to_missing? method" do
+  it "returns a method object if respond_to_missing?(method) is true" do
     m = KernelSpecs::RespondViaMissing.new.send(@method, :handled_publicly)
     m.should be_an_instance_of Method
     m.call(42).should == "Done handled_publicly([42])"
   end
 
+  it "the returned method object if respond_to_missing?(method) calls #method_missing with a Symbol name" do
+    m = KernelSpecs::RespondViaMissing.new.send(@method, "handled_publicly")
+    m.should be_an_instance_of Method
+    m.call(42).should == "Done handled_publicly([42])"
+  end
+
   it "raises a NameError for an invalid method name" do
     class KernelSpecs::Foo; def bar; 'done'; end; end
     -> {
diff --git a/spec/ruby/core/kernel/shared/require.rb b/spec/ruby/core/kernel/shared/require.rb
index d656b3b2f2..9a2c38be1a 100644
--- a/spec/ruby/core/kernel/shared/require.rb
+++ b/spec/ruby/core/kernel/shared/require.rb
@@ -546,8 +546,12 @@ describe :kernel_require, shared: true do
       ScratchPad.recorded.should == []
     end
 
-    it "complex, enumerator, rational and thread are already required" do
-      provided = %w[complex enumerator rational thread]
+    provided = %w[complex enumerator rational thread]
+    ruby_version_is "2.7" do
+      provided << 'ruby2_keywords'
+    end
+
+    it "#{provided.join(', ')} are already required" do
       features = ruby_exe("puts $LOADED_FEATURES", options: '--disable-gems')
       provided.each { |feature|
         features.should =~ /\b#{feature}\.(rb|so|jar)$/
diff --git a/spec/ruby/core/main/ruby2_keywords_spec.rb b/spec/ruby/core/main/ruby2_keywords_spec.rb
new file mode 100644
index 0000000000..0999cddeed
--- /dev/null
+++ b/spec/ruby/core/main/ruby2_keywords_spec.rb
@@ -0,0 +1,11 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+ruby_version_is "2.7" do
+  describe "main.ruby2_keywords" do
+    it "is the same as Object.ruby2_keywords" do
+      main = TOPLEVEL_BINDING.receiver
+      main.should have_private_method(:ruby2_keywords)
+    end
+  end
+end
diff --git a/spec/ruby/core/module/attr_accessor_spec.rb b/spec/ruby/core/module/attr_accessor_spec.rb
index e6a6ac7b66..ba5289cbea 100644
--- a/spec/ruby/core/module/attr_accessor_spec.rb
+++ b/spec/ruby/core/module/attr_accessor_spec.rb
@@ -33,7 +33,20 @@ describe "Module#attr_accessor" do
       attr_accessor :spec_attr_accessor
     end
 
-    -> { true.spec_attr_accessor = "a" }.should raise_error(RuntimeError)
+    -> { true.spec_attr_accessor = "a" }.should raise_error(FrozenError)
+  end
+
+  it "raises FrozenError if the receiver if frozen" do
+    c = Class.new do
+      attr_accessor :foo
+    end
+    obj = c.new
+    obj.foo = 1
+    obj.foo.should == 1
+
+    obj.freeze
+    -> { obj.foo = 42 }.should raise_error(FrozenError)
+    obj.foo.should == 1
   end
 
   it "converts non string/symbol names to strings using to_str" do
diff --git a/spec/ruby/core/module/attr_writer_spec.rb b/spec/ruby/core/module/attr_writer_spec.rb
index dbf30c8144..0e9d201317 100644
--- a/spec/ruby/core/module/attr_writer_spec.rb
+++ b/spec/ruby/core/module/attr_writer_spec.rb
@@ -29,7 +29,17 @@ describe "Module#attr_writer" do
       attr_writer :spec_attr_writer
     end
 
-    -> { true.spec_attr_writer = "a" }.should raise_error(RuntimeError)
+    -> { true.spec_attr_writer = "a" }.should raise_error(FrozenError)
+  end
+
+  it "raises FrozenError if the receiver if frozen" do
+    c = Class.new do
+      attr_writer :foo
+    end
+    obj = c.new
+    obj.freeze
+
+    -> { obj.foo = 42 }.should raise_error(FrozenError)
   end
 
   it "converts non string/symbol names to strings using to_str" do
diff --git a/spec/ruby/core/module/const_defined_spec.rb b/spec/ruby/core/module/const_defined_spec.rb
index 0673adca3d..75730395e8 100644
--- a/spec/ruby/core/module/const_defined_spec.rb
+++ b/spec/ruby/core/module/const_defined_spec.rb
@@ -40,6 +40,11 @@ describe "Module#const_defined?" do
     ConstantSpecs::ContainerA::ChildA.const_defined?(:CS_CONST4, true).should be_true
   end
 
+  it "coerces the inherit flag to a boolean" do
+    ConstantSpecs::ContainerA::ChildA.const_defined?(:CS_CONST4, nil).should be_false
+    ConstantSpecs::ContainerA::ChildA.const_defined?(:CS_CONST4, :true).should be_true
+  end
+
   it "returns true if the given String names a constant defined in the receiver" do
     ConstantSpecs.const_defined?("CS_CONST2").should == true
     ConstantSpecs.const_defined?("ModuleA").should == true
diff --git a/spec/ruby/core/module/const_get_spec.rb b/spec/ruby/core/module/const_get_spec.rb
index 0a6702903f..9f9fafe5bb 100644
--- a/spec/ruby/core/module/const_get_spec.rb
+++ b/spec/ruby/core/module/const_get_spec.rb
@@ -88,6 +88,14 @@ describe "Module#const_get" do
     end.should raise_error(NameError)
   end
 
+  it "coerces the inherit flag to a boolean" do
+    ConstantSpecs::ContainerA::ChildA.const_get(:CS_CONST4, :true).should == :const4
+
+    -> do
+      ConstantSpecs::ContainerA::ChildA.const_get(:CS_CONST1, nil)
+    end.should raise_error(NameError)
+  end
+
   it "accepts a toplevel scope qualifier" do
     ConstantSpecs.const_get("::CS_CONST1").should == :const1
   end
diff --git a/spec/ruby/core/module/refine_spec.rb b/spec/ruby/core/module/refine_spec.rb
index 54217a9326..e5f65f5f96 100644
--- a/spec/ruby/core/module/refine_spec.rb
+++ b/spec/ruby/core/module/refine_spec.rb
@@ -574,6 +574,43 @@ describe "Module#refine" do
     end
 
     ruby_version_is "" ... "2.7" do
+      it "is not honored by Kernel#public_method" do
+        klass = Class.new
+        refinement = Module.new do
+          refine klass do
+            def foo; end
+          end
+        end
+
+        -> {
+          Module.new do
+            using refinement
+            klass.new.public_method(:foo)
+          end
+        }.should raise_error(NameError, /undefined method `foo'/)
+      end
+    end
+
+    ruby_version_is "2.7" do
+      it "is honored by Kernel#public_method" do
+        klass = Class.new
+        refinement = Module.new do
+          refine klass do
+            def foo; end
+          end
+        end
+
+        result = nil
+        Module.new do
+          using refinement
+          result = klass.new.public_method(:foo).class
+        end
+
+        result.should == Method
+      end
+    end
+
+    ruby_version_is "" ... "2.7" do
       it "is not honored by Kernel#instance_method" do
         klass = Class.new
         refinement = Module.new do
@@ -592,7 +629,7 @@ describe "Module#refine" do
     end
 
     ruby_version_is "2.7" do
-      it "is honored by Kernel#method" do
+      it "is honored by Kernel#instance_method" do
         klass = Class.new
         refinement = Module.new do
           refine klass do
diff --git a/spec/ruby/core/proc/shared/call.rb b/spec/ruby/core/proc/shared/call.rb
index c30ea84b23..dbec34df4b 100644
--- a/spec/ruby/core/proc/shared/call.rb
+++ b/spec/ruby/core/proc/shared/call.rb
@@ -49,6 +49,9 @@ describe :proc_call_on_proc_or_lambda, shared: true do
 
     a = proc {|x| x}.send(@method, 1, 2, 3)
     a.should == 1
+
+    a = proc {|x:| x}.send(@method, 2, x: 1)
+    a.should == 1
   end
 
   it "will call #to_ary on argument and return self if return is nil" do
diff --git a/spec/ruby/core/regexp/case_compare_spec.rb b/spec/ruby/core/regexp/case_compare_spec.rb
index a621713f6f..5ae8b56c6a 100644
--- a/spec/ruby/core/regexp/case_compare_spec.rb
+++ b/spec/ruby/core/regexp/case_compare_spec.rb
@@ -22,4 +22,14 @@ describe "Regexp#===" do
     (/abc/ === nil).should be_false
     (/abc/ === /abc/).should be_false
   end
+
+  it "uses #to_str on string-like objects" do
+    stringlike = Class.new do
+      def to_str
+        "abc"
+      end
+    end.new
+
+    (/abc/ === stringlike).should be_true
+  end
 end
diff --git a/spec/ruby/core/signal/trap_spec.rb b/spec/ruby/core/signal/trap_spec.rb
index 831a5ee23e..45879b7147 100644
--- a/spec/ruby/core/signal/trap_spec.rb
+++ b/spec/ruby/core/signal/trap_spec.rb
@@ -49,7 +49,21 @@ platform_is_not :windows do
 
     it "registers an handler doing nothing with :IGNORE" do
       Signal.trap :HUP, :IGNORE
+      Signal.trap(:HUP, @saved_trap).should == "IGNORE"
+    end
+
+    it "can register a new handler after :IGNORE" do
+      Signal.trap :HUP, :IGNORE
+
+      done = false
+      Signal.trap(:HUP) do
+        ScratchPad.record :block_trap
+        done = true
+      end
+
       Process.kill(:HUP, Process.pid).should == 1
+      Thread.pass until done
+      ScratchPad.recorded.should == :block_trap
     end
 
     it "ignores the signal when passed nil" do
diff --git a/spec/ruby/core/string/scrub_spec.rb b/spec/ruby/core/string/scrub_spec.rb
index 86fd4e85ba..b513acfb70 100644
--- a/spec/ruby/core/string/scrub_spec.rb
+++ b/spec/ruby/core/string/scrub_spec.rb
@@ -105,4 +105,18 @@ describe "String#scrub!" do
     input.scrub! { |b| "<?>" }
     input.should == "a<?>"
   end
+
+  it "maintains the state of frozen strings that are already valid" do
+    input = "a"
+    input.freeze
+    input.scrub!
+    input.frozen?.should be_true
+  end
+
+  it "preserves the instance variables of already valid strings" do
+    input = "a"
+    input.instance_variable_set(:@a, 'b')
+    input.scrub!
+    input.instance_variable_get(:@a).should == 'b'
+  end
 end
diff --git a/spec/ruby/core/time/shared/now.rb b/spec/ruby/core/time/shared/now.rb
index 80f66a1134..f4018d72f4 100644
--- a/spec/ruby/core/time/shared/now.rb
+++ b/spec/ruby/core/time/shared/now.rb
@@ -19,15 +19,15 @@ describe :time_now, shared: true do
   end
 
   it "has at least microsecond precision" do
-    times = []
-    10_000.times do
-      times << Time.now.nsec
-    end
-
     # The clock should not be less accurate than expected (times should
     # not all be a multiple of the next precision up, assuming precisions
     # are multiples of ten.)
     expected = 1_000
-    times.select { |t| t % (expected * 10) == 0  }.size.should_not == times.size
+    t = 0
+    10_000.times.find do
+      t = Time.now.nsec
+      t % (expected * 10) != 0
+    end
+    (t % (expected * 10)).should != 0
   end
 end