7 files changed, 199 insertions, 3 deletions
diff --git a/spec/ruby/language/fixtures/freeze_magic_comment_required_diff_enc.rb b/spec/ruby/language/fixtures/freeze_magic_comment_required_diff_enc.rb
index 7a1f872e05..f72a32e879 100644
--- a/spec/ruby/language/fixtures/freeze_magic_comment_required_diff_enc.rb
+++ b/spec/ruby/language/fixtures/freeze_magic_comment_required_diff_enc.rb
@@ -2,4 +2,3 @@
 # frozen_string_literal: true
 
 $second_literal_id = "abc".object_id
-
diff --git a/spec/ruby/language/fixtures/variables.rb b/spec/ruby/language/fixtures/variables.rb
index 07265dbb2b..527caa7a78 100644
--- a/spec/ruby/language/fixtures/variables.rb
+++ b/spec/ruby/language/fixtures/variables.rb
@@ -82,4 +82,76 @@ module VariablesSpecs
   def self.false
     false
   end
+
+  class EvalOrder
+    attr_reader :order
+
+    def initialize
+      @order = []
+    end
+
+    def reset
+      @order = []
+    end
+
+    def foo
+      self << "foo"
+      FooClass.new(self)
+    end
+
+    def bar
+      self << "bar"
+      BarClass.new(self)
+    end
+
+    def a
+      self << "a"
+    end
+
+    def b
+      self << "b"
+    end
+
+    def node
+      self << "node"
+
+      node = Node.new
+      node.left = Node.new
+      node.left.right = Node.new
+
+      node
+    end
+
+    def <<(value)
+      order << value
+    end
+
+    class FooClass
+      attr_reader :evaluator
+
+      def initialize(evaluator)
+        @evaluator = evaluator
+      end
+
+      def []=(_index, _value)
+        evaluator << "foo[]="
+      end
+    end
+
+    class BarClass
+      attr_reader :evaluator
+
+      def initialize(evaluator)
+        @evaluator = evaluator
+      end
+
+      def baz=(_value)
+        evaluator << "bar.baz="
+      end
+    end
+
+    class Node
+      attr_accessor :left, :right
+    end
+  end
 end
diff --git a/spec/ruby/language/pattern_matching_spec.rb b/spec/ruby/language/pattern_matching_spec.rb
index f3cc86fa0b..e4b7a5105e 100644
--- a/spec/ruby/language/pattern_matching_spec.rb
+++ b/spec/ruby/language/pattern_matching_spec.rb
@@ -205,7 +205,7 @@ describe "Pattern matching" do
         in []
         end
       RUBY
-    }.should raise_error(SyntaxError, /syntax error, unexpected `in'/)
+    }.should raise_error(SyntaxError, /syntax error, unexpected `in'|\(eval\):3: syntax error, unexpected keyword_in/)
 
     -> {
       eval <<~RUBY
@@ -214,7 +214,7 @@ describe "Pattern matching" do
         when 1 == 1
         end
       RUBY
-    }.should raise_error(SyntaxError, /syntax error, unexpected `when'/)
+    }.should raise_error(SyntaxError, /syntax error, unexpected `when'|\(eval\):3: syntax error, unexpected keyword_when/)
   end
 
   it "checks patterns until the first matching" do
@@ -251,6 +251,18 @@ describe "Pattern matching" do
     }.should raise_error(NoMatchingPatternError, /\[0, 1\]/)
   end
 
+  it "raises NoMatchingPatternError if no pattern matches and evaluates the expression only once" do
+    evals = 0
+    -> {
+      eval <<~RUBY
+        case (evals += 1; [0, 1])
+        in [0]
+        end
+      RUBY
+    }.should raise_error(NoMatchingPatternError, /\[0, 1\]/)
+    evals.should == 1
+  end
+
   it "does not allow calculation or method calls in a pattern" do
     -> {
       eval <<~RUBY
diff --git a/spec/ruby/language/predefined_spec.rb b/spec/ruby/language/predefined_spec.rb
index d1cda25918..f6cec5fa75 100644
--- a/spec/ruby/language/predefined_spec.rb
+++ b/spec/ruby/language/predefined_spec.rb
@@ -979,6 +979,10 @@ describe "Global variable $VERBOSE" do
     $VERBOSE = @verbose
   end
 
+  it "is false by default" do
+    $VERBOSE.should be_false
+  end
+
   it "converts truthy values to true" do
     [true, 1, 0, [], ""].each do |true_value|
       $VERBOSE = true_value
diff --git a/spec/ruby/language/proc_spec.rb b/spec/ruby/language/proc_spec.rb
index f8a29962b0..c5876fb2ed 100644
--- a/spec/ruby/language/proc_spec.rb
+++ b/spec/ruby/language/proc_spec.rb
@@ -161,6 +161,18 @@ describe "A Proc" do
     end
   end
 
+  describe "taking |*a, b| arguments" do
+    it "assigns [] to the argument when passed no values" do
+      proc { |*a, b| [a, b] }.call.should == [[], nil]
+    end
+  end
+
+  describe "taking |a, *b, c| arguments" do
+    it "assigns [] to the argument when passed no values" do
+      proc { |a, *b, c| [a, b, c] }.call.should == [nil, [], nil]
+    end
+  end
+
   describe "taking |a, | arguments" do
     before :each do
       @l = lambda { |a, | a }
diff --git a/spec/ruby/language/singleton_class_spec.rb b/spec/ruby/language/singleton_class_spec.rb
index c1fb682ea0..7512f0eb39 100644
--- a/spec/ruby/language/singleton_class_spec.rb
+++ b/spec/ruby/language/singleton_class_spec.rb
@@ -291,3 +291,20 @@ describe "Instantiating a singleton class" do
     }.should raise_error(TypeError)
   end
 end
+
+describe "Frozen properties" do
+  it "is frozen if the object it is created from is frozen" do
+    o = Object.new
+    o.freeze
+    klass = o.singleton_class
+    klass.frozen?.should == true
+  end
+
+  it "will be frozen if the object it is created from becomes frozen" do
+    o = Object.new
+    klass = o.singleton_class
+    klass.frozen?.should == false
+    o.freeze
+    klass.frozen?.should == true
+  end
+end
diff --git a/spec/ruby/language/variables_spec.rb b/spec/ruby/language/variables_spec.rb
index c900c03d37..cd862727ac 100644
--- a/spec/ruby/language/variables_spec.rb
+++ b/spec/ruby/language/variables_spec.rb
@@ -1,6 +1,86 @@
 require_relative '../spec_helper'
 require_relative 'fixtures/variables'
 
+describe "Evaluation order during assignment" do
+  context "with single assignment" do
+    it "evaluates from left to right" do
+      obj = VariablesSpecs::EvalOrder.new
+      obj.instance_eval do
+        foo[0] = a
+      end
+
+      obj.order.should == ["foo", "a", "foo[]="]
+    end
+  end
+
+  context "with multiple assignment" do
+    ruby_version_is ""..."3.1" do
+      it "does not evaluate from left to right" do
+        obj = VariablesSpecs::EvalOrder.new
+
+        obj.instance_eval do
+          foo[0], bar.baz = a, b
+        end
+
+        obj.order.should == ["a", "b", "foo", "foo[]=", "bar", "bar.baz="]
+      end
+
+      it "cannot be used to swap variables with nested method calls" do
+        node = VariablesSpecs::EvalOrder.new.node
+
+        original_node = node
+        original_node_left = node.left
+        original_node_left_right = node.left.right
+
+        node.left, node.left.right, node = node.left.right, node, node.left
+        # Should evaluate in the order of:
+        # RHS: node.left.right, node, node.left
+        # LHS:
+        # * node(original_node), original_node.left = original_node_left_right
+        # * node(original_node), node.left(changed in the previous assignment to original_node_left_right),
+        #   original_node_left_right.right = original_node
+        # * node = original_node_left
+
+        node.should == original_node_left
+        node.right.should_not == original_node
+        node.right.left.should_not == original_node_left_right
+      end
+    end
+
+    ruby_version_is "3.1" do
+      it "evaluates from left to right, receivers first then methods" do
+        obj = VariablesSpecs::EvalOrder.new
+        obj.instance_eval do
+          foo[0], bar.baz = a, b
+        end
+
+        obj.order.should == ["foo", "bar", "a", "b", "foo[]=", "bar.baz="]
+      end
+
+      it "can be used to swap variables with nested method calls" do
+        node = VariablesSpecs::EvalOrder.new.node
+
+        original_node = node
+        original_node_left = node.left
+        original_node_left_right = node.left.right
+
+        node.left, node.left.right, node = node.left.right, node, node.left
+        # Should evaluate in the order of:
+        # LHS: node, node.left(original_node_left)
+        # RHS: original_node_left_right, original_node, original_node_left
+        # Ops:
+        # * node(original_node), original_node.left = original_node_left_right
+        # * original_node_left.right = original_node
+        # * node = original_node_left
+
+        node.should == original_node_left
+        node.right.should == original_node
+        node.right.left.should == original_node_left_right
+      end
+    end
+  end
+end
+
 describe "Multiple assignment" do
   context "with a single RHS value" do
     it "assigns a simple MLHS" do