Make Array methods return Array instances instead of subclass instances

This changes the following methods to return Array instances instead
of subclass instances:

* Array#drop
* Array#drop_while
* Array#flatten
* Array#slice!
* Array#slice/#[]
* Array#take
* Array#take_while
* Array#uniq
* Array#*

Fixes [Bug #6087]

4 files changed, 86 insertions, 28 deletions

diff --git a/spec/ruby/core/array/flatten_spec.rb b/spec/ruby/core/array/flatten_spec.rb
index e7cd114b9b..b2aa015764 100644
--- a/spec/ruby/core/array/flatten_spec.rb
+++ b/spec/ruby/core/array/flatten_spec.rb
@@ -75,12 +75,24 @@ describe "Array#flatten" do
     [[obj]].flatten(1)
   end
 
-  it "returns subclass instance for Array subclasses" do
-    ArraySpecs::MyArray[].flatten.should be_an_instance_of(ArraySpecs::MyArray)
-    ArraySpecs::MyArray[1, 2, 3].flatten.should be_an_instance_of(ArraySpecs::MyArray)
-    ArraySpecs::MyArray[1, [2], 3].flatten.should be_an_instance_of(ArraySpecs::MyArray)
-    ArraySpecs::MyArray[1, [2, 3], 4].flatten.should == ArraySpecs::MyArray[1, 2, 3, 4]
-    [ArraySpecs::MyArray[1, 2, 3]].flatten.should be_an_instance_of(Array)
+  ruby_version_is ''...'3.0' do
+    it "returns subclass instance for Array subclasses" do
+      ArraySpecs::MyArray[].flatten.should be_an_instance_of(ArraySpecs::MyArray)
+      ArraySpecs::MyArray[1, 2, 3].flatten.should be_an_instance_of(ArraySpecs::MyArray)
+      ArraySpecs::MyArray[1, [2], 3].flatten.should be_an_instance_of(ArraySpecs::MyArray)
+      ArraySpecs::MyArray[1, [2, 3], 4].flatten.should == ArraySpecs::MyArray[1, 2, 3, 4]
+      [ArraySpecs::MyArray[1, 2, 3]].flatten.should be_an_instance_of(Array)
+    end
+  end
+
+  ruby_version_is '3.0' do
+    it "returns Array instance for Array subclasses" do
+      ArraySpecs::MyArray[].flatten.should be_an_instance_of(Array)
+      ArraySpecs::MyArray[1, 2, 3].flatten.should be_an_instance_of(Array)
+      ArraySpecs::MyArray[1, [2], 3].flatten.should be_an_instance_of(Array)
+      ArraySpecs::MyArray[1, [2, 3], 4].flatten.should == Array[1, 2, 3, 4]
+      [ArraySpecs::MyArray[1, 2, 3]].flatten.should be_an_instance_of(Array)
+    end
   end
 
   it "is not destructive" do
diff --git a/spec/ruby/core/array/multiply_spec.rb b/spec/ruby/core/array/multiply_spec.rb
index 8ccec13d42..16e407348b 100644
--- a/spec/ruby/core/array/multiply_spec.rb
+++ b/spec/ruby/core/array/multiply_spec.rb
@@ -76,10 +76,20 @@ describe "Array#* with an integer" do
       @array = ArraySpecs::MyArray[1, 2, 3, 4, 5]
     end
 
-    it "returns a subclass instance" do
-      (@array * 0).should be_an_instance_of(ArraySpecs::MyArray)
-      (@array * 1).should be_an_instance_of(ArraySpecs::MyArray)
-      (@array * 2).should be_an_instance_of(ArraySpecs::MyArray)
+    ruby_version_is ''...'3.0' do
+      it "returns a subclass instance" do
+        (@array * 0).should be_an_instance_of(ArraySpecs::MyArray)
+        (@array * 1).should be_an_instance_of(ArraySpecs::MyArray)
+        (@array * 2).should be_an_instance_of(ArraySpecs::MyArray)
+      end
+    end
+
+    ruby_version_is '3.0' do
+      it "returns an Array instance" do
+        (@array * 0).should be_an_instance_of(Array)
+        (@array * 1).should be_an_instance_of(Array)
+        (@array * 2).should be_an_instance_of(Array)
+      end
     end
 
     it "does not call #initialize on the subclass instance" do
diff --git a/spec/ruby/core/array/shared/slice.rb b/spec/ruby/core/array/shared/slice.rb
index f36890fa4e..845be768c6 100644
--- a/spec/ruby/core/array/shared/slice.rb
+++ b/spec/ruby/core/array/shared/slice.rb
@@ -397,28 +397,56 @@ describe :array_slice, shared: true do
       @array = ArraySpecs::MyArray[1, 2, 3, 4, 5]
     end
 
-    it "returns a subclass instance with [n, m]" do
-      @array.send(@method, 0, 2).should be_an_instance_of(ArraySpecs::MyArray)
+    ruby_version_is ''...'3.0' do
+      it "returns a subclass instance with [n, m]" do
+        @array.send(@method, 0, 2).should be_an_instance_of(ArraySpecs::MyArray)
+      end
+
+      it "returns a subclass instance with [-n, m]" do
+        @array.send(@method, -3, 2).should be_an_instance_of(ArraySpecs::MyArray)
+      end
+
+      it "returns a subclass instance with [n..m]" do
+        @array.send(@method, 1..3).should be_an_instance_of(ArraySpecs::MyArray)
+      end
+
+      it "returns a subclass instance with [n...m]" do
+        @array.send(@method, 1...3).should be_an_instance_of(ArraySpecs::MyArray)
+      end
+
+      it "returns a subclass instance with [-n..-m]" do
+        @array.send(@method, -3..-1).should be_an_instance_of(ArraySpecs::MyArray)
+      end
+
+      it "returns a subclass instance with [-n...-m]" do
+        @array.send(@method, -3...-1).should be_an_instance_of(ArraySpecs::MyArray)
+      end
     end
 
-    it "returns a subclass instance with [-n, m]" do
-      @array.send(@method, -3, 2).should be_an_instance_of(ArraySpecs::MyArray)
-    end
+    ruby_version_is '3.0' do
+      it "returns a Array instance with [n, m]" do
+        @array.send(@method, 0, 2).should be_an_instance_of(Array)
+      end
 
-    it "returns a subclass instance with [n..m]" do
-      @array.send(@method, 1..3).should be_an_instance_of(ArraySpecs::MyArray)
-    end
+      it "returns a Array instance with [-n, m]" do
+        @array.send(@method, -3, 2).should be_an_instance_of(Array)
+      end
 
-    it "returns a subclass instance with [n...m]" do
-      @array.send(@method, 1...3).should be_an_instance_of(ArraySpecs::MyArray)
-    end
+      it "returns a Array instance with [n..m]" do
+        @array.send(@method, 1..3).should be_an_instance_of(Array)
+      end
 
-    it "returns a subclass instance with [-n..-m]" do
-      @array.send(@method, -3..-1).should be_an_instance_of(ArraySpecs::MyArray)
-    end
+      it "returns a Array instance with [n...m]" do
+        @array.send(@method, 1...3).should be_an_instance_of(Array)
+      end
+
+      it "returns a Array instance with [-n..-m]" do
+        @array.send(@method, -3..-1).should be_an_instance_of(Array)
+      end
 
-    it "returns a subclass instance with [-n...-m]" do
-      @array.send(@method, -3...-1).should be_an_instance_of(ArraySpecs::MyArray)
+      it "returns a Array instance with [-n...-m]" do
+        @array.send(@method, -3...-1).should be_an_instance_of(Array)
+      end
     end
 
     it "returns an empty array when m == n with [m...n]" do
diff --git a/spec/ruby/core/array/uniq_spec.rb b/spec/ruby/core/array/uniq_spec.rb
index fd604987c1..5911c23e6a 100644
--- a/spec/ruby/core/array/uniq_spec.rb
+++ b/spec/ruby/core/array/uniq_spec.rb
@@ -128,8 +128,16 @@ describe "Array#uniq" do
     [false, nil, 42].uniq { :bar }.should == [false]
   end
 
-  it "returns subclass instance on Array subclasses" do
-    ArraySpecs::MyArray[1, 2, 3].uniq.should be_an_instance_of(ArraySpecs::MyArray)
+  ruby_version_is ''...'3.0' do
+    it "returns subclass instance on Array subclasses" do
+      ArraySpecs::MyArray[1, 2, 3].uniq.should be_an_instance_of(ArraySpecs::MyArray)
+    end
+  end
+
+  ruby_version_is '3.0' do
+    it "returns Array instance on Array subclasses" do
+      ArraySpecs::MyArray[1, 2, 3].uniq.should be_an_instance_of(Array)
+    end
   end
 
   it "properly handles an identical item even when its #eql? isn't reflexive" do