Fix BigDecimal#clone to return the receiver rather than a new object.

Author: nirvdrum

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 Bug fixes:
 
-* Fixed `BigDecimal#dup` so it now just returns the receiver, per Ruby 2.5+ semantics (#1680).
+* Fixed `BigDecimal#{clone,dup}` so it now just returns the receiver, per Ruby 2.5+ semantics (#1680).
 * Fixed creating `BigDecimal` instances from non-finite `Float` values (#1685).
 * Fixed `BigDecimal#inspect` output for non-finite values (e.g, NaN or -Infinity) (#1683).
 * Implemented `rb_eval_string_protect`.

lib/truffle/bigdecimal.rb

@@ -79,9 +79,10 @@ def self.limit(limit = nil)
     end
   end
 
-  def dup
+  def clone
     self
   end
+  alias_method :dup, :clone
 
   # TODO (pitr 20-jun-2015): remove when lazy setup is added
   def self.name

spec/ruby/library/bigdecimal/clone_spec.rb

@@ -0,0 +1,6 @@
+require_relative '../../spec_helper'
+require_relative 'shared/clone'
+
+describe "BigDecimal#dup" do
+  it_behaves_like :bigdecimal_clone, :clone
+end

spec/ruby/library/bigdecimal/dup_spec.rb

@@ -1,23 +1,6 @@
 require_relative '../../spec_helper'
-require 'bigdecimal'
+require_relative 'shared/clone'
 
 describe "BigDecimal#dup" do
-  before :each do
-    @obj = BigDecimal("1.2345")
-  end
-
-  ruby_version_is "" ... "2.5" do
-    it "copies the BigDecimal's value to a newly allocated object" do
-      copy = @obj.dup
-
-      copy.should_not equal(@obj)
-      copy.should == @obj
-    end
-  end
-
-  ruby_version_is "2.5" do
-    it "returns self" do
-      @obj.dup.should equal(@obj)
-    end
-  end
+  it_behaves_like :bigdecimal_clone, :dup
 end

spec/ruby/library/bigdecimal/shared/clone.rb

@@ -0,0 +1,24 @@
+require 'bigdecimal'
+
+describe :bigdecimal_clone, shared: true do
+  before :each do
+    @obj = BigDecimal("1.2345")
+  end
+
+  ruby_version_is "" ... "2.5" do
+    it "copies the BigDecimal's value to a newly allocated object" do
+      copy = @obj.public_send(@method)
+
+      copy.should_not equal(@obj)
+      copy.should == @obj
+    end
+  end
+
+  ruby_version_is "2.5" do
+    it "returns self" do
+      copy = @obj.public_send(@method)
+
+      copy.should equal(@obj)
+    end
+  end
+end