Duplicate hash when converting keyword hash to keywords

This mirrors the behavior when manually splatting a hash.  This
mirrors the changes made in setup_parameters_complex in
6081ddd6e6f2297862b3c7e898d28a76b8f9240b, so that splatting to a
non-iseq method works the same as splatting to an iseq method.

1 files changed, 8 insertions, 0 deletions

diff --git a/test/ruby/test_keyword.rb b/test/ruby/test_keyword.rb
index 25337712fe..0f67c28963 100644
--- a/test/ruby/test_keyword.rb
+++ b/test/ruby/test_keyword.rb
@@ -2692,6 +2692,10 @@ class TestKeywordArguments < Test::Unit::TestCase
         args
       end
 
+      def pass_cfunc(*args)
+        self.class.new(*args).init_args
+      end
+
       ruby2_keywords def block(*args)
         ->(*args, **kw){[args, kw]}.(*args)
       end
@@ -2915,6 +2919,10 @@ class TestKeywordArguments < Test::Unit::TestCase
       assert_equal([[1], h1], o.foo(:pass_bar, 1, :a=>1))
     end
 
+    assert_warn(/The last argument is used as the keyword parameter.* for `initialize'/m) do
+      assert_equal([[1], h1], o.foo(:pass_cfunc, 1, :a=>1))
+    end
+
     assert_warn(/Skipping set of ruby2_keywords flag for bar \(method accepts keywords or method does not accept argument splat\)/) do
       assert_nil(c.send(:ruby2_keywords, :bar))
     end