`Hash#dup` for kwsplat arguments

On `f(*a, **kw)` method calls, a rest keyword parameter is identically
same Hash object is passed and it should make `#dup`ed Hahs.

fix https://bugs.ruby-lang.org/issues/19526

1 files changed, 10 insertions, 0 deletions

diff --git a/test/ruby/test_keyword.rb b/test/ruby/test_keyword.rb
index 94b5323ab0..ef594bd52e 100644
--- a/test/ruby/test_keyword.rb
+++ b/test/ruby/test_keyword.rb
@@ -447,6 +447,16 @@ class TestKeywordArguments < Test::Unit::TestCase
     assert_equal(false, public_send(:yo, **{}).frozen?)
     assert_equal_not_same(kw, public_send(:yo, **kw))
     assert_equal_not_same(h, public_send(:yo, **h))
+
+    def self.yo(*a, **kw) = kw
+    assert_equal_not_same kw, yo(**kw)
+    assert_equal_not_same kw, yo(**kw, **kw)
+
+    singleton_class.send(:remove_method, :yo)
+    def self.yo(opts) = opts
+    assert_equal_not_same h, yo(*[], **h)
+    a = []
+    assert_equal_not_same h, yo(*a, **h)
   end
 
   def test_regular_kwsplat