fix bug in keyword + protected combination

Test included for the situation formerly was not working.

test/ruby/test_keyword.rb

@@ -4859,4 +4859,20 @@ class TestKeywordArgumentsSymProcRefinements < Test::Unit::TestCase
     assert_equal([1, h3], c.call(**h3, &:m2))
     assert_equal([1, h3], c.call(a: 1, **h2, &:m2))
   end
+
+  def test_protected_kwarg
+    mock = Class.new do
+      def foo
+        bar('x', y: 'z')
+      end
+      protected
+      def bar(x, y)
+        nil
+      end
+    end
+
+    assert_nothing_raised do
+      mock.new.foo
+    end
+  end
 end

vm_insnhelper.c

@@ -2879,8 +2879,15 @@ vm_call_method(rb_execution_context_t *ec, rb_control_frame_t *cfp, struct rb_ca
 		else {
 		    /* caching method info to dummy cc */
 		    VM_ASSERT(cc->me != NULL);
-                    struct rb_call_data cd_entry = *cd;
-                    return vm_call_method_each_type(ec, cfp, calling, &cd_entry);
+                    if (ci->flag & VM_CALL_KWARG) {
+                        struct rb_kwarg_call_data *kcd = (void *)cd;
+                        struct rb_kwarg_call_data cd_entry = *kcd;
+                        return vm_call_method_each_type(ec, cfp, calling, (void *)&cd_entry);
+                    }
+                    else {
+                        struct rb_call_data cd_entry = *cd;
+                        return vm_call_method_each_type(ec, cfp, calling, &cd_entry);
+                    }
 		}
 	    }
             return vm_call_method_each_type(ec, cfp, calling, cd);