Suppress duplicated keyword warning

Author: eregon

spec/ruby/language/method_spec.rb

@@ -596,7 +596,9 @@ def m(**k) k end
       m(a: 1, b: 2).should == { a: 1, b: 2 }
       m(*[]).should == {}
       m(**{}).should == {}
-      m(**{a: 1, b: 2}, **{a: 4, c: 7}).should == { a: 4, b: 2, c: 7 }
+      suppress_warning {
+        eval "m(**{a: 1, b: 2}, **{a: 4, c: 7})"
+      }.should == { a: 4, b: 2, c: 7 }
       -> { m(2) }.should raise_error(ArgumentError)
     end