diff --git a/test/ruby/test_syntax.rb b/test/ruby/test_syntax.rb
index 64405a37e9..2e0d306c21 100644
--- a/test/ruby/test_syntax.rb
+++ b/test/ruby/test_syntax.rb
@@ -1392,7 +1392,7 @@ eom
     obj = Object.new
     def obj.test
       x = nil
-      y = (return until x unless x)
+      _y = (return until x unless x)
     end
     assert_nil obj.test, "[Bug #16695]"
   end