Thanks for providing the patch. Unfortunately, I'm not sure it is sufficient because you do not have a guarantee that items inserted in the HASH_TABLE are always of type STRING. I'm proposing a different patch which will simply use `same_string' rather than `~' for comparing STRING objects all the time.

The benefit is that is should as efficient as the original solution (no need to create a temporary object for lookup.

The next 6.4 release will have the patch included. Let me know if it also works for you.