I ran into this same problem in Class::MOP (more specifically Class::MOP::Package). IIRC the value it creates is always a reference to undef, so I just deal with it as a special case for SCALAR and check for the ref to undef. I figure that it still behaves appropriately in most use cases, which is ugly, but there is little else that can be done. Of course if you do find a solution, please let me know :)