> Wouldn't it be cleaner if x was the same type as hash?  Note that
> unsigned long is now wrong.  What is needed is "unsigned integer type
> of the same size as Py_hash_t."  If Py_hash_t has to stay signed, I
> think we should at least not rely of sizeof(Py_hash_t) to always
> remain the same as sizeof(size_t).

But this is an absolute requirement, a guarantee that we provide
forever, and the whole point of this patch. Py_hash_t *will* be
a signed version of size_t, just as Py_ssize_t. Not by chance, but
by careful, inherent design.