This came up in issue 17468: currently, populating tp_del from C (as generators now do) doesn't automatically create a __del__ wrapper visible from Python.

The rationale given in the initial commit is that there's no need to define a wrapper, since tp_del won't be populated from C code (that will use tp_dealloc instead), but there's now at least one case where it *is* populated from C (generators), which means it behaves *as if* __del__ is defined (since the interpreter actually checks the tp_del slot), but *looks* like __del__ *isn't* defined (since there is no wrapper created).

Independent of the memory leak concerns with generators defining tp_del, it would be better if a wrapper function was defined so the existence of the method was at least visible from Python code.