Nick Coghlan <ncoghlan@gmail.com> added the comment: @Rémi Aye, filling out derived slots is one of the things PyType_Ready does. This would need a discussion on python-dev before going ahead and doing it though, as the closest equivalent we have to this right now is the "negative" derivation, where overriding __eq__ without overriding __hash__ implicitly marks the derived class as unhashable (look for "type->tp_hash = PyObject_HashNotImplemented;"). ---------- _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue33039> _______________________________________