Message 295153 - Python tracker
Without this segfault, I think you do a wrong operation. In other cases, for example: >>> issubclass(10, int) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: issubclass() arg 1 must be a class `issubclass` will return TypeError on instance, if you test as `issubclass(Failure, int)` or `issubclass(Failure().__class__, int`, it should get the correct answer.