Bug report

In python < 3.9, creating a subclass of both enum.Enum and typing.Generic (or a subclass of typing.Generic) causes an error.

from enum import Enum
from typing import Generic, TypeVar

T = TypeVar("T")


class Foo(Generic[T]):
    ...


class Bar(Foo[int], Enum):
    x = 0

Error:

Traceback (most recent call last):
  File "test.py", line 11, in <module>
    class Bar(Foo[int], Enum):
  File "...\enum_newest.py", line 566, in __new__
    raise exc
  File "...\enum_newest.py", line 275, in __set_name__
    enum_member = enum_class._new_member_(enum_class, *args)
  File "...\Python38\lib\typing.py", line 875, in __new__
    obj = super().__new__(cls, *args, **kwds)
  File "...\enum_newest.py", line 1132, in __new__
    raise ve_exc
ValueError: 0 is not a valid Bar

Trying this with newer versions of enum.py does not appear to solve the issue, meaning it probably has something to do with a change in typing.Generic in python = 3.9 that happened to fix it. I wasn't able to test newer versions of typing.py since it was pretty complicated and used imports not available in previous versions.

I also couldn't find anything about such a change to typing.Generic, and I'm not sure if this is a more general issue concerning how enum.Enum plays with special situations considering the current enum.py still gives the above error.