Marking a private `Enum` member as `member()` does not work

[sobolevn]

Consider this example:

from enum import Enum, member

class Pet(Enum):
    __CAT = member(1)

reveal_type(Pet.__CAT)  # N: Revealed type is "enum.member[Literal[1]?]"

Link: https://mypy-play.net/?mypy=latest&python=3.12&gist=63b056215c22ba7ff09e2559dd2ae08a

However, in runtimes it fails with AttributeError, because __CAT is mangled to _Pet__CAT as regular private names are.

We need to fix this corner-case.

Refs #18491
Refs #18557

[sobolevn]

I also think that the revealed type should be just Literal[1] ...?

[tyralla]

PR #16715 deals with name mangling. Would it fix this issue as well?

[sobolevn]

Yes, this problem is not related to Enum. It happens for all similar case:

from enum import Enum

class A:
    def __init__(self) -> None:
        self.__private = 1
        
A().__private  # false positive