Enum value lookup accepts incompatible argument types without a diagnostic #5398

import enum
from typing import TYPE_CHECKING, Self

class Category(enum.Enum):
    if TYPE_CHECKING:
        @property
        def value(self) -> str: ...

        def __init__(self, value: str) -> None:
            self._id: str
    else:

        def __init__(self, value: str, id: str) -> None:
            self._value_ = value
            self._id = id

    GAMES = "GAMES", "0_0"
    MUSIC = "MUSIC", "1_1"

    @property
    def id(self) -> str:
        return self._id

    @classmethod
    def _missing_(cls, value: object) -> Self:
        msg = f"'{value}' is not a valid {cls.__name__}"

        if isinstance(value, str):
            value = value.casefold().strip()
            for member in cls:
                if (value == member.value.casefold()) or (value == member.name.casefold()) or (value == member.id):
                    return member
            raise ValueError(msg)
        raise ValueError(msg)

Category("GAMES")
Category(None) # runtime error