Pyright/Pylance fails to infer type of generic classmethod T as Unknown by design

[sunfkny]

Pyright unable to infer the type of Generic classmethod microsoft/pyright#7721

This break these classmethod Option.Some, Option.maybe, Result.Ok, Result.Err but shortcut function Some, maybe, Ok, Err still works, documentation should mention this

[sunfkny]

Use staticmethod and another type argument also fix this Pyright Playground

from typing import Generic, TypeVar, reveal_type

T = TypeVar("T")
T2 = TypeVar("T2")

class Option(Generic[T]):
    def __init__(self, value: T):
        self._val = value

    @staticmethod
    def Some(val: T2) -> "Option[T2]":
        return Option(val)

reveal_type(Option.Some(2))