No first-class bound method support

[ikonst]

class X:
    def f(self) -> None:
        pass


reveal_type(X().f)
reveal_type(X().f.__self__)

I'd expect X().f to be some Callable derived generic type for bound methods.
I'd expect X().f.__self__ to be typed X. Currently __self__ is defined in the typeshed for types.MethodType as returning object.

Playground: https://mypy-play.net/?mypy=latest&python=3.11&gist=0de8d7a90f1d3770b3b600052c1671b1

[jorenham]

For what it's worth: With mypy 1.15 this is still an issue, and Pyright behaves correctly. This is also an issue for unbound methods.

class A:
    def f(self) -> None: ...

reveal_type(A.f.__self__)   # mypy ❌ [attr-defined], pyright ✅ type[A]
reveal_type(A().f.__self__) # mypy ❌ [attr-defined], pyright ✅ A

main.py:4: error: "Callable[[A], None]" has no attribute "__self__"  [attr-defined]
main.py:5: error: "Callable[[], None]" has no attribute "__self__"  [attr-defined]

• https://mypy-play.net/?mypy=latest&python=3.13&flags=strict&gist=3505152b1e345f7dd1549b3b6bdb118a
• https://pyright-play.net/?strict=true&code=MYGwhgzhAECCBcAoaLoBMCmAzaWAUEGIWAlNALQB80AcgPYB2G80AdO4ogE4YBuGYEAH0ALgE8ADhjyxWWVkKGFiiktz4Dh4qTLwk5CpUSyrEQA