Return type is Self when calling an inherited decorated classmethod that returns Self

[injust]

Bug Report

When calling an inherited decorated classmethod that returns Self, mypy does not resolve the type and thinks the type of the return value is Self.

To Reproduce

https://mypy-play.net/?mypy=latest&python=3.13&flags=strict&gist=664aeee2f4339ce869129dfba8017289

from __future__ import annotations

from collections.abc import Callable
from functools import wraps
from typing import Any, Self, TypeVar

type JSON = dict[str, Any]
T = TypeVar("T")


def debug(make: Callable[[type[T], JSON], T]) -> Callable[[type[T], JSON], T]:
    @wraps(make)
    def wrapper(cls: type[T], data: JSON) -> T:
        return make(cls, data)

    return wrapper


class Foo:
    data: JSON
    
    def __init__(self, data: JSON) -> None:
        self.data = data

    @classmethod
    @debug
    def make(cls, data: JSON) -> Self:
        return cls(data)


class Bar(Foo):
    pass


def test() -> Bar:
    return Bar.make({})

Expected Behavior

The code should type check.

Actual Behavior

main.py:36: error: Incompatible return value type (got "Self", expected "Bar")  [return-value]
Found 1 error in 1 file (checked 1 source file)

Your Environment

• Mypy version used: 1.15.0
• Mypy command-line flags: --strict
• Python version used: 3.13

[sterliakov]

This is almost a duplicate of #18993 - if you reveal_type(Foo.make({})), that will be Self. We leak self types from decorated classmethods somewhere.