using a decorator on an overloaded function where the decorator uses `Concatenate` causes false positive "Overloaded function implementation does not accept all possible arguments" error

from typing import Callable, Concatenate, TypeVar, overload, ParamSpec

T = TypeVar("T")
P = ParamSpec("P")
R = TypeVar("R")


def foo(fn: Callable[Concatenate[T, P], R]) -> Callable[Concatenate[T, P], R]:
    return fn


class Foo:
    @overload
    def bar(self, a: str) -> str: ...
    @overload
    def bar(self, a: int) -> int: ...

    # error: Overloaded function implementation does not accept all possible arguments of signature 1
    # error: Overloaded function implementation does not accept all possible arguments of signature 2
    @foo
    def bar(self, a: object) -> object: ...

playground

Start with the provided reproducer in the mypy playground and inspect how overloaded implementations are checked when the implementation is decorated with a Callable using Concatenate. Confirm the false-positive errors for both overloads, then verify that valid decorated overloads pass without weakening the existing argument-compatibility checks.