Error for lambda containing Any even when type can be inferred

Using mypy 0.641 with the --disallow-any-expr flag and this sample using @overload

from typing import Callable, Tuple, TypeVar, overload

T = TypeVar('T')
A0 = TypeVar('A0')
A1 = TypeVar('A1')


@overload
def foo(
    vars: Tuple[A0],
    op: Callable[[A0], T]
) -> T: ...


@overload
def foo(
    vars: Tuple[A0, A1],
    op: Callable[[A0, A1], T]
) -> T: ...


def foo(vars, op):
    pass


def foo_not_overloaded(
    vars: Tuple[A0, A1],
    op: Callable[[A0, A1], T]
) -> T:
    pass


a = 5
b = 3

foo((a, b), lambda a, b: a - b)

produces

typist2.py:36: error: Expression type contains "Any" (has type "Callable[[Any, Any], Any]")
typist2.py:36: error: Expression has type "Any"

However mypy seems to be able to infer the type of the lambda because if I modify the last line to read

foo((a, b), lambda a, b: a - b.bad)

mypy correctly identifies that "int" has no attribute "bad", sprinkling some prints on the mypy source also reveals it figures out it's a (int, int) -> int at some point.

foo_not_overloaded checks without trouble and so does using a plain def instead of the lambda.

Commencez avec le reproducer fourni en utilisant mypy 0.641 et comparez l’appel surchargé à foo avec foo_not_overloaded et avec le cas d’un simple def. Suivez le type inféré de la lambda dans le chemin de surcharge, puis vérifiez que la lambda valide ne déclenche plus d’erreurs disallow-any-expr, tandis que la variante a - b.bad signale toujours l’attribut invalide.