Mypy fails to resolve a less specific `TypeVar` in higher-order functions.

Bug Report

Mypy fails to resolve a less specific TypeVar to a common subtype of arguments when in a higher-order function call.

For context: #22532

To Reproduce

(Example from @andersk)

from typing import Callable, TypeVar

T = TypeVar("T")
def f(g: Callable[[], T], x: T) -> T:
    return x

x: object = 1
y: object = f(object, x)  # ok
z: object = f(object, 1)  # error: Argument 1 to "f" has incompatible type "Type[object]"; expected "Callable[[], int]"

Expected Behavior

z: object = f(object, 1)

When resolving the arguments in f(object, 1), mypy should bind object to T. Given that the type of object (Callable[[], object]) is a subtype of Callable[[], object] and the type of 1 is a subtype of object, this should be accepted.

Actual Behavior

z: object = f(object, 1)  # error: Argument 1 to "f" has incompatible type "Type[object]"; expected "Callable[[], int]"

Instead of using the less specific object, mypy determines that T -> int and refuses to resolve it as object.

Your Environment

• Mypy version used: 0.961
• Mypy command-line flags:
• Mypy configuration options from mypy.ini (and other config files): strict = true
• Python version used: 3.8
• Operating system and version: Ubuntu 20.04

Inizia riproducendo l’esempio fornito di funzione di ordine superiore con mypy 0.961, Python 3.8 e strict=true. Analizza come l’inferenza di TypeVar gestisce gli argomenti Callable e interi, quindi verifica che la chiamata che usa object venga accettata senza l’errore di incompatibilità segnalato.