Literal infers tuple literal as Union of the items though this syntax is forbidden by PEP 586

The section Illegal parameters for Literal at type check time describes that tuple literals inside Literal are forbidden:

Tuples containing valid literal types like Literal[(1, "foo", "bar")]. The user could always express this type as Tuple[Literal[1], Literal["foo"], Literal["bar"]] instead. Also, tuples are likely to be confused with the Literal[1, 2, 3] shortcut.

Nevertheless mypy seems to be taking this shortcut since it doesn't flag the following code:

from typing_extensions import Literal

a : Literal[(1, 2)] = 1 

Python 3.7, mypy 0.740, typing-extensions 3.7.4.

Commencez par reproduire l’extrait Python signalé avec Literal[(1, 2)] et confirmez si mypy l’accepte. Localisez le chemin de vérification de type de Literal et ses tests existants ; le travail est considéré comme terminé lorsque les littéraux de tuple dans Literal sont refusés conformément à PEP 586.