Mypy should warn about conditions whose value can be deduced

Feature

Mypy can warn about left and right operands of conditions its value mypy can deduce. Unfortunately, it cannot do so for conditions consisting of one operand.

Pitch

val = 1337

if val is not None:
    pass

if val is not None and True:
    pass

Mypy can hint about the pointless left hand operand in the second if. Unfortunately, it does not do so for the first if. Supporting this use case would help the programmer to simplify her code by suggesting conditions to remove.

Commencez par le diagnostic existant de mypy pour l’opérande de gauche sans effet dans l’exemple and True, puis localisez l’implémentation et les tests qui le produisent. Ajoutez une couverture pour le cas à opérande unique if val is not None et vérifiez que mypy signale la condition pouvant être supprimée sans régression du comportement existant.