René's URL Explorer Experiment

Title: Wrong type inferred when "not in" narrowing Any · Issue #17841 · python/mypy · GitHub

Open Graph Title: Wrong type inferred when "not in" narrowing Any · Issue #17841 · python/mypy

X Title: Wrong type inferred when "not in" narrowing Any · Issue #17841 · python/mypy

Description: The revealed type here is str | None, which doesn't make sense: from typing import Any def f(x: Any) -> None: if x is not None and x not in ["x"]: return reveal_type(x) # "str | None" The behavior was changed in ed0cd4a. The inferred typ...

Open Graph Description: The revealed type here is str | None, which doesn't make sense: from typing import Any def f(x: Any) -> None: if x is not None and x not in ["x"]: return reveal_type(x) # "str | None" The behavior ...

X Description: The revealed type here is str | None, which doesn't make sense: from typing import Any def f(x: Any) -> None: if x is not None and x not in ["x"]: return reveal_type(x) # "str...

Opengraph URL: https://github.com/python/mypy/issues/17841

X: @github

direct link

Domain: github.com

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Wrong type inferred when \"not in\" narrowing Any ","articleBody":"The revealed type here is `str | None`, which doesn't make sense:\r\n```py\r\nfrom typing import Any\r\n\r\ndef f(x: Any) -\u003e None:\r\n    if x is not None and x not in [\"x\"]:\r\n        return\r\n    reveal_type(x)  # \"str | None\"\r\n```\r\nThe behavior was changed in ed0cd4acba02ed19b1cf18ac0ac416dc251d7714. The inferred type before this commit was `Any`, which seems reasonable.","author":{"url":"https://github.com/JukkaL","@type":"Person","name":"JukkaL"},"datePublished":"2024-09-27T10:03:38.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/17841/mypy/issues/17841"}

Links:

Viewport: width=device-width