René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"generics inferred differently when assigning to variable even though the variable's type is the same","articleBody":"```py\r\nfrom typing import Callable, TypeVar\r\n\r\nA = TypeVar(\"A\")\r\nB = TypeVar(\"B\")\r\n\r\n\r\ndef func(a: A, b: B, fn: Callable[[A], A]) -\u003e A | B:\r\n    ...\r\n\r\n\r\ninferred = func(\r\n    1,\r\n    None,\r\n    lambda value: reveal_type(value),  # Revealed type is \"builtins.int\"\r\n)\r\nreveal_type(inferred)  # \"Union[builtins.int, None]\"\r\n\r\nexplicit: int | None\r\nexplicit = func(\r\n    1,\r\n    None,\r\n    lambda value: reveal_type(value), # Revealed type is \"Union[builtins.int, None]\"\r\n)\r\nreveal_type(explicit)  # \"Union[builtins.int, None]\"\r\n```\r\nhttps://mypy-play.net/?mypy=latest\u0026python=3.10\u0026gist=7c2af9e77a6246ee6fb3e5052722eec1","author":{"url":"https://github.com/DetachHead","@type":"Person","name":"DetachHead"},"datePublished":"2021-11-04T08:02:55.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/11455/mypy/issues/11455"}