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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[1.12, 1.13] Regression in enum narrowing","articleBody":"**Bug Report**\r\n\r\nRegression in 1.12.\r\n\r\nTry to narrowing union between StrEnum (or IntEnum) and Literal no longer works since mypy 1.12.0\r\n\r\n**To Reproduce**\r\nIssue can be reproduce with this code sample\r\n```python\r\nfrom typing_extensions import Literal\r\nfrom typing import Union\r\nfrom enum import StrEnum\r\n\r\nclass Foo(StrEnum):\r\n    FOO = 'a'\r\n\r\n\r\ndef foo(a: Union[Foo, Literal['foo']]) -\u003e Foo:\r\n    if a == 'foo':\r\n        return Foo.FOO\r\n\r\n    return a\r\n```\r\n[playground link](https://mypy-play.net/?mypy=1.12.0\u0026python=3.12\u0026gist=19f4a8eaf079d73e704b4bb42e48b2fd)\r\nfailing test can be found [here](https://github.com/Fred-si/mypy/blob/d3b4ef5e5abbf74f7a7002423e50175743f898bf/test-data/unit/check-literal.test#L2988-L3017)\r\n\r\n\r\n**Expected Behavior**\r\nAfter the if branch return, variable type should be narrowed to Foo and mypy should not produce error\r\n\r\n**Actual Behavior**\r\nAfter the if branch return, variable type is considered as \"Union[Foo, Literal['foo']]\" and my\r\n\u003c!-- What went wrong? Paste mypy's output. --\u003e\r\n\r\n**Your Environment**\r\n- Mypy version used: 1.12, 1.13, master\r\n- Mypy command-line flags: none\r\n- Mypy configuration options from `mypy.ini` (and other config files): none\r\n- Python version used: all versions from 3.8 to 3.13\r\n\r\n","author":{"url":"https://github.com/Fred-si","@type":"Person","name":"Fred-si"},"datePublished":"2024-10-24T12:14:42.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/18029/mypy/issues/18029"}