Walrus in the right operand of and does not narrow the assigned name

Describe the Bug

import os 


def f(u: str | os.PathLike[str]) -> str:
    if u and (u := str(u)):
        return u  # u is still considered str | os.PathLike[str]
    return ""

Works in mypy: https://mypy-play.net/?gist=f82f0c2d77e3124400ac7bb728fc225a

Real world code: https://github.com/scrapy/scrapy/blob/1bc0473909e4e5a3d0b62710715b6383c5641765/scrapy/pipelines/files.py#L661

Sandbox Link

https://pyrefly.org/sandbox/?project=v2.pVQ7DsIwDL2KpQ4JS71X4gYMPQBLBVGpkBpEas7PsxNARW2XbvnZct5vLTK_piRFvAjTixkMUoypbmHS03AP5i4jGoufGIXQjrxQc9QLL4cFbUnBOO_wL538D9WK2nxAZUDkCejoBakFmOvzWCGwAt2m6ZEa5k95fPYcRr7GS-JZBZMKqHt1g2XhvB1FU0FC2z10usym2yLTKZd4scnPGw

(Only applicable for extension issues) IDE Information

No response

#claim

@Nidhi-Gahlawat

@Nidhi-Gahlawat we couldn't find a merged PR from you, and we only allow multiple simultaneous claims from repeat contributors. You're already assigned to #5554.

#claim

@TimonGaertner

@TimonGaertner you've claimed this issue — it's now assigned to you. Thanks for picking it up! 🎉

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Walrus in the right operand of `and` does not narrow the assigned name #5581

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Walrus in the right operand of and does not narrow the assigned name #5581

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Describe the Bug

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Nidhi-Gahlawat commented on Nov 9, 2026

github-actions commented on Nov 9, 2026

TimonGaertner commented on Nov 12, 2026

github-actions commented on Nov 12, 2026

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Walrus in the right operand of `and` does not narrow the assigned name #5581