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Title: Fix bug when narrowing union containing custom eq against custom eq by hauntsaninja · Pull Request #20754 · python/mypy · GitHub

Open Graph Title: Fix bug when narrowing union containing custom eq against custom eq by hauntsaninja · Pull Request #20754 · python/mypy

X Title: Fix bug when narrowing union containing custom eq against custom eq by hauntsaninja · Pull Request #20754 · python/mypy

Description: Optional static typing for Python. Contribute to python/mypy development by creating an account on GitHub.

Open Graph Description: I rewrote the logic for custom equality in #20643 . This is a soundness bug in that rewrite. Fixes #20750

X Description: I rewrote the logic for custom equality in #20643 . This is a soundness bug in that rewrite. Fixes #20750

Opengraph URL: https://github.com/python/mypy/pull/20754

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Fix bug when narrowing union containing custom eq against custom eqhttps://github.com/python/mypy/pull/20754/commits/a69197d720b37965cb848e1b1ded62e8dd617bf7
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Unsoundly narrow away from None with custom eqhttps://github.com/hauntsaninja/mypy/commit/e90f655af707e9623505ffc1afa3b418ab7de0f4
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