Support `==`-based narrowing of Optional

python / mypy

Optional static typing for Python

https://www.mypy-lang.org/

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Support `==`-based narrowing of Optional #18163

Closed tyralla closed 6 days ago

tyralla commented 1 week ago

Closes #18135

This change implements the third approach mentioned in #18135, which is stricter than similar narrowings, as clarified by the new/modified code comments. Personally, I prefer this more stringent way but could also switch this PR to approach two if there is consent that convenience is more important than type safety here.

github-actions[bot] commented 1 week ago

According to mypy_primer, this change doesn't affect type check results on a corpus of open source code. ✅