Fix false negatives in walrus vs inference fallback logic #20622
+123
−38
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According to mypy_primer, this change doesn't affect type check results on a corpus of open source code. ✅ |
hauntsaninja
approved these changes
Jan 20, 2026
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Fixes #20606
This fixes couple edge cases where walrus interferes with type inference fallback logic. This is not a complete fix, but I think it is OK for now as these are probably rare situations. Most changes in
binder.pyare a pure performance optimization to compensate the fact thatframe_context()will be more hot now. I also leave a TODO explaining a more proper fix for the assignment case (and other possible cases), return case should be already good (it is simpler since we don't need to apply any of the narrowing).