Avoid narrowing to unreachable at module level#21144
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hauntsaninja merged 2 commits intopython:masterfrom Apr 2, 2026
Merged
Avoid narrowing to unreachable at module level#21144hauntsaninja merged 2 commits intopython:masterfrom
hauntsaninja merged 2 commits intopython:masterfrom
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Helps with confusing symptoms in python#21132
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According to mypy_primer, this change doesn't affect type check results on a corpus of open source code. ✅ |
ilevkivskyi
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Apr 1, 2026
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ilevkivskyi
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I think not narrowing to unreachable in top-levels is fine. Top-levels are special already, e.g. we don't defer them.
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Helps with confusing symptoms in #21132
It is unfortunate that it makes the logic a little more ad hoc / might lead to minimal repros being a little more confusing. But I think this is still a better and more helpful state to be in than before #20660 (relevant PR from the narrowing rewrite).
Hopefully we can add the ability to check unreachable code, which will fix this and other issues.