fix TypeIs[T] with free TypeVar produces no narrowing #4849 - #4867
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asukaminato0721 wants to merge 1 commit into
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fix TypeIs[T] with free TypeVar produces no narrowing #4849#4867asukaminato0721 wants to merge 1 commit into
asukaminato0721 wants to merge 1 commit into
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According to mypy_primer, this change doesn't affect type check results on a corpus of open source code. ✅ |
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Summary
Fixes #4849
TypeIs[T]now narrows using T's bound when arguments cannot determine T, while keeping the negative branch conservative.Test Plan
add test