Fix false positive for NamedTuple subtype of TupleType#21529
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JiwaniZakir wants to merge 1 commit into
Open
Fix false positive for NamedTuple subtype of TupleType#21529JiwaniZakir wants to merge 1 commit into
JiwaniZakir 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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When checking whether an Instance (specifically a NamedTuple instance) is a subtype of a TupleType, mypy incorrectly returned False even though the NamedTuple and its TupleType representation refer to the same underlying type. The fix is in mypy/subtypes.py in the SubtypeVisitor.visit_instance method: when the mapped type is a NamedTuple and shares its TypeInfo with the right-hand TupleType's partial fallback, we now return True. To verify, create a NamedTuple and assign it to a variable typed as the equivalent tuple; mypy should no longer report a false positive error.
Fixes #21528