Fix generic NamedTuple class pattern matching#21140
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paulorochaoliveira wants to merge 4 commits intopython:masterfrom
Open
Fix generic NamedTuple class pattern matching#21140paulorochaoliveira wants to merge 4 commits intopython:masterfrom
paulorochaoliveira wants to merge 4 commits intopython:masterfrom
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According to mypy_primer, this change doesn't affect type check results on a corpus of open source code. ✅ |
| proper_narrowed_type_for_members.partial_fallback.type.is_named_tuple | ||
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| narrowed_type_for_members = proper_narrowed_type_for_members.partial_fallback | ||
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This keeps the tuple form for class-pattern narrowing, but switches to the namedtuple fallback for keyword field lookup. Without that conversion, generic NamedTuple fields are effectively erased during member access inside the pattern.
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Fixes #21050
Description
Preserve named tuple field information when matching against generic class-based
NamedTuples.This updates class-pattern narrowing so a generic named tuple type object is normalized to its named tuple instance fallback before pattern analysis. That keeps keyword field lookup on the named tuple instance type instead of the tuple alias form, so field names and concrete type arguments are preserved.
Tests
Added regressions for:
NamedTuplewithGeneric[T]syntax in match class patternsNamedTuplesyntax in match class patterns