Fix isinstance on namedtuple type aliases#21103
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paulorochaoliveira wants to merge 2 commits intopython:masterfrom
Open
Fix isinstance on namedtuple type aliases#21103paulorochaoliveira wants to merge 2 commits intopython:masterfrom
paulorochaoliveira wants to merge 2 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. ✅ |
A5rocks
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Mar 29, 2026
| @@ -557,6 +557,10 @@ def visit_call_expr_inner(self, e: CallExpr, allow_none_return: bool = False) -> | |||
| and node | |||
| and isinstance(node.node, TypeAlias) | |||
| and not node.node.no_args | |||
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I feel like no_args should be True in this case? In which case this if statement is fine.
I'd rather that, unless there's a good reason for existing behavior...
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Summary
Fix #21100
Fix a false positive where
isinstance(x, Alias)reportsParameterized generics cannot be used with class or instance checkswhen
Aliasis aTypeAliasto a class inheriting fromNamedTuple.Changes
isinstancerejection pathTypeAlias = FoowhereFoois aNamedTupleTesting
./venv/bin/pytest -n0 mypy/test/testcheck.py -k "testIsinstanceTypeAliasToNamedTuple or testIsinstanceTypeArgsAliases or testAliasNonGeneric"./venv/bin/pytest -n0 mypy/test/testcheck.py -k check-isinstance.test