diff --git a/mypy/indirection.py b/mypy/indirection.py index 06a158818fbe..8c24c7242c96 100644 --- a/mypy/indirection.py +++ b/mypy/indirection.py @@ -39,8 +39,9 @@ def find_modules(self, typs: Iterable[types.Type]) -> set[str]: def _visit(self, typ: types.Type) -> None: if isinstance(typ, types.TypeAliasType): # Avoid infinite recursion for recursive type aliases. - if typ not in self.seen_aliases: - self.seen_aliases.add(typ) + if typ in self.seen_aliases: + return + self.seen_aliases.add(typ) typ.accept(self) def _visit_type_tuple(self, typs: tuple[types.Type, ...]) -> None: diff --git a/test-data/unit/check-incremental.test b/test-data/unit/check-incremental.test index defe7402730f..1658e56f582b 100644 --- a/test-data/unit/check-incremental.test +++ b/test-data/unit/check-incremental.test @@ -2577,6 +2577,13 @@ C(1)[0] [builtins fixtures/list.pyi] [out] +[case testSerializeRecursiveAlias] +from typing import Callable, Union + +Node = Union[str, int, Callable[[], "Node"]] +n: Node +[out] + [case testSerializeRecursiveAliases1] from typing import Type, Callable, Union