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fix: handle union-bound TypeVar in type[T] callable analysis #21191

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fix: handle union-bound TypeVar in type[T] callable analysis #21191

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fix: handle union-bound TypeVar in type[T] callable analysis
Bahtya Apr 9, 2026
8f458ba
fix: use union bound as return type for TypeVar with union bound in t…
Apr 9, 2026
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fix: use union bound as return type for TypeVar with union bound in t… 
…ype[T] analysis

When a TypeVar has a union bound (e.g., T = TypeVar("T", bound=A | B)),
analyzing type[T] as a callable should return the union bound (A | B)
as the return type, not the TypeVar (T) itself.

This fixes the testMatchTypeObjectTypeVar test case where calling a
type[T_Choice] where T_Choice is bound to One | Two should return
One | Two, not T_Choice.

Bahtya
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Bahtya committed Apr 9, 2026
commit 8f458ba0a90435301393b008821657fa5d6e5cad
13 changes: 10 additions & 3 deletions mypy/checkexpr.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1941,14 +1941,21 @@ def analyze_type_type_callee(self, item: ProperType, context: Context) -> Type:
# with typevar.
callee = self.analyze_type_type_callee(get_proper_type(item.upper_bound), context)
callee = get_proper_type(callee)
# When the TypeVar has a union bound, use the bound as the return type
# instead of the TypeVar itself, since calling the constructor should
# return an instance of one of the union members.
return_type = item
upper_bound = get_proper_type(item.upper_bound)
if isinstance(upper_bound, UnionType):
return_type = upper_bound
if isinstance(callee, CallableType):
callee = callee.copy_modified(ret_type=item)
callee = callee.copy_modified(ret_type=return_type)
elif isinstance(callee, Overloaded):
callee = Overloaded([c.copy_modified(ret_type=item) for c in callee.items])
callee = Overloaded([c.copy_modified(ret_type=return_type) for c in callee.items])
elif isinstance(callee, UnionType):
callee = UnionType(
[
self._replace_callable_return_type(tp, item)
self._replace_callable_return_type(tp, return_type)
for tp in callee.relevant_items()
],
callee.line,
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