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[ty] Meta-type of type variables should be type[..] #18439

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Merged
merged 1 commit into from
Jun 3, 2025
Merged

[ty] Meta-type of type variables should be type[..] #18439

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19 changes: 19 additions & 0 deletions crates/ty_python_semantic/resources/mdtest/generics/pep695/variables.md
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Original file line number Diff line number Diff line change
Expand Up @@ -766,4 +766,23 @@ def constrained[T: (Callable[[], int], Callable[[], str])](f: T):
reveal_type(f()) # revealed: int | str
```

## Meta-type

The meta-type of a typevar is the same as the meta-type of the upper bound, or the union of the
meta-types of the constraints:

```py
def normal[T](x: T):
reveal_type(type(x)) # revealed: type

def bound_object[T: object](x: T):
reveal_type(type(x)) # revealed: type

def bound_int[T: int](x: T):
reveal_type(type(x)) # revealed: type[int]

def constrained[T: (int, str)](x: T):
reveal_type(type(x)) # revealed: type[int] | type[str]
```

[pep 695]: https://peps.python.org/pep-0695/
2 changes: 1 addition & 1 deletion crates/ty_python_semantic/src/types.rs
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Expand Up @@ -5243,7 +5243,7 @@ impl<'db> Type<'db> {
Type::Tuple(_) => KnownClass::Tuple.to_class_literal(db),

Type::TypeVar(typevar) => match typevar.bound_or_constraints(db) {
None => KnownClass::Object.to_class_literal(db),
None => KnownClass::Type.to_instance(db),
Some(TypeVarBoundOrConstraints::UpperBound(bound)) => bound.to_meta_type(db),
Some(TypeVarBoundOrConstraints::Constraints(constraints)) => {
// TODO: If we add a proper `OneOf` connector, we should use that here instead
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