Import class as annotation

Importing a class and using it only as a type annotation (x: Foo).

a -> b::KeyExport("Foo") is necessary to resolve the import.

a -> b::KeyClassMetadata(0) is superfluous for annotation-only usage. It's triggered by type_of_instance in targs.rs which calls get_metadata_for_class to check is_typed_dict() — because Type::ClassType and Type::TypedDict are different type variants, the code must decide which to create. The is_typed_dict check requires resolving the class's bases to see if any ancestor is TypedDict, which recursively demands metadata up the MRO.

Fixing this requires unifying ClassType and TypedDict into a single type variant, deferring the TypedDict distinction until TypedDict-specific features are actually used.

Files

a.py:

from b import Foo
x: Foo

b.py:

class Foo:
    x: int = 1

Check a.py

a: Solutions
b: Answers

(32 builtin demands hidden)
a -> b::Load(module_exists)
a -> b::Exports(export_exists)
a -> b::Exports(get_deprecated)
a -> b::KeyExport(Name("Foo"))
a -> b::KeyClassMetadata(ClassDefIndex(0))