Is is_typeddict with Generics supposed to eval to false?

[semohr]

Is is_typeddict supposed to return False for generic TypedDict specializations, or is this a bug? The documentation does not mention this.

Example:

from typing import is_typeddict, Generic, TypeVar, TypedDict

A = TypeVar("A", bound=TypedDict)

class Attributes(TypedDict, total=False):
    title: str

class Resource(TypedDict, Generic[A]):
    a: A 
    
print(is_typeddict(Resource[Attributes]))
# False
# Would have expected True...

Live demo: https://www.online-python.com/Pa6C0sWjIh

Hope this is the right place to report this.

[semohr]

@srittau Since you have turned into a discussion, do you have an opinion on this? My impression is that this is a bug, although I understand that properly validating specializations to ensure they are still TypedDicts could be quite a headache.

[davidhalter]

I personally somewhat agree, but I'm not sure the typing discussions are the right place for this. is_typeddict is mostly relevant for runtime checks and I would therefore recommend you to open an issue on the cpython issue tracker, where this could be fixed or closed.