Summary

Currently the type of a functools.cached_property is Unknown, as the standardlibrary functools does not have type annotations.

from functools import cached_property
from typing import reveal_type


class Foo:
    @cached_property
    def foo(self) -> str:
        return "This is expensive"


reveal_type(Foo().foo)

Output:

info[revealed-type]: Revealed type
  --> main.py:11:11
   |
11 | reveal_type(Foo().foo)
   |             ^^^^^^^^^ `Unknown`
   |

Expected:
Some variant of bound method Foo.foo() -> str, which is what ty reveals without the decorator.

Playground link

Is this an issue with typeshed?

Version

ty 0.0.1-alpha.24