[spec] a protocol type should be assignable to object? #1780

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1. carljm

   added

   topic: typing specFor improving the typing specFor improving the typing spec

   on Jun 17, 2024
2. JelleZijlstra commented on Jun 17, 2024

   

   JelleZijlstra

   on Jun 17, 2024

   Member

   More actions

   Mypy, pyre, and pyright all already allow protocol types to be assigned to object. Test program:

   from typing import Protocol
   
   def f(x: object) -> None:
       pass
   
   def g(x: int) -> None:
       pass
   
   class X(Protocol):
       foo: int
   
   def h(x: X) -> None:
       f(x)  # OK: protocol is assignable to object
       g(x)  # E: protocol is not assignable to int

   • pyright: https://pyright-play.net/?strict=true&code=GYJw9gtgBALgngBwJYDsDmUkQWEMoAK4MYAxmADYBQVAJgKbBTAAUAHgFxRgBGAVvVIwAlFAC0APigA5MCnocqUZVAQBDAM4aaDJmnZdUI8VNnzFK1Zu1VSFa1AAaLImBLkKwiyuBgwhlBgdRigACwMnUUkZOQUlH3ZheOV9NiSgA
   • mypy: https://mypy-play.net/?mypy=latest&python=3.10&gist=4fdb9e9e55ca4dac48d44adf95da3ba6
   • pyre: https://pyre-check.org/play?input=from%20typing%20import%20Protocol%0A%0Adef%20f(x%3A%20object)%20-%3E%20None%3A%0A%20%20%20%20pass%0A%0Adef%20g(x%3A%20int)%20-%3E%20None%3A%0A%20%20%20%20pass%0A%0Aclass%20X(Protocol)%3A%0A%20%20%20%20foo%3A%20int%0A%0Adef%20h(x%3A%20X)%20-%3E%20None%3A%0A%20%20%20%20f(x)%0A%20%20%20%20g(x)%0A

   👍React with 👍1Reacted by Carl Meyer