Class Generic ParamSpec cannot be used in Callable

[isra17]

Bug Report

Mypy doesn't seem to support a Generic class with a ParamSpec argument to use this ParamSpec in an inherited generic class.

eg:

import typing as t

TCallable = t.TypeVar("TCallable", bound=t.Callable[..., t.Any])
P = t.ParamSpec("P")

class X(t.Generic[TCallable]):
  pass  
  
class Y(t.Generic[P], X[t.Callable[P, t.Any]]): # error: The first argument to Callable must be a list of types or "..."
  pass

To Reproduce

https://mypy-play.net/?mypy=master&python=3.10&gist=9edf71a609a6a1fe5764db342beaa710

This code seems to work on Pyright

Expected Behavior

The code above should pass.

Actual Behavior

The code above have an error: error: The first argument to Callable must be a list of types or "...". This error seems to be from some codepath unaware of ParamSpec.

Your Environment

• Mypy version used: 0.931 and master
• Python version used: 3.10

[isra17]

A colleague made a good even more minimal use-case which seems to be the actual root cause:

import typing as t

P = t.ParamSpec("P")
R = t.TypeVar("R")

class Callable(t.Generic[P, R]):
  pass

class Y( 
    t.Generic[P],
    Callable[P, t.Any], # error: ParamSpec "P" is unbound
): 
  pass

Quickly debugging Mypy shows the Callable error comes from:

mypy/mypy/typeanal.py

Line 744 in 0a03ba0

return None

[AlexWaygood]

Reproduced on mypy 0.950 (and on mypy master as of 27/04/2022):

from typing import Generic, ParamSpec

P = ParamSpec("P")
class Foo(Generic[P]): ...
class Bar(Foo[P]): ...  # error: ParamSpec "P" is unbound

[AlexWaygood]

@A5rocks / @cdce8p, do either of you have any idea where the error in mypy is here?

The specific line immediately responsible for emitting the error is here, but I'm struggling to get much further than that:

mypy/mypy/typeanal.py

Line 217 in c6cf7cd

self.fail('ParamSpec "{}" is unbound'.format(t.name), t)

[A5rocks]

This seems fixed as of mypy 1.0

[hauntsaninja]

Thanks :-)