pyright 1.1.191 raising reportUnknownVariableType for reusable validators

[ITProKyle]

Checks

• I added a descriptive title to this issue
• I have searched (google, github) for similar issues and couldn't find anything
• I have read and followed the docs and still think this is a bug

Bug

Output of python -c "import pydantic.utils; print(pydantic.utils.version_info())":

             pydantic version: 1.8.2
            pydantic compiled: True
                 install path: /Users/kyle/.pyenv/versions/3.9.7/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/pydantic
               python version: 3.9.7 (default, Sep 22 2021, 08:26:25)  [Clang 13.0.0 (clang-1300.0.29.3)]
                     platform: macOS-11.6-x86_64-i386-64bit
     optional deps. installed: ['typing-extensions']

from typing import Any

import pydantic


def reusable_validator(v: Any) -> Any:
    return v


class MyModel(pydantic.BaseModel):
    example: str

    # Type of "_reusable_validator" is "classmethod[Unknown]" (reportUnknownVariableType)
    _reusable_validator = pydantic.validator("example", allow_reuse=True)(
        reusable_validator
    )

This appears to be caused by the latest version of typeshed changing classmethod to a generic.

Making the following change resolves this issue for the reported use case but there are other usages of classmethod that need to be updated to cover other cases that will result in the same error from pyright.

_T = TypeVar("_T", bound=AnyCallable)

def validator(
    *fields: str,
    pre: bool = False,
    each_item: bool = False,
    always: bool = False,
    check_fields: bool = True,
    whole: bool = None,
    allow_reuse: bool = False,
) -> Callable[[_T], classmethod[_T]]:

[chunleng]

@ITProKyle I used the face the same issue until I updated pydantic to 1.9. You might want to check if it solves the issue for you too

[ITProKyle]

I can confirm that this was resolved in pydantic 1.9.