typing.cast is ignored in case of no-member error checker

[PiotrBatko-BlockchainWares]

Bug description

In following code Pylint reports no-member error. It's right, because list_wrapper hasn't such member. I used typing.cast and type annotations to force Pylint to think, that list_wrapper has different type, but Pylint ignores it.

# pylint: disable=missing-module-docstring, missing-class-docstring, too-few-public-methods, missing-function-docstring

import typing

class ListWrapper:
    pass

def some_func():
    list_wrapper: typing.List = typing.cast(typing.List, ListWrapper())
    list_wrapper.append(42)

Of course, this simplified example has no sense and such Python code will always fail at runtime. I have a little bit more complicated real use case, with __setattr__ and __getattr__ methods, where I assign to member variable such wrapper, like in example above, but overridden __getattr__ will return different type, which will not cause error at runtime. I wanted to use typing.cast to inform Pylint, that returned types for member variables will be different, but it has no effect.

I am not sure if it is a bug or I am using Pylint incorrectly. I can prepare simplified example of my real use case if it would be helpful.

Configuration

No response

Command used

python -m pylint example.py

Pylint output

************* Module example
example.py:12:4: E1101: Instance of 'ListWrapper' has no 'append' member (no-member)

------------------------------------------------------------------
Your code has been rated at 1.67/10 (previous run: 1.67/10, +0.00)

Expected behavior

No error reported.

Pylint version

pylint 2.13.9
astroid 2.11.5
Python 3.8.13 (default, Apr 19 2022, 00:53:22) 
[GCC 7.5.0]

OS / Environment

Ubuntu 20.04.4 LTS

Additional dependencies

No response

[DanielNoord]

We don't really support typing.cast. That's more something for mypy and pyright which are real type checkers. I'm not sure if this should even be on our todo list. Perhaps it's better to leave those tools to do what they do best and let us handle what we do best.

class ListWrapper:
    def __init__(self):
        self.list = []
    def append(self, x):
        self.list.append(x)

def some_func():
    list_wrapper = ListWrapper()
    list_wrapper.append(42)

If we raise no-member on the above snippet that is indeed a bug. But I don't think pylint should solve this by relying on typing.cast but rather on better inference of methods and attributes.

[jacobtylerwalls]

Duplicate of #4534, which was more or less wontfixed in the discussion at pylint-dev/astroid#1076 (comment) unless we can find a way to deal with subtle TypeVar issues.

(Daniel's example does not raise any no-member. ✔️ )