unsubscriptable-object with type[int] on Python 3.9

[SuperStormer]

PEP585 specifies that type implements __class_getitem__, yet pylint still errors. However, this does not occur with other PEP585 types such as list or tuple, which I believe was previously fixed. type also needs to be fixed in the same way.

Steps to reproduce

1. Create file a.py:

a: type[int] = int

2. Run pylint --rcfile=/dev/null a.py

Current behavior

************* Module a
a.py:1:0: C0114: Missing module docstring (missing-module-docstring)
a.py:1:3: E1136: Value 'type' is unsubscriptable (unsubscriptable-object)

----------------------------------------------------------------------
Your code has been rated at -50.00/10 (previous run: -50.00/10, +0.00)

Expected behavior

Only the missing-module-docstring line should be printed, not the unsubscriptable-object.

pylint --version output

Installed via pip install git+https://github.com/PyCQA/pylint/ git+https://github.com/PyCQA/astroid
pylint commit b3b8ed2
astroid commit 99d9c77cc276b1c5f5d76d91282d05b5df3a2c21

pylint 2.6.1-dev1
astroid 2.5.0
Python 3.9.1 (default, Dec  8 2020, 07:51:42)
[GCC 10.2.0]

[hippo91]

@SuperStormer thanks for your report. I can reproduce it.
The problem seems to come form the fact that in python3.9 the type object has no __class_getitem__ method whereas, for example, listobject has one.

In [7]: type.__class_getitem__
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-7-00c2935419fa> in <module>
----> 1 type.__class_getitem__

AttributeError: type object 'type' has no attribute '__class_getitem__'

In [8]: list.__class_getitem__
Out[8]: <function list.__class_getitem__>

[hippo91]

@PCManticore i think we would need an astroid brain to handle this. What do you think about it? By the way is it possible and a good idea to enable a brain for a specific python version?

[PCManticore]

@hippo91 Yes, it's definitely a good idea to add a brain just for a given Python version.

[hippo91]

This issue should be solved by pylint-dev/astroid#883