Pylint: typing.Pattern not treated as a type

[jolaf]

The following code:

from re import compile as reCompile
from typing import Pattern

pattern = reCompile(r'')
print(isinstance(pattern, Pattern))

produces the following output:

$ python3 Test.py
True
$ pylint3 Test.py
************* Module Test
Test.py:5: [W1116(isinstance-second-argument-not-valid-type), ] Second argument of isinstance is not a type

$ python3 --version
Python 3.6.9
$ pylint3 --version
pylint 2.5.0
astroid 2.4.0
Python 3.6.9 (default, Apr 18 2020, 01:56:04) 

Clearly, there's some problem with checking Pattern, as, for example, isinstance({}, Mapping) produces no warning.

[Pierre-Sassoulas]

Thank you for the issue, I can reproduce this with the latest pylint.

[analog-cbarber]

Same with Sequence. Of course, technically these are not in fact type instances, but can still be used with isinstance.

[dumblob]

Totally agreed. IMHO most (any?) types/protocols from typing and collections (especially collections.abc) shall be treated as OK for isinstance().

Btw. this seems to be duplicate of https://github.com/PyCQA/pylint/issues/3507 and probably https://github.com/PyCQA/pylint/issues/2287 as well as https://github.com/PyCQA/pylint/issues/1162 (see discussions in them as there is also the idea to "copy" the implementation mypy uses - i.e. assert isinstance()).

[QBCARL]

Same with Callable