Pylint doesn't warn if isinstance's second argument doesn't consist entirely of types.

[bnsh]

Not really sure if it's a real issue... But, the bug (my own) bit me, and I thought pylint would have saved me from it...

Here's the example code:

#! /usr/bin/env python3
# vim: expandtab shiftwidth=4 tabstop=4

"""This program demonstrates that pylint doesn't catch
   instanceof "types" """

def main():
    print(isinstance("x", hash))

if __name__ == "__main__":
    main()

If I run it tho, I get:

$ python3 ./demo.py 
Traceback (most recent call last):
  File "./demo.py", line 11, in <module>
    main()
  File "./demo.py", line 8, in main
    print(isinstance("x", hash))
TypeError: isinstance() arg 2 must be a type or tuple of types

it's pylint clean tho:

$ python3 -m pylint --version
pylint 2.4.3
astroid 2.3.2
Python 3.6.9 (default, Nov  7 2019, 10:44:02) 
[GCC 8.3.0]
$ python3 -m pylint -r n demo.py 

--------------------------------------------------------------------
Your code has been rated at 10.00/10 (previous run: 10.00/10, +0.00)

Is that a problem? (In this case, I said "hash" where I meant "dict")

Thanks!

[PCManticore]

Thank you for the report. This is definitely an issue we should be able to detect.

[anubh-v]

I'll attempt this.