false positive bad-reversed-sequence when used with dicts

[jnsnow]

Steps to reproduce

reproducer.py:

"""false positive: bad-reversed-sequence"""
x = {'hello': 'world'}
for key in reversed(x):
    print(key)

> pylint reproducer.py

************* Module reproducer
reproducer.py:3:11: E0111: The first reversed() argument is not a sequence (bad-reversed-sequence)

Current behavior

Using a dictionary with reversed() causes a bad-reversed-sequence error to be emitted.

Expected behavior

This is fine in Python 3.7 and up, where dictionaries have a known order. Though they are not Sequence types as such, they do implement the __reversed__ method.

pylint --version output

pylint 2.6.0
astroid 2.4.2
Python 3.8.6 (default, Sep 25 2020, 00:00:00)
[GCC 10.2.1 20200723 (Red Hat 10.2.1-1)]

[hippo91]

@jnsnow thanks for the report. I can reproduce it.

[hippo91]

For anyone wanting to make a first contribution, take a look at the base.py module, in the method _check_reversed.