duplicate-key checker doesn't detect duplicate Enum keys

[Neki]

Bug description

The pylint 'duplicate-key' checker doesn't detect duplicate keys when said keys are enum members.

Consider the following code snippet:

from enum import Enum

# shows that the duplicate-key checker is activated, but irrelevant for the actual issue
produces_a_warning = {"key": "value 1", "key": "value 2"}

class MyEnum(Enum):
    KEY = "key"

does_not_produce_a_warning = {MyEnum.KEY: "value 1", MyEnum.KEY: "value 2"}

Running pylint with the default rc file generates only one warning:

duplicate_keys.py:4:21: W0109: Duplicate key 'key' in dictionary (duplicate-key)

pylint should also have detected that the dictionary does_not_produce_a_warning includes a duplicated key.

Configuration

No response

Command used

pylint duplicate_keys.py

Pylint output

************* Module duplicate_keys
duplicate_keys.py:4:21: W0109: Duplicate key 'key' in dictionary (duplicate-key)

Expected behavior

pylint should also have detected that the dictionary does_not_produce_a_warning includes a duplicated key, and should have produced two warnings.

Pylint version

pylint 2.11.1
astroid 2.8.0
Python 3.8.10 (default, Sep 28 2021, 16:10:42)
[GCC 9.3.0]

OS / Environment

Ubuntu 20.04

Additional dependencies

No response

[jaydesl]

I think I could help out here!

[Pierre-Sassoulas]

Thanks a lot for offering your help @jaydesl, I assigned you the issue :)