False positive ``undefined-variable`` when using class reference of sibling class

[laf0rge]

Bug description

I'm getting false positives when using the following construct, where the name of a sibling class is used in the argument list of defining another sibling class.

The code works perfectly fine, cpython executes it and the result is the expected result. It is just pylint-2.12.2 which is complaining about this:

class EF_DIR(LinFixedEF):
    class ApplicationLabel(BER_TLV_IE, tag=0x50):
        _construct = GreedyString('ascii')

    class ApplicationTemplate(BER_TLV_IE, tag=0x61,
                              nested=[iso7816_4.ApplicationId, ApplicationLabel, iso7816_4.FileReference,
                                      iso7816_4.CommandApdu, iso7816_4.DiscretionaryData,
                                      iso7816_4.DiscretionaryTemplate, iso7816_4.URL,
                                      iso7816_4.ApplicationRelatedDOSet]):
        pass

    def __init__(self, fid='2f00', sfid=0x1e, name='EF.DIR', desc='Application Directory'):
        super().__init__(fid, sfid=sfid, name=name, desc=desc, rec_len={5, 54})
        self._tlv = EF_DIR.ApplicationTemplate

The full code example can be fond at https://gerrit.osmocom.org/c/pysim/+/27130/6 and can be cloned via

git clone https://gerrit.osmocom.org/pysim
cd pysim
git fetch https://gerrit.osmocom.org/pysim refs/changes/30/27130/6
git checkout FETCH_HEAD

Command used

python3 -m pylint --errors-only \                                                                                              
        --disable E1102 \
        --disable E0401 \
        --enable W0301 \
        pySim *.py

Pylint output

************* Module pySim.ts_102_221
pySim/ts_102_221.py:599:63: E0602: Undefined variable 'ApplicationLabel' (undefined-variable)

Expected behavior

pylint should not throw an error for something that parses and executes fine in cpthon.

Pylint version

2.12.2

OS / Environment

Debian GNU/Linux

[Pierre-Sassoulas]

I confirmed the false positive with latest pylint using:

class MyClass:
    pass


class EF_DIR:
    class ApplicationLabel(MyClass, tag=0x50):
        pass

    class ApplicationTemplate(MyClass, nested=[ApplicationLabel]):
        pass

    def __init__(self):
        pass