Pylint: used-before-assignment false positive with walrus operator inside if expression

[craigc40]

Steps to reproduce

1. Save the following in a file

def func(): return None
s = 'foo' if (fval := func()) is None else fval

1. run pylint on the script

Current behavior
Pylint returns

E0601: Using variable 'fval' before assignment (used-before-assignment)

Expected behavior

No error (fval is assigned in the walrus assignment before being read)

pylint --version output

pylint 2.4.4
astroid 2.3.3
Python 3.8.1 (tags/v3.8.1:1b293b6, Dec 18 2019, 22:39:24) [MSC v.1916 32 bit (Intel)]

[craigc40]

Hi @AWhetter, I was curious why this report wouldn't be categorized as a bug instead of as an enhancement. The walrus operator is already supported by pylint, so isn't it a bug for pylint to report used-before-assignment in this use case since the variable is actually being used?

[AWhetter]

Bugs are when we have implemented something but it isn't working as intended.
pylint can parse the walrus operator but we haven't actually implemented support for it. It's a new feature.

[kootenpv]

Unless I am mistaken it means we should disable used-before-assignment for code that uses the walrus operator?