Ensure that FalsyConstantCompareViolation counts NamedExpr

[sobolevn]

Currently we don't handle NamedExpr in this violation.

One can write this code:

if (x := []) == other:
    ...

And it won't be handled properly. Here's how direct values are compared:

  1:4      WPS520 Found compare with falsy constant
  if [] == other:
     ^

File to fix:

wemake-python-styleguide/wemake_python_styleguide/visitors/ast/compares.py

Line 151 in ea20c44

def visit_Compare(self, node: ast.Compare) -> None:

We also need to test this violation. Make sure that you use pytest.skipif(PY38, ...) because this syntax is only valid starting from python3.8+

Related #1137

[edytagarbarz]

Let me fix this one

[sobolevn]

Sure! Thank you, @edytagarbarz! Make sure to read our contributing guides

I am here to help: ask anything you need.

[sobolevn]

@edytagarbarz friendly ping to make sure you don't have any problems with the task. But, if there's something I can help you with - feel free to ask! 👍

[sobolevn]

By the way, this commit does pretty much the same thing as you need: 4fa9f41 Check it out!

[edytagarbarz]

Thank you @sobolevn! Configuration took me a while but now no problems at all :)