WPS122 should allow a no-op loop var

Bug report

What’s wrong

Imagine I want to do something 3 times but I don’t care about the attempt number. So I’d normally write something like this:

for _ in range(3):
    do_something()

But then the linter complains with WPS122 Found all unused variables definition: _ which is incorrect. While things like assignment allow to fix this with

-_something_unused = get_useless_result()
+get_useless_result()

it is impossible with for-loops not to define this loop variable at all.

How is that should be

This case shouldn’t be a violation of the given rule.

System information

N/A

[sobolevn]

It is not released. Will be released in 0.15

[sobolevn]

The same applies for comprehensions.