Linting of noqa comments

[kasium]

describe the request

1. Flake8 itself is picky about noqa comments, so e.g. noqa F123 or flake8 : noqa might not do what the users expect
2. Also e.g. a project might want to ban the usage of flake8: noqa or bare noqa comments.

As far as I'm aware of there is flake8-noqa, which hacks into the internals of flake8 which was already discussed here: #603 (comment).

Writing a plugin which verifies correct comments (1) can be done, but (2) is not possible w/o hacks, since noqa disables all errors. Therefore my feature request: can maybe flake8 directly offer this? It's maybe similar to pylint errors suppressed-message and locally-disabled. It would be a great addition to flake8. However, this basically means, that flake8 needs to implement own checks which is maybe out of scope for a framework...

[asottile]

#603