New check: B040

[Zac-HD]

PyCQA/flake8-bugbear#474 / PyCQA/flake8-bugbear#477

[zanieb]

Makes sense to me!

[jakkdl]

note that I explicitly decided not to cover some thorny cases, but given you have the full logic for unused variables already, I think it might make sense for you to cover them.
See discussion in the linked PR and the end of the file with test cases

[Heidar-An]

Hey! I've been using this crate for some time now and I'd love to contribute back! However, I'm a bit confused by the initial comment, what exactly are we trying to fix?

[Zac-HD]

We'd like to implement the new lint rule from upstream - this is basically a 'please port it' feature request!

[divident]

@Zac-HD Hi, I have added the rule that covers the same set of errors as one in upstream and even covers the unhandled cases there. Currently it only doesn't cover the reassignment of the exception like

try:
    ...
except Exception as e:
    e2 = ValueError()  # should error
    e2.add_note(str(e))