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## Summary
Fixes false positive in B909 (`loop-iterator-mutation`) where mutations
inside return/break statements were incorrectly flagged as violations.
The fix adds tracking for when mutations occur within return/break
statements and excludes them from violation detection, as they don't
cause the iteration issues B909 is designed to prevent.
## Test Plan
- Added test cases covering the reported false positive scenarios to
`B909.py`
- Verified existing B909 tests continue to pass (no regressions)
- Ran `cargo test -p ruff_linter --lib flake8_bugbear` successfully
Fixes#18399
## Summary
Pretty sure this should still be an error, but also, I think I added
this because of ecosystem CI? So want to see what pops up.
Closes https://github.com/astral-sh/ruff/issues/12164.
## Summary
This PR adds the implementation for the current
[flake8-bugbear](https://github.com/PyCQA/flake8-bugbear)'s B038 rule.
The B038 rule checks for mutation of loop iterators in the body of a for
loop and alerts when found.
Rational:
Editing the loop iterator can lead to undesired behavior and is probably
a bug in most cases.
Closes#9511.
Note there will be a second iteration of B038 implemented in
`flake8-bugbear` soon, and this PR currently only implements the weakest
form of the rule.
I'd be happy to also implement the further improvements to B038 here in
ruff 🙂
See https://github.com/PyCQA/flake8-bugbear/issues/454 for more
information on the planned improvements.
## Test Plan
Re-using the same test file that I've used for `flake8-bugbear`, which
is included in this PR (look for the `B038.py` file).
Note: this is my first time using `rust` (beside `rustlings`) - I'd be
very happy about thorough feedback on what I could've done better
🙂 - Bring it on 😀
