This pull request fixes the bug described in issue
[#19153](https://github.com/astral-sh/ruff/issues/19153).
The issue occurred when `PERF403` incorrectly flagged cases involving
tuple unpacking in a for loop. For example:
```python
def f():
v = {}
for (o, p), x in [("op", "x")]:
v[x] = o, p
```
This code was wrongly suggested to be rewritten into a dictionary
comprehension, which changes the semantics.
Changes in this PR:
Updated the `PERF403` rule to correctly handle tuple unpacking in loop
targets.
Added regression tests to ensure this case (and similar ones) are no
longer flagged incorrectly.
Why:
This ensures that `PERF403` only triggers when a dictionary
comprehension is semantically equivalent to the original loop,
preventing false positives.
---------
Co-authored-by: Brent Westbrook <brentrwestbrook@gmail.com>
## Summary
This change adds an auto-fix for manual dict comprehensions. It also
copies many of the improvements from #13919 (and associated PRs fixing
issues with it), and moves some of the utility functions from
`manual_list_comprehension.rs` into a separate `helpers.rs` to be used
in both.
## Test Plan
I added a preview test case to showcase the new fix and added a test
case in `PERF403.py` to make sure lines with semicolons function. I
didn't yet make similar tests to the ones I added earlier to
`PERF401.py`, but the logic is the same, so it might be good to add
those to make sure they work.
Lior Weissman
Robsdedude
Victor Hugo Gomes
chiri
w0nder1ng
Alex Waygood
Charlie Marsh