Fix manual_pop_if captured collection suggestions

[zjubiology]

changelog: [manual_pop_if]: avoid invalid automatic suggestions when the predicate borrows the collection

manual_pop_if could emit a machine-applicable suggestion when the predicate also referenced the collection being popped from.

For example, rewriting:

if vec
    .last()
    .is_some_and(|x| vec.len() > 1 && *x > 10)
{
    vec.pop().unwrap();
}

to vec.pop_if(...) requires a mutable borrow of vec while the predicate closure also immutably borrows it, causing E0502.

Only provide an automatic suggestion when the collection is a simple local path and the predicate does not reference that local. Continue emitting the lint with a help message for captured or non-local collection expressions.

Also retain the parameter pattern and avoid automatic rewrites for non-default binding modes such as ref and mut, since the predicate parameter changes from &T to &mut T.

Add UI coverage for all supported condition forms, complex collection expressions, and non-default parameter bindings.

[rustbot]

Thanks for the pull request, and welcome!

You should hear from one of our reviewers after this PR gets at least 2 reviews from the community.

Please see the contribution instructions for more information.

[notriddle]

I’m not going to pretend to understand all of the code in here, but the test cases are improved, and the general idea of scanning for usages makes sense.

View changes since this review