let_and_return: avoid "does not live long enough" errors
EDIT: Add #3324 to the list of fixes
<details>
<summary>Description of old impl</summary>
<br>
Avoid suggesting turning the RHS expression of the last statement into the block tail expression if a temporary borrows from a local that would be destroyed before.
This is my first incursion into MIR so there's probably room for improvement!
</details>
Avoid linting if the return type of some method or function called in the last statement has a lifetime parameter.
changelog: Fix false positive in [`let_and_return`]
Fixes#3792Fixes#3324
Make `PolyTraitRef::self_ty` return `Binder<Ty>`
This came up during review of #71618. The current implementation is the same as a call to `skip_binder` but harder to audit. Make it preserve binding levels and add a call to `skip_binder` at all use sites so they can be audited as part of #72507.
Give corrected code
This PR adds corrected code for doc examples.
I did this in several commits to facilitate review.
Don't hesitate to tell me if I forgot some.
Also, sometimes I felt it was not necessary to give corrected code, but I maybe wrong.
fixes: #4829
changelog: Improve documentation examples across multiple lints.
New lint: iter_next_slice
Hello, this is a work-in-progress PR for issue: https://github.com/rust-lang/rust-clippy/issues/5572
I have implemented lint to replace `iter().next()` for `slice[index..]` and `array` with `get(index)` and `get(0)` respectively. However since I made a lot of changes, I would like to request some feedback before continuing so that I could fix mistakes.
Thank you!
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changelog: implement `iter_next_slice` lint and test, and modify `needless_continues`, `for_loop_over_options_result` UI tests since they have `iter().next()`
