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!
---
changelog: implement `iter_next_slice` lint and test, and modify `needless_continues`, `for_loop_over_options_result` UI tests since they have `iter().next()`
Add regression test for endless loop / update `pulldown_cmark`
Closes#4917
This was fixed in pulldown_cmark 0.7.1, specifically raphlinus/pulldown-cmark#438
changelog: none
Rework suggestion generation of `unit_arg` lint
Found this bug while running `cargo fix --clippy` on quite a big codebase:
This would replace something like:
```rust
Some(fn_that_actually_does_something(&a, b))
```
with
```rust
Some(())
```
which obviously suppresses side effects.
Since pretty much every expression could have side effects, I think making this suggestion `MaybeIncorrect` is the best thing to do here.
A correct suggestion would be:
```rust
fn_that_actually_does_something(&a, b);
Some(())
```
Somehow the suggestion is not correctly applied to the arguments, when more than one argument is a unit value. I have to look into this a little more, though.
changelog: Fixes suggestion of `unit_arg` lint, so that it suggests semantic equivalent code
Fixes#4741
len_zero: skip ranges if feature `range_is_empty` is not enabled
If the feature is not enabled, calling `is_empty()` on a range is ambiguous. Moreover, the two possible resolutions are unstable methods, one inherent to the range and the other being part of the `ExactSizeIterator` trait.
Since `len_zero` only checks for existing `is_empty()` inherent methods, we only take into account the `range_is_empty` feature.
Related: https://github.com/rust-lang/rust/issues/48111#issuecomment-445132965
changelog: len_zero: avoid linting ranges without #![feature(range_is_empty)]
Fixes: #3807
Extend useless conversion
This PR extends `useless_conversion` lint with `TryFrom` and `TryInto`
fixes: #5344
changelog: Extend `useless_conversion` with `TryFrom` and `TryInto`
Make empty_line_after_outer_attr an early lint
Fixes#5567
Unfortunately I couldn't find a way to reproduce the issue without syn/quote. Considering that most real-world macros use syn and/or quote, I think it's okay to pull them in anyway.
changelog: Fix false positive in [`empty_line_after_outer_attr`]
reversed_empty_ranges: add suggestion for &slice[N..N]
As discussed in the issue thread, the user accepted this solution. Let me know if this is what we want, or if changing the way we lint the N..N case is prefered.
changelog: reversed_empty_ranges: add suggestion for &slice[N..N]
Closes#5628
