Re: [PATCH] rust: allow `clippy::needless_lifetimes`

[Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>]

On Sat, Nov 16, 2024 at 7:16 PM Miguel Ojeda <ojeda@kernel.org> wrote:
>
> In beta Clippy (i.e. Rust 1.83.0), the `needless_lifetimes` lint has
> been extended [1] to suggest eliding `impl` lifetimes, e.g.
>
>     error: the following explicit lifetimes could be elided: 'a
>     --> rust/kernel/list.rs:647:6
>         |
>     647 | impl<'a, T: ?Sized + ListItem<ID>, const ID: u64> FusedIterator for Iter<'a, T, ID> {}
>         |      ^^                                                                  ^^
>         |
>         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_lifetimes
>         = note: `-D clippy::needless-lifetimes` implied by `-D warnings`
>         = help: to override `-D warnings` add `#[allow(clippy::needless_lifetimes)]`
>     help: elide the lifetimes
>         |
>     647 - impl<'a, T: ?Sized + ListItem<ID>, const ID: u64> FusedIterator for Iter<'a, T, ID> {}
>     647 + impl<T: ?Sized + ListItem<ID>, const ID: u64> FusedIterator for Iter<'_, T, ID> {}
>
> A possibility would have been to clean them -- the RFC patch [2] did
> this, while asking if we wanted these cleanups. There is an open issue
> [3] in Clippy about being able to differentiate some of the new cases,
> e.g. those that do not involve introducing `'_`. Thus it seems others
> feel similarly.
>
> Thus, for the time being, we decided to `allow` the lint.
>
> Link: https://github.com/rust-lang/rust-clippy/pull/13286 [1]
> Link: https://lore.kernel.org/rust-for-linux/20241012231300.397010-1-ojeda@kernel.org/ [2]
> Link: https://github.com/rust-lang/rust-clippy/issues/13514 [3]
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Applied to `rust-next` so that no one gets warnings on Thursday under
`CLIPPY=1` -- thanks everyone!

Cheers,
Miguel