Re: [PATCH] drm/panic: clean new `clippy::needless_range_loop` lint for Rust 1.100.0

[Jocelyn Falempe <jfalempe@redhat.com>]

On 31/08/2026 19:54, Miguel Ojeda wrote:
> On Wed, Aug 26, 2026 at 4:56 PM Miguel Ojeda <ojeda@kernel.org> wrote:
>>
>> Starting with Rust 1.100.0 (expected 2026-11-12), Clippy warns:
>>
>>      warning: the loop variable `i` is only used to index `self.decimals`
>>         --> drivers/gpu/drm/drm_panic_qr.rs:410:18
>>          |
>>      410 |         for i in 0..len {
>>          |                  ^^^^^^
>>          |
>>      note: for this index operation
>>         --> drivers/gpu/drm/drm_panic_qr.rs:411:13
>>          |
>>      411 |             self.decimals[i] = (chunk % 10) as u8;
>>          |             ^^^^^^^^^^^^^^^^
>>          = help: for further information visit https://rust-lang.github.io/rust-clippy/main/index.html#needless_range_loop
>>          = note: `-W clippy::needless-range-loop` implied by `-W clippy::all`
>>          = help: to override `-W clippy::all` add `#[allow(clippy::needless_range_loop)]`
>>      help: consider using an iterator
>>          |
>>      410 -         for i in 0..len {
>>      410 +         for <item> in self.decimals.iter_mut().take(len) {
>>          |
>>
>> The lint did not trigger here before because it could not handle arrays
>> behind a field access such as `self.decimals` -- Clippy was improved to
>> catch those cases [1][2].
>>
>> Thus clean the warning by iterating over a slice rather than using
>> `take()` so that an out-of-range `len` still triggers the same bounds
>> check as the indexed loop.
>>
>> Cc: stable@vger.kernel.org # Needed in 6.18.y and later.
>> Link: https://github.com/rust-lang/rust-clippy/issues/16631 [1]
>> Link: https://github.com/rust-lang/rust-clippy/pull/16634 [2]
>> Assisted-by: LLM
>> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
>> ---
>> One may want to keep the loop in a shape similar to e.g. the one above,
>> though.
> 
> Jocelyn: I will likely send another rust-fixes PR during this cycle,
> so I can put this one there if you agree with it.

Sorry for replying late.
That looks good to me, and you can take this patch in the rust-fixes tree.

Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
> 
> Thanks!
> 
> Cheers,
> Miguel
>