Re: [PATCH] rust: pin-init: replace clippy `expect` with `allow`

[Tamir Duberstein]

On Sun, Feb 15, 2026 at 9:57 AM Benno Lossin <lossin@xxxxxxxxxx> wrote:
>
> On Sun Feb 15, 2026 at 3:24 PM CET, Tamir Duberstein wrote:
> > On Sun, Feb 15, 2026 at 8:22 AM Benno Lossin <lossin@xxxxxxxxxx> wrote:
> >>
> >> `clippy` has changed behavior in [1] (Rust 1.95) where it no longer
> >> warns about the `let_and_return` lint when a comment is placed between
> >> the let binding and the return expression. Nightly thus fails to build,
> >> because the expectation is no longer fulfilled.
> >>
> >> Thus replace the expectation with an `allow`.
> >>
> >> Link: https://github.com/rust-lang/rust-clippy/pull/16461 [1]
> >> Signed-off-by: Benno Lossin <lossin@xxxxxxxxxx>
> >> ---
> >>  rust/pin-init/src/lib.rs | 4 ++--
> >>  1 file changed, 2 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/rust/pin-init/src/lib.rs b/rust/pin-init/src/lib.rs
> >> index 49945fc07f25..fe4c85ae3f02 100644
> >> --- a/rust/pin-init/src/lib.rs
> >> +++ b/rust/pin-init/src/lib.rs
> >> @@ -1143,13 +1143,13 @@ unsafe fn __pinned_init(self, slot: *mut T) -> Result<(), E> {
> >>  ///
> >>  /// - `*mut U` must be castable to `*mut T` and any value of type `T` written through such a
> >>  ///   pointer must result in a valid `U`.
> >> -#[expect(clippy::let_and_return)]
> >>  pub const unsafe fn cast_pin_init<T, U, E>(init: impl PinInit<T, E>) -> impl PinInit<U, E> {
> >>      // SAFETY: initialization delegated to a valid initializer. Cast is valid by function safety
> >>      // requirements.
> >>      let res = unsafe { pin_init_from_closure(|ptr: *mut U| init.__pinned_init(ptr.cast::<T>())) };
> >>      // FIXME: remove the let statement once the nightly-MSRV allows it (1.78 otherwise encounters a
> >>      // cycle when computing the type returned by this function)
> >> +    #[allow(clippy::let_and_return)]
> >
> > Consider adding `reason = "..."`.
>
> Isn't the FIXME comment directly above enough? I don't want to duplicate
> the information and the string constant explaining the reason looks
> ugly.

The FIXME explains why the allowance is needed, but it doesn't explain
why it is an allow rather than an expect.