Conflicting unhelpful suggestion related to `Peekable::next_if_eq`

Code

let mut it = vec![].iter().peekable();
it.next_if_eq(&0); // suggests removing `&`
it.next_if_eq(0); // suggests adding `&`
it.next_if_eq(&&0); // actually correct

Current output

error[E0277]: can't compare `&_` with `{integer}`
   --> src/main.rs:3:15
    |
  3 | it.next_if_eq(&0); // suggests removing `&`
    |    ---------- ^^ no implementation for `&_ == {integer}`
    |    |
    |    required by a bound introduced by this call
    |
    = help: the trait `PartialEq<{integer}>` is not implemented for `&_`
note: required by a bound in `Peekable::<I>::next_if_eq`
   --> /playground/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/iter/adapters/peekable.rs:316:18
    |
313 |     pub fn next_if_eq<T>(&mut self, expected: &T) -> Option<I::Item>
    |            ---------- required by a bound in this associated function
...
316 |         I::Item: PartialEq<T>,
    |                  ^^^^^^^^^^^^ required by this bound in `Peekable::<I>::next_if_eq`
help: consider removing the leading `&`-reference
    |
  3 - it.next_if_eq(&0); // suggests removing `&`
  3 + it.next_if_eq(0); // suggests removing `&`
    |

error[E0308]: mismatched types
   --> src/main.rs:4:15
    |
  4 | it.next_if_eq(0); // suggests adding `&`
    |    ---------- ^ expected `&_`, found integer
    |    |
    |    arguments to this method are incorrect
    |
    = note: expected reference `&_`
                    found type `{integer}`
note: method defined here
   --> /playground/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/iter/adapters/peekable.rs:313:12
    |
313 |     pub fn next_if_eq<T>(&mut self, expected: &T) -> Option<I::Item>
    |            ^^^^^^^^^^
help: consider borrowing here
    |
  4 | it.next_if_eq(&0); // suggests adding `&`
    |               +

Desired output

Rationale and extra context

The current diagnostic suggests removing the borrow on the first line, however the real solution is to add a second borrow, as the iterator is yielding &{integer}, so one needs to pass a &&{integer} to satisfy the fn args.

Other cases

Rust Version

rustc 1.91.1 (ed61e7d7e 2025-11-07)
binary: rustc
commit-hash: ed61e7d7e242494fb7057f2657300d9e77bb4fcb
commit-date: 2025-11-07
host: x86_64-pc-windows-msvc
release: 1.91.1
LLVM version: 21.1.2

Anything else?

No response

Reproduce the diagnostic with the Rust example in the issue, then inspect the Peekable::next_if_eq signature and the compiler diagnostic that handles the two argument-type errors. Trace why the first case recommends removing a borrow, and update the relevant suggestion logic so the output reflects the required additional borrow. Done means the conflicting suggestions are corrected for both examples and covered by an appropriate compiler test.