Diagnostic: suggest removing &mut instead of making the function argument mutable

[Alvenix]

For the following code:

fn main() {
    let mut borrowed = 843;
    example(&mut borrowed);
}

fn example(borrowed: &mut usize) {
    example2(&mut borrowed);
}

fn example2(_: &mut usize) {}

The compiler provide the following error message:

 --> src/main.rs:7:14
  |
6 | fn example(borrowed: &mut usize) {
  |            -------- help: consider changing this to be mutable: `mut borrowed`
7 |     example2(&mut borrowed);
  |              ^^^^^^^^^^^^^ cannot borrow as mutable

Although the suggestion actually work. (Because of type coercion). I think it would be a little nicer to suggest removing &mut when calling the function.

My friend who is new to Rust got a similar suggestion (and misunderstood it) which made him confused.

[tesuji]

@rustbot claim

[tesuji]

Duplicate of #75871.

[jyn514]

Closing as duplicate.