Compiler's help suggestion is incorrect when passing Option<String> into a function expecting Option<&str>

[scizzorz]

Code

fn foo(_s: Option<&str>) {
}

fn main() {
    let s = Some("".to_string());
    foo(s);
}

// AND:

fn foo(_s: Option<&str>) {
}

fn main() {
    let s = Some("".to_string());
    foo(s.map(|x| &*x));
}

Current output

error[E0308]: mismatched types
 --> foo.rs:6:9
  |
6 |     foo(s);
  |     --- ^ expected `&str`, found struct `String`
  |     |
  |     arguments to this function are incorrect
  |
  = note: expected enum `Option<&str>`
             found enum `Option<String>`
note: function defined here
 --> foo.rs:1:4
  |
1 | fn foo(_s: Option<&str>) {
  |    ^^^ ----------------
help: try converting the passed type into a `&str`
  |
6 |     foo(s.map(|x| &*x));
  |          +++++++++++++

error: aborting due to previous error

For more information about this error, try `rustc --explain E0308`.

// AND:

error[E0515]: cannot return value referencing function parameter `x`
 --> foo.rs:6:19
  |
6 |     foo(s.map(|x| &*x));
  |                   ^^-
  |                   | |
  |                   | `x` is borrowed here
  |                   returns a value referencing data owned by the current function

error: aborting due to previous error

For more information about this error, try `rustc --explain E0515`.

Desired output

I believe the help suggestion should be valid code. I was able to solve this error with:

fn foo(s: Option<&str>) {
}

fn main() {
    let s = Some("".to_string());
    foo(s.as_ref().map(AsRef::as_ref));
}

Rationale and extra context

rustc's help suggestions are often extremely helpful, but in this case the suggested change simply does not work and also doesn't provide any further help or explanation about why it doesn't work.

Other cases

No response

Anything else?

No response

[kadiwa4]

It should preferably suggest foo(s.as_deref());

[clubby789]

as_deref doesn't work for Option<&String> -> Option<&str>, discussed in the original issue which resulted in the first diagnostic #89856
Misread the issue!