Confusing error message when trying to pattern match on slice containing String

[sivertjoe]

Given the following code:

fn main()
{
    let foo = vec!["foo".to_string()];
    
    match foo.as_slice()
    {
        &["foo".to_string()] => {}
        _ => {}
    };
}

The current output is:

error: expected one of `,`, `...`, `..=`, `..`, `]`, or `|`, found `.`
 --> src/main.rs:8:16
  |
8 |         &["foo".to_string()] => {}
  |                ^
  |                |
  |                expected one of `,`, `...`, `..=`, `..`, `]`, or `|`
  |                help: missing `,`

error[E0531]: cannot find tuple struct or tuple variant `to_string` in this scope
 --> src/main.rs:8:17
  |
8 |         &["foo".to_string()] => {}
  |                 ^^^^^^^^^ not found in this scope

error[E0308]: mismatched types
 --> src/main.rs:8:11
  |
6 |     match foo.as_slice()
  |           -------------- this expression has type `&[String]`
7 |     {
8 |         &["foo".to_string()] => {}
  |           ^^^^^ expected struct `String`, found `&str`

Some errors have detailed explanations: E0308, E0531.
For more information about an error, try `rustc --explain E0308`.
error: could not compile `playground` due to 3 previous errors

Ideally the output should look the same as if I did:

match foo.as_slice()
{
    &[String::from("foo")] => {}
    _ => {}
};

which is:

error[E0164]: expected tuple struct or tuple variant, found associated function `String::from`
 --> src/main.rs:8:11
  |
8 |         &[String::from("foo")] => {}
  |           ^^^^^^^^^^^^^^^^^^^ `fn` calls are not allowed in patterns
  |
  = help: for more information, visit https://doc.rust-lang.org/book/ch18-00-patterns.html

So maybe a better output for my first example would be

error[E0164]: expected tuple struct or tuple variant, found associated function `std::str::to_string`
 --> src/main.rs:8:11
  |
8 |          &["foo".to_string()] => {}
  |           ^^^^^^^^^^^^^^^^^^^ `fn` calls are not allowed in patterns
  |
  = help: for more information, visit https://doc.rust-lang.org/book/ch18-00-patterns.html

[Nadrieril]

Closing as a duplicate of #112593 (which has mentoring instructions)