ices/71955.rs: fixed with errors

[github-actions]

Issue: rust-lang/rust#71955

trait Parser<'s> {
    type Output;
    
    fn call(&self, input: &'s str) -> (&'s str, Self::Output);
}

impl<'s, F, T> Parser<'s> for F
where F: Fn(&'s str) -> (&'s str, T) {
    type Output = T;
    fn call(&self, input: &'s str) -> (&'s str, T) {
        self(input)
    }
}

fn foo<F1, F2>(
    f1: F1,
    base: &'static str,
    f2: F2
) 
where 
    F1: for<'a> Parser<'a>,
    F2: FnOnce(&<F1 as Parser>::Output) -> bool
{
    let s: String = base.to_owned();
    let str_ref = s.as_ref();
    let (remaining, produced) = f1.call(str_ref);
    assert!(f2(&produced));
    assert_eq!(remaining.len(), 0);
}

struct Wrapper<'a>(&'a str);

fn main() {
    fn bar<'a>(s: &'a str) -> (&'a str, &'a str) {
        (&s[..1], &s[..])
    }
    
    fn baz<'a>(s: &'a str) -> (&'a str, Wrapper<'a>) {
        (&s[..1], Wrapper(&s[..]))
    }
    
    foo(bar, "string", |s| s.len() == 5);
    foo(baz, "string", |s| s.0.len() == 5);
}

=== stdout ===
=== stderr ===
error[E0271]: type mismatch resolving `<for<'a> fn(&'a str) -> (&'a str, &'a str) {bar} as FnOnce<(&str,)>>::Output == (&str, <for<'a> fn(&'a str) -> (&'a str, &'a str) {bar} as Parser<'_>>::Output)`
  --> /home/runner/work/glacier/glacier/ices/71955.rs:42:5
   |
42 |     foo(bar, "string", |s| s.len() == 5);
   |     ^^^ expected associated type, found `&str`
   |
   = note: expected tuple `(&str, <for<'a> fn(&'a str) -> (&'a str, &'a str) {bar} as Parser<'_>>::Output)`
              found tuple `(&str, &str)`
   = help: consider constraining the associated type `<for<'a> fn(&'a str) -> (&'a str, &'a str) {bar} as Parser<'_>>::Output` to `&str` or calling a method that returns `<for<'a> fn(&'a str) -> (&'a str, &'a str) {bar} as Parser<'_>>::Output`
   = note: for more information, visit https://doc.rust-lang.org/book/ch19-03-advanced-traits.html
note: required because of the requirements on the impl of `Parser<'_>` for `for<'a> fn(&'a str) -> (&'a str, &'a str) {bar}`
  --> /home/runner/work/glacier/glacier/ices/71955.rs:7:16
   |
7  | impl<'s, F, T> Parser<'s> for F
   |                ^^^^^^^^^^     ^
note: required by a bound in `foo`
  --> /home/runner/work/glacier/glacier/ices/71955.rs:22:9
   |
15 | fn foo<F1, F2>(
   |    --- required by a bound in this
...
22 |     F2: FnOnce(&<F1 as Parser>::Output) -> bool
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `foo`

error[E0271]: type mismatch resolving `<for<'a> fn(&'a str) -> (&'a str, Wrapper<'a>) {baz} as FnOnce<(&str,)>>::Output == (&str, <for<'a> fn(&'a str) -> (&'a str, Wrapper<'a>) {baz} as Parser<'_>>::Output)`
  --> /home/runner/work/glacier/glacier/ices/71955.rs:43:5
   |
43 |     foo(baz, "string", |s| s.0.len() == 5);
   |     ^^^ expected associated type, found struct `Wrapper`
   |
   = note: expected tuple `(&str, <for<'a> fn(&'a str) -> (&'a str, Wrapper<'a>) {baz} as Parser<'_>>::Output)`
              found tuple `(&str, Wrapper<'_>)`
   = help: consider constraining the associated type `<for<'a> fn(&'a str) -> (&'a str, Wrapper<'a>) {baz} as Parser<'_>>::Output` to `Wrapper<'_>` or calling a method that returns `<for<'a> fn(&'a str) -> (&'a str, Wrapper<'a>) {baz} as Parser<'_>>::Output`
   = note: for more information, visit https://doc.rust-lang.org/book/ch19-03-advanced-traits.html
note: required because of the requirements on the impl of `Parser<'_>` for `for<'a> fn(&'a str) -> (&'a str, Wrapper<'a>) {baz}`
  --> /home/runner/work/glacier/glacier/ices/71955.rs:7:16
   |
7  | impl<'s, F, T> Parser<'s> for F
   |                ^^^^^^^^^^     ^
note: required by a bound in `foo`
  --> /home/runner/work/glacier/glacier/ices/71955.rs:22:9
   |
15 | fn foo<F1, F2>(
   |    --- required by a bound in this
...
22 |     F2: FnOnce(&<F1 as Parser>::Output) -> bool
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `foo`

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0271`.
==============