ices/59494.rs: fixed with errors

[github-actions]

Issue: rust-lang/rust#59494

fn t7p<A,B,C>( f:impl Fn(B) -> C, g:impl Fn(A) -> B ) -> impl Fn(A) -> C
{
  move |a:A| -> C { f(g(a)) }
}

fn t8n<A,B,C>( f:impl Fn(A) -> B, g:impl Fn(A) -> C ) -> impl Fn(A) -> (B,C)
  where
    A: Copy
{
  move |a:A| -> (B,C) {
    let b = a;
    let fa = f(a);
    let ga = g(b);
    (fa, ga)
  }
}

fn main() {

  let f = |(_,_)| {  };
  let g = |(a,_)| { a };
  let t7 = |env| { |a| { |b| {  t7p(f, g)(((env,a),b))  }}};
  let t8 = t8n(t7, t7p(f, g));
}

=== stdout ===
=== stderr ===
error[E0277]: expected a `Fn<(_,)>` closure, found `impl Fn<(((_, _), _),)>`
  --> /home/runner/work/glacier/glacier/ices/59494.rs:23:20
   |
6  | fn t8n<A,B,C>( f:impl Fn(A) -> B, g:impl Fn(A) -> C ) -> impl Fn(A) -> (B,C)
   |                                          ---------- required by this bound in `t8n`
...
23 |   let t8 = t8n(t7, t7p(f, g));
   |                    ^^^^^^^^^ expected an `Fn<(_,)>` closure, found `impl Fn<(((_, _), _),)>`
   |
   = help: the trait `Fn<(_,)>` is not implemented for `impl Fn<(((_, _), _),)>`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0277`.
==============