ices/74713.rs: fixed with errors (rust-lang#617)

=== stdout ===
=== stderr ===
warning: the feature `const_generics` is incomplete and may not be safe to use and/or cause compiler crashes
 --> /home/runner/work/glacier/glacier/ices/74713.rs:1:12
  |
1 | #![feature(const_generics)]
  |            ^^^^^^^^^^^^^^
  |
  = note: `#[warn(incomplete_features)]` on by default
  = note: see issue #44580 <rust-lang/rust#44580> for more information

error[E0308]: mismatched types
 --> /home/runner/work/glacier/glacier/ices/74713.rs:5:10
  |
5 |       [(); {
  |  __________^
6 | |         let _: &'a ();
7 | |     }]: ,
  | |_____^ expected `usize`, found `()`

error: aborting due to previous error; 1 warning emitted

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

Co-authored-by: rustbot <[email protected]>

Author: github-actions[bot]