ices/67945-4.rs: fixed with errors

[github-actions]

Issue: rust-lang/rust#67945

// reproducer by nikomatsakis
use std::marker::PhantomData;

use std::mem::{self, MaybeUninit};

struct Bug<S> {
    A: [(); {
        let x: Option<Box<S>> = None;
        0
    }],
}

=== stdout ===
=== stderr ===
error: generic parameters may not be used in const operations
 --> /home/runner/work/glacier/glacier/ices/67945-4.rs:8:27
  |
8 |         let x: Option<Box<S>> = None;
  |                           ^ cannot perform const operation using `S`
  |
  = note: type parameters may not be used in const expressions
  = help: use `#![feature(const_generics)]` and `#![feature(const_evaluatable_checked)]` to allow generic const expressions

warning: unused import: `std::marker::PhantomData`
 --> /home/runner/work/glacier/glacier/ices/67945-4.rs:2:5
  |
2 | use std::marker::PhantomData;
  |     ^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: `#[warn(unused_imports)]` on by default

warning: unused imports: `MaybeUninit`, `self`
 --> /home/runner/work/glacier/glacier/ices/67945-4.rs:4:16
  |
4 | use std::mem::{self, MaybeUninit};
  |                ^^^^  ^^^^^^^^^^^

error[E0601]: `main` function not found in crate `67945_4`
  --> /home/runner/work/glacier/glacier/ices/67945-4.rs:2:1
   |
2  | / use std::marker::PhantomData;
3  | |
4  | | use std::mem::{self, MaybeUninit};
5  | |
...  |
10 | |     }],
11 | | }
   | |_^ consider adding a `main` function to `/home/runner/work/glacier/glacier/ices/67945-4.rs`

error[E0392]: parameter `S` is never used
 --> /home/runner/work/glacier/glacier/ices/67945-4.rs:6:12
  |
6 | struct Bug<S> {
  |            ^ unused parameter
  |
  = help: consider removing `S`, referring to it in a field, or using a marker such as `PhantomData`

error: aborting due to 3 previous errors; 2 warnings emitted

Some errors have detailed explanations: E0392, E0601.
For more information about an error, try `rustc --explain E0392`.
==============