ices/53092.rs: fixed with errors

[github-actions]

Issue: rust-lang/rust#53092

#![feature(const_fn)]
#![feature(const_fn_union)]
#![feature(type_alias_impl_trait)]
#![feature(untagged_unions)]

const fn transmute<T, U>(from: T) -> U {
    use std::mem::ManuallyDrop;

    union Transform<FROM, INTO> {
        from: ManuallyDrop<FROM>,
        into: ManuallyDrop<INTO>,
    }

    let transformer = Transform {
        from: ManuallyDrop::new(from),
    };

    unsafe { ManuallyDrop::into_inner(transformer.into) }
}

type Bug<T, U> = impl Fn(T) -> U + Copy;

const CONST_BUG: Bug<u8, ()> = transmute(|_: u8| ());

fn make_bug<T, U: From<T>>() -> Bug<T, U> {
    |x| x.into()
}

fn main() {
    let x = CONST_BUG(0);
}

=== stdout ===
=== stderr ===
error[E0658]: `impl Trait` in type aliases is unstable
  --> /home/runner/work/glacier/glacier/ices/53092.rs:21:18
   |
21 | type Bug<T, U> = impl Fn(T) -> U + Copy;
   |                  ^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: see issue #63063 <https://github.com/rust-lang/rust/issues/63063> for more information
   = help: add `#![feature(min_type_alias_impl_trait)]` to the crate attributes to enable

warning: the feature `type_alias_impl_trait` is incomplete and may not be safe to use and/or cause compiler crashes
 --> /home/runner/work/glacier/glacier/ices/53092.rs:3:12
  |
3 | #![feature(type_alias_impl_trait)]
  |            ^^^^^^^^^^^^^^^^^^^^^
  |
  = note: `#[warn(incomplete_features)]` on by default
  = note: see issue #63063 <https://github.com/rust-lang/rust/issues/63063> for more information

error[E0658]: type alias impl trait is not permitted here
  --> /home/runner/work/glacier/glacier/ices/53092.rs:23:32
   |
23 | const CONST_BUG: Bug<u8, ()> = transmute(|_: u8| ());
   |                                ^^^^^^^^^^^^^^^^^^^^^
   |
   = note: see issue #63065 <https://github.com/rust-lang/rust/issues/63065> for more information
   = help: add `#![feature(impl_trait_in_bindings)]` to the crate attributes to enable

error: concrete type differs from previous defining opaque type use
  --> /home/runner/work/glacier/glacier/ices/53092.rs:25:1
   |
25 | fn make_bug<T, U: From<T>>() -> Bug<T, U> {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `[type error]`, got `[closure@/home/runner/work/glacier/glacier/ices/53092.rs:26:5: 26:17]`
   |
note: previous use here
  --> /home/runner/work/glacier/glacier/ices/53092.rs:23:1
   |
23 | const CONST_BUG: Bug<u8, ()> = transmute(|_: u8| ());
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to 3 previous errors; 1 warning emitted

For more information about this error, try `rustc --explain E0658`.
==============