ices/68295.rs: fixed with errors

[github-actions]

Issue: rust-lang/rust#68295

pub struct Matrix<R, C, S> {
    _phantoms: std::marker::PhantomData<(R, C, S)>,
}

impl<R, C, S> Matrix<R, C, S> {
    pub fn into_owned(self) -> Matrix<R, C, Owned<R, C, ()>>
    where
        (): Allocator<R, C>,
    {
        unimplemented!()
    }
}

impl<D, S> Matrix<D, D, S> {
    pub fn hermitian_part(&self) -> Matrix<D, D, Owned<D, D, ()>>
    where
        (): Allocator<D, D>,
    {
        unimplemented!()
    }
}

pub trait Allocator<R, C> {
    type Buffer;
}

pub trait Trait<R, C, A> {
    type Power;
}

impl<R, C, A: Allocator<R, C>> Trait<R, C, A> for () {
    type Power = A::Buffer;
}

pub type Owned<R, C, G> = <G as Trait<R, C, ()>>::Power;

pub fn crash<R, C>(input: Matrix<R, C, ()>) -> Matrix<R, C, u32>
where
    (): Allocator<R, C>,
{
    input.into_owned()
}

fn main() {}

=== stdout ===
=== stderr ===
error[E0308]: mismatched types
  --> /home/runner/work/glacier/glacier/ices/68295.rs:41:5
   |
37 | pub fn crash<R, C>(input: Matrix<R, C, ()>) -> Matrix<R, C, u32>
   |                                                ----------------- expected `Matrix<R, C, u32>` because of return type
...
41 |     input.into_owned()
   |     ^^^^^^^^^^^^^^^^^^ expected `u32`, found associated type
   |
   = note: expected struct `Matrix<_, _, u32>`
              found struct `Matrix<_, _, <() as Allocator<R, C>>::Buffer>`
   = help: consider constraining the associated type `<() as Allocator<R, C>>::Buffer` to `u32`
   = note: for more information, visit https://doc.rust-lang.org/book/ch19-03-advanced-traits.html

error: aborting due to previous error

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