ices/65774.rs: fixed with errors

[github-actions]

Issue: rust-lang/rust#65774

#![feature(associated_type_defaults)]

trait MyDisplay { fn method(&self) { } }

impl<'a, T: MyDisplay> MyDisplay for &'a mut T { }

struct T;

trait MPU {
    type MpuConfig: MyDisplay = T;
}

struct S;

impl MPU for S { }

trait MyWrite {
    fn my_write(&self, _: &dyn MyDisplay) { }
}

trait ProcessType {
    fn process_detail_fmt(&self, _: &mut dyn MyWrite);
}

struct Process;

impl ProcessType for Process {
    fn process_detail_fmt(&self, writer: &mut dyn MyWrite)
    {

        let mut val: Option<<S as MPU>::MpuConfig> = None;
        let valref: &mut <S as MPU>::MpuConfig = val.as_mut().unwrap();

        // // This causes a different ICE (but its similar if you squint right):
        // //
        // // `Unimplemented` selecting `Binder(<T as MyDisplay>)` during codegen
        //
        // writer.my_write(valref)

        // This one causes the ICE:
        // FulfillmentError(Obligation(predicate=Binder(TraitPredicate(<T as MyDisplay>)), depth=1),Unimplemented)
        let closure = |config: &mut <S as MPU>::MpuConfig| writer.my_write(&config);
        closure(valref);
    }
}

fn create() -> &'static dyn ProcessType {
    let input: Option<&mut Process> = None;
    let process: &mut Process = input.unwrap();
    process
}

pub fn main() {
    create();
}

=== stdout ===
=== stderr ===
error[E0277]: the trait bound `T: MyDisplay` is not satisfied
  --> /home/runner/work/glacier/glacier/ices/65774.rs:10:21
   |
9  | trait MPU {
   | --------- required by `MPU`
10 |     type MpuConfig: MyDisplay = T;
   |                     ^^^^^^^^^ the trait `MyDisplay` is not implemented for `T`

error[E0277]: the trait bound `T: MyDisplay` is not satisfied
  --> /home/runner/work/glacier/glacier/ices/65774.rs:15:6
   |
15 | impl MPU for S { }
   |      ^^^ the trait `MyDisplay` is not implemented for `T`

error: aborting due to 2 previous errors

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