ices/72554.rs: fixed with errors

[github-actions]

Issue: rust-lang/rust#72554

use std::collections::BTreeSet;

#[derive(Hash)]
pub enum ElemDerived {
    A(ElemDerived)
}

pub enum Elem {
    Derived(ElemDerived)
}

pub struct Set(BTreeSet<Elem>);

impl Set {
    pub fn into_iter(self) -> impl Iterator<Item = Elem> {
        self.0.into_iter()
    }
}

fn main() {}

=== stdout ===
=== stderr ===
error[E0072]: recursive type `ElemDerived` has infinite size
 --> /home/runner/work/glacier/glacier/ices/72554.rs:4:1
  |
4 | pub enum ElemDerived {
  | ^^^^^^^^^^^^^^^^^^^^ recursive type has infinite size
5 |     A(ElemDerived)
  |       ----------- recursive without indirection
  |
  = help: insert indirection (e.g., a `Box`, `Rc`, or `&`) at some point to make `ElemDerived` representable

error: aborting due to previous error

For more information about this error, try `rustc --explain E0072`.
==============

[JohnTitor]

Fixed by latest nightly.