ices/109141.rs: fixed with errors

[github-actions]

Issue: rust-lang/rust#109141

#![feature(generic_const_exprs)]

impl EntriesBuffer {
    fn a(&self) -> impl Iterator {
        self.0.iter_mut()
    }
}

struct EntriesBuffer(Box<[[u8; HashesEntryLEN]; 5]>);

fn main() {}

=== stdout ===
=== stderr ===
error[E0425]: cannot find value `HashesEntryLEN` in this scope
 --> /home/runner/work/glacier/glacier/ices/109141.rs:9:32
  |
9 | struct EntriesBuffer(Box<[[u8; HashesEntryLEN]; 5]>);
  |                                ^^^^^^^^^^^^^^ not found in this scope
  |
help: you might be missing a const parameter
  |
9 | struct EntriesBuffer<const HashesEntryLEN: /* Type */>(Box<[[u8; HashesEntryLEN]; 5]>);
  |                     ++++++++++++++++++++++++++++++++++

warning: the feature `generic_const_exprs` is incomplete and may not be safe to use and/or cause compiler crashes
 --> /home/runner/work/glacier/glacier/ices/109141.rs:1:12
  |
1 | #![feature(generic_const_exprs)]
  |            ^^^^^^^^^^^^^^^^^^^
  |
  = note: see issue #76560 <https://github.com/rust-lang/rust/issues/76560> for more information
  = note: `#[warn(incomplete_features)]` on by default

error[E0596]: cannot borrow `*self.0` as mutable, as it is behind a `&` reference
 --> /home/runner/work/glacier/glacier/ices/109141.rs:5:9
  |
5 |         self.0.iter_mut()
  |         ^^^^^^^^^^^^^^^^^ `self` is a `&` reference, so the data it refers to cannot be borrowed as mutable
  |
help: consider changing this to be a mutable reference
  |
4 |     fn a(&mut self) -> impl Iterator {
  |          ~~~~~~~~~

error: aborting due to 2 previous errors; 1 warning emitted

Some errors have detailed explanations: E0425, E0596.
For more information about an error, try `rustc --explain E0425`.
==============