error[E0658]: mutable references are not allowed in constants
  --> $DIR/write_to_mut_ref_dest.rs:11:27
   |
LL |         let b: *mut u32 = &mut a;
   |                           ^^^^^^
   |
   = note: see issue #57349 <https://github.com/rust-lang/rust/issues/57349> for more information
   = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable

error[E0658]: dereferencing raw mutable pointers in constants is unstable
  --> $DIR/write_to_mut_ref_dest.rs:12:18
   |
LL |         unsafe { *b = 5; }
   |                  ^^^^^^
   |
   = note: see issue #57349 <https://github.com/rust-lang/rust/issues/57349> for more information
   = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable

error: aborting due to 2 previous errors

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