error[E0658]: dereferencing raw mutable pointers in constants is unstable
  --> $DIR/const-suggest-feature.rs:2:5
   |
LL |     *std::ptr::null_mut() = 0;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = 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
   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date

error: aborting due to 1 previous error

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