warning: shared reference of mutable static is discouraged
  --> $DIR/reference-of-mut-static-safe.rs:9:14
   |
LL |     let _x = &X;
   |              ^^ shared reference of mutable static
   |
   = note: for more information, see issue #114447 <https://github.com/rust-lang/rust/issues/114447>
   = note: reference of mutable static is a hard error from 2024 edition
   = note: mutable statics can be written to by multiple threads: aliasing violations or data races will cause undefined behavior
   = note: `#[warn(static_mut_ref)]` on by default
help: shared references are dangerous since if there's any kind of mutation of that static while the reference lives, that's UB; use `addr_of!` instead to create a raw pointer
   |
LL |     let _x = addr_of!(X);
   |              ~~~~~~~~~~~

error[E0133]: use of mutable static is unsafe and requires unsafe function or block
  --> $DIR/reference-of-mut-static-safe.rs:9:15
   |
LL |     let _x = &X;
   |               ^ use of mutable static
   |
   = note: mutable statics can be mutated by multiple threads: aliasing violations or data races will cause undefined behavior

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

For more information about this error, try `rustc --explain E0133`.