warning: mutable reference of mutable static is discouraged
  --> $DIR/borrowck-thread-local-static-mut-borrow-outlives-fn.rs:17:26
   |
LL |         S1 { a: unsafe { &mut X1 } }
   |                          ^^^^^^^ mutable 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: mutable references are dangerous since if there's any other pointer or reference used for that static while the reference lives, that's UB; use `addr_of_mut!` instead to create a raw pointer
   |
LL |         S1 { a: unsafe { addr_of_mut!(X1) } }
   |                          ~~~~~~~~~~~~~~~~

warning: 1 warning emitted