warning: creating a mutable reference to mutable static is discouraged
  --> $DIR/borrowck-thread-local-static-mut-borrow-outlives-fn.rs:17:26
   |
LL |         S1 { a: unsafe { &mut X1 } }
   |                          ^^^^^^^ mutable reference to mutable static
   |
   = note: for more information, see issue #114447 <https://github.com/rust-lang/rust/issues/114447>
   = note: this will be a hard error in the 2024 edition
   = note: this mutable reference has lifetime `'static`, but if the static gets accessed (read or written) by any other means, or any other reference is created, then any further use of this mutable reference is Undefined Behavior
   = note: `#[warn(static_mut_refs)]` on by default
help: use `addr_of_mut!` instead to create a raw pointer
   |
LL |         S1 { a: unsafe { addr_of_mut!(X1) } }
   |                          ~~~~~~~~~~~~~~~~

warning: 1 warning emitted