error: borrowed data cannot be stored outside of its closure
  --> $DIR/regions-escape-bound-fn.rs:18:27
   |
LL |     let mut x: Option<&isize> = None;
   |         ----- borrowed data cannot be stored into here...
LL |     with_int(|y| x = Some(y));
   |              ---          ^ cannot be stored outside of its closure
   |              |
   |              ...because it cannot outlive this closure

error: aborting due to previous error