error[E0505]: cannot move out of `a.x` because it is borrowed
  --> $DIR/borrowck-move-subcomponent.rs:15:14
   |
LL |   let a : S = S { x : Box::new(1) };
   |       - binding `a` declared here
LL |   let pb = &a;
   |            -- borrow of `a` occurs here
LL |   let S { x: ax } = a;
   |              ^^ move out of `a.x` occurs here
LL |   f(pb);
   |     -- borrow later used here

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0505`.