error[E0505]: cannot move out of `alloc` because it is borrowed
  --> $DIR/leak-alloc.rs:26:10
   |
LL |     let alloc = Alloc {};
   |         ----- binding `alloc` declared here
LL |     let boxed = Box::new_in(10, alloc.by_ref());
   |                                 ----- borrow of `alloc` occurs here
LL |     let theref = Box::leak(boxed);
LL |     drop(alloc);
   |          ^^^^^ move out of `alloc` occurs here
LL |
LL |     use_value(*theref)
   |               ------- borrow later used here

error: aborting due to 1 previous error

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