error[E0505]: cannot move out of `fancy_num` because it is borrowed
  --> $DIR/E0504.rs:9:13
   |
LL |     let fancy_num = FancyNum { num: 5 };
   |         --------- binding `fancy_num` declared here
LL |     let fancy_ref = &fancy_num;
   |                     ---------- borrow of `fancy_num` occurs here
LL |
LL |     let x = move || {
   |             ^^^^^^^ move out of `fancy_num` occurs here
LL |         println!("child function: {}", fancy_num.num);
   |                                        ------------- move occurs due to use in closure
...
LL |     println!("main function: {}", fancy_ref.num);
   |                                   ------------- borrow later used here
   |
note: if `FancyNum` implemented `Clone`, you could clone the value
  --> $DIR/E0504.rs:1:1
   |
LL | struct FancyNum {
   | ^^^^^^^^^^^^^^^ consider implementing `Clone` for this type
...
LL |     let fancy_ref = &fancy_num;
   |                     ---------- you could clone this value

error: aborting due to 1 previous error

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