error[E0599]: the method `clone` exists for struct `Box<R>`, but its trait bounds were not satisfied
  --> $DIR/unique-pinned-nocopy.rs:12:16
   |
LL |   struct R {
   |   -------- doesn't satisfy `R: Clone`
...
LL |       let _j = i.clone();
   |                  ^^^^^ method cannot be called on `Box<R>` due to unsatisfied trait bounds
   |
  ::: $SRC_DIR/alloc/src/boxed.rs:LL:COL
   |
LL | / pub struct Box<
LL | |     T: ?Sized,
LL | |     #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global,
LL | | >(Unique<T>, A);
   | |_- doesn't satisfy `Box<R>: Clone`
   |
   = note: the following trait bounds were not satisfied:
           `R: Clone`
           which is required by `Box<R>: Clone`
   = help: items from traits can only be used if the trait is implemented and in scope
   = note: the following trait defines an item `clone`, perhaps you need to implement it:
           candidate #1: `Clone`
help: consider annotating `R` with `#[derive(Clone)]`
   |
LL | #[derive(Clone)]
   |

error: aborting due to previous error

For more information about this error, try `rustc --explain E0599`.