error[E0599]: the method `clone` exists for struct `Box`, 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` due to unsatisfied trait bounds --> $SRC_DIR/alloc/src/boxed.rs:LL:COL ::: $SRC_DIR/alloc/src/boxed.rs:LL:COL | = note: doesn't satisfy `Box: Clone` | = note: the following trait bounds were not satisfied: `R: Clone` which is required by `Box: 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)] LL | struct R { | error: aborting due to previous error For more information about this error, try `rustc --explain E0599`.