error[E0277]: the trait bound `T: Copy` is not satisfied --> $DIR/wf-in-fn-ret.rs:10:16 | LL | fn bar() -> MustBeCopy | ^^^^^^^^^^^^^ the trait `Copy` is not implemented for `T` | note: required by a bound in `MustBeCopy` --> $DIR/wf-in-fn-ret.rs:6:21 | LL | struct MustBeCopy { | ^^^^ required by this bound in `MustBeCopy` help: consider restricting type parameter `T` | LL | fn bar() -> MustBeCopy | +++++++++++++++++++ error: aborting due to previous error For more information about this error, try `rustc --explain E0277`.