error[E0038]: the trait `Bar` is not dyn compatible --> $DIR/sized-2.rs:10:31 | LL | fn make_bar(t: &T) -> &dyn Bar { | ^^^^^^^ `Bar` is not dyn compatible | note: for a trait to be dyn compatible it needs to allow building a vtable for more information, visit --> $DIR/sized-2.rs:5:18 | LL | trait Bar | --- this trait is not dyn compatible... LL | where Self : Sized | ^^^^^ ...because it requires `Self: Sized` error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0038`.