error[E0038]: the trait `Bar` cannot be made into an object --> $DIR/object-safety-sized.rs:12:30 | LL | fn make_bar(t: &T) -> &dyn Bar { | ^^^^^^^^ `Bar` cannot be made into an object | note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit --> $DIR/object-safety-sized.rs:8:13 | LL | trait Bar : Sized { | --- ^^^^^ ...because it requires `Self: Sized` | | | this trait cannot be made into an object... error: aborting due to previous error For more information about this error, try `rustc --explain E0038`.