error[E0228]: the lifetime bound for this object type cannot be deduced from context; please supply an explicit bound --> $DIR/object-lifetime-default-dyn-binding-nonstatic1.rs:20:50 | LL | fn bar<'a>(x: &'a str) -> &'a dyn Foo<'a, Item = dyn Bar> { &() } | ^^^^^^^ error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0228`.