error[E0224]: at least one trait is required for an object type --> $DIR/only-maybe-bound.rs:13:12 | LL | trait _1 = _0; | -------- this alias does not contain a trait ... LL | type _T0 = dyn _1; | ^^^^^^ error[E0224]: at least one trait is required for an object type --> $DIR/only-maybe-bound.rs:19:12 | LL | trait _2 = _1 + _1; | -------- this alias does not contain a trait LL | LL | type _T1 = dyn _2; | ^^^^^^ error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0224`.