1error[E0277]: the trait bound `(): Add<A>` is not satisfied 2 --> $DIR/associated-types-ICE-when-projecting-out-of-err.rs:23:11 3 | 4LL | r = r + a; 5 | ^ the trait `Add<A>` is not implemented for `()` 6 7error: aborting due to previous error 8 9For more information about this error, try `rustc --explain E0277`. 10