error[E0191]: the value of the associated type `Output` in `Add` must be specified --> $DIR/issue-21950.rs:10:25 | LL | type Output; | ----------- `Output` defined here ... LL | let x = &10 as &dyn Add; | ^^^ help: specify the associated type: `Add` error[E0393]: the type parameter `Rhs` must be explicitly specified --> $DIR/issue-21950.rs:10:25 | LL | trait Add { | ------------------- type parameter `Rhs` must be specified for this ... LL | let x = &10 as &dyn Add; | ^^^ help: set the type parameter to the desired type: `Add` | = note: because of the default `Self` reference, type parameters must be specified on object types error: aborting due to 2 previous errors Some errors have detailed explanations: E0191, E0393. For more information about an error, try `rustc --explain E0191`.