|  | error[E0393]: the type parameter `C` must be explicitly specified | 
|  | --> $DIR/default-param-self-projection.rs:13:17 | 
|  | | | 
|  | LL | trait A<C = <Self as D>::E> {} | 
|  | | --------------------------- type parameter `C` must be specified for this | 
|  | ... | 
|  | LL |     let B: &dyn A = &(); | 
|  | |                 ^ | 
|  | | | 
|  | = note: because the parameter default references `Self`, the parameter must be specified on the object type | 
|  | help: set the type parameter to the desired type | 
|  | | | 
|  | LL |     let B: &dyn A<C> = &(); | 
|  | |                  +++ | 
|  |  | 
|  | error: aborting due to 1 previous error | 
|  |  | 
|  | For more information about this error, try `rustc --explain E0393`. |