error[E0620]: cast to unsized type: `i32` as `dyn MyAdd<i32>`
  --> $DIR/type-parameter-defaults-referencing-Self-ppaux.rs:14:13
   |
LL |     let y = x as dyn MyAdd<i32>;
   |             ^^^^^^^^^^^^^^^^^^^
   |
help: consider using a box or reference as appropriate
  --> $DIR/type-parameter-defaults-referencing-Self-ppaux.rs:14:13
   |
LL |     let y = x as dyn MyAdd<i32>;
   |             ^

error[E0038]: the trait `MyAdd` cannot be made into an object
  --> $DIR/type-parameter-defaults-referencing-Self-ppaux.rs:14:18
   |
LL | trait MyAdd<Rhs=Self> { fn add(&self, other: &Rhs) -> Self; }
   |                            --- method `add` references the `Self` type in its parameters or return type
...
LL |     let y = x as dyn MyAdd<i32>;
   |                  ^^^^^^^^^^^^^^ the trait `MyAdd` cannot be made into an object

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0038, E0620.
For more information about an error, try `rustc --explain E0038`.