error[E0038]: the trait `X` is not dyn compatible
  --> $DIR/issue-50781.rs:11:16
   |
LL | impl Trait for dyn X {}
   |                ^^^^^ `X` is not dyn compatible
   |
note: for a trait to be dyn compatible it needs to allow building a vtable
      for more information, visit <https://doc.rust-lang.org/reference/items/traits.html#dyn-compatibility>
  --> $DIR/issue-50781.rs:4:8
   |
LL | trait X {
   |       - this trait is not dyn compatible...
LL |     fn foo(&self) where Self: Trait;
   |        ^^^ ...because method `foo` references the `Self` type in its `where` clause
   = help: consider moving `foo` to another trait
   = help: only type `()` implements `X`; consider using it directly instead.

error[E0038]: the trait `X` is not dyn compatible
  --> $DIR/issue-50781.rs:16:23
   |
LL |     <dyn X as X>::foo(&());
   |                       ^^^ `X` is not dyn compatible
   |
note: for a trait to be dyn compatible it needs to allow building a vtable
      for more information, visit <https://doc.rust-lang.org/reference/items/traits.html#dyn-compatibility>
  --> $DIR/issue-50781.rs:4:8
   |
LL | trait X {
   |       - this trait is not dyn compatible...
LL |     fn foo(&self) where Self: Trait;
   |        ^^^ ...because method `foo` references the `Self` type in its `where` clause
   = help: consider moving `foo` to another trait
   = help: only type `()` implements `X`; consider using it directly instead.
   = note: required for the cast from `&()` to `&dyn X`

error[E0038]: the trait `X` is not dyn compatible
  --> $DIR/issue-50781.rs:16:6
   |
LL |     <dyn X as X>::foo(&());
   |      ^^^^^ `X` is not dyn compatible
   |
note: for a trait to be dyn compatible it needs to allow building a vtable
      for more information, visit <https://doc.rust-lang.org/reference/items/traits.html#dyn-compatibility>
  --> $DIR/issue-50781.rs:4:8
   |
LL | trait X {
   |       - this trait is not dyn compatible...
LL |     fn foo(&self) where Self: Trait;
   |        ^^^ ...because method `foo` references the `Self` type in its `where` clause
   = help: consider moving `foo` to another trait
   = help: only type `()` implements `X`; consider using it directly instead.

error: aborting due to 3 previous errors

For more information about this error, try `rustc --explain E0038`.