error[E0741]: `C` must be annotated with `#[derive(PartialEq, Eq)]` to be used as the type of a const parameter
  --> $DIR/forbid-non-structural_match-types.rs:11:19
   |
LL | struct D<const X: C>;
   |                   ^ `C` doesn't derive both `PartialEq` and `Eq`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0741`.