1 Only `structural_match` types (that is, types that derive `PartialEq` and `Eq`)
2 may be used as the types of const generic parameters.
5 #![feature(const_generics)]
9 struct B<const X: A>; // error!
12 To fix this example, we derive `PartialEq` and `Eq`.
15 #![feature(const_generics)]
17 #[derive(PartialEq, Eq)]
20 struct B<const X: A>; // ok!