error[E0741]: `Nat` must implement `ConstParamTy` to be used as the type of a const generic parameter
  --> $DIR/issue-80471.rs:9:17
   |
LL | fn foo<const N: Nat>() {}
   |                 ^^^
   |
help: add `#[derive(ConstParamTy)]` to the struct
   |
LL + #[derive(ConstParamTy)]
LL | enum Nat {
   |

error: aborting due to 1 previous error

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