error[E0741]: `Bar` must implement `ConstParamTy` to be used as the type of a const generic parameter
  --> $DIR/issue-97278.rs:11:20
   |
LL | fn test<const BAR: Bar>() {}
   |                    ^^^
   |
help: add `#[derive(ConstParamTy)]` to the struct
   |
LL + #[derive(ConstParamTy)]
LL | enum Bar {
   |

error: aborting due to previous error

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