error[E0741]: `Foo` must implement `ConstParamTy` to be used as the type of a const generic parameter --> $DIR/unify-op-with-fn-call.rs:18:29 | LL | struct Evaluatable; | ^^^ | help: add `#[derive(ConstParamTy)]` to the struct | LL + #[derive(ConstParamTy)] LL | struct Foo(u8); | error[E0741]: `Foo` must implement `ConstParamTy` to be used as the type of a const generic parameter --> $DIR/unify-op-with-fn-call.rs:20:17 | LL | fn foo(a: Evaluatable<{ N + N }>) { | ^^^ | help: add `#[derive(ConstParamTy)]` to the struct | LL + #[derive(ConstParamTy)] LL | struct Foo(u8); | error[E0741]: `Foo` must implement `ConstParamTy` to be used as the type of a const generic parameter --> $DIR/unify-op-with-fn-call.rs:24:17 | LL | fn bar() {} | ^^^ | help: add `#[derive(ConstParamTy)]` to the struct | LL + #[derive(ConstParamTy)] LL | struct Foo(u8); | error: aborting due to 3 previous errors For more information about this error, try `rustc --explain E0741`.