error: generic parameters may not be used in enum discriminant values --> $DIR/issue-67945-2.rs:4:28 | LL | Var = type_ascribe!(0, S), | ^ cannot perform const operation using `S` | = note: type parameters may not be used in enum discriminant values error[E0392]: parameter `S` is never used --> $DIR/issue-67945-2.rs:3:10 | LL | enum Bug { | ^ unused parameter | = help: consider removing `S`, referring to it in a field, or using a marker such as `PhantomData` = help: if you intended `S` to be a const parameter, use `const S: usize` instead error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0392`.