error: `[usize; 0]` is forbidden as the type of a const generic parameter --> $DIR/issue-68615-adt.rs:6:23 | LL | struct Const {} | ^^^^^^^^^^ | = note: the only supported types are integers, `bool` and `char` help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types | LL + #![feature(adt_const_params)] | error: aborting due to 1 previous error