error: `[u32; LEN]` is forbidden as the type of a const generic parameter --> $DIR/issue-73491.rs:8:19 | LL | fn hoge() {} | ^^^^^^^^^^ | = 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