error: `[u32; _]` is forbidden as the type of a const generic parameter
  --> $DIR/issue-73491.rs:8:19
   |
LL | fn hoge<const IN: [u32; LEN]>() {}
   |                   ^^^^^^^^^^
   |
   = note: the only supported types are integers, `bool` and `char`
   = help: more complex types are supported with `#![feature(const_generics)]`

error: aborting due to previous error