error: using function pointers as const generic parameters is forbidden
  --> $DIR/ice-118285-fn-ptr-value.rs:1:25
   |
LL | struct Checked<const F: fn(usize) -> bool>;
   |                         ^^^^^^^^^^^^^^^^^
   |
   = note: the only supported types are integers, `bool`, and `char`

error: aborting due to 1 previous error