error: unconstrained generic constant
  --> $DIR/issue-90455.rs:6:8
   |
LL |     n: [u64; num_limbs(N)],
   |        ^^^^^^^^^^^^^^^^^^^
   |
help: try adding a `where` bound
   |
LL | struct FieldElement<const N: &'static str> where [(); num_limbs(N)]: {
   |                                            +++++++++++++++++++++++++

error: aborting due to 1 previous error

