Derived creates a comparator function that constructs a comparator for the type 'a t given a comparator for the type 'a.
Derived
comparator
'a t
'a
M : sig ... end
type 'a t
type 'cmp comparator_witness
val comparator : ('a, 'cmp) comparator ‑> ('a t, 'cmp comparator_witness) comparator