module type With_Diff_One = sig .. end
sig
end
type t
val diff_if_one : t -> t -> t Lattice_bounds.or_bottom
t -> t -> t Lattice_bounds.or_bottom
diff_if_one t1 t2 is an over-approximation of t1-t2.
diff_if_one t1 t2
t1-t2
t1
t2