BatHashcons.HHashing utilities
hc0_ h corresponds to the hashcode of a first constructor applied to an object of hashcode h
val hc0 : 'a hobj -> inthc0 ho is the hashcode of a first constructor applied to the hashed object ho
hc1_ h k corresponds to the hashcode of the kth constructor applied to an object of hashcode h.
val hc1 : 'a hobj -> int -> inthc1 ho k corresponds to the hashcode of the kth constructor applied to the hashed object ho.