Module Accessor.Identical

An Identical.t is similar to a Type_equal.t, but it relates two pairs of types with each other instead of merely two types. It is a more natural way of using an equality accessor than Type_equal.t would be, since you only need to match on one constructor.

type ('a, 'b, 'at, 'bt) t =
| T : ('a'b'a'b) t