COVARIANT_2 (preface.Preface_qcheck.Model.COVARIANT

type ('a, 'b) t

val generator : 
  'a QCheck2.Gen.t ->
  'b QCheck2.Gen.t ->
  ('a, 'b) t QCheck2.Gen.t

val observable : 
  'a QCheck2.Observable.t ->
  'b QCheck2.Observable.t ->
  ('a, 'b) t QCheck2.Observable.t

val pp : 
  (Stdlib.Format.formatter -> 'a -> unit) ->
  (Stdlib.Format.formatter -> 'b -> unit) ->
  Stdlib.Format.formatter ->
  ('a, 'b) t ->
  unit

val equal : 
  ('a -> 'a -> bool) ->
  ('b -> 'b -> bool) ->
  ('a, 'b) t ->
  ('a, 'b) t ->
  bool