M : Creators_generic with type (a, b, c) options := (a, b, c) Options.t with type (a, b, c) t := (a, b, c) T.t with type (a, b, c) tree := (a, b, c) Tree.t with type a key := a Key.t
Options : T.T3
Key : T.T1
Tree : T.T3
T : T.T3