Monad_plus.For_monoidal
module M : Preface_specs.MONAD_PLUS
include Indexed_monad_plus.LAWS_MONOID with type ('a, _) t := 'a M.t
include Indexed_monad.LAWS with type ('a, 'index) t := 'a M.t
include Indexed_bind.LAWS with type ('a, 'index) t := 'a M.t