include Core_kernel.Monad.S2 with type ('a, 'b) t = ('a, 'b) Core_kernel.Result.t Async_kernel__.Deferred1.tinclude Base__.Monad_intf.Syntax2 with type (a, e) t := (a, e) tmodule Let_syntax : sig ... endmodule Monad_infix : Base__.Monad_intf.Infix2 with type (a, e) t := (a, e) tval return : 'a ‑> ('a, _) t