(* TEST
flags = " -w a -rectypes "
ocamlc_byte_exit_status = "2"
* setup-ocamlc.byte-build-env
** ocamlc.byte
*** check-ocamlc.byte-output
*)

type _ t = C : ((('a -> 'o) -> 'o) -> ('b -> 'o) -> 'o) t
let f : type a o. ((a -> o) -> o) t -> (a -> o) -> o =
 fun C k -> k (fun x -> x);;