Dear OCaml users,

today I tried to recompile a project that uses both some janestreet
derivers and visitors.ppx. To my horror, it now fails to compile with an
error about the visitors argument:

utop # #require "visitors.ppx";;
utop # type foo = int list [@@deriving visitors {variety="reduce"}];;
Error: Reference to undefined global
`VisitorsRuntime'
utop # #require "ppx_sexp_conv";;
utop # type foo = int list [@@deriving visitors {variety="reduce"}];;
Error: non-optional labeled argument expected

There is another error that might be related when I try it combination with
ppx_metaquot:

utop # #require "visitors.ppx";;
utop # type foo = int list [@@deriving visitors {variety="reduce"}];;
Error: Reference to undefined global
`VisitorsRuntime'
utop # #require "ppx_metaquot";;
utop # type foo = int list [@@deriving visitors {variety="reduce"}];;
Error: Attribute `deriving' was not used


The first error looks like ppx_type_conv gets confused about what is a
janestreet deriver and what is something else. The second error, well I
have no idea...

Does anyone know a workaround?

thanks,

Christoph