workaround

lens/column.ml

@@ -1,14 +1,22 @@
 open Lens_utility
 module Type = Phrase_type
 
-type t = {
-  table : string;
-  name : string;
-  alias : string;
-  typ : Type.t;
-  present : bool;
-}
-[@@deriving show, sexp]
+include struct
+  (* Workaround for issue #1187 (i.e., the @@deriving sexp clause on t
+     below creates code triggering warning 40):
+     We disable warning 40 within this module, and immediately include it. *)
+
+  [@@@ocaml.warning "-40"]
+
+  type t = {
+    table : string;
+    name : string;
+    alias : string;
+    typ : Type.t;
+    present : bool;
+  }
+  [@@deriving show, sexp]
+end
 
 let make ~table ~name ~alias ~typ ~present =
   { table; name; alias; typ; present }

lens/database.ml

@@ -2,15 +2,23 @@ open Operators
 open Lens_utility
 module LPV = Phrase_value
 
-type t = {
-  serialize : unit -> string;
-  driver_name : unit -> string;
-  escape_string : string -> string;
-  quote_field : string -> string;
-  execute : string -> unit;
-  execute_select :
-    string -> field_types:(string * Phrase_type.t) list -> Phrase_value.t list;
-}
+include struct
+  (* Workaround for issue #1187 (i.e., the @@deriving sexp clause on t
+     below creates code triggering warning 40):
+     We disable warning 40 within this module, and immediately include it. *)
+
+  [@@@ocaml.warning "-40"]
+
+  type t = {
+    serialize : unit -> string;
+    driver_name : unit -> string;
+    escape_string : string -> string;
+    quote_field : string -> string;
+    execute : string -> unit;
+    execute_select :
+      string -> field_types:(string * Phrase_type.t) list -> Phrase_value.t list;
+  }
+end
 
 module E = struct
   type t =
@@ -48,7 +56,13 @@ let show _ = "<db_driver>"
 let pp f v = Format.fprintf f "%s" (show v)
 
 module Table = struct
-  type t = { name : string; keys : string list list } [@@deriving sexp]
+  include struct
+    (* Defining t withing a module and immediately including it as a way to
+       disable warning 40 exactly on the code generated for the
+       @@deriving clauses below *)
+    [@@@ocaml.warning "-40"]
+    type t = { name : string; keys : string list list } [@@deriving sexp]
+  end
 
   let name t = t.name
 end

lens/sort.ml

@@ -2,13 +2,21 @@ open Lens_utility
 open Lens_utility.O
 module Column = Column
 
-type t = {
-  fds : Fun_dep.Set.t;
-  predicate : Phrase.t option;
-  query : Phrase.t option;
-  cols : Column.t list;
-}
-[@@deriving show, sexp]
+include struct
+  (* Workaround for issue #1187 (i.e., the @@deriving sexp clause on t
+     below creates code triggering warning 40):
+     We disable warning 40 within this module, and immediately include it. *)
+
+  [@@@ocaml.warning "-40"]
+
+  type t = {
+    fds : Fun_dep.Set.t;
+    predicate : Phrase.t option;
+    query : Phrase.t option;
+    cols : Column.t list;
+  }
+  [@@deriving show, sexp]
+end
 
 let fds t = t.fds
 

lens/value.ml

@@ -1,25 +1,33 @@
 open Lens_utility
 
-type t =
-  | Lens of { table : Database.Table.t; sort : Sort.t }
-  | LensMem of { records : Phrase_value.t list; sort : Sort.t }
-  | LensSelect of { lens : t; predicate : Phrase.t; sort : Sort.t }
-  | LensJoin of {
-      left : t;
-      right : t;
-      on : (string * string * string) list;
-      del_left : Phrase.t;
-      del_right : Phrase.t;
-      sort : Sort.t;
-    }
-  | LensDrop of {
-      lens : t;
-      drop : string;
-      key : string;
-      default : Phrase_value.t;
-      sort : Sort.t;
-    }
-[@@deriving sexp]
+include struct
+  (* Workaround for issue #1187 (i.e., the @@deriving sexp clause on t
+     below creates code triggering warning 40):
+     We disable warning 40 within this module, and immediately include it. *)
+
+  [@@@ocaml.warning "-40"]
+
+  type t =
+    | Lens of { table : Database.Table.t; sort : Sort.t }
+    | LensMem of { records : Phrase_value.t list; sort : Sort.t }
+    | LensSelect of { lens : t; predicate : Phrase.t; sort : Sort.t }
+    | LensJoin of {
+        left : t;
+        right : t;
+        on : (string * string * string) list;
+        del_left : Phrase.t;
+        del_right : Phrase.t;
+        sort : Sort.t;
+      }
+    | LensDrop of {
+        lens : t;
+        drop : string;
+        key : string;
+        default : Phrase_value.t;
+        sort : Sort.t;
+      }
+  [@@deriving sexp]
+end
 
 let serialize v =
   let sexp = sexp_of_t v in

links.opam

@@ -35,7 +35,7 @@ depends: [
   "result"
   "ocamlfind"
   "menhir" {>= "20210419"}
-  "ppx_sexp_conv" {<= "v0.15.1"}
+  "ppx_sexp_conv"
   "calendar" {>= "2.0.4"}
   "rdf_lwt" {>= "0.13.0"}
 ]