Add support for OCaml 5.3

Author: kit-ty-kate

.github/workflows/workflow.yml

@@ -20,6 +20,7 @@ jobs:
         ocaml-compiler:
           - "4.14"
           - "5.2"
+          - "5.3"
 
     runs-on: ${{ matrix.os }}
 

eliom.opam

@@ -18,7 +18,7 @@ homepage: "https://ocsigen.org/eliom/"
 bug-reports: "https://github.com/ocsigen/eliom/issues"
 depends: [
   "dune" {>= "3.18"}
-  "ocaml" {>= "4.12" & < "5.3"}
+  "ocaml" {>= "4.12"}
   "ocamlfind"
   "ppx_deriving"
   "ppxlib" {>= "0.15"}

src/ppx/ppx_eliom_utils.ml

@@ -453,9 +453,18 @@ module Cmo = struct
     in
     type_of_out_type ty
 
+  [%%if ocaml_version >= (5, 3, 0)]
+  let typ ty =
+    let ty =
+      Out_type.prepare_for_printing [ty];
+      Out_type.tree_of_typexp Type_scheme ty
+    in
+    type_of_out_type ty
+  [%%else]
   let typ ty =
     let ty = Printtyp.tree_of_type_scheme ty in
     type_of_out_type ty
+  [%%endif]
 
   let find err loc =
     let {Lexing.pos_fname; pos_cnum; _} = loc.Location.loc_start in