module type S := ...: core

8 files changed, 20 insertions, 6 deletions

diff --git a/parsing/ast_helper.ml b/parsing/ast_helper.ml
index 2d51dda743..41f5fb9b8d 100644
--- a/parsing/ast_helper.ml
+++ b/parsing/ast_helper.ml
@@ -271,6 +271,7 @@ module Sig = struct
   let mod_subst ?loc a = mk ?loc (Psig_modsubst a)
   let rec_module ?loc a = mk ?loc (Psig_recmodule a)
   let modtype ?loc a = mk ?loc (Psig_modtype a)
+  let modtype_subst ?loc a = mk ?loc (Psig_modtypesubst a)
   let open_ ?loc a = mk ?loc (Psig_open a)
   let include_ ?loc a = mk ?loc (Psig_include a)
   let class_ ?loc a = mk ?loc (Psig_class a)
diff --git a/parsing/ast_helper.mli b/parsing/ast_helper.mli
index a498ece07d..42ce9e2e98 100644
--- a/parsing/ast_helper.mli
+++ b/parsing/ast_helper.mli
@@ -288,6 +288,7 @@ module Sig:
     val mod_subst: ?loc:loc -> module_substitution -> signature_item
     val rec_module: ?loc:loc -> module_declaration list -> signature_item
     val modtype: ?loc:loc -> module_type_declaration -> signature_item
+    val modtype_subst: ?loc:loc -> module_type_declaration -> signature_item
     val open_: ?loc:loc -> open_description -> signature_item
     val include_: ?loc:loc -> include_description -> signature_item
     val class_: ?loc:loc -> class_description list -> signature_item
diff --git a/parsing/ast_iterator.ml b/parsing/ast_iterator.ml
index 1cdb95310a..d1efda9782 100644
--- a/parsing/ast_iterator.ml
+++ b/parsing/ast_iterator.ml
@@ -285,7 +285,7 @@ module MT = struct
     | Psig_modsubst x -> sub.module_substitution sub x
     | Psig_recmodule l ->
         List.iter (sub.module_declaration sub) l
-    | Psig_modtype x -> sub.module_type_declaration sub x
+    | Psig_modtype x | Psig_modtypesubst x -> sub.module_type_declaration sub x
     | Psig_open x -> sub.open_description sub x
     | Psig_include x -> sub.include_description sub x
     | Psig_class l -> List.iter (sub.class_description sub) l
diff --git a/parsing/ast_mapper.ml b/parsing/ast_mapper.ml
index 720c16af34..7575f47b0b 100644
--- a/parsing/ast_mapper.ml
+++ b/parsing/ast_mapper.ml
@@ -318,6 +318,8 @@ module MT = struct
     | Psig_recmodule l ->
         rec_module ~loc (List.map (sub.module_declaration sub) l)
     | Psig_modtype x -> modtype ~loc (sub.module_type_declaration sub x)
+    | Psig_modtypesubst x ->
+        modtype_subst ~loc (sub.module_type_declaration sub x)
     | Psig_open x -> open_ ~loc (sub.open_description sub x)
     | Psig_include x -> include_ ~loc (sub.include_description sub x)
     | Psig_class l -> class_ ~loc (List.map (sub.class_description sub) l)
diff --git a/parsing/depend.ml b/parsing/depend.ml
index f1a155c1ba..d202ad3faf 100644
--- a/parsing/depend.ml
+++ b/parsing/depend.ml
@@ -382,7 +382,7 @@ and add_sig_item (bv, m) item =
       let bv' = add bv and m' = add m in
       List.iter (fun pmd -> add_modtype bv' pmd.pmd_type) decls;
       (bv', m')
-  | Psig_modtype x ->
+  | Psig_modtype x | Psig_modtypesubst x->
       begin match x.pmtd_type with
         None -> ()
       | Some mty -> add_modtype bv mty
diff --git a/parsing/parsetree.mli b/parsing/parsetree.mli
index 8337c289b3..8137de7470 100644
--- a/parsing/parsetree.mli
+++ b/parsing/parsetree.mli
@@ -769,6 +769,8 @@ and signature_item_desc =
   | Psig_modtype of module_type_declaration
         (* module type S = MT
            module type S *)
+  | Psig_modtypesubst of module_type_declaration
+        (* module type S :=  ...  *)
   | Psig_open of open_description
         (* open X *)
   | Psig_include of include_description
diff --git a/parsing/pprintast.ml b/parsing/pprintast.ml
index 29351cc02a..d20ad646d4 100644
--- a/parsing/pprintast.ml
+++ b/parsing/pprintast.ml
@@ -1159,14 +1159,18 @@ and signature_item ctxt f x : unit =
       pp f "@[<hov2>include@ %a@]%a"
         (module_type ctxt) incl.pincl_mod
         (item_attributes ctxt) incl.pincl_attributes
-  | Psig_modtype {pmtd_name=s; pmtd_type=md; pmtd_attributes=attrs} ->
+  | Psig_modtype {pmtd_name=s; pmtd_type=md; pmtd_attributes=attrs}
+  | Psig_modtypesubst {pmtd_name=s; pmtd_type=md; pmtd_attributes=attrs} as p ->
       pp f "@[<hov2>module@ type@ %s%a@]%a"
         s.txt
-        (fun f md -> match md with
-           | None -> ()
-           | Some mt ->
+        (fun f md -> match md, p with
+           | None, _ -> ()
+           | Some mt, Psig_modtype _ ->
                pp_print_space f () ;
                pp f "@ =@ %a" (module_type ctxt) mt
+           | Some mt, _ ->
+               pp_print_space f () ;
+               pp f "@ :=@ %a" (module_type ctxt) mt
         ) md
         (item_attributes ctxt) attrs
   | Psig_class_type (l) -> class_type_declaration_list ctxt f l
diff --git a/parsing/printast.ml b/parsing/printast.ml
index c196256ecd..9469bf1720 100644
--- a/parsing/printast.ml
+++ b/parsing/printast.ml
@@ -730,6 +730,10 @@ and signature_item i ppf x =
       line i ppf "Psig_modtype %a\n" fmt_string_loc x.pmtd_name;
       attributes i ppf x.pmtd_attributes;
       modtype_declaration i ppf x.pmtd_type
+  | Psig_modtypesubst x ->
+      line i ppf "Psig_modtypesubst %a\n" fmt_string_loc x.pmtd_name;
+      attributes i ppf x.pmtd_attributes;
+      modtype_declaration i ppf x.pmtd_type
   | Psig_open od ->
       line i ppf "Psig_open %a %a\n" fmt_override_flag od.popen_override
         fmt_longident_loc od.popen_expr;