Upgrade from ocaml-migrate-parsetree to Ppxlib

ocaml-migrate-parsetree is now deprecated. This upgrades the code to use
Ppxlib. Remaining work to do: handle locations correctly so that tools
like Merlin are not buggy on code that uses the PPX.

Author: OlivierNicole

dune-project

@@ -1,2 +1,2 @@
-(lang dune 2.0)
+(lang dune 3.1)
 (name ppx_stage)

ppx/binding.ml

@@ -1,9 +1,13 @@
+(*
 open Migrate_parsetree
 open Ast_408
 
 open Asttypes
 open Parsetree
 open Ast_helper
+*)
+open Ppxlib
+open Ppxlib.Ast_builder.Default
 
 type binding_site = Binder of int | Context of int
 
@@ -30,7 +34,7 @@ and analyse_exp_desc env loc = function
        | PStr [ {pstr_desc=Pstr_eval (e, _); _} ] ->
           e
        | _ ->
-          raise (Location.(Error (error ~loc ("[%e] expects an expression")))) in
+         raise (Location.(Error (Error.make ~sub:[] ~loc ("[%e] expects an expression")))) in
      let h = env.fresh_hole () in
      Hashtbl.add env.hole_table h (env.bindings, code);
      Pexp_ident { txt = Lident ("," ^ string_of_int h); loc }
@@ -95,9 +99,8 @@ and analyse_exp_desc env loc = function
      let env' = analyse_pat env pat in
      Pexp_for (pat, analyse_exp env e1, analyse_exp env e2, dir, analyse_exp env' body)
   (* several missing... *)
-       
 
-  | _ -> raise (Location.(Error (error ~loc ("expression not supported in staged code"))))
+  | _ -> raise (Location.(Error (Error.make ~sub:[] ~loc ("expression not supported in staged code"))))
 
 and analyse_exp_opt env = function
   | None -> None
@@ -109,16 +112,16 @@ and analyse_pat env pat =
 
 and analyse_pat_desc env loc = function
   | Ppat_any -> env
-  | Ppat_var v -> analyse_pat_desc env loc (Ppat_alias (Pat.any (), v))
+  | Ppat_var v -> analyse_pat_desc env loc (Ppat_alias (ppat_any ~loc, v))
   | Ppat_alias (pat, v) ->
      let env = analyse_pat env pat in
      { env with bindings = IdentMap.add v.txt (env.fresh_binder ()) env.bindings }
   | Ppat_constant _ -> env
   | Ppat_interval _ -> env
   | Ppat_tuple pats -> List.fold_left analyse_pat env pats
   | Ppat_construct (_loc, None) -> env
-  | Ppat_construct (_loc, Some pat) -> analyse_pat env pat
-  | _ -> raise (Location.(Error (error ~loc ("pattern not supported in staged code"))))
+  | Ppat_construct (_loc, Some (_locs, pat)) -> analyse_pat env pat
+  | _ -> raise (Location.(Error (Error.make ~sub:[] ~loc ("pattern not supported in staged code"))))
 
 and analyse_case env {pc_lhs; pc_guard; pc_rhs} =
   let env' = analyse_pat env pc_lhs in
@@ -131,7 +134,7 @@ and analyse_attributes = function
 | {attr_payload=PStr []; _} :: rest ->
    analyse_attributes rest
 | {attr_name={loc;txt}; _} :: _ ->
-   raise (Location.(Error (error ~loc ("attribute " ^ txt ^ " not supported in staged code"))))
+    raise (Location.(Error (Error.make ~sub:[] ~loc ("attribute " ^ txt ^ " not supported in staged code"))))
 
 
 let analyse_binders (context : int IdentMap.t) (e : expression) :
@@ -150,8 +153,8 @@ let analyse_binders (context : int IdentMap.t) (e : expression) :
   e', hole_table
 
 
-
-open Ast_mapper
+(* CR OlivierNicole: copy-paste from runtime/internal.ml? *)
+(*
 type substitutable =
 | SubstContext of int
 | SubstHole of int
@@ -241,3 +244,5 @@ let module_remapper f =
     { pmod with pmod_desc }
   in
   { default_mapper with expr; typ; pat; module_type; open_description; module_expr }
+*)
+let module_remapper = Ppx_stage.Internal.module_remapper

ppx/dune

@@ -3,6 +3,7 @@
  (public_name ppx_stage.ppx)
  (kind ppx_rewriter)
  (ppx_runtime_libraries ppx_stage.runtime-lib)
- (preprocess
-  (pps ppx_tools_versioned.metaquot_408))
- (libraries ocaml-migrate-parsetree ppx_tools_versioned ppx_stage.runtime-lib))
+ (preprocess (pps ppxlib.metaquot))
+ (libraries ; ocaml-migrate-parsetree ppx_tools_versioned
+   ppx_stage.runtime-lib
+   ppxlib))