From 53499cd971ea2a184f6d1717095eecf554a9ae5b Mon Sep 17 00:00:00 2001
From: Rudi Grinberg <me@rgrinberg.com>
Date: Sun, 3 Dec 2023 10:49:24 -0600
Subject: [PATCH] refactor: make stanzas private (#9362)

This requires going through a functor to construct all stanzas. The
capability will be useful to eliminate physical equality for stanzas.

Signed-off-by: Rudi Grinberg <me@rgrinberg.com>
---
 bin/describe/describe_external_lib_deps.ml    |   6 +-
 bin/describe/describe_pp.ml                   |   2 +-
 bin/describe/describe_workspace.ml            |   2 +-
 bin/dune_init.ml                              |   6 +-
 src/dune_lang/stanza.ml                       |   7 +
 src/dune_lang/stanza.mli                      |   8 +-
 src/dune_rules/artifacts_db.ml                |   4 +-
 src/dune_rules/cinaps.ml                      |   4 +-
 src/dune_rules/coq/coq_stanza.ml              |  12 +-
 src/dune_rules/cram/cram_stanza.ml            |   4 +-
 src/dune_rules/ctypes/ctypes_field.ml         |   4 +-
 src/dune_rules/dir_contents.ml                |   8 +-
 src/dune_rules/dir_status.ml                  |  10 +-
 src/dune_rules/dune_env.ml                    |   4 +-
 src/dune_rules/dune_file.ml                   | 134 ++++++++++++------
 src/dune_rules/dune_file.mli                  |  41 +++---
 src/dune_rules/foreign.ml                     |   4 +
 src/dune_rules/foreign.mli                    |   2 +
 src/dune_rules/foreign_sources.ml             |   6 +-
 src/dune_rules/gen_rules.ml                   |  18 +--
 .../generate_sites_module_stanza.ml           |   4 +-
 src/dune_rules/install_rules.ml               |  18 +--
 src/dune_rules/mdx.ml                         |   4 +-
 src/dune_rules/melange/melange_stanzas.ml     |   4 +-
 src/dune_rules/menhir/menhir_stanza.ml        |   4 +-
 src/dune_rules/ml_sources.ml                  |   4 +-
 src/dune_rules/only_packages.ml               |   4 +-
 src/dune_rules/packages.ml                    |   2 +-
 src/dune_rules/scope.ml                       |  14 +-
 src/dune_rules/super_context.ml               |   4 +-
 src/dune_rules/utop.ml                        |   4 +-
 31 files changed, 224 insertions(+), 128 deletions(-)

diff --git a/bin/describe/describe_external_lib_deps.ml b/bin/describe/describe_external_lib_deps.ml
index cefc714b276..182bb74c33e 100644
--- a/bin/describe/describe_external_lib_deps.ml
+++ b/bin/describe/describe_external_lib_deps.ml
@@ -149,7 +149,7 @@ let libs db (context : Context.t) (build_system : Dune_rules.Main.build_system)
     Memo.parallel_map dune_file.stanzas ~f:(fun stanza ->
       let dir = dune_file.dir in
       match stanza with
-      | Dune_rules.Dune_file.Executables exes ->
+      | Dune_rules.Dune_file.Executables.T exes ->
         let* ocaml = Context.ocaml context in
         resolve_libs
           db
@@ -161,7 +161,7 @@ let libs db (context : Context.t) (build_system : Dune_rules.Main.build_system)
           Item.Kind.Executables
           (exes_extensions ocaml.lib_config exes.modes)
         >>| List.singleton
-      | Dune_rules.Dune_file.Library lib ->
+      | Dune_rules.Dune_file.Library.T lib ->
         resolve_libs
           db
           dir
@@ -172,7 +172,7 @@ let libs db (context : Context.t) (build_system : Dune_rules.Main.build_system)
           Item.Kind.Library
           []
         >>| List.singleton
-      | Dune_rules.Dune_file.Tests tests ->
+      | Dune_rules.Dune_file.Tests.T tests ->
         let* ocaml = Context.ocaml context in
         resolve_libs
           db
diff --git a/bin/describe/describe_pp.ml b/bin/describe/describe_pp.ml
index 1c4416a3d6f..498bd7c6abf 100644
--- a/bin/describe/describe_pp.ml
+++ b/bin/describe/describe_pp.ml
@@ -62,7 +62,7 @@ let get_pped_file super_context file =
            dune_file.stanzas
            |> List.fold_left ~init:None ~f:(fun acc stanza ->
              match stanza with
-             | Dune_rules.Dune_file.Library lib ->
+             | Dune_rules.Dune_file.Library.T lib ->
                let preprocess =
                  Dune_rules.Preprocess.Per_module.(
                    lib.buildable.preprocess |> single_preprocess)
diff --git a/bin/describe/describe_workspace.ml b/bin/describe/describe_workspace.ml
index 663ae9b05e5..2a2951e8bb7 100644
--- a/bin/describe/describe_workspace.ml
+++ b/bin/describe/describe_workspace.ml
@@ -537,7 +537,7 @@ module Crawl = struct
         Memo.parallel_map dune_file.stanzas ~f:(fun stanza ->
           let dir = Path.Build.append_source (Context.build_dir context) dune_file.dir in
           match stanza with
-          | Dune_file.Executables exes ->
+          | Dune_file.Executables.T exes ->
             executables sctx ~options ~project:dune_file.project ~dir exes
           | _ -> Memo.return None)
         >>| List.filter_opt)
diff --git a/bin/dune_init.ml b/bin/dune_init.ml
index 885d2e49f45..f13b1b1b6a9 100644
--- a/bin/dune_init.ml
+++ b/bin/dune_init.ml
@@ -54,9 +54,9 @@ module File = struct
     let stanzas_conflict (a : Stanza.t) (b : Stanza.t) =
       let open Dune_file in
       match a, b with
-      | Executables a, Executables b -> executables_conflict a b
-      | Library a, Library b -> libraries_conflict a b
-      | Tests a, Tests b -> tests_conflict a b
+      | Executables.T a, Executables.T b -> executables_conflict a b
+      | Library.T a, Library.T b -> libraries_conflict a b
+      | Tests.T a, Tests.T b -> tests_conflict a b
       (* NOTE No other stanza types currently supported *)
       | _ -> false
     ;;
diff --git a/src/dune_lang/stanza.ml b/src/dune_lang/stanza.ml
index 1bfdaf36d14..0a32f07b22c 100644
--- a/src/dune_lang/stanza.ml
+++ b/src/dune_lang/stanza.ml
@@ -3,6 +3,13 @@ open Dune_sexp
 
 type t = ..
 
+module Make (S : sig
+    type t
+  end) =
+struct
+  type t += T of S.t
+end
+
 module Parser = struct
   type nonrec t = string * t list Decoder.t
 end
diff --git a/src/dune_lang/stanza.mli b/src/dune_lang/stanza.mli
index 4c40e8dc495..e78c128f968 100644
--- a/src/dune_lang/stanza.mli
+++ b/src/dune_lang/stanza.mli
@@ -3,7 +3,13 @@
 open! Stdune
 open Dune_sexp
 
-type t = ..
+type t = private ..
+
+module Make (S : sig
+    type t
+  end) : sig
+  type t += T of S.t
+end
 
 val latest_version : Syntax.Version.t
 
diff --git a/src/dune_rules/artifacts_db.ml b/src/dune_rules/artifacts_db.ml
index bbda641613b..0e4cffdda89 100644
--- a/src/dune_rules/artifacts_db.ml
+++ b/src/dune_rules/artifacts_db.ml
@@ -67,9 +67,9 @@ let get_installed_binaries ~(context : Context.t) stanzas =
     in
     Memo.List.map d.stanzas ~f:(fun stanza ->
       match (stanza : Stanza.t) with
-      | Dune_file.Install { section = Section Bin; files; _ } ->
+      | Dune_file.Install_conf.T { section = Section Bin; files; _ } ->
         binaries_from_install files
-      | Dune_file.Executables
+      | Dune_file.Executables.T
           ({ install_conf = Some { section = Section Bin; files; _ }; _ } as exes) ->
         let* available =
           let* enabled_if =
diff --git a/src/dune_rules/cinaps.ml b/src/dune_rules/cinaps.ml
index 01e30ef38b2..8851297a5f2 100644
--- a/src/dune_rules/cinaps.ml
+++ b/src/dune_rules/cinaps.ml
@@ -15,7 +15,9 @@ type t =
 let name = "cinaps"
 let cinaps_alias = Alias.Name.of_string name
 
-type Stanza.t += T of t
+include Stanza.Make (struct
+    type nonrec t = t
+  end)
 
 let syntax =
   Dune_lang.Syntax.create
diff --git a/src/dune_rules/coq/coq_stanza.ml b/src/dune_rules/coq/coq_stanza.ml
index 4111a69e92e..27a511ed65b 100644
--- a/src/dune_rules/coq/coq_stanza.ml
+++ b/src/dune_rules/coq/coq_stanza.ml
@@ -44,7 +44,9 @@ module Coqpp = struct
        { modules; loc })
   ;;
 
-  type Stanza.t += T of t
+  include Stanza.Make (struct
+      type nonrec t = t
+    end)
 
   let p = "coq.pp", decode >>| fun x -> [ T x ]
 end
@@ -129,7 +131,9 @@ module Extraction = struct
        { prelude; extracted_modules; buildable })
   ;;
 
-  type Stanza.t += T of t
+  include Stanza.Make (struct
+      type nonrec t = t
+    end)
 
   let p = "coq.extraction", decode >>| fun x -> [ T x ]
 end
@@ -230,7 +234,9 @@ module Theory = struct
        })
   ;;
 
-  type Stanza.t += T of t
+  include Stanza.Make (struct
+      type nonrec t = t
+    end)
 
   let coqlib_warn x =
     User_warning.emit
diff --git a/src/dune_rules/cram/cram_stanza.ml b/src/dune_rules/cram/cram_stanza.ml
index 2d2c5819c16..cc615b99997 100644
--- a/src/dune_rules/cram/cram_stanza.ml
+++ b/src/dune_rules/cram/cram_stanza.ml
@@ -31,7 +31,9 @@ type t =
   ; runtest_alias : (Loc.t * bool) option
   }
 
-type Stanza.t += T of t
+include Stanza.Make (struct
+    type nonrec t = t
+  end)
 
 let decode =
   fields
diff --git a/src/dune_rules/ctypes/ctypes_field.ml b/src/dune_rules/ctypes/ctypes_field.ml
index 9f54d36cad6..9eba5b46a29 100644
--- a/src/dune_rules/ctypes/ctypes_field.ml
+++ b/src/dune_rules/ctypes/ctypes_field.ml
@@ -149,7 +149,9 @@ type t =
   ; version : Syntax.Version.t
   }
 
-type Stanza.t += T of t
+include Stanza.Make (struct
+    type nonrec t = t
+  end)
 
 let decode =
   let open Dune_lang.Decoder in
diff --git a/src/dune_rules/dir_contents.ml b/src/dune_rules/dir_contents.ml
index 7713498ea0d..8721f8346c2 100644
--- a/src/dune_rules/dir_contents.ml
+++ b/src/dune_rules/dir_contents.ml
@@ -129,7 +129,7 @@ let build_mlds_map stanzas ~dir ~files =
       |> Memo.return)
   in
   Memo.parallel_map stanzas ~f:(function
-    | Documentation doc ->
+    | Documentation.T doc ->
       let+ mlds =
         let+ mlds = Memo.Lazy.force mlds in
         Ordered_set_lang.Unordered_string.eval
@@ -194,19 +194,19 @@ end = struct
           | Coq_stanza.Extraction.T s ->
             Memo.return (Coq_stanza.Extraction.ml_target_fnames s)
           | Menhir_stanza.T menhir -> Memo.return (Menhir_stanza.targets menhir)
-          | Rule rule ->
+          | Rule.T rule ->
             Simple_rules.user_rule sctx rule ~dir ~expander
             >>| (function
              | None -> []
              | Some targets ->
                (* CR-someday amokhov: Do not ignore directory targets. *)
                Path.Build.Set.to_list_map targets.files ~f:Path.Build.basename)
-          | Copy_files def ->
+          | Copy_files.T def ->
             Simple_rules.copy_files sctx def ~src_dir ~dir ~expander
             >>| Path.Set.to_list_map ~f:Path.basename
           | Generate_sites_module_stanza.T def ->
             Generate_sites_module_rules.setup_rules sctx ~dir def >>| List.singleton
-          | Library { buildable; _ } | Executables { buildable; _ } ->
+          | Library.T { buildable; _ } | Executables.T { buildable; _ } ->
             let select_deps_files = select_deps_files buildable.libraries in
             let ctypes_files =
               (* Also manually add files generated by ctypes rules. *)
diff --git a/src/dune_rules/dir_status.ml b/src/dune_rules/dir_status.ml
index 164b2b7ca1a..59777df42ee 100644
--- a/src/dune_rules/dir_status.ml
+++ b/src/dune_rules/dir_status.ml
@@ -56,7 +56,7 @@ let current_group dir = function
 let get_include_subdirs stanzas =
   List.fold_left stanzas ~init:None ~f:(fun acc stanza ->
     match stanza with
-    | Include_subdirs (loc, x) ->
+    | Include_subdirs.T (loc, x) ->
       if Option.is_some acc
       then
         User_error.raise
@@ -70,9 +70,9 @@ let find_module_stanza stanzas =
   List.find_map stanzas ~f:(fun stanza ->
     match stanza with
     | Melange_stanzas.Emit.T { loc; _ }
-    | Library { buildable = { loc; _ }; _ }
-    | Executables { buildable = { loc; _ }; _ }
-    | Tests { exes = { buildable = { loc; _ }; _ }; _ } -> Some loc
+    | Library.T { buildable = { loc; _ }; _ }
+    | Executables.T { buildable = { loc; _ }; _ }
+    | Tests.T { exes = { buildable = { loc; _ }; _ }; _ } -> Some loc
     | _ -> None)
 ;;
 
@@ -92,7 +92,7 @@ let error_no_module_consumer ~loc (qualification : Include_subdirs.qualification
 let extract_directory_targets ~dir stanzas =
   Memo.List.fold_left stanzas ~init:Path.Build.Map.empty ~f:(fun acc stanza ->
     match stanza with
-    | Rule { targets = Static { targets = l; _ }; loc = rule_loc; _ } ->
+    | Rule.T { targets = Static { targets = l; _ }; loc = rule_loc; _ } ->
       List.fold_left l ~init:acc ~f:(fun acc (target, kind) ->
         let loc = String_with_vars.loc target in
         match (kind : Targets_spec.Kind.t) with
diff --git a/src/dune_rules/dune_env.ml b/src/dune_rules/dune_env.ml
index 0d4c77b2307..37bf7da15ce 100644
--- a/src/dune_rules/dune_env.ml
+++ b/src/dune_rules/dune_env.ml
@@ -322,4 +322,6 @@ let fire_hooks t ~profile =
       User_warning.emit ?loc paragraphs))
 ;;
 
-type Stanza.t += T of t
+include Stanza.Make (struct
+    type nonrec t = t
+  end)
diff --git a/src/dune_rules/dune_file.ml b/src/dune_rules/dune_file.ml
index ff3b8736dd9..52427cf2174 100644
--- a/src/dune_rules/dune_file.ml
+++ b/src/dune_rules/dune_file.ml
@@ -1090,9 +1090,14 @@ module Library = struct
       ~instrumentation_backend
       ~melange_runtime_deps
   ;;
+
+  include Stanza.Make (struct
+      type nonrec t = t
+    end)
 end
 
 module Plugin = struct
+  (* CR-rgrinberg: this shouldn't live here *)
   type t =
     { package : Package.t
     ; name : Package.Name.t
@@ -1110,6 +1115,10 @@ module Plugin = struct
        and+ optional = field_b "optional" in
        { name; libraries; site; package; optional })
   ;;
+
+  include Stanza.Make (struct
+      type nonrec t = t
+    end)
 end
 
 module Install_conf = struct
@@ -1122,6 +1131,10 @@ module Install_conf = struct
     ; enabled_if : Blang.t
     }
 
+  include Stanza.Make (struct
+      type nonrec t = t
+    end)
+
   let decode =
     fields
       (let+ loc = loc
@@ -1552,6 +1565,10 @@ module Executables = struct
     ; dune_version : Dune_lang.Syntax.Version.t
     }
 
+  include Stanza.Make (struct
+      type nonrec t = t
+    end)
+
   let bootstrap_info_extension =
     let syntax =
       Dune_lang.Syntax.create
@@ -1713,6 +1730,10 @@ module Rule = struct
     ; package : Package.t option
     }
 
+  include Stanza.Make (struct
+      type nonrec t = t
+    end)
+
   type action_or_field =
     | Action
     | Field
@@ -1971,6 +1992,10 @@ module Alias_conf = struct
     ; loc : Loc.t
     }
 
+  include Stanza.Make (struct
+      type nonrec t = t
+    end)
+
   let decode =
     fields
       (let* deps =
@@ -2006,6 +2031,10 @@ module Tests = struct
     ; action : Dune_lang.Action.t option
     }
 
+  include Stanza.Make (struct
+      type nonrec t = t
+    end)
+
   let gen_parse names =
     fields
       (let* deps =
@@ -2080,6 +2109,10 @@ module Toplevel = struct
     ; pps : Preprocess.Without_instrumentation.t Preprocess.t
     }
 
+  include Stanza.Make (struct
+      type nonrec t = t
+    end)
+
   let decode =
     let open Dune_lang.Decoder in
     fields
@@ -2114,6 +2147,10 @@ module Copy_files = struct
     ; syntax_version : Dune_lang.Syntax.Version.t
     }
 
+  include Stanza.Make (struct
+      type nonrec t = t
+    end)
+
   let long_form =
     let check = Dune_lang.Syntax.since Stanza.syntax (2, 7) in
     let+ alias = field_o "alias" (check >>> Dune_lang.Alias.decode)
@@ -2148,6 +2185,10 @@ module Documentation = struct
     ; mld_files : Ordered_set_lang.t
     }
 
+  include Stanza.Make (struct
+      type nonrec t = t
+    end)
+
   let decode =
     fields
       (let+ package = Stanza_common.Pkg.field ~stanza:"documentation"
@@ -2166,6 +2207,12 @@ module Include_subdirs = struct
     | No
     | Include of qualification
 
+  type stanza = Loc.t * t
+
+  include Stanza.Make (struct
+      type nonrec t = stanza
+    end)
+
   let decode ~enable_qualified =
     sum
       [ "no", return No
@@ -2190,6 +2237,10 @@ module Library_redirect = struct
   module Local = struct
     type nonrec t = (Loc.t * Lib_name.Local.t) t
 
+    include Stanza.Make (struct
+        type nonrec t = t
+      end)
+
     let for_lib (lib : Library.t) ~new_public_name ~loc : t =
       { loc; new_public_name; old_name = lib.name; project = lib.project }
     ;;
@@ -2243,6 +2294,10 @@ module Deprecated_library_name = struct
 
   type t = Old_name.t Library_redirect.t
 
+  include Stanza.Make (struct
+      type nonrec t = t
+    end)
+
   let old_public_name (t : t) = Public_lib.name (fst t.old_name)
 
   let decode =
@@ -2263,48 +2318,39 @@ module Deprecated_library_name = struct
   ;;
 end
 
-type Stanza.t +=
-  | Library of Library.t
-  | Foreign_library of Foreign.Library.t
-  | Executables of Executables.t
-  | Rule of Rule.t
-  | Install of Install_conf.t
-  | Alias of Alias_conf.t
-  | Copy_files of Copy_files.t
-  | Documentation of Documentation.t
-  | Tests of Tests.t
-  | Include_subdirs of Loc.t * Include_subdirs.t
-  | Toplevel of Toplevel.t
-  | Library_redirect of Library_redirect.Local.t
-  | Deprecated_library_name of Deprecated_library_name.t
-  | Plugin of Plugin.t
+module Include = struct
+  type t = Loc.t * string
+
+  include Stanza.Make (struct
+      type nonrec t = t
+    end)
+end
 
 module Stanzas = struct
   type t = Stanza.t list
 
-  let rules l = List.map l ~f:(fun x -> Rule x)
-  let execs exe = [ Executables exe ]
+  let rules l = List.map l ~f:(fun x -> Rule.T x)
+  let execs exe = [ Executables.T exe ]
 
-  type Stanza.t += Include of Loc.t * string
   type constructors = Stanza.Parser.t list
 
   let stanzas : constructors =
     [ ( "library"
       , let+ x = Library.decode in
-        let base = [ Library x ] in
+        let base = [ Library.T x ] in
         match Library_redirect.Local.of_lib x with
         | None -> base
-        | Some r -> Library_redirect r :: base )
+        | Some r -> Library_redirect.Local.T r :: base )
     ; ( "foreign_library"
       , let+ () = Dune_lang.Syntax.since Stanza.syntax (2, 0)
         and+ x = Foreign.Library.decode in
-        [ Foreign_library x ] )
+        [ Foreign.Library.T x ] )
     ; "executable", Executables.single >>| execs
     ; "executables", Executables.multi >>| execs
     ; ( "rule"
       , let+ loc = loc
         and+ x = Rule.decode in
-        [ Rule { x with loc } ] )
+        [ Rule.T { x with loc } ] )
     ; ( "ocamllex"
       , let+ loc = loc
         and+ x = Rule.ocamllex in
@@ -2315,23 +2361,23 @@ module Stanzas = struct
         rules (Rule.ocamlyacc_to_rule loc x) )
     ; ( "install"
       , let+ x = Install_conf.decode in
-        [ Install x ] )
+        [ Install_conf.T x ] )
     ; ( "alias"
       , let+ x = Alias_conf.decode in
-        [ Alias x ] )
+        [ Alias_conf.T x ] )
     ; ( "copy_files"
       , let+ x = Copy_files.decode in
-        [ Copy_files x ] )
+        [ Copy_files.T x ] )
     ; ( "copy_files#"
       , let+ x = Copy_files.decode in
-        [ Copy_files { x with add_line_directive = true } ] )
+        [ Copy_files.T { x with add_line_directive = true } ] )
     ; ( "include"
       , let+ loc = loc
         and+ fn = relative_file in
-        [ Include (loc, fn) ] )
+        [ Include.T (loc, fn) ] )
     ; ( "documentation"
       , let+ d = Documentation.decode in
-        [ Documentation d ] )
+        [ Documentation.T d ] )
     ; ( "jbuild_version"
       , let+ () = Dune_lang.Syntax.deleted_in Stanza.syntax (1, 0)
         and+ _ = Jbuild_version.decode in
@@ -2339,11 +2385,11 @@ module Stanzas = struct
     ; ( "tests"
       , let+ () = Dune_lang.Syntax.since Stanza.syntax (1, 0)
         and+ t = Tests.multi in
-        [ Tests t ] )
+        [ Tests.T t ] )
     ; ( "test"
       , let+ () = Dune_lang.Syntax.since Stanza.syntax (1, 0)
         and+ t = Tests.single in
-        [ Tests t ] )
+        [ Tests.T t ] )
     ; ( "external_variant"
       , let+ () = Dune_lang.Syntax.deleted_in Stanza.syntax (2, 6) in
         [] )
@@ -2357,15 +2403,15 @@ module Stanzas = struct
           let enable_qualified = Dune_project.is_extension_set project Coq_stanza.key in
           Include_subdirs.decode ~enable_qualified
         and+ loc = loc in
-        [ Include_subdirs (loc, t) ] )
+        [ Include_subdirs.T (loc, t) ] )
     ; ( "toplevel"
       , let+ () = Dune_lang.Syntax.since Stanza.syntax (1, 7)
         and+ t = Toplevel.decode in
-        [ Toplevel t ] )
+        [ Toplevel.T t ] )
     ; ( "deprecated_library_name"
       , let+ () = Dune_lang.Syntax.since Stanza.syntax (2, 0)
         and+ t = Deprecated_library_name.decode in
-        [ Deprecated_library_name t ] )
+        [ Deprecated_library_name.T t ] )
     ; ( "cram"
       , let+ () = Dune_lang.Syntax.since Stanza.syntax (2, 7)
         and+ t = Cram_stanza.decode
@@ -2390,7 +2436,7 @@ module Stanzas = struct
     ; ( "plugin"
       , let+ () = Dune_lang.Syntax.since Site.dune_site_syntax (0, 1)
         and+ t = Plugin.decode in
-        [ Plugin t ] )
+        [ Plugin.T t ] )
     ]
   ;;
 
@@ -2413,7 +2459,7 @@ module Stanzas = struct
   let rec parse_file_includes ~stanza_parser ~context sexps =
     List.concat_map sexps ~f:(parse stanza_parser)
     |> Memo.List.concat_map ~f:(function
-      | Include (loc, fn) ->
+      | Include.T (loc, fn) ->
         let open Memo.O in
         let* sexps, context = Include_stanza.load_sexps ~context (loc, fn) in
         parse_file_includes ~stanza_parser ~context sexps
@@ -2455,14 +2501,14 @@ module Stanzas = struct
 end
 
 let stanza_package = function
-  | Library lib -> Library.package lib
-  | Alias { package = Some package; _ }
-  | Rule { package = Some package; _ }
-  | Install { package; _ }
-  | Plugin { package; _ }
-  | Executables { install_conf = Some { package; _ }; _ }
-  | Documentation { package; _ }
-  | Tests { package = Some package; _ } -> Some package
+  | Library.T lib -> Library.package lib
+  | Alias_conf.T { package = Some package; _ }
+  | Rule.T { package = Some package; _ }
+  | Install_conf.T { package; _ }
+  | Plugin.T { package; _ }
+  | Executables.T { install_conf = Some { package; _ }; _ }
+  | Documentation.T { package; _ }
+  | Tests.T { package = Some package; _ } -> Some package
   | Coq_stanza.Theory.T { package = Some package; _ } -> Some package
   | _ -> None
 ;;
@@ -2486,7 +2532,7 @@ let is_promoted_rule =
   in
   fun version rule ->
     match rule with
-    | Rule { mode; _ } | Menhir_stanza.T { mode; _ } -> is_promoted_mode version mode
+    | Rule.T { mode; _ } | Menhir_stanza.T { mode; _ } -> is_promoted_mode version mode
     | _ -> false
 ;;
 
diff --git a/src/dune_rules/dune_file.mli b/src/dune_rules/dune_file.mli
index 11a27a76c72..870ac47cfcd 100644
--- a/src/dune_rules/dune_file.mli
+++ b/src/dune_rules/dune_file.mli
@@ -171,6 +171,8 @@ module Library : sig
     ; melange_runtime_deps : Loc.t * Dep_conf.t list
     }
 
+  type Stanza.t += T of t
+
   val sub_dir : t -> string option
   val package : t -> Package.t option
 
@@ -221,6 +223,8 @@ module Plugin : sig
     ; site : Loc.t * (Package.Name.t * Site.t)
     ; optional : bool
     }
+
+  type Stanza.t += T of t
 end
 
 module Install_conf : sig
@@ -232,6 +236,8 @@ module Install_conf : sig
     ; package : Package.t
     ; enabled_if : Blang.t
     }
+
+  type Stanza.t += T of t
 end
 
 module Executables : sig
@@ -281,6 +287,8 @@ module Executables : sig
     ; dune_version : Dune_lang.Syntax.Version.t
     }
 
+  type Stanza.t += T of t
+
   (** Check if the executables have any foreign stubs or archives. *)
   val has_foreign : t -> bool
 
@@ -299,6 +307,8 @@ module Copy_files : sig
     ; files : String_with_vars.t
     ; syntax_version : Dune_lang.Syntax.Version.t
     }
+
+  type Stanza.t += T of t
 end
 
 module Rule : sig
@@ -314,6 +324,8 @@ module Rule : sig
     ; aliases : Alias.Name.t list
     ; package : Package.t option
     }
+
+  type Stanza.t += T of t
 end
 
 module Alias_conf : sig
@@ -326,6 +338,8 @@ module Alias_conf : sig
     ; enabled_if : Blang.t
     ; loc : Loc.t
     }
+
+  type Stanza.t += T of t
 end
 
 module Documentation : sig
@@ -334,6 +348,8 @@ module Documentation : sig
     ; package : Package.t
     ; mld_files : Ordered_set_lang.t
     }
+
+  type Stanza.t += T of t
 end
 
 module Tests : sig
@@ -346,6 +362,8 @@ module Tests : sig
     ; build_if : Blang.t
     ; action : Dune_lang.Action.t option
     }
+
+  type Stanza.t += T of t
 end
 
 module Toplevel : sig
@@ -355,6 +373,8 @@ module Toplevel : sig
     ; loc : Loc.t
     ; pps : Preprocess.Without_instrumentation.t Preprocess.t
     }
+
+  type Stanza.t += T of t
 end
 
 module Include_subdirs : sig
@@ -365,6 +385,9 @@ module Include_subdirs : sig
   type t =
     | No
     | Include of qualification
+
+  type stanza = Loc.t * t
+  type Stanza.t += T of stanza
 end
 
 (** The purpose of [Library_redirect] stanza is to create a redirection from an
@@ -388,6 +411,7 @@ module Library_redirect : sig
 
   module Local : sig
     type nonrec t = (Loc.t * Lib_name.Local.t) t
+    type Stanza.t += T of t
 
     val of_private_lib : Library.t -> t option
   end
@@ -403,26 +427,11 @@ module Deprecated_library_name : sig
   end
 
   type t = Old_name.t Library_redirect.t
+  type Stanza.t += T of t
 
   val old_public_name : t -> Lib_name.t
 end
 
-type Stanza.t +=
-  | Library of Library.t
-  | Foreign_library of Foreign.Library.t
-  | Executables of Executables.t
-  | Rule of Rule.t
-  | Install of Install_conf.t
-  | Alias of Alias_conf.t
-  | Copy_files of Copy_files.t
-  | Documentation of Documentation.t
-  | Tests of Tests.t
-  | Include_subdirs of Loc.t * Include_subdirs.t
-  | Toplevel of Toplevel.t
-  | Library_redirect of Library_redirect.Local.t
-  | Deprecated_library_name of Deprecated_library_name.t
-  | Plugin of Plugin.t
-
 val stanza_package : Stanza.t -> Package.t option
 
 (** [of_ast project ast] is the list of [Stanza.t]s derived from decoding the
diff --git a/src/dune_rules/foreign.ml b/src/dune_rules/foreign.ml
index 25e91be5f7a..c7dc9a131e0 100644
--- a/src/dune_rules/foreign.ml
+++ b/src/dune_rules/foreign.ml
@@ -263,6 +263,10 @@ module Library = struct
        and+ stubs = Stubs.decode_stubs ~for_library:true in
        { archive_name; archive_name_loc; stubs })
   ;;
+
+  include Stanza.Make (struct
+      type nonrec t = t
+    end)
 end
 
 module Source = struct
diff --git a/src/dune_rules/foreign.mli b/src/dune_rules/foreign.mli
index e90a0d0de85..e256b2adc3a 100644
--- a/src/dune_rules/foreign.mli
+++ b/src/dune_rules/foreign.mli
@@ -160,6 +160,8 @@ module Library : sig
     }
 
   val decode : t Dune_lang.Decoder.t
+
+  type Stanza.t += T of t
 end
 
 (** A foreign source file that has a [path] and all information of the
diff --git a/src/dune_rules/foreign_sources.ml b/src/dune_rules/foreign_sources.ml
index 5e45b89d1b1..b673b71ca13 100644
--- a/src/dune_rules/foreign_sources.ml
+++ b/src/dune_rules/foreign_sources.ml
@@ -175,7 +175,7 @@ let make stanzas ~(sources : Foreign.Sources.Unresolved.t) ~dune_version =
         ~init:([], [], [])
         ~f:(fun ((libs, foreign_libs, exes) as acc) stanza ->
           match (stanza : Stanza.t) with
-          | Library lib ->
+          | Library.T lib ->
             let all =
               eval_foreign_stubs
                 ~dune_version
@@ -184,12 +184,12 @@ let make stanzas ~(sources : Foreign.Sources.Unresolved.t) ~dune_version =
                 ~sources
             in
             (lib, all) :: libs, foreign_libs, exes
-          | Foreign_library library ->
+          | Foreign.Library.T library ->
             let all = eval_foreign_stubs ~dune_version [ library.stubs ] ~sources None in
             ( libs
             , (library.archive_name, (library.archive_name_loc, all)) :: foreign_libs
             , exes )
-          | Executables exe | Tests { exes = exe; _ } ->
+          | Executables.T exe | Tests.T { exes = exe; _ } ->
             let all =
               eval_foreign_stubs
                 ~dune_version
diff --git a/src/dune_rules/gen_rules.ml b/src/dune_rules/gen_rules.ml
index 49f4e196456..f939b462449 100644
--- a/src/dune_rules/gen_rules.ml
+++ b/src/dune_rules/gen_rules.ml
@@ -109,10 +109,10 @@ end = struct
     let toplevel_setup = Toplevel.Stanza.setup in
     let open Dune_file in
     match stanza with
-    | Toplevel toplevel ->
+    | Toplevel.T toplevel ->
       let+ () = toplevel_setup ~sctx ~dir ~toplevel in
       empty_none
-    | Library lib ->
+    | Library.T lib ->
       (* XXX why are we setting up private doc rules for disabled libraries? *)
       let* () = Odoc.setup_private_library_doc_alias sctx ~scope ~dir:ctx_dir lib
       and+ enabled_if =
@@ -122,10 +122,10 @@ end = struct
         ~loc:lib.buildable.loc
         (fun () -> Lib_rules.rules lib ~sctx ~dir ~scope ~dir_contents ~expander)
         enabled_if
-    | Foreign_library lib ->
+    | Foreign.Library.T lib ->
       let+ () = Lib_rules.foreign_rules lib ~sctx ~dir ~dir_contents ~expander in
       empty_none
-    | Executables exes ->
+    | Executables.T exes ->
       Expander.eval_blang expander exes.enabled_if
       >>= if_available (fun () ->
         let+ () =
@@ -139,14 +139,14 @@ end = struct
               (List.map exes.names ~f:(fun (_, exe) ->
                  Path.Build.relative dir (exe ^ Js_of_ocaml.Ext.exe)))
         })
-    | Alias alias ->
+    | Alias_conf.T alias ->
       let+ () = Simple_rules.alias sctx alias ~dir ~expander in
       empty_none
-    | Tests tests ->
+    | Tests.T tests ->
       Expander.eval_blang expander tests.build_if
       >>= if_available_buildable ~loc:tests.exes.buildable.loc (fun () ->
         Test_rules.rules tests ~sctx ~dir ~scope ~expander ~dir_contents)
-    | Copy_files { files = glob; _ } ->
+    | Copy_files.T { files = glob; _ } ->
       let+ source_dirs =
         let+ src_glob = Expander.No_deps.expand_str expander glob in
         if Filename.is_relative src_glob
@@ -160,10 +160,10 @@ end = struct
         else None
       in
       { empty_none with source_dirs }
-    | Install i ->
+    | Install_conf.T i ->
       let+ () = install_stanza_rules ~ctx_dir ~expander i in
       empty_none
-    | Plugin p ->
+    | Plugin.T p ->
       let+ () = Plugin_rules.setup_rules ~sctx ~dir p in
       empty_none
     | Cinaps.T cinaps ->
diff --git a/src/dune_rules/generate_sites_module/generate_sites_module_stanza.ml b/src/dune_rules/generate_sites_module/generate_sites_module_stanza.ml
index c32e1fb04e0..1eae1a26868 100644
--- a/src/dune_rules/generate_sites_module/generate_sites_module_stanza.ml
+++ b/src/dune_rules/generate_sites_module/generate_sites_module_stanza.ml
@@ -26,4 +26,6 @@ let decode =
      { loc; module_; sourceroot; relocatable; sites; plugins })
 ;;
 
-type Stanza.t += T of t
+include Stanza.Make (struct
+    type nonrec t = t
+  end)
diff --git a/src/dune_rules/install_rules.ml b/src/dune_rules/install_rules.ml
index d0e8a9f10ad..d8502b8f18c 100644
--- a/src/dune_rules/install_rules.ml
+++ b/src/dune_rules/install_rules.ml
@@ -329,7 +329,7 @@ end = struct
     let+ keep =
       let open Dune_file in
       match (stanza : Stanza.t) with
-      | Library lib ->
+      | Library.T lib ->
         let* enabled_if = Expander.eval_blang expander lib.enabled_if in
         if enabled_if
         then
@@ -337,10 +337,10 @@ end = struct
           then Lib.DB.available (Scope.libs scope) (Dune_file.Library.best_name lib)
           else Memo.return true
         else Memo.return false
-      | Documentation _ -> Memo.return true
-      | Install { enabled_if; _ } -> Expander.eval_blang expander enabled_if
-      | Plugin _ -> Memo.return true
-      | Executables ({ install_conf = Some _; _ } as exes) ->
+      | Documentation.T _ -> Memo.return true
+      | Install_conf.T { enabled_if; _ } -> Expander.eval_blang expander enabled_if
+      | Plugin.T _ -> Memo.return true
+      | Executables.T ({ install_conf = Some _; _ } as exes) ->
         Expander.eval_blang expander exes.enabled_if
         >>= (function
          | false -> Memo.return false
@@ -455,14 +455,14 @@ end = struct
       let new_entries =
         let open Dune_file in
         match (stanza : Stanza.t) with
-        | Install i | Executables { install_conf = Some i; _ } ->
+        | Install_conf.T i | Executables.T { install_conf = Some i; _ } ->
           entries_of_install_stanza ~dir ~expander ~package_db i
-        | Library lib ->
+        | Library.T lib ->
           let sub_dir = Dune_file.Library.sub_dir lib in
           let* dir_contents = Dir_contents.get sctx ~dir in
           lib_install_files sctx ~scope ~dir ~sub_dir lib ~dir_contents
         | Coq_stanza.Theory.T coqlib -> Coq_rules.install_rules ~sctx ~dir coqlib
-        | Documentation d ->
+        | Documentation.T d ->
           let* dc = Dir_contents.get sctx ~dir in
           let+ mlds = Dir_contents.mlds dc d in
           List.map mlds ~f:(fun mld ->
@@ -474,7 +474,7 @@ end = struct
                 mld
             in
             Install.Entry.Sourced.create ~loc:d.loc entry)
-        | Plugin t -> Plugin_rules.install_rules ~sctx ~package_db ~dir t
+        | Plugin.T t -> Plugin_rules.install_rules ~sctx ~package_db ~dir t
         | _ -> Memo.return []
       in
       let name = Package.name package in
diff --git a/src/dune_rules/mdx.ml b/src/dune_rules/mdx.ml
index 63327a4cb7c..dffdd259acf 100644
--- a/src/dune_rules/mdx.ml
+++ b/src/dune_rules/mdx.ml
@@ -192,7 +192,9 @@ type t =
 
 let enabled_if t = t.enabled_if
 
-type Stanza.t += T of t
+include Stanza.Make (struct
+    type nonrec t = t
+  end)
 
 let syntax =
   let name = "mdx" in
diff --git a/src/dune_rules/melange/melange_stanzas.ml b/src/dune_rules/melange/melange_stanzas.ml
index b1b217d90eb..bccdfd7993f 100644
--- a/src/dune_rules/melange/melange_stanzas.ml
+++ b/src/dune_rules/melange/melange_stanzas.ml
@@ -21,7 +21,9 @@ module Emit = struct
     ; dune_version : Dune_lang.Syntax.Version.t
     }
 
-  type Stanza.t += T of t
+  include Stanza.Make (struct
+      type nonrec t = t
+    end)
 
   let implicit_alias = Alias.Name.of_string "melange"
 
diff --git a/src/dune_rules/menhir/menhir_stanza.ml b/src/dune_rules/menhir/menhir_stanza.ml
index 9b14a6e2d32..0b241548d10 100644
--- a/src/dune_rules/menhir/menhir_stanza.ml
+++ b/src/dune_rules/menhir/menhir_stanza.ml
@@ -41,7 +41,9 @@ let decode =
      { merge_into; flags; modules; mode; loc; infer; enabled_if })
 ;;
 
-type Stanza.t += T of t
+include Stanza.Make (struct
+    type nonrec t = t
+  end)
 
 let () =
   Dune_project.Extension.register_simple
diff --git a/src/dune_rules/ml_sources.ml b/src/dune_rules/ml_sources.ml
index 11845b2cf62..1dd04d18185 100644
--- a/src/dune_rules/ml_sources.ml
+++ b/src/dune_rules/ml_sources.ml
@@ -428,7 +428,7 @@ let modules_of_stanzas =
   fun stanzas ~project ~dir ~libs ~lookup_vlib ~modules ~include_subdirs ->
     Memo.parallel_map stanzas ~f:(fun stanza ->
       match (stanza : Stanza.t) with
-      | Library lib ->
+      | Library.T lib ->
         (* jeremiedimino: this [Resolve.get] means that if the user writes an
            invalid [implements] field, we will get an error immediately even if
            the library is not built. We should change this to carry the
@@ -447,7 +447,7 @@ let modules_of_stanzas =
         in
         let obj_dir = Library.obj_dir lib ~dir in
         `Library (lib, sources, modules, obj_dir)
-      | Executables exes | Tests { exes; _ } ->
+      | Executables.T exes | Tests.T { exes; _ } ->
         let obj_dir = Dune_file.Executables.obj_dir ~dir exes in
         let+ sources, modules =
           let { Buildable.loc = stanza_loc; modules = modules_settings; _ } =
diff --git a/src/dune_rules/only_packages.ml b/src/dune_rules/only_packages.ml
index 44b7b19ed1f..2c94826123a 100644
--- a/src/dune_rules/only_packages.ml
+++ b/src/dune_rules/only_packages.ml
@@ -93,10 +93,10 @@ let filter_out_stanzas_from_hidden_packages ~visible_pkgs =
     then Some stanza
     else (
       match stanza with
-      | Dune_file.Library l ->
+      | Dune_file.Library.T l ->
         let open Option.O in
         let+ redirect = Dune_file.Library_redirect.Local.of_private_lib l in
-        Dune_file.Library_redirect redirect
+        Dune_file.Library_redirect.Local.T redirect
       | _ -> None))
 ;;
 
diff --git a/src/dune_rules/packages.ml b/src/dune_rules/packages.ml
index 2256bcaa803..8eefe5819a3 100644
--- a/src/dune_rules/packages.ml
+++ b/src/dune_rules/packages.ml
@@ -14,7 +14,7 @@ let mlds_by_package_def =
       let* dune_files = Context.name ctx |> Only_packages.filtered_stanzas in
       Memo.parallel_map dune_files ~f:(fun dune_file ->
         Memo.parallel_map dune_file.stanzas ~f:(function
-          | Documentation d ->
+          | Documentation.T d ->
             let dir = Path.Build.append_source (Context.build_dir ctx) dune_file.dir in
             let* dc = Dir_contents.get sctx ~dir in
             let+ mlds = Dir_contents.mlds dc d in
diff --git a/src/dune_rules/scope.ml b/src/dune_rules/scope.ml
index c307b7d474e..bee36d5ae33 100644
--- a/src/dune_rules/scope.ml
+++ b/src/dune_rules/scope.ml
@@ -344,12 +344,12 @@ module DB = struct
         ~f:(fun dune_file stanza (acc, coq_acc) ->
           let build_dir = Context.build_dir context in
           match stanza with
-          | Dune_file.Library lib ->
+          | Dune_file.Library.T lib ->
             let ctx_dir = Path.Build.append_source build_dir dune_file.dir in
             Library_related_stanza.Library (ctx_dir, lib) :: acc, coq_acc
-          | Dune_file.Deprecated_library_name d ->
+          | Dune_file.Deprecated_library_name.T d ->
             Deprecated_library_name d :: acc, coq_acc
-          | Dune_file.Library_redirect d -> Library_redirect d :: acc, coq_acc
+          | Dune_file.Library_redirect.Local.T d -> Library_redirect d :: acc, coq_acc
           | Coq_stanza.Theory.T coq_lib ->
             let ctx_dir = Path.Build.append_source build_dir dune_file.dir in
             acc, (ctx_dir, coq_lib) :: coq_acc
@@ -417,7 +417,7 @@ module DB = struct
       let+ libs =
         Dune_file.Memo_fold.fold_stanzas stanzas ~init:[] ~f:(fun d stanza acc ->
           match stanza with
-          | Dune_file.Library ({ visibility = Private (Some pkg); _ } as lib) ->
+          | Dune_file.Library.T ({ visibility = Private (Some pkg); _ } as lib) ->
             let+ lib =
               let* scope = find_by_dir (Path.Build.append_source build_dir d.dir) in
               let db = libs scope in
@@ -428,7 +428,7 @@ module DB = struct
              | Some lib ->
                let name = Package.name pkg in
                (name, Lib_entry.Library (Lib.Local.of_lib_exn lib)) :: acc)
-          | Dune_file.Library { visibility = Public pub; _ } ->
+          | Dune_file.Library.T { visibility = Public pub; _ } ->
             let+ lib = Lib.DB.find public_libs (Dune_file.Public_lib.name pub) in
             (match lib with
              | None ->
@@ -439,8 +439,8 @@ module DB = struct
                let package = Dune_file.Public_lib.package pub in
                let name = Package.name package in
                (name, Lib_entry.Library (Lib.Local.of_lib_exn lib)) :: acc)
-          | Dune_file.Deprecated_library_name ({ old_name = old_public_name, _; _ } as d)
-            ->
+          | Dune_file.Deprecated_library_name.T
+              ({ old_name = old_public_name, _; _ } as d) ->
             let package = Dune_file.Public_lib.package old_public_name in
             let name = Package.name package in
             Memo.return ((name, Lib_entry.Deprecated_library_name d) :: acc)
diff --git a/src/dune_rules/super_context.ml b/src/dune_rules/super_context.ml
index 763de365132..c379a28a576 100644
--- a/src/dune_rules/super_context.ml
+++ b/src/dune_rules/super_context.ml
@@ -334,9 +334,9 @@ let add_packages_env context ~base stanzas packages =
                 add_in_package_section acc pkg_name section
             in
             match stanza with
-            | Dune_file.Install { section = Site { pkg; site; loc }; _ } ->
+            | Dune_file.Install_conf.T { section = Site { pkg; site; loc }; _ } ->
               add_in_package_sites pkg site loc
-            | Dune_file.Plugin { site = loc, (pkg, site); _ } ->
+            | Dune_file.Plugin.T { site = loc, (pkg, site); _ } ->
               add_in_package_sites pkg site loc
             | _ -> Memo.return acc)
       in
diff --git a/src/dune_rules/utop.ml b/src/dune_rules/utop.ml
index 0359c815f70..b1f43a66804 100644
--- a/src/dune_rules/utop.ml
+++ b/src/dune_rules/utop.ml
@@ -54,7 +54,7 @@ let libs_and_ppx_under_dir sctx ~db ~dir =
           | Some (d : Dune_file.t) ->
             Memo.List.fold_left d.stanzas ~init:Libs_and_ppxs.empty ~f:(fun (acc, pps) ->
                 function
-                | Dune_file.Library l ->
+                | Dune_file.Library.T l ->
                   let+ lib =
                     let open Memo.O in
                     let+ resolve =
@@ -88,7 +88,7 @@ let libs_and_ppx_under_dir sctx ~db ~dir =
                              (Lib_info.loc info, Lib_info.name info)
                              pps ))
                      else acc, pps)
-                | Dune_file.Executables exes ->
+                | Dune_file.Executables.T exes ->
                   let+ libs =
                     let open Memo.O in
                     let* compile_info =