diff --git a/CHANGES.md b/CHANGES.md
index 9d34eae5b8f..e35f1565c6d 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -15,6 +15,12 @@
   Introducing a new `external_variant` stanza. (#2169, fixes #2134, @TheLortex,
   review by @diml)
 
+- Add proper line directives when copying `.cc` and `.cxx` sources (#2275,
+  @rgrinberg)
+
+- Fix error message for missing C++ sources. The `.cc` extension was always
+  ignored before. (#2275, @rgrinberg)
+
 1.10.0 (04/06/2019)
 -------------------
 
diff --git a/bin/import.ml b/bin/import.ml
index ac6b787a1dd..82b0b0d65c2 100644
--- a/bin/import.ml
+++ b/bin/import.ml
@@ -23,7 +23,7 @@ module Build          = Dune.Build
 module Action         = Dune.Action
 module Dep            = Dune.Dep
 module Action_to_sh   = Dune.Action_to_sh
-module Path_dune_lang = Dune.Path_dune_lang
+module Dpath = Dune.Dpath
 module Install        = Dune.Install
 module Watermarks     = Dune.Watermarks
 module Promotion      = Dune.Promotion
diff --git a/bin/print_rules.ml b/bin/print_rules.ml
index 9305d237261..ac0bcf5ab39 100644
--- a/bin/print_rules.ml
+++ b/bin/print_rules.ml
@@ -47,7 +47,7 @@ let print_rule_sexp ppf (rule : Build_system.Rule.t) =
     Action.for_shell action |> Action.For_shell.encode
   in
   let paths ps =
-    Dune_lang.Encoder.list Path_dune_lang.encode (Path.Set.to_list ps)
+    Dune_lang.Encoder.list Dpath.encode (Path.Set.to_list ps)
   in
   let sexp =
     Dune_lang.Encoder.record (
diff --git a/src/action.ml b/src/action.ml
index ed538564ae6..97c9f5198ab 100644
--- a/src/action.ml
+++ b/src/action.ml
@@ -72,10 +72,10 @@ module Prog = struct
   type t = (Path.t, Not_found.t) result
 
   let decode : t Dune_lang.Decoder.t =
-    Dune_lang.Decoder.map Path_dune_lang.decode ~f:Result.ok
+    Dune_lang.Decoder.map Dpath.decode ~f:Result.ok
 
   let encode = function
-    | Ok s -> Path_dune_lang.encode s
+    | Ok s -> Dpath.encode s
     | Error (e : Not_found.t) -> Dune_lang.Encoder.string e.program
 end
 
@@ -91,7 +91,7 @@ module String_with_sexp = struct
   let encode = Dune_lang.Encoder.string
 end
 
-include Action_ast.Make(Prog)(Path_dune_lang)(String_with_sexp)(Ast)
+include Action_ast.Make(Prog)(Dpath)(String_with_sexp)(Ast)
 type program = Prog.t
 type path = Path.t
 type string = String.t
diff --git a/src/action_unexpanded.ml b/src/action_unexpanded.ml
index 67207b35b4f..c9b5838e886 100644
--- a/src/action_unexpanded.ml
+++ b/src/action_unexpanded.ml
@@ -23,7 +23,7 @@ let check_mkdir loc path =
       "(mkdir ...) is not supported for paths outside of the workspace:\n\
       \  %a\n"
       (Dune_lang.pp Dune)
-      (List [Dune_lang.unsafe_atom_of_string "mkdir"; Path_dune_lang.encode path])
+      (List [Dune_lang.unsafe_atom_of_string "mkdir"; Dpath.encode path])
 
 module Partial = struct
   module Program = Unresolved.Program
diff --git a/src/alias.ml b/src/alias.ml
index 2a7df86b967..7f613fbc4e4 100644
--- a/src/alias.ml
+++ b/src/alias.ml
@@ -101,6 +101,6 @@ let fmt         = make_standard "fmt"
 let encode { dir ; name } =
   let open Dune_lang.Encoder in
   record
-    [ "dir", Path_dune_lang.encode (Path.build dir)
+    [ "dir", Dpath.encode (Path.build dir)
     ; "name", string name
     ]
diff --git a/src/build_system.ml b/src/build_system.ml
index df5323b2f9e..b61109f2898 100644
--- a/src/build_system.ml
+++ b/src/build_system.ml
@@ -589,9 +589,9 @@ let remove_old_artifacts t ~dir ~(subdirs_to_keep : Subdir_set.t) =
 let no_rule_found =
   fun t ~loc fn ->
     let fail fn ~loc =
-      Errors.fail_opt loc "No rule found for %s" (Utils.describe_target fn)
+      Errors.fail_opt loc "No rule found for %s" (Dpath.describe_target fn)
     in
-    match Utils.analyse_target fn with
+    match Dpath.analyse_target fn with
     | Other _ -> fail fn ~loc
     | Regular (ctx, _) ->
       if String.Map.mem t.contexts ctx then
@@ -930,7 +930,7 @@ The following targets are not:
 
     let corresponding_source_dir ~dir =
       let t = t () in
-      match Utils.analyse_target dir with
+      match Dpath.analyse_target dir with
       | Install _ | Alias _ | Other _ ->
         None
       | Regular (_ctx, sub_dir) ->
@@ -982,7 +982,7 @@ The following targets are not:
 
   let load_dir_step2_exn t ~dir =
     let context_name, sub_dir =
-      match Utils.analyse_path dir with
+      match Dpath.analyse_path dir with
       | Build (Install (ctx, path)) ->
         Context_or_install.Install ctx, path
       | Build (Regular (ctx, path)) ->
@@ -1576,7 +1576,7 @@ end = struct
       ~output:(Allow_cutoff (module Unit))
       ~doc:"Build a file."
       ~input:(module Path)
-      ~visibility:(Public Path_dune_lang.decode)
+      ~visibility:(Public Dpath.decode)
       Async
       build_file_impl
 
diff --git a/src/c.ml b/src/c.ml
index b85bb677640..16be2879d34 100644
--- a/src/c.ml
+++ b/src/c.ml
@@ -1,5 +1,7 @@
 open Stdune
 
+let header_ext = ".h"
+
 module Kind = struct
   type t =
     | C
@@ -32,17 +34,24 @@ module Kind = struct
       cxx_version_introduced ~obj ~dune_version ~version_introduced:(1, 10)
     | _ -> Unrecognized
 
-  let possible_fns t fn ~dune_version =
-    match t with
-    | C -> [fn ^ ".c"]
+  let possible_exts ~dune_version = function
+    | C -> [".c"]
     | Cxx ->
-      let cxx = [fn ^ ".cpp"] in
+      let exts = [".cpp"] in
+      let exts =
+        if dune_version >= (1, 10) then
+          ".cc" :: exts
+        else
+          exts
+      in
       if dune_version >= (1, 8) then
-        (fn ^ ".cxx") :: cxx
-      else if dune_version >= (1, 10) then
-        (fn ^ ".cxx") :: (fn ^ ".cc") :: cxx
+        ".cxx" :: exts
       else
-        cxx
+        exts
+
+  let possible_fns t fn ~dune_version =
+    possible_exts t ~dune_version
+    |> List.map ~f:(fun ext -> fn ^ ext)
 
   module Dict = struct
     type 'a t =
@@ -122,3 +131,11 @@ module Sources = struct
     in
     {Kind.Dict. c; cxx}
 end
+
+let all_possible_exts =
+  let exts = Kind.possible_exts ~dune_version:Stanza.latest_version in
+  header_ext :: exts C @ exts Cxx
+
+let c_cxx_or_header ~fn =
+  let ext = Filename.extension fn in
+  List.mem ~set:all_possible_exts ext
diff --git a/src/c.mli b/src/c.mli
index 26c702ea30e..6e15c733a22 100644
--- a/src/c.mli
+++ b/src/c.mli
@@ -1,5 +1,7 @@
 open Stdune
 
+val header_ext : string
+
 module Kind : sig
   type t =
     | C
@@ -65,3 +67,5 @@ module Sources : sig
 
   val split_by_kind : t -> t Kind.Dict.t
 end
+
+val c_cxx_or_header : fn:string -> bool
diff --git a/src/dep.ml b/src/dep.ml
index ae3c32fe6ae..fe1bf868147 100644
--- a/src/dep.ml
+++ b/src/dep.ml
@@ -68,7 +68,7 @@ module T = struct
     match t with
     | Glob g -> pair string File_selector.encode ("glob", g)
     | Env e -> pair string string ("Env", e)
-    | File f -> pair string Path_dune_lang.encode ("File", f)
+    | File f -> pair string Dpath.encode ("File", f)
     | Alias a -> pair string Alias.encode ("Alias", a)
     | Universe -> string "Universe"
 end
diff --git a/src/dep_path.ml b/src/dep_path.ml
index c6a2da1d91c..6cee8f1a8dc 100644
--- a/src/dep_path.ml
+++ b/src/dep_path.ml
@@ -10,8 +10,8 @@ module Entry = struct
     | Loc of Loc.t
 
   let pp = function
-    | Path p -> Pp.text (Utils.describe_path p)
-    | Alias p -> Pp.textf "alias %s" (Utils.describe_path p)
+    | Path p -> Pp.text (Dpath.describe_path p)
+    | Alias p -> Pp.textf "alias %s" (Dpath.describe_path p)
     | Library (path, lib_name) ->
       Pp.textf "library %S in %s"
         (Lib_name.to_string lib_name)
diff --git a/src/dpath.ml b/src/dpath.ml
new file mode 100644
index 00000000000..bdcbfa58811
--- /dev/null
+++ b/src/dpath.ml
@@ -0,0 +1,114 @@
+open Stdune
+
+type target_kind =
+  | Regular of string * Path.Source.t
+  | Alias   of string * Path.Source.t
+  | Install of string * Path.Source.t
+  | Other of Path.Build.t
+
+type path_kind =
+  | Source of Path.Source.t
+  | External of Path.External.t
+  | Build of target_kind
+
+let analyse_target (fn as original_fn) : target_kind =
+  match Path.Build.extract_first_component fn with
+  | Some (".aliases", sub) ->
+    (match Path.Local.split_first_component sub with
+     | None -> Other fn
+     | Some (ctx, fn) ->
+       if Path.Local.is_root fn then
+         Other original_fn
+       else
+         let basename =
+           match String.rsplit2 (Path.Local.basename fn) ~on:'-' with
+           | None -> assert false
+           | Some (name, digest) ->
+             assert (String.length digest = 32);
+             name
+         in
+         Alias (ctx,
+                Path.Source.relative
+                  (Path.Source.of_local (Path.Local.parent_exn fn))
+                  basename))
+  | Some ("install", sub) ->
+    (match Path.Local.split_first_component sub with
+     | None -> Other fn
+     | Some (ctx, fn) ->
+       Install (ctx, Path.Source.of_local fn))
+  | Some (ctx, sub) ->
+    Regular (ctx, Path.Source.of_local sub)
+  | None ->
+    Other fn
+
+let describe_target fn =
+  let ctx_suffix = function
+    | "default" -> ""
+    | ctx -> sprintf " (context %s)" ctx
+  in
+  match analyse_target fn with
+  | Alias (ctx, p) ->
+    sprintf "alias %s%s" (Path.Source.to_string_maybe_quoted p) (ctx_suffix ctx)
+  | Install (ctx, p) ->
+    sprintf "install %s%s" (Path.Source.to_string_maybe_quoted p) (ctx_suffix ctx)
+  | Regular (ctx, fn) ->
+    sprintf "%s%s" (Path.Source.to_string_maybe_quoted fn) (ctx_suffix ctx)
+  | Other fn ->
+    Path.Build.to_string_maybe_quoted fn
+
+let describe_path (p : Path.t) =
+  match p with
+  | External _ | In_source_tree _ ->
+    Path.to_string_maybe_quoted p
+  | In_build_dir p -> describe_target p
+
+let analyse_path (fn : Path.t) = match fn with
+  | In_source_tree src -> Source src
+  | External e -> External e
+  | In_build_dir build -> Build (analyse_target build)
+
+type t = Path.t
+
+let encode p =
+  let make constr arg =
+    Dune_lang.List [
+      Dune_lang.atom constr
+    ; Dune_lang.atom_or_quoted_string arg
+    ]
+  in
+  let open Path in
+  match p with
+  | In_build_dir p ->
+    make "In_build_dir" (Path.Build.to_string p)
+  | In_source_tree p ->
+    make "In_source_tree" (Path.Source.to_string p)
+  | External p ->
+    make "External" (Path.External.to_string p)
+
+let decode =
+  let open Dune_lang.Decoder in
+  let external_ =
+    plain_string (fun ~loc t ->
+      if Filename.is_relative t then
+        Dune_lang.Decoder.of_sexp_errorf loc "Absolute path expected"
+      else
+        Path.parse_string_exn ~loc t
+    )
+  in
+  sum
+    [ "In_build_dir"  , string    >>| Path.(relative build_dir)
+    ; "In_source_tree", string    >>| Path.(relative root)
+    ; "External"      , external_
+    ]
+
+module Local = struct
+  let encode ~dir:from p =
+    let open Dune_lang.Encoder in
+    string (Path.reach ~from p)
+
+  let decode ~dir =
+    let open Dune_lang.Decoder in
+    let+ (error_loc, path) = located string
+    in
+    Path.relative ~error_loc dir path
+end
diff --git a/src/dpath.mli b/src/dpath.mli
new file mode 100644
index 00000000000..2b4884341e1
--- /dev/null
+++ b/src/dpath.mli
@@ -0,0 +1,28 @@
+open Stdune
+
+type target_kind =
+  | Regular of string (* build context *) * Path.Source.t
+  | Alias   of string (* build context *) * Path.Source.t
+  | Install of string (* build context *) * Path.Source.t
+  | Other of Path.Build.t
+
+type path_kind =
+  | Source of Path.Source.t
+  | External of Path.External.t
+  | Build of target_kind
+
+(** Return the name of an alias from its stamp file *)
+val analyse_target : Path.Build.t -> target_kind
+val analyse_path : Path.t -> path_kind
+
+(** Nice description of a target *)
+val describe_target : Path.Build.t -> string
+val describe_path : Path.t -> string
+
+include Dune_lang.Conv with type t = Path.t
+
+module Local : sig
+  val encode : dir:Path.t -> Path.t Dune_lang.Encoder.t
+
+  val decode : dir:Path.t -> Path.t Dune_lang.Decoder.t
+end
diff --git a/src/dune_package.ml b/src/dune_package.ml
index 31b591f4c1e..5ffaa3430e9 100644
--- a/src/dune_package.ml
+++ b/src/dune_package.ml
@@ -92,7 +92,7 @@ module Lib = struct
         } =
     let open Dune_lang.Encoder in
     let no_loc f (_loc, x) = f x in
-    let path = Path_dune_lang.Local.encode ~dir:package_root in
+    let path = Dpath.Local.encode ~dir:package_root in
     let paths name f = field_l name path f in
     let mode_paths name (xs : Path.t Mode.Dict.List.t) =
       field_l name sexp (Mode.Dict.List.encode path xs) in
@@ -131,7 +131,7 @@ module Lib = struct
 
   let decode ~base =
     let open Stanza.Decoder in
-    let path = Path_dune_lang.Local.decode ~dir:base in
+    let path = Dpath.Local.decode ~dir:base in
     let field_l s x = field ~default:[] s (list x) in
     let libs s = field_l s (located Lib_name.decode) in
     let paths s = field_l s path in
diff --git a/src/dune_package.mli b/src/dune_package.mli
index f52dccbe24a..20ec32b1ec6 100644
--- a/src/dune_package.mli
+++ b/src/dune_package.mli
@@ -83,5 +83,5 @@ module Or_meta : sig
     -> (Syntax.Version.t * Dune_lang.t list) t
     -> Dune_lang.t list
 
-  val load : Path_dune_lang.t -> Sub_system_info.t t
+  val load : Dpath.t -> Sub_system_info.t t
 end
diff --git a/src/file_selector.ml b/src/file_selector.ml
index 82047021756..87dd7238028 100644
--- a/src/file_selector.ml
+++ b/src/file_selector.ml
@@ -26,7 +26,7 @@ let pp fmt t = Dyn.pp fmt (to_dyn t)
 let encode { dir; predicate } =
   let open Dune_lang.Encoder in
   record
-    [ "dir", Path_dune_lang.encode dir
+    [ "dir", Dpath.encode dir
     ; "predicate", Predicate.encode predicate
     ]
 
diff --git a/src/lib_archives.ml b/src/lib_archives.ml
index e532474a53d..c3027cee294 100644
--- a/src/lib_archives.ml
+++ b/src/lib_archives.ml
@@ -20,7 +20,7 @@ let make ~(ctx : Context.t) ~dir ~dir_contents (lib : Library.t) =
     let virtual_library = Library.is_virtual lib in
     List.concat
       [ if_ (byte && not virtual_library)
-          [ Library.archive ~dir lib ~ext:".cma" ]
+          [ Library.archive ~dir lib ~ext:(Mode.compiled_lib_ext Byte) ]
       ; if virtual_library then (
           let files =
             Dir_contents.c_sources_of_library dir_contents
@@ -33,18 +33,18 @@ let make ~(ctx : Context.t) ~dir ~dir_contents (lib : Library.t) =
           []
       ; if_ (native && not virtual_library)
           (let files =
-             [ Library.archive ~dir lib ~ext:".cmxa"
+             [ Library.archive ~dir lib ~ext:(Mode.compiled_lib_ext Native)
              ; Library.archive ~dir lib ~ext:ctx.ext_lib
              ]
            in
            if Dynlink_supported.get lib.dynlink ctx.natdynlink_supported then
-             files @ [ Library.archive ~dir lib ~ext:".cmxs" ]
+             files @ [ Library.archive ~dir lib ~ext:(Mode.plugin_ext Native) ]
            else
              files)
       ; List.map lib.buildable.js_of_ocaml.javascript_files
           ~f:(Path.Build.relative dir)
       ; List.map lib.install_c_headers ~f:(fun fn ->
-          Path.Build.relative dir (fn ^ ".h"))
+          Path.Build.relative dir (fn ^ C.header_ext))
       ]
   in
   let dlls =
diff --git a/src/lib_file_deps.ml b/src/lib_file_deps.ml
index 565fe9b12fb..c323d748fe3 100644
--- a/src/lib_file_deps.ml
+++ b/src/lib_file_deps.ml
@@ -11,7 +11,7 @@ module Group = struct
   let ext = function
     | Cmi -> Cm_kind.ext Cmi
     | Cmx -> Cm_kind.ext Cmx
-    | Header -> ".h"
+    | Header -> C.header_ext
 
   let obj_dir t obj_dir =
     match t with
diff --git a/src/lib_rules.ml b/src/lib_rules.ml
index 62d804e99e5..e590f9b0650 100644
--- a/src/lib_rules.ml
+++ b/src/lib_rules.ml
@@ -248,7 +248,7 @@ module Gen (P : sig val sctx : Super_context.t end) = struct
       List.fold_left all_dirs ~init:[] ~f:(fun acc dc ->
         String.Set.fold (Dir_contents.text_files dc) ~init:acc
           ~f:(fun fn acc ->
-            if String.is_suffix fn ~suffix:".h" then
+            if String.is_suffix fn ~suffix:C.header_ext then
               Path.relative (Path.build (Dir_contents.dir dc)) fn :: acc
             else
               acc))
diff --git a/src/meta.ml b/src/meta.ml
index 5d30d403fb8..87790d59343 100644
--- a/src/meta.ml
+++ b/src/meta.ml
@@ -189,10 +189,10 @@ let directory   s = rule "directory"  []      Set s
 let archive p s   = rule "archive"    [Pos p] Set s
 let plugin  p s   = rule "plugin"     [Pos p] Set s
 let archives name =
-  [ archive "byte"   (name ^ ".cma" )
-  ; archive "native" (name ^ ".cmxa")
-  ; plugin  "byte"   (name ^ ".cma" )
-  ; plugin  "native" (name ^ ".cmxs")
+  [ archive "byte"   (name ^ (Mode.compiled_lib_ext Byte))
+  ; archive "native" (name ^ (Mode.compiled_lib_ext Native))
+  ; plugin  "byte"   (name ^ (Mode.compiled_lib_ext Byte))
+  ; plugin  "native" (name ^ (Mode.plugin_ext Native))
   ]
 
 let builtins ~stdlib_dir ~version:ocaml_version =
diff --git a/src/path_dune_lang.ml b/src/path_dune_lang.ml
deleted file mode 100644
index 95cefa106d0..00000000000
--- a/src/path_dune_lang.ml
+++ /dev/null
@@ -1,47 +0,0 @@
-open Stdune
-open Path
-
-type t = Path.t
-
-let encode p =
-  let make constr arg =
-    Dune_lang.List [
-      Dune_lang.atom constr
-    ; Dune_lang.atom_or_quoted_string arg
-    ]
-  in
-  match p with
-  | In_build_dir p ->
-    make "In_build_dir" (Path.Build.to_string p)
-  | In_source_tree p ->
-    make "In_source_tree" (Path.Source.to_string p)
-  | External p ->
-    make "External" (Path.External.to_string p)
-
-let decode =
-  let open Dune_lang.Decoder in
-  let external_ =
-    plain_string (fun ~loc t ->
-      if Filename.is_relative t then
-        Dune_lang.Decoder.of_sexp_errorf loc "Absolute path expected"
-      else
-        Path.parse_string_exn ~loc t
-    )
-  in
-  sum
-    [ "In_build_dir"  , string    >>| Path.(relative build_dir)
-    ; "In_source_tree", string    >>| Path.(relative root)
-    ; "External"      , external_
-    ]
-
-module Local = struct
-  let encode ~dir:from p =
-    let open Dune_lang.Encoder in
-    string (Path.reach ~from p)
-
-  let decode ~dir =
-    let open Dune_lang.Decoder in
-    let+ (error_loc, path) = located string
-    in
-    Path.relative ~error_loc dir path
-end
diff --git a/src/path_dune_lang.mli b/src/path_dune_lang.mli
deleted file mode 100644
index 7a7d4a01768..00000000000
--- a/src/path_dune_lang.mli
+++ /dev/null
@@ -1,9 +0,0 @@
-open Stdune
-
-include Dune_lang.Conv with type t = Path.t
-
-module Local : sig
-  val encode : dir:Path.t -> Path.t Dune_lang.Encoder.t
-
-  val decode : dir:Path.t -> Path.t Dune_lang.Decoder.t
-end
diff --git a/src/process.ml b/src/process.ml
index 08d30727f38..3067aca2965 100644
--- a/src/process.ml
+++ b/src/process.ml
@@ -195,7 +195,7 @@ module Fancy = struct
         | [] -> List.rev targets_acc, String.Set.(to_list (of_list ctxs_acc))
         | path :: rest ->
           let add_ctx ctx acc = if ctx = "default" then acc else ctx :: acc in
-          match Utils.analyse_target path with
+          match Dpath.analyse_target path with
           | Other path ->
             split_paths (Path.Build.to_string path :: targets_acc) ctxs_acc rest
           | Regular (ctx, filename) ->
diff --git a/src/stanza.ml b/src/stanza.ml
index f8f10a74bfd..acae95d2db0 100644
--- a/src/stanza.ml
+++ b/src/stanza.ml
@@ -6,10 +6,12 @@ module Parser = struct
   type nonrec t = string * t list Dune_lang.Decoder.t
 end
 
+let latest_version = (1, 10)
+
 let syntax =
   Syntax.create ~name:"dune" ~desc:"the dune language"
     [ (0, 0) (* Jbuild syntax *)
-    ; (1, 10)
+    ; latest_version
     ]
 
 module File_kind = struct
diff --git a/src/stanza.mli b/src/stanza.mli
index a5afd51ac4d..864e159a912 100644
--- a/src/stanza.mli
+++ b/src/stanza.mli
@@ -4,6 +4,8 @@ open! Stdune
 
 type t = ..
 
+val latest_version : Syntax.Version.t
+
 module Parser : sig
   (** Type of stanza parser.
 
diff --git a/src/super_context.ml b/src/super_context.ml
index f74d9a599bd..ab57831c7d2 100644
--- a/src/super_context.ml
+++ b/src/super_context.ml
@@ -700,7 +700,7 @@ module Action = struct
           "This action has targets in a different directory than the current \
            one, this is not allowed by dune at the moment:\n%s"
           (List.map targets ~f:(fun target ->
-             sprintf "- %s" (Utils.describe_path (Path.build target)))
+             sprintf "- %s" (Dpath.describe_path (Path.build target)))
            |> String.concat ~sep:"\n"));
     let build =
       Build.record_lib_deps (Expander.Resolved_forms.lib_deps forms)
diff --git a/src/utils.ml b/src/utils.ml
index 908eb8b1784..76a6332d560 100644
--- a/src/utils.ml
+++ b/src/utils.ml
@@ -65,73 +65,6 @@ let signal_name =
     | None -> sprintf "%d\n" n
     | Some s -> s
 
-type target_kind =
-  | Regular of string * Path.Source.t
-  | Alias   of string * Path.Source.t
-  | Install of string * Path.Source.t
-  | Other of Path.Build.t
-
-type path_kind =
-  | Source of Path.Source.t
-  | External of Path.External.t
-  | Build of target_kind
-
-let analyse_target (fn as original_fn) : target_kind =
-  match Path.Build.extract_first_component fn with
-  | Some (".aliases", sub) ->
-    (match Path.Local.split_first_component sub with
-     | None -> Other fn
-     | Some (ctx, fn) ->
-       if Path.Local.is_root fn then
-         Other original_fn
-       else
-         let basename =
-           match String.rsplit2 (Path.Local.basename fn) ~on:'-' with
-           | None -> assert false
-           | Some (name, digest) ->
-             assert (String.length digest = 32);
-             name
-         in
-         Alias (ctx,
-                Path.Source.relative
-                  (Path.Source.of_local (Path.Local.parent_exn fn))
-                  basename))
-  | Some ("install", sub) ->
-    (match Path.Local.split_first_component sub with
-     | None -> Other fn
-     | Some (ctx, fn) ->
-       Install (ctx, Path.Source.of_local fn))
-  | Some (ctx, sub) ->
-    Regular (ctx, Path.Source.of_local sub)
-  | None ->
-    Other fn
-
-let analyse_path (fn : Path.t) = match fn with
-  | In_source_tree src -> Source src
-  | External e -> External e
-  | In_build_dir build -> Build (analyse_target build)
-
-let describe_target fn =
-  let ctx_suffix = function
-    | "default" -> ""
-    | ctx -> sprintf " (context %s)" ctx
-  in
-  match analyse_target fn with
-  | Alias (ctx, p) ->
-    sprintf "alias %s%s" (Path.Source.to_string_maybe_quoted p) (ctx_suffix ctx)
-  | Install (ctx, p) ->
-    sprintf "install %s%s" (Path.Source.to_string_maybe_quoted p) (ctx_suffix ctx)
-  | Regular (ctx, fn) ->
-    sprintf "%s%s" (Path.Source.to_string_maybe_quoted fn) (ctx_suffix ctx)
-  | Other fn ->
-    Path.Build.to_string_maybe_quoted fn
-
-let describe_path (p : Path.t) =
-  match p with
-  | External _ | In_source_tree _ ->
-    Path.to_string_maybe_quoted p
-  | In_build_dir p -> describe_target p
-
 let library_object_directory ~dir name =
   Path.Build.relative dir ("." ^ Lib_name.Local.to_string name ^ ".objs")
 
@@ -182,9 +115,10 @@ let install_file ~(package : Package.Name.t) ~findlib_toolchain =
 
 let line_directive ~filename:fn ~line_number =
   let directive =
-    match Filename.extension fn with
-    | ".c" | ".cpp" | ".h" -> "line"
-    | _ -> ""
+    if C.c_cxx_or_header ~fn then
+      "line"
+    else
+      ""
   in
   sprintf "#%s %d %S\n" directive line_number fn
 
diff --git a/src/utils.mli b/src/utils.mli
index 767a0552e95..828ade68a67 100644
--- a/src/utils.mli
+++ b/src/utils.mli
@@ -12,10 +12,6 @@ val bash_exn : needed_to:string -> Path.t
 (** Convert a signal number to a name: INT, TERM, ... *)
 val signal_name : int -> string
 
-(** Nice description of a target *)
-val describe_target : Path.Build.t -> string
-val describe_path : Path.t -> string
-
 (** Return the directory where the object files for the given
     library should be stored. *)
 val library_object_directory
@@ -38,21 +34,6 @@ val executable_object_directory
   -> string
   -> Path.Build.t
 
-type target_kind =
-  | Regular of string (* build context *) * Path.Source.t
-  | Alias   of string (* build context *) * Path.Source.t
-  | Install of string (* build context *) * Path.Source.t
-  | Other of Path.Build.t
-
-type path_kind =
-  | Source of Path.Source.t
-  | External of Path.External.t
-  | Build of target_kind
-
-(** Return the name of an alias from its stamp file *)
-val analyse_target : Path.Build.t -> target_kind
-val analyse_path : Path.t -> path_kind
-
 (** Raise an error about a program not found in the PATH or in the tree *)
 val program_not_found
   :  ?context:string
diff --git a/src/vcs.ml b/src/vcs.ml
index e22081dd567..e9d54440e6c 100644
--- a/src/vcs.ml
+++ b/src/vcs.ml
@@ -48,7 +48,7 @@ module T = struct
   let decode =
     let open Stanza.Decoder in
     record
-      (let+ root = field "root" Path_dune_lang.decode
+      (let+ root = field "root" Dpath.decode
        and+ kind = field "kind" Kind.decode
        in
        { root; kind })