diff --git a/bin/main.ml b/bin/main.ml
index d6c16d2a..318f1046 100644
--- a/bin/main.ml
+++ b/bin/main.ml
@@ -528,9 +528,11 @@ let resolve_package_install setup pkg =
   match Main.package_install_file setup pkg with
   | Ok path -> path
   | Error () ->
-    die "Unknown package %s!%s" (pkg :> string)
-      (hint (pkg :> string)
-         ((Package.Name.Map.keys setup.packages) :> string list))
+    let pkg = Package.Name.to_string pkg in
+    die "Unknown package %s!%s" pkg
+      (hint pkg
+         (Package.Name.Map.keys setup.packages
+         |> List.map ~f:Package.Name.to_string))
 
 let target_hint (setup : Main.setup) path =
   assert (Path.is_local path);
diff --git a/src/install.ml b/src/install.ml
index b95739c8..8f213595 100644
--- a/src/install.ml
+++ b/src/install.ml
@@ -63,7 +63,7 @@ module Section = struct
   end
 
   let install_dir t ~(package : Package.Name.t) =
-    let package = (package :> string) in
+    let package = Package.Name.to_string package in
     match t with
     | Bin        -> Paths.bin
     | Sbin       -> Paths.sbin
diff --git a/src/install_rules.ml b/src/install_rules.ml
index 4d6e104b..75b813f4 100644
--- a/src/install_rules.ml
+++ b/src/install_rules.ml
@@ -57,7 +57,7 @@ module Gen(P : Install_params) = struct
     |> Package.Name.Map.iter ~f:(fun ((pkg : Package.t), libs) ->
       let path = Path.append ctx.build_dir pkg.path in
       SC.on_load_dir sctx ~dir:path ~f:(fun () ->
-        let meta_fn = "META." ^ (pkg.name :> string) in
+        let meta_fn = "META." ^ (Package.Name.to_string pkg.name) in
 
         let meta_template = Path.relative path (meta_fn ^ ".template"     ) in
         let meta          = Path.relative path  meta_fn                     in
@@ -79,7 +79,7 @@ module Gen(P : Install_params) = struct
                     ~else_:(loop rest)
               in
               loop
-                [ (pkg.name :> string) ^ ".version"
+                [ (Package.Name.to_string pkg.name) ^ ".version"
                 ; "version"
                 ; "VERSION"
                 ]
@@ -95,7 +95,7 @@ module Gen(P : Install_params) = struct
         let meta_contents =
           version >>^ fun version ->
           Gen_meta.gen
-            ~package:(pkg.name :> string)
+            ~package:(Package.Name.to_string pkg.name)
             ~version
             libs
         in
@@ -233,7 +233,7 @@ module Gen(P : Install_params) = struct
       Install.Entry.make Lib opam ~dst:"opam" :: entries
     in
     let entries =
-      let meta_fn = "META." ^ (package :> string) in
+      let meta_fn = "META." ^ (Package.Name.to_string package) in
       let meta = Path.append ctx.build_dir (Path.relative package_path meta_fn) in
       Install.Entry.make Lib meta ~dst:"META" :: entries
     in
diff --git a/src/jbuild.ml b/src/jbuild.ml
index 5e3c8e8c..4d13b680 100644
--- a/src/jbuild.ml
+++ b/src/jbuild.ml
@@ -109,7 +109,7 @@ module Scope_info = struct
       in
       let root = pkg.path in
       List.iter rest ~f:(fun pkg -> assert (pkg.Package.path = root));
-      { name = Some (name :> string)
+      { name = Some (Package.Name.to_string name)
       ; packages =
           Package.Name.Map.of_list_exn (List.map pkgs ~f:(fun pkg ->
             pkg.Package.name, pkg))
@@ -118,11 +118,13 @@ module Scope_info = struct
 
   let package_listing packages =
     let longest_pkg =
-      String.longest_map packages ~f:(fun p -> (p.Package.name :> string))
+      String.longest_map packages ~f:(fun p ->
+        Package.Name.to_string p.Package.name)
     in
     String.concat ~sep:"\n"
       (List.map packages ~f:(fun pkg ->
-         sprintf "- %-*s (because of %s)" longest_pkg (pkg.Package.name :> string)
+         sprintf "- %-*s (because of %s)" longest_pkg
+           (Package.Name.to_string pkg.Package.name)
            (Path.to_string (Package.opam_file pkg))))
 
   let default t =
@@ -149,22 +151,24 @@ module Scope_info = struct
     | Some pkg ->
       Ok pkg
     | None ->
+      let name_s = Package.Name.to_string name in
       if Package.Name.Map.is_empty t.packages then
         Error (sprintf
                  "You cannot declare items to be installed without \
                   adding a <package>.opam file at the root of your project.\n\
                   To declare elements to be installed as part of package %S, \
                   add a %S file at the root of your project."
-                 (name :> string) (Package.Name.opam_fn name))
+                 name_s (Package.Name.opam_fn name))
       else
         Error (sprintf
                  "The current scope doesn't define package %S.\n\
                   The only packages for which you can declare \
                   elements to be installed in this directory are:\n\
                   %s%s"
-                 (name :> string)
+                 name_s
                  (package_listing (Package.Name.Map.values t.packages))
-                 (hint (name :> string) (Package.Name.Map.keys t.packages :> string list)))
+                 (hint name_s (Package.Name.Map.keys t.packages
+                              |> List.map ~f:Package.Name.to_string)))
 
   let package t sexp =
     match resolve t (Package.Name.of_string (string sexp)) with
diff --git a/src/jbuild_load.ml b/src/jbuild_load.ml
index a520d2a1..74dd2c8b 100644
--- a/src/jbuild_load.ml
+++ b/src/jbuild_load.ml
@@ -201,7 +201,7 @@ let load ?extra_ignored_subtrees ?(ignore_promoted_rules=false) () =
       | [pkg] -> pkg
       | _ ->
         die "Too many opam files for package %S:\n%s"
-          (name :> string)
+          (Package.Name.to_string name)
           (String.concat ~sep:"\n"
              (List.map pkgs ~f:(fun pkg ->
                 sprintf "- %s" (Path.to_string (Package.opam_file pkg))))))
diff --git a/src/main.ml b/src/main.ml
index 0f163010..6e550dc8 100644
--- a/src/main.ml
+++ b/src/main.ml
@@ -31,11 +31,13 @@ let setup ?(log=Log.no_log)
   Option.iter only_packages ~f:(fun set ->
     Package.Name.Set.iter set ~f:(fun pkg ->
       if not (Package.Name.Map.mem conf.packages pkg) then
+        let pkg_name = Package.Name.to_string pkg in
         die "@{<error>Error@}: I don't know about package %s \
              (passed through --only-packages/--release)%s"
-          (pkg :> string)
-          (hint (pkg :> string)
-             (Package.Name.Map.keys conf.packages :> string list))));
+          pkg_name
+          (hint pkg_name
+             (Package.Name.Map.keys conf.packages
+             |> List.map ~f:Package.Name.to_string))));
   let workspace =
     match workspace with
     | Some w -> w
@@ -96,7 +98,7 @@ let external_lib_deps ?log ~packages () =
        List.map packages ~f:(fun pkg ->
          match package_install_file setup pkg with
          | Ok path -> path
-         | Error () -> die "Unknown package %S" (pkg :> string))
+         | Error () -> die "Unknown package %S" (Package.Name.to_string pkg))
      in
      match String_map.find setup.stanzas "default" with
      | None -> die "You need to set a default context to use external-lib-deps"
diff --git a/src/package.ml b/src/package.ml
index 66eb5a7e..a2980349 100644
--- a/src/package.ml
+++ b/src/package.ml
@@ -1,15 +1,12 @@
 
 module Name = struct
-  type t = string
+  include Interned.Make()
 
-  let of_string x = x
+  let of_string = make
 
-  let opam_fn t = t ^ ".opam"
+  let opam_fn (t : t) = to_string t ^ ".opam"
 
-  module Map = Import.String_map
-  module Set = Import.String_set
-
-  let pp = Format.pp_print_string
+  let pp fmt t = Format.pp_print_string fmt (to_string t)
 end
 
 
diff --git a/src/package.mli b/src/package.mli
index 3ab3ecd6..6737b100 100644
--- a/src/package.mli
+++ b/src/package.mli
@@ -1,16 +1,15 @@
 (** Information about a package defined in the workspace *)
 
 module Name : sig
-  type t = private string
+  type t
 
   val of_string : string -> t
 
   val opam_fn : t -> string
 
-  module Map : Stdune.Map.S with type key = t
-  module Set : Stdune.Set.S with type elt = t
-
   val pp : Format.formatter -> t -> unit
+
+  include Interned.S with type t := t
 end
 
 type t =
diff --git a/src/super_context.ml b/src/super_context.ml
index a9ea49c9..207badf1 100644
--- a/src/super_context.ml
+++ b/src/super_context.ml
@@ -336,7 +336,7 @@ module Pkg_version = struct
   let spec sctx (p : Package.t) =
     let fn =
       Path.relative (Path.append sctx.context.build_dir p.path)
-        (sprintf "%s.version.sexp" (p.name :> string))
+        (sprintf "%s.version.sexp" (Package.Name.to_string p.name))
     in
     Build.Vspec.T (fn, (module V))
 
diff --git a/src/utils.ml b/src/utils.ml
index 0e9ab80d..801635fe 100644
--- a/src/utils.ml
+++ b/src/utils.ml
@@ -143,7 +143,7 @@ let g () =
     []
 
 let install_file ~(package : Package.Name.t) ~findlib_toolchain =
-  let package = (package :> string) in
+  let package = Package.Name.to_string package in
   match findlib_toolchain with
   | None -> package ^ ".install"
   | Some x -> sprintf "%s-%s.install" package x