diff --git a/src/build.ml b/src/build.ml
index d30b712f..7a5ad6e5 100644
--- a/src/build.ml
+++ b/src/build.ml
@@ -26,7 +26,7 @@ module Repr = struct
     | Fanout : ('a, 'b) t * ('a, 'c) t -> ('a, 'b * 'c) t
     | Paths : Path.Set.t -> ('a, 'a) t
     | Paths_for_rule : Path.Set.t -> ('a, 'a) t
-    | Paths_glob : glob_state ref -> ('a, Path.t list) t
+    | Paths_glob : glob_state ref -> ('a, Path.Set.t) t
     (* The reference gets decided in Build_interpret.deps *)
     | If_file_exists : Path.t * ('a, 'b) if_file_exists_state ref -> ('a, 'b) t
     | Contents : Path.t -> ('a, string) t
@@ -55,7 +55,7 @@ module Repr = struct
 
   and glob_state =
     | G_unevaluated of Loc.t * Path.t * Re.re
-    | G_evaluated   of Path.t list
+    | G_evaluated   of Path.Set.t
 
   let get_if_file_exists_exn state =
     match !state with
diff --git a/src/build.mli b/src/build.mli
index bb13b950..0112e6d6 100644
--- a/src/build.mli
+++ b/src/build.mli
@@ -59,7 +59,7 @@ val path_set : Path.Set.t -> ('a, 'a) t
 
 (** Evaluate a glob and record all the matched files as dependencies
     of the action produced by the build arrow. *)
-val paths_glob : loc:Loc.t -> dir:Path.t -> Re.re -> ('a, Path.t list) t
+val paths_glob : loc:Loc.t -> dir:Path.t -> Re.re -> ('a, Path.Set.t) t
 
 (* CR-someday diml: rename to [source_files_recursively_in] *)
 (** Compute the set of source of all files present in the sub-tree
@@ -193,7 +193,7 @@ module Repr : sig
     | Fanout : ('a, 'b) t * ('a, 'c) t -> ('a, 'b * 'c) t
     | Paths : Path.Set.t -> ('a, 'a) t
     | Paths_for_rule : Path.Set.t -> ('a, 'a) t
-    | Paths_glob : glob_state ref -> ('a, Path.t list) t
+    | Paths_glob : glob_state ref -> ('a, Path.Set.t) t
     | If_file_exists : Path.t * ('a, 'b) if_file_exists_state ref -> ('a, 'b) t
     | Contents : Path.t -> ('a, string) t
     | Lines_of : Path.t -> ('a, string list) t
@@ -221,10 +221,10 @@ module Repr : sig
 
   and glob_state =
     | G_unevaluated of Loc.t * Path.t * Re.re
-    | G_evaluated   of Path.t list
+    | G_evaluated   of Path.Set.t
 
   val get_if_file_exists_exn : ('a, 'b) if_file_exists_state ref -> ('a, 'b) t
-  val get_glob_result_exn : glob_state ref -> Path.t list
+  val get_glob_result_exn : glob_state ref -> Path.Set.t
 end
 
 val repr : ('a, 'b) t -> ('a, 'b) Repr.t
diff --git a/src/build_interpret.ml b/src/build_interpret.ml
index 2272c691..a4e7de9f 100644
--- a/src/build_interpret.ml
+++ b/src/build_interpret.ml
@@ -66,7 +66,7 @@ let static_deps t ~all_targets ~file_tree =
     | Paths_glob state -> begin
         match !state with
         | G_evaluated l ->
-          { acc with action_deps = Path.Set.union acc.action_deps (Path.Set.of_list l) }
+          { acc with action_deps = Path.Set.union acc.action_deps l }
         | G_unevaluated (loc, dir, re) ->
           let targets = all_targets ~dir in
           let result =
@@ -87,7 +87,7 @@ let static_deps t ~all_targets ~file_tree =
               (* diml: we should probably warn in this case as well *)
               ()
           end;
-          state := G_evaluated (Path.Set.to_list result);
+          state := G_evaluated result;
           let action_deps = Path.Set.union result acc.action_deps in
           { acc with action_deps }
       end
diff --git a/src/super_context.ml b/src/super_context.ml
index bbc2f7b1..d9ff5648 100644
--- a/src/super_context.ml
+++ b/src/super_context.ml
@@ -484,6 +484,7 @@ module Deps = struct
         | Ok re ->
           let dir = Path.parent_exn path in
           Build.paths_glob ~loc ~dir (Re.compile re)
+          >>^ Path.Set.to_list
         | Error (_pos, msg) ->
           Loc.fail loc "invalid glob: %s" msg
       end