diff --git a/lib/lists.nix b/lib/lists.nix
index 9f2ccc00caf..30d87ece664 100644
--- a/lib/lists.nix
+++ b/lib/lists.nix
@@ -633,8 +633,7 @@ rec {
     else
       let
         x = head list;
-        xs = unique (drop 1 list);
-      in [x] ++ remove x xs;
+      in [x] ++ unique (remove x list);
 
   /* Intersects list 'e' and another list. O(nm) complexity.