diff --git a/lib/trivial.nix b/lib/trivial.nix
index f9952d0..1ba84d5 100644
--- a/lib/trivial.nix
+++ b/lib/trivial.nix
@@ -33,7 +33,7 @@ rec {
        mkRel /home/test/ "file.txt"
        => "/home/test/file.txt"
     */
-  mkRel = path: file: builtins.toString (path + "/${file}");
+  mkRel = path: file: path + "/${file}";
 
   compose = f: g: (x: g (f x));
 }