diff --git a/overlay.nix b/overlay.nix
index 25edd66..d50ed18 100644
--- a/overlay.nix
+++ b/overlay.nix
@@ -1,10 +1,10 @@
 final: /* Future last stage */
 prev:  /* Previous stage */
 
-with final.lib;
-
 let
-  callPackage = final.callPackage;
+  inherit (prev.lib) collect isDerivation mapAttrs;
+
+  inherit (final) callPackage;
 
   mkDeps = name: pkgs: final.runCommand name { }
     "printf '%s\n' ${toString (collect (x: x ? outPath) pkgs)} > $out";