diff --git a/pkgs/lib/default.nix b/pkgs/lib/default.nix
index 2f87de0cd0c..34d1cdda148 100644
--- a/pkgs/lib/default.nix
+++ b/pkgs/lib/default.nix
@@ -456,7 +456,7 @@ rec {
       [({
 	#inherit (attrs) description;
         description = if attrs ? description then attrs.description else 
-          throw ("No description ${toString l}");
+          throw ("No description ${toString l} : ${whatis attrs}");
       }
       //(if attrs ? example then {inherit(attrs) example;} else {} )
       //(if attrs ? default then {inherit(attrs) default;} else {} )