diff --git a/lib/index.js b/lib/index.js
index 4278110..d0f4c05 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -58,7 +58,7 @@ var _assign = function(target, source) {
         //}
 
       } else { // unknown type....
-        throw new Error('Assignment error');
+        throw new Error('Assignment error: source: \''+JSON.stringify(s)+', typeof source: \''+(typeof source)+'\'');
       }
     }
   }