@@ -27,10 +27,11 @@
 @interface OFUndefinedKeyException: OFException
 {
 	id _object;
 	OFString *_Nullable _key;
 	id _Nullable _value;
+	OF_RESERVE_IVARS(OFUndefinedKeyException, 4)
 }
 
 /**
  * @brief The object on which the key is undefined.
  */