@@ -24,11 +24,11 @@
  *
  * @brief An exception indicating that unlocking a lock failed.
  */
 @interface OFUnlockFailedException: OFException
 {
-	id <OFLocking> _lock;
+	id <OFLocking> _Nullable _lock;
 	int _errNo;
 }
 
 /**
  * @brief The lock which could not be unlocked.