@@ -268,10 +268,16 @@
 # define OF_DESIGNATED_INITIALIZER \
     __attribute__((__objc_designated_initializer__))
 #else
 # define OF_DESIGNATED_INITIALIZER
 #endif
+
+#if __has_attribute(__objc_boxable__)
+# define OF_BOXABLE __attribute__((__objc_boxable__))
+#else
+# define OF_BOXABLE
+#endif
 
 #if __has_attribute(__swift_name__)
 # define OF_SWIFT_NAME(name) __attribute__((__swift_name__(name)))
 #else
 # define OF_SWIFT_NAME(name)