@@ -14,12 +14,16 @@
  * file.
  */
 
 #import "OFCountedSet.h"
 
+OF_ASSUME_NONNULL_BEGIN
+
 @class OFMapTable;
 
 @interface OFCountedSet_hashtable: OFCountedSet
 {
 	OFMapTable *_mapTable;
 }
 @end
+
+OF_ASSUME_NONNULL_END