Instance variables are unavailable after upgrade to Xcode 7.3

Question

Before I update to Xcode 7.3, all these code are working perfectly fine. It is from library YAJLDocument.h, .m

@interface YAJLDocument : NSObject <YAJLParserDelegate> {

  id root_; // NSArray or NSDictionary
  YAJLParser *parser_;

  // TODO(gabe): This should be __weak
  id<YAJLDocumentDelegate> delegate_;

  __weak NSMutableDictionary *dict_; // weak; if map in progress, points to the current map 
  __weak NSMutableArray *array_; // weak; If array in progress, points the current array
  __weak NSString *key_; // weak; If map in progress, points to current key

  NSMutableArray *stack_;
  NSMutableArray *keyStack_;

  YAJLDecoderCurrentType currentType_;

  YAJLParserStatus parserStatus_;

}

But after I update to Xcode 7.3, I got a lot of error like this. How shall I do?