1#define NS_DESIGNATED_INITIALIZER __attribute__((objc_designated_initializer))
2
3@class NSString;
4
5@interface B1
6-(instancetype)init;
7@end
8
9@interface S1 : B1
10@property (nonatomic) int prop;
11+(instancetype)s1;
12-(instancetype)initWithFoo:(NSString*)foo NS_DESIGNATED_INITIALIZER;
13@end
14