Objective-C µframework - trying to imitate Result patter

Result.h

NS_ASSUME_NONNULL_BEGIN

#define ResultSuccess(result) [Result<typeof(result)> succeededWithResult:result]
#define ResultFailure(error) [Result failedWithError:result]

typedef NS_ENUM(NSInteger, ResultType) {
    ResultTypeSuccess,
    ResultTypeFailure
};

@interface Result <__covariant ResultObjectType> : NSObject

@property (nonatomic, assign, readonly) ResultType type;
@property (nonatomic, strong, readonly, nullable) ResultObjectType result;
@property (nonatomic, strong, readonly, nullable) NSError *error;

+ (instancetype)failureWithError:(NSError *)error;
+ (instancetype)successWithResult:(ResultObjectType)result;

@end

NS_ASSUME_NONNULL_END

Result.m

#import Result.h"


@interface Result ()

@property (nonatomic, assign, readwrite) ResultType type;
@property (nonatomic, strong, readwrite, nullable) id result;
@property (nonatomic, strong, readwrite, nullable) NSError *error;


@end


@implementation Result

- (instancetype)initWithType:(ResultType)type result:(id)result error:(NSError *)error {
    self = [super init];
    if (self) {
        self.type = type;
        self.result = result;
        self.error = error;
    }
    return self;
}

#pragma mark - Interface

+ (instancetype)failedWithError:(NSError *)error {
    return [[Result alloc] initWithType:ResultTypeFailure result:nil error:error];
}

+ (instancetype)successWithResult:(id)result {
    return [[Result alloc] initWithType:ResultTypeSuccess result:result error:nil];
}

@end