NSMutableArray from NSArray copy

NSArray unrecognized selector exception

#import <Foundation/Foundation.h>

int main(int argc, const char **argv) {
    @autoreleasepool {
        NSMutableArray *mutableArray;
        NSString *str = @"one two three";
        mutableArray = [[str componentsSeparatedByString:@" "] copy];
        [mutableArray addObject:@"four"];
        for (NSString *s in mutableArray) {
            NSLog(@"%@", s);
        }
    }
    return 0;
}

$ clang -o test test.m -framework Foundation
$ ./test
2013-09-02 10:32:08.365 test[10130:707] -[__NSArrayI addObject:]: unrecognized selector sent to instance 0x10b214f70
2013-09-02 10:32:08.368 test[10130:707] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSArrayI addObject:]: unrecognized selector sent to instance 0x10b214f70'
*** First throw call stack:
(
        0   CoreFoundation                      0x00007fff89501f56 __exceptionPreprocess + 198
        1   libobjc.A.dylib                     0x00007fff89684d5e objc_exception_throw + 43
        2   CoreFoundation                      0x00007fff8958e1be -[NSObject doesNotRecognizeSelector:] + 190
        3   CoreFoundation                      0x00007fff894eee23 ___forwarding___ + 371
        4   CoreFoundation                      0x00007fff894eec38 _CF_forwarding_prep_0 + 232
        5   test                                0x000000010b192ca0 main + 192
        6   test                                0x000000010b192bd4 start + 52
)
terminate called throwing an exceptionAbort trap: 6