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The NSString's constructor 'initWithFormat:arguments:' produces a crash on x86_64 archs.
The crash is reproducible on iOS simulator (iOS 9.0, iPhone 6 Plus, simulator 13A344) running on OS X El Capitan 10.11.5 (15F34).

The case is to have a method which produces a string from a given format and a list of arguments represented by NSArray. The idea is to convert the NSArray object to va_list and use the 'initWithFormat:arguments:' method. This works well on iOS devices, however it crashes on OS X. 

Here are some code snippets that produce crash:
1.
[...]
NSMutableData *data = [NSMutableData dataWithLength:(sizeof(id) * args.count)];
[args getObjects:(__unsafe_unretained id *)data.mutableBytes range:NSMakeRange(0, args.count)];
NSString *result = [[NSString alloc] initWithFormat:dictionary[@"message"] arguments:data.mutableBytes]; // <--------- Produces a crash
[...]

2.
[...]
    void *argList = malloc(sizeof(NSString *) * [arguments count]);
    [arguments getObjects:( __unsafe_unretained id *)argList];
   NSString *result =  = [[NSString alloc] initWithFormat:formatString arguments:argList]; // <--------- Produces a crash
[...]