Warning: Converting to Boxing Syntax requires casting 'long' to 'int'

Question

Any idea how to get this warning to go away. The code runs fine, I just don't like warnings in my project. I have never come across this warning before so I am making a mountain out of a mole hill I think. Boxing syntax? Is that referring to the square brackets? This warning shows up when trying to modernize an old project in Objective-C using Xcode.

for (int i = 0; i <= 6; i++) {

   [sequence addObject:[NSNumber numberWithInt:random()% 6]]; 

}

It throws an error stating:

Converting to boxing syntax requires casting 'long' to 'int'

Answer 1

"Boxing" refers to the new syntax for boxing C expressions, e.g.

NSNumber *n = @(2*3+4)

instead of

NSNumber *n = [NSNumber numberWithInt:(2*3+4)];

(see http://clang.llvm.org/docs/ObjectiveCLiterals.html for details).

In your case,

[NSNumber numberWithInt:random()% 6]

creates a number object containing an int, but

@(random()% 6)

would create a number object containing a long, because random() is declared as

long random(void);

So to get exactly the same behavior as before the conversion, you would have to write

[NSNumber numberWithInt:(int)(random()% 6)]

which is then converted to

@((int)(random()% 6))

If you don't care which "flavor" of number object you get, then just convert that line manually to

[sequence addObject:@(random()% 6)];

but Xcode cannot decide that for you.