Unsigned math is evil (C/Objective-C)

gistfile1.txt

const NSUInteger test = 10u - 20u;
const NSInteger test2 = 10u - 20u;
const NSInteger test2_U = (NSUInteger)10 - (NSUInteger)20;
const NSUInteger test3 = 10 - 20;
const NSInteger test4 = 10 - 20;
const NSInteger test5 = 10u - 20;
    
64bit:
test	NSUInteger	4294967286
test2	NSInteger	4294967286
test2_U	NSInteger	-10
test3	NSUInteger	18446744073709551606
test4	NSInteger	-10
test5	NSInteger	4294967286

32bit:
test	NSUInteger	4294967286
test2	NSInteger	-10
test2_U	NSInteger	-10
test3	NSUInteger	4294967286
test4	NSInteger	-10
test5	NSInteger	-10