[<Test 0x1002120d0> setNilValueForKey]: could not set nil as the value for the key primitive.

gistfile1.m

#import <Foundation/Foundation.h>
#import <ReactiveCocoa/ReactiveCocoa.h>

@interface Test : NSObject
@property (nonatomic, strong) Test *object;
@property (nonatomic) NSUInteger primitive;
@end
@implementation Test
@end

@interface Main : NSObject
- (void)main;
@end

@implementation Main

- (void)main {
	Test *source = [[Test alloc] init];
	source.object = [[Test alloc] init];
	Test *destination = [[Test alloc] init];
	destination.object = [[Test alloc] init];

	[RACAble(source, object.primitive) toProperty:@keypath(destination, object.primitive) onObject:destination];
	source.object = nil;
}

@end

int main(int argc, const char * argv[])
{

	@autoreleasepool {
		Main *main = [[Main alloc] init];
		[main main];
	}
	return 0;
}