gistfile1.txt

@class Foo;
@interface Foo2 : NSObject
@property (nonatomic, strong) Foo* foo;
- (void) releaseFoo;
@end

@interface Foo : NSObject
- (void) boo:(void(^)())block foo2:(Foo2*)foo2;
@end

@implementation Foo

- (void) boo:(void(^)())block foo2:(Foo2*)foo2
{
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        [foo2 releaseFoo];
        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
            block(self);
        });
        
    });
}

@end

@implementation Foo2

- (void) boo
{
    self.foo = [[Foo alloc] init];
    NSLog(@"%ld", CFGetRetainCount((__bridge CFTypeRef)(self.foo)));
    
    
    __weak id wfoo = self.foo;
    NSLog(@"%ld", CFGetRetainCount((__bridge CFTypeRef)(self.foo)));
    
    [self.foo boo:^() {
        NSLog(@"%@", wfoo);
        NSLog(@"%ld", CFGetRetainCount((__bridge CFTypeRef)(self.foo)));
        
    } foo2:self];
}

- (void) releaseFoo
{
    NSLog(@"%ld", CFGetRetainCount((__bridge CFTypeRef)(self.foo)));
    self.foo = nil;
}

@end

@interface AppDelegate ()

@end

@implementation AppDelegate


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    Foo2* foo2 = [[Foo2 alloc] init];
    [foo2 boo];
    // Override point for customization after application launch.
    return YES;
}