title: Message sent to dealloc UIViewController with error: EXC_BREAKPOINT (code=EXC_I386_BPT)
body: <p>I have an app that uses a transition file to flip from page to page.  I am using ARC and works just fine on 5.1, but crashes all the time on 4.3 simulator.  Looking at the thread and the extended detail from instruments, it points to 2 lines of code (shown below) with the error: EXC_BREAKPOINT (code=EXC_I386_BPT).  Looks like the UIViewController is being deallocated.  Not sure how to fix this.  Thanks in advance for any help you can offer!</p>
  
  <pre><code>@synthesize containerView = _containerView;
  @synthesize viewController = _viewController;  //ERROR LINE#1
  
  - (id)initWithViewController:(UIViewController *)viewController
  {
      if (self = [super init]) 
      {
        _viewController = viewController;
      }
      return self;
  }
  
  - (void)loadView
  {
      self.wantsFullScreenLayout = YES;
      UIView *view = [[UIView alloc] initWithFrame:[UIScreen mainScreen].applicationFrame];
      view.autoresizingMask = UIViewAutoresizingFlexibleHeight|UIViewAutoresizingFlexibleWidth;
      self.view = view;
  
      _containerView = [[UIView alloc] initWithFrame:view.bounds];
      _containerView.autoresizingMask = UIViewAutoresizingFlexibleWidth|UIViewAutoresizingFlexibleHeight;
      [self.view addSubview:_containerView];
  
      [_containerView addSubview:self.viewController.view];
  }
  
  - (void)transitionToViewController:(UIViewController *)aViewController
                     withOptions:(UIViewAnimationOptions)options
  {    
      aViewController.view.frame = self.containerView.bounds;
  
      [UIView transitionWithView:self.containerView
                        duration:0.65f
                         options:options
                      animations:^{ [self.viewController.view removeFromSuperview];
                          [self.containerView addSubview:aViewController.view];}
                      completion:^(BOOL finished)
     //ERROR LINE#2                 { self.viewController = aViewController;}];
  }
  </code></pre>