What holds strong reference onto my viewController?

I am removing viewController from controller hierarchy with removeFromParentViewController, but deinit of view controller not get called. How can I check what holds strong reference on it?

Any way to see reference graph exist in memory?

This is how my swap` method looks like:

public class func swap(fromViewController: UIViewController!, toViewController: UIViewController!, containerViewController: UIViewController!) {

    fromViewController.willMoveToParentViewController(nil)
    containerViewController.addChildViewController(toViewController)
    toViewController.view.frame = containerViewController.view.bounds

    containerViewController.transitionFromViewController(fromViewController, toViewController: toViewController, duration: 0.2, options: UIViewAnimationOptions.TransitionCrossDissolve, animations: {}, completion: {finished in
        fromViewController.removeFromParentViewController()
        toViewController.didMoveToParentViewController(containerViewController)
    })
}

In transitionFromViewController completion should I add / remove destination / source views?

Any way to access refCount of a viewController in Swift?

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I tried to analyse code with Instruments. Figure out what hold strong reference to view controller, but couldn't figure out. Any help?

You can use profile the code with Instruments. In Xcode, select Product > Profile. When Instruments loads, select Allocations as the template.

This will allow you to trace which objects are setting what strong references.