Initializer for conditional binding must have optional type, not 'UIView'

Hello! I am trying to simply run this project but getting an error "Initializer for conditional binding must have optional type, not 'UIView'" in DismissAnimator.swift on the line of "let containerView = transitionContext.containerView":

func animateTransition(using transitionContext: UIViewControllerContextTransitioning) { guard let fromVC = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.from), let toVC = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.to), let containerView = transitionContext.containerView else { return }

How do I fix that? Thanks!

[TheRyanHickman]

Its a swift 3 issue, I am too, also hopeful for a solution to the issue.

[chenr2]

Maybe move the let containerView = trainsitionContext.containerView line above the guard statement.

And for the PresentMenuAnimator, move the snapshot into the guard statement.

    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
        let containerView = transitionContext.containerView
        guard
            let fromVC = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.from),
            let toVC = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.to),
            let snapshot = fromVC.view.snapshotView(afterScreenUpdates: false)
            else {
                return
        }
        containerView.insertSubview(toVC.view, belowSubview: fromVC.view)

        // replace main view with snapshot
        snapshot.tag = MenuHelper.snapshotNumber
        snapshot.isUserInteractionEnabled = false
        snapshot.layer.shadowOpacity = 0.7
        containerView.insertSubview(snapshot, aboveSubview: toVC.view)
        fromVC.view.isHidden = true

        UIView.animate(
            withDuration: transitionDuration(using: transitionContext),
            animations: {
                snapshot.center.x += UIScreen.main.bounds.width * MenuHelper.menuWidth
            },
            completion: { _ in
                fromVC.view.isHidden = false
                transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
            }
        )
    }

[LgdMagic]

what is MenuHelper?

[chenr2]

MenuHelper is just some file that tries to abstract the transition animation code.