is duplicated by:

• SR-7939 Spurious Warning when down casting to [String]

relates to:

• SR-4209 Unnecessary message for non-optional to non-optional cast

Issue Description:

I have this code in my view controller:

    var accessoryView : UIView!
    override func viewDidLoad() {
        super.viewDidLoad()
        let arr = UINib(nibName:"AccessoryView", bundle:nil).instantiate(withOwner:nil)
        self.accessoryView = arr[0] as! UIView
    }

This elicits a warning: "Treating a forced downcast to 'UIView' as optional will never produce 'nil'"

Now, I have to cast `arr[0]` down because it arrives as an array of Any. And I have to make `accessoryView` an Optional because I won't have its value until `viewDidLoad`. And I want to make it an implicitly unwrapped Optional because I intend to use it a lot and I don't want a bunch of extra punctuation in my code.

So it seems to me that this warning is too zealous; I'm being "punished" for doing something quite natural and called for by the situation.

I have no objection to changing `as!` to `as?` and silencing the warning. But it seems silly that I should have to, when I know for a fact that this Any is a UIView. Why should I be forced to express doubt about something of which I'm certain.

I also have no objection to wrapping the cast in parentheses to silence the warning.

So I'm not saying that there are no ways out of this warning. It's not a problem; I can silence the warning and move on. I'm just wondering whether the warning should be reconsidered; perhaps, in our zeal to recast IUOs as normal Optionals with special behavior, we may have tightened up the rules a little too far.