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Issue Description:

I'm seeing a really weird issue where objects get corrupted when using generics on the iOS 9.2/9.3 simulators. I've attached an Xcode project showing the issue. Also I've reproduced the problematic part of the code below:

class MainObject: NSObject {
    let a = BaseView<Double>()
    let b = BaseView<Int>()

    override init() {
        super.init()
        a.label.text = "HELLO" // Crash here on iOS 9 simulator
                               // Change type of b to BaseView<Int>() - doesn't crash
    }
}

class BaseView<T>: UIView {
    private let x = UIPickerView()
    let label: UILabel = UILabel()
    private var value : T?    
}

It looks like the initialisation of 'b' in MainObject is causing 'a' to become corrupted. The crash is:

2017-04-25 13:31:41.687 Test[13321:33688179] -[UIPickerView setText:]: unrecognized selector sent to instance 0x7af38670

It appears that when trying to read the label property we actually end up reading the x property instead. I suspect this is something to do with the difference in the sizing of the specialisation (Int vs Double); if I change both a and b to be of type BaseView<Double>, then problem goes away.

Other observations:

• This only seems to occur in the iOS 9.2/9.3 simulator

• It doesn't crash on an iOS 9.2 device (although this may be chance)

• iOS 10 simulator is fine

• I'm not sure if this is a platform issue or a swift one

• Problem was seen in both Xcode 8.2.1 and Xcode 8.3.2