let view = UIView()
view.addSubview(UILabel())

//print(view.recursiveDescription)
//↑ error: value of type 'UIView' has no member 'recursiveDescription'

print(view.performSelector("recursiveDescription"))
// Unmanaged<AnyObject>(_value: <UIView: 0x7fff30d1f0f0; frame = (0 0; 0 0); layer = <CALayer: 0x7fff30d0e050>>
//    | <UILabel: 0x7fff32803140; frame = (0 0; 0 0); userInteractionEnabled = NO; layer = <_UILabelLayer: 0x7fff328036a0>>)