In a swift static var extension, how to or can you access and return the concrete class?

Question

Consider

extension UIView {
    
    static var Trick: UIIView {
        let v = UIView()
        v.backgroundColor = .yellow
        return v
    }
}

hence addSubview(UIView.Trick) and so on.

However

private lazy var yellowLabel: UILabel = {
    let v = UILabel.Typical
    v.font = U.systemFont(ofSize: 200)
    return v
}()

of course is wrong. Is there a way to ......

extension V where V is one of the UIView types {
    
    static var Trick: V {
        let v = " V "()
        v.backgroundColor = .yellow
        return v
    }
}

Is there a way?

Answer 1

The type of the computed property in a class extension can be Self to specify the concrete type on which the property is called. Also Self() creates an instance of that concrete type:

extension UIView {
    static var Trick: Self {
        let v = Self()
        v.backgroundColor = .yellow
        return v
    }
}

Now

private lazy var yellowLabel: UILabel = {
    let v = UILabel.Trick // <-- Type of `v` is UILabel
    v.font = .systemFont(ofSize: 200)
    return v
}()

compiles and works as expected.