protocol PureEnumProtocol {
    func test()
}

enum PureEnum: PureEnumProtocol {

    static var v = 1    // Still possible
    //var v = 1         // Enums must not contain stored properties
    func test() {
        //v = 2         // Impossible
        print("PureTest", PureEnum.v)
    }

    // Redundant stub initializer is needed
    case pure
    init() {
        self = .pure
    }
}

let pureEnum: PureEnumProtocol = PureEnum()
pureEnum.test()