class Class {}
protocol Protocol {}

enum Enum {
    case value1(Class)
    case value2(Protocol)
}

var value: Class? = Class()
weak var weakValue: Class? = value

func leak(_ e: Enum?) {
    switch (e) {
    case .value2: return
    default: return
    }
}

leak(Enum.value1(value!))

value = nil

assert(weakValue == nil)