AnyGetableAndSavable.swift

protocol AnyGetableAndSavable {
    associatedtype T
    func get() -> T
    func save()
}
class GetAndSaver<U>: AnyGetableAndSavable {
    typealias T = U
    var value: T
    required init(value: T) {
        self.value = value
    }
    func get() -> U {
        return value
    }
    func save() {
        //save
    }
}
class Hoge {
    var getAndSaver: AnyGetableAndSavable = GetAndSaver<Int>(value: 1)
    // protocol 'AnyGetableAndSavable' can only be used as a generic constraint because it has Self or associated type requirements
}