ios之不确定如何避免 Swift switch 的默认语句中出现垃圾

Switch 语句在 Swift 中必须是详尽无遗的，所以我必须在我的默认语句中添加一些东西来让编译器满意。

private enum TextFieldType: Int { 
    case street1 = 0 
    case street2 
    case street3 
    case town 
    case postcode 
    case phone 
    case email 
} 
 
@IBAction func textFieldEditingChanged(textField: UITextField, forEvent event: UIEvent) { 
    switch textField.tag { 
    case TextFieldType.street1.rawValue: 
        self.model?.address1 = textField.text 
    case TextFieldType.street2.rawValue: 
        self.model?.address2 = textField.text 
    case TextFieldType.street3.rawValue: 
        self.model?.address3 = textField.text 
    case TextFieldType.town.rawValue: 
        self.model?.town = textField.text 
    case TextFieldType.postcode.rawValue: 
        self.model?.postcode = textField.text 
    case TextFieldType.phone.rawValue: 
        self.model?.primaryPhone = textField.text 
    case TextFieldType.email.rawValue: 
        self.model?.email = textField.text 
    default: 
        println("") 
    } 
} 

在这种情况下(如上)，您将如何处理默认语句？为了它而放置 println("") 是不正确的。