2

我在操场上浓缩了我的问题场景:

@objc protocol Prot {}
class Cla : Prot {}

var myArray: [ (aString: String, prot: [Prot] ) ] = []
var myProts: [Prot]? = [Cla()]

// error: type 'T' does not conform to protocol 'IntegerLiteralConvertible'
myArray.append(aString: "myname", prot: myProts!)

// works
myArray.append(aString: "myname", prot: myProts! as [Prot])

// works
if let myProts: [Prot] = myProts {
    myArray.append(aString: "myname", prot: myProts)
}

为什么这里不接受强制解包?

Xcode 6.1.1

4

1 回答 1

0

只是编译器感到困惑 - 试试这个:

let tuple = (aString: "myname", prot: myProts!)
myArray.append(tuple)

出于某种原因,在某些情况下,当传递给函数/方法时,它无法检测到元组。而且,正如经常发生的那样,错误消息并没有多大帮助。

于 2015-01-23T20:38:16.750 回答