为什么我不能以这种方式在我的[(String,[ProtocolType])]中插入一个(String,[ProtocolConformer])元组?

时间:2015-01-23 20:19:19

标签: ios swift tuples xcode6.1 forced-unwrapping

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

1 个答案:

答案 0 :(得分:0)

只是编译器感到困惑 - 试试这个:

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

由于某种原因,在某些情况下,它无法在传递给函数/方法时检测到元组。并且,正如经常发生的那样,错误消息没有多大帮助。