XCode 7 beta 2 String不可转换为StringLiteralConvertible

Question

我正在做一个游乐场来检查swift 2.0，这种情况发生了：

我不知道我是否遗失了什么，或者这是正常还是什么？谢谢。 在swift 1.2中正如预期的那样工作XCode 6.3。 编辑：代码

//: Playground - noun: a place where people can play


import Foundation

var str = "Hello, playground"

let languageType: String = "Swift"

var version = 1.0 //infered
let introduced = 2014 //infered
let isAwesome = true //infered
let π = 3.1415927
let  = "dogcow"

let someString = "I appear to be a string"

let pathComponent = "~/Documents/Swift".pathComponents

var s = String("bla vla nla")

for character in "catDog" {

    print(character)
}

Answer 1

String for String在Swift 2中已经改变，为了完成你想要做的事情，你会改用for character in "catDog".characters {...}

一个很好的参考是Nate Cook的swiftdoc.org