浅谈swift 4.0中private所发生的变化

class ViewController: UIViewController {
 var test = ""
 private var test1 = ""
 fileprivate var test2 = ""
 override func viewDidLoad() {
  super.viewDidLoad()
  testIt() // 之前会报错 需要修改为fileprivate
 }
 func testForNormal(){ 
 }
 private func testForPrivate(){ 
 }
 fileprivate func testForfileprivate(){  
 }
 override func didReceiveMemoryWarning() {
  super.didReceiveMemoryWarning()
  // Dispose of any resources that can be recreated.
 }
}
extension ViewController {
 private func testIt(){
  testForPrivate() /// swift 4.0 可以访问 之前不行
 }
}
class other {
 let a = ViewController()
 func lalal(){
  _ = a.test /// Normal
  _ = a.test2 /// fileprivate
  a.testForNormal() /// Normal
  a.testForfileprivate() /// fileprivate
  a.testForPrivate() /// 报错 'testForPrivate' is inaccessible due to 'private' protection level
 } 
}