Xcode 8 Official version has been released，I want the first time my project to the Swift 3 --After all, this is a trend。
During the migration process, I encountered a lot of problems--such as Xcode provides automated migration tool is not working，I've been waiting for more than two hours，after that I give up，I chose to manually migrate--after all,，Xcode's auto-correction is also very good。
however--[……]