Answer is late, but I want to see my answer more people for this situation.
This is not Xcode Problem. Erasing Derived data is just temporary work.
I guess you are included by one of them
- Your application is support Above iOS 7 (not iOS 8)
- Use Cocoapod or 3rd party app
Autocomplete is not working when you develop with swift above iOS7. Swift did't recommend to use static lib, but iOS7 support only static lib not dynamic lib.
(see this post https://blog.cocoapods.org/CocoaPods-0.36/,
http://corinnekrych.blogspot.kr/2015/04/how-well-does-swift-plays-on-ios7.html)
- Change your project to iOS 8
- Cocoapod will need use_frameworks! if you want to support dynamic lib.
If you use dynamic link, You don't have to write header in Bridge_header. Import it in Swift file like Import UIKit
One more trick is just clean your Project will make Swift Auto complete, but after rebuild, you can't use auto complete.