I\'m currently developing an iOS app using swift and Xcode 6 (Beta 3).
Everything went fine so far but now as my project grows, Xcode suddenly began indexing and it
I had this issue with XCode 6.3 when creating a C++ project. Before switching over to developing in SubLime, my last ditch effort was to delete the XCode app and reinstall. It was a long process, but my version of XCode is now updated to 7.3 and everything is working as it should.
So if nothing else seems to be working, you could try deleting XCode from your applications folder and then reinstalling. Just be sure you aren't deleting any project files you want to keep.