Getting dyld_fatal_error after updating to Xcode 6 beta 4 using swift

Question

I just recently downloaded Xcode 6 beta 4, and my swift project compiles with no errors but before it gets to my code I get a dyld_fatal_error just above start in the call s

Answer 1

Most extremely weird problems like this can be solved with a Clean & Build (or perhaps relaunch Xcode). You might also consider deleting the relevant folders from ~/Library/Developer/Xcode/DerivedData.