I am trying to set up a simple core data app. But after I create the NSManagedObject subclasses from the Editor menu I get numerous errors that I do not understand.<unknown>:0: error: filename "Fields2+CoreDataClass.swift" used twice: '/Current Projects/Stages/Stages/CoreData/Fields2+CoreDataClass.swift' and '/Users/me/Library/Developer/Xcode/DerivedData/Stages-bvmokbzazpxlmwaxrpiatcooijvt/Build/Intermediates.noindex/Stages.build/Debug-iphoneos/Stages.build/DerivedSources/CoreDataGenerated/Stages/Fields2+CoreDataClass.swift'<unknown>:0: note: filenames are used to distinguish private declarations with the same nameCommand /Applications/Xcode-beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swiftc failed with exit code 1In the extension for Fields2 I get'Fields2' is ambiguous for type lookup in this contextthen I get@NSManaged only allowed on an instance property or method for all of the properties in Fields2Is this a bug? Or am I doing something wrong? What is going on and how do I fix it?