i\'ve tested swift on a little iPhone project using Xcode 6 beta 2.
The project uses core data to access 2 entities (User/Contract) in a data model. Inside the IOS Simu
It seems to be a bug for now. As explained on this post: https://devforums.apple.com/message/996259#996259.
The workaround for this bug is to use a NSString instead of passing a String as the entity name:
let myEntity: NSString = "EntityName"
var fetchRequest = NSFetchRequest(entityName: myEntity)