Could not instantiate class named IBNSLayoutConstraint

Question

I\'m using XCode6 beta and trying out Swift. When I put some auto layout constraints in a view controller the app crashes with the following error: Terminating app

Answer 1

What ended up happening to me was that I cut a subview inside of Interface Builder to copy it into another xib. This left the subview in original xib Interface builder with it being greyed out. After removing the subview from it's original place (by selecting and deleting). I was able to get rid of the error.