I was getting a similar problem: Turns out it was some issue involving breakpoints. I deleted them all, erased derived data, clean, restarted Xcode and it worked

Similar problem here, using Xcode 26 beta 4 and a physical device with iOS 16.4 public override func buildMenu(with builder: any UIMenuBuilder) { if #available(iOS 17.0, *) { builder.remove(menu: .autoFill) } super.buildMenu(with: builder) } If i comment the line 3, the error dissapears. So I guess there is a problem with the #available(iOS 17.0, *), maybe it is being ignored or it's deprecated. (this code was working without problems when using Xcode 16.3)