Here are two versions of the expanded macro - the first with @Observable, the second without. As far as I can see the expansions are identical. However the expansion of @Observable adds @ObservationTracked before the query, so that must be the cause of the error. I can find no explanation anywhere in the documentation or searching online. I'm thinking it's a bug.

Try clearing the derived data. Go to Settings, choose the locations tab and open a Finder window showing the Derived data folder. Just delete the folder.

Thanks. You are probably correct, but I can't find any docs to support this. Anyway, I have started using the Query struct. See my later post about this. https://developer.apple.com/forums/thread/751155

Fixed the problem by completely removing Xcode 16 and reinstalling.

I am using Xcode 16.1 beta 2 and have set writingToolsBehavior = .complete, yet the writing tools don't appear on the iPhone 16 pro running iOS 18.1. When is this going to work?

Here is a shot of the compilation build output: This project has been in the works for several years and this issue suddenly appeared. The minimum deployment is IOS 18. I use Xcode 16.1.

Thanks for your answer. There is still a problem if you allow additions to the list as in the post you provided. If you delete all the entries the edit button still displays 'done' when I think it should either be hidden or reset to 'edit'. If you don't tap on 'done' and add a new item then this will be displayed with the delete button visible. I can find no way to reset the edit button and think this is a bug in iOS.

I have triple checked and nowhere does the project set the minimum requirement to IOS 7. The problem is still there with Xcode 16.2 and a minumum IOS level of 18. The error says something called Driver threw the error during the Swift planning phase. What is the Driver?

Can someone from Apple please respond to my last post.