Oh!! I remember reading that it was an enum in the docs but my brain didn't think of using a Switch statement like this 🤦🏼‍♂️. Thank you for your response. This answers my question.

Interesting, I thought I was doing something wrong or missing something since I'm more of a newbie developer. I might take time to submit that as feedback if I see this working on iOS 17.

This issue is fixed for me on beta 7 of iOS 17 and Xcode 15.

I'm also having the same issue on Xcode 15 beta 6 on macOS Ventura on an iOS 17 device running beta 6.

Interesting, my enum error is fixed with Xcode 15 Beta 3, you should check if yours is fixed to.

I digged a little more into the error, it looks like when I had an Enum type to the CustomType that I'm trying to use SwiftData doesn't like that? I still don't understand the error though.