This is still an issue—debug messages are not showing in Console.app, running macOS Sonoma 14.5 and Xcode 16.0 beta 4. Xcode's own Console works fine.

Apple confirmed that capturing group.id is the correct way to do it. They explained that the reason for that is because the predicate requires all captured values to be Codable and Sendable. And since Group is neither, it won't work and requires a local capture. I haven't tested this further, as I am not actively exploring moving to iOS 17 at this point.

I did a bit more experimenting. The problem doesn't seem to be in the optionality of the types per se, as even the following doesn't work: @Model final class Item { var timestamp: Date var group: Group } @Model final class Group { var name: String var items: [Item] } What does work is comparing the objects' IDs: This works: func query(group: Group) { let id = group.id let predicate = #Predicate<Item> { item in item.group?.id == id // Compiles } } However, if the id is not in a local variable, the Predicate macro doesn't compile: func query(group: Group) { let predicate = #Predicate<Item> { item in item.group?.id == group.id // Doesn't compile } }

@newwbee Can you please show your code? I have just tested and neither of those variations (where you put the inverse) work: @Model final class Item { var timestamp: Date @Relationship var group: Group? } @Model final class Group { var name: String @Relationship(inverse: \Item.group) var items: [Item] } @Model final class Item { var timestamp: Date @Relationship(inverse: \Group.items) var group: Group? } @Model final class Group { var name: String @Relationship var items: [Item] }

Still an issue with the final release of iOS 17. Given the following models (initializers omitted for brevity): @Model final class Item { var timestamp: Date var group: Group? } @Model final class Group { var name: String var items: [Item] } This predicate doesn't compile: func query(group: Group) { let predicate = #Predicate<Item> { $0.group == group } } Force-unwrapping doesn't work either: $0.group! == group.

Oh, for crying out loud, Apple! What is this? Another half-baked feature, as if we didn't get enough of these already (SwiftUI, Mac Catalyst, Xcode previews, ...).