Just starting the journey of swiftui, but I don't understand why this works for the contentview preview and not during runtime. (I'm using the simulator.)

class HostingController: WKHostingController<ContentView> {
    let appState = AppState()
    override var body: ContentView {
        return ContentView().environmentObject(appState) as! ContentView
    }
}

preview works

struct ContentView_Previews: PreviewProvider {
    static let appState = AppState()
    static var previews: some View {
        Group {
            ContentView().environmentObject(appState)
        }
    }
}

The error I receive is "Could not cast value of type AppState to SwiftUI.AnyView." I understand the error, but I thought this was the correct way of setting a environmentObject to the contentView. So did something change in Xcode 12/WatchOS 7? My AppState is a class with ObservableObject protocol.