I tried Nankea's solution, but it doesn't work for SwiftUI's View: public protocol ViewExtension: View { } extension View: ViewExtension { } // I don't know why this doesn't have to be public! public extension ViewExtension {     /// Places an alphabetical index next to the view.     /// - Parameter style: A style to apply to the index.     /// - Returns: The view with the added index.     public func alphabeticalIndex(style: AlphabeticalIndexStyle = AlphabeticalIndexStyle.default) -> some View {         self.modifier(AlphabeticalIndex(style: style))     } } I get "Extension of protocol 'View' cannot have an inheritance clause" on the second line. This REALLY needs to be fixed!

Answer: https://stackoverflow.com/questions/71027541/how-to-define-a-generic-swiftui-view-that-can-accept-sectioned-fetch-results-for

It seems that the symbol in question is some kind of custom symbol. Not going to use it.

SwiftData is not ready for prime time until this gets addressed!