im running an example from the egui repo, and have had the same problem when making an app of my own. I am fairly new to rust, when I compile the following error is thrown: mismatched types
expected struct Box<(dyn App + 'static)>
found enum Result<Box<MyApp>, _>.

fn main() -> Result<(), eframe::Error> {
    let options = eframe::NativeOptions {
        viewport: egui::ViewportBuilder::default()
            .with_inner_size([640.0, 240.0]) // wide enough for the drag-drop overlay text
            .with_drag_and_drop(true),
        ..Default::default()
    };
    eframe::run_native(
        "Native file dialogs and drag-and-drop files",
        options,
        Box::new(|_cc| Ok(Box::<MyApp>::default().into())),
    )
}

I have looked at the exmaples, and searched through issues, and looked it up.