// Mistake: callback function missing &mut Ctx first param.
// Fix: add &mut MyCtx as the first parameter.
use nexus_rt::{IntoCallback, Res, Resource, WorldBuilder};
struct MyCtx;
#[derive(Resource)]
struct Config;
// Missing &mut MyCtx — should be fn(&mut MyCtx, Res<Config>, u32)
fn bad_callback(_config: Res<Config>, _event: u32) {
}
fn main() {
let mut wb = WorldBuilder::new();
wb.register(Config);
let world = wb.build();
let reg = world.registry();
let _cb = bad_callback.into_callback(MyCtx, ®);
}