#![feature(generators)]
#![feature(generator_trait)]

use std::marker::PhantomData;
use std::ops::Generator;

trait Trait: 'static { }

struct Index<T: ?Sized = dyn Trait> {
  id: i32, ty: PhantomData<T>
}

fn new_index() -> Index { Index { id: 10, ty: PhantomData } }

fn with_ctx<F: FnOnce(&mut i32) -> T, T>(f: F) -> T {
  let mut ctx = 123;
  f(&mut ctx)
}

fn accept_gen<G: Generator>(g: G) { }

fn main() {
  accept_gen(static move || {
    let poll = with_ctx(|ctx| new_index());
    yield 20;
  });
}