Code shared from the Rust Playground

playground.rs

#![feature(generators, generator_trait)]

use std::ops::Generator;
use std::mem::size_of;

fn test() -> impl Generator<Yield=(), Return=()> {
    return || {
        yield ();
    }
}

fn consume<F, O>(f: F)
    where F: Fn() -> O
{
    println!("{}", size_of::<O>());
}

fn main() {
    consume(test);
}