type Range = std::ops::Range<usize>;

fn demo(r: &Range) {
    println!("{:?}", r);
}

fn tell(x: usize) -> usize {
    x
}

fn main() {
    demo(tell(1)..tell(10));
    //~^ ERROR mismatched types
    demo(1..10);
    //~^ ERROR mismatched types
}