Code shared from the Rust Playground

playground.rs

pub struct Foo;

fn main() {
    let f = Foo;
    let x = f.quux::<{
        impl Foo {
            pub fn quux<const N: usize>(&self) -> usize {
                N
            }
        }
        10
    }>();
    assert_eq!(x, 10);
}

#[allow(dead_code)]
fn recheck() {
    let f = Foo;
    assert_eq!(f.quux::<10>(), 10);
}