Code shared from the Rust Playground

playground.rs

#![allow(dead_code)]
#![allow(unused_variables)]

struct IndiciesSource;
struct NoIndicies;

impl From<NoIndicies> for IndiciesSource {
    fn from(_: NoIndicies) -> Self {
        IndiciesSource
    }
}

fn thing(a_thing: IndiciesSource) {
    println!("Read a thing.");
}

#[cfg(test)]
mod test {
    use super::*;
    #[test]
    fn do_thing() {
        let what_a_thing = NoIndicies;
        thing(what_a_thing);
        assert!(true);
    }
}