Code shared from the Rust Playground

playground.rs

struct Int32(i32);
struct Int64(i64);

pub trait Num {
    fn new() -> Self;
}

impl Num for Int32 {
    fn new() -> Self { Int32(0) }
}

impl Num for Int64 {
    fn new() -> Self { Int64(0) }
}

fn my_function<T: Num>() -> T {
    let my_num = T::new();
    // Do something with my_num
    return my_num;
}

fn main() {
    let i_32 = my_function::<Int32>();
}