He is saying that you can’t do something like,
let x = Y { 10, 20, 30 };
but you can do
println!("{}{}{}", 10, 20, 30);
But wouldn’t a better comparison be with println!("{a}{b}{c}", ...)?
println!("{a}{b}{c}", ...)
Which you can do, but you have to then write println!("{a}{b}{c}", a=a, b=b, c=c);. You can’t just write println!("{a}{b}{c}", a, b, c);.
println!("{a}{b}{c}", a=a, b=b, c=c);
println!("{a}{b}{c}", a, b, c);
In theory we could allow that, but we don’t today.
