Yeah, Rust does that as well. The issue the author is talking about here is that when you write a closure:

    fn foo(inputs: &[Input]) -> Result<Vec<Output>, Error> {
        inputs
        .iter()
        .map(|input| { input.something_fallible()? })
        .collect()
    }

that ? is an early return from the closure, not foo. The correct way to do this is:

    fn foo(inputs: &[Input]) -> Result<Vec<Output>, Error> {
        inputs
        .iter()
        .map(|input| { input.something_fallible() })
        .collect::<Result<Vec<Output>, Error>>()
    }

ref: https://play.rust-lang.org/?version=stable&mode=debug&editio...