fn first_some() -> Result<Option<()>, ()> {
    if let Some(x) = foo()? {
        return Ok(Some(x))
    }
    if let Some(x) = bar()? {
        return Ok(Some(x))
    }
    if let Some(x) = baz()? {
        return Ok(Some(x))
    }
    Ok(None)
}

fn foo() -> Result<Option<()>, ()> {
    unimplemented!()
}

fn bar() -> Result<Option<()>, ()> {
    unimplemented!()
}

fn baz() -> Result<Option<()>, ()> {
    unimplemented!()
}

fn main() {
    let _ = first_some();
}