?-operator
https://github.com/rust-lang/rfcs/blob/master/text/0243-trait-based-exception-handling.md

unwrap, expect
https://www.reddit.com/r/rust/comments/5rbage/the_practicability_of_unwrap_function/

samples:
https://www.reddit.com/r/rust/comments/5s7uu1/trivialities_about_early_returning_an_option/

/// Like try, but for iterators that return `Option<Result<_, _>>`.
macro_rules! itry {
    ($e:expr) => {
        match $e {
            Ok(v) => v,
            Err(err) => return Some(Err(From::from(err))),
        }
    }
}

try_opt!, option_try!, otry!
unwrap_or_return! (mac-crate)
https://doc.rust-lang.org/std/ops/trait.Carrier.html

2020
https://www.reddit.com/r/rust/comments/jdvtu4/javas_error_handling_system_is_better_than_that/
2018
https://www.reddit.com/r/rust/comments/8lt8k6/do_i_really_need_failureerrorchain/