I would personally rely on match ergonomics[1] and borrow e instead of using ref in the pattern[2]. [1]: https://github.com/rust-lang/rfcs/blob/master/text/200

I would personally rely on match ergonomics[1] and borrow e instead of using ref in the pattern[2]. [1]: https://github.com/rust-lang/rfcs/blob/master/text/2005-match-ergonomics.md https://github.com/rust-lang/rfcs/blob/master/text/2005-matc... [2]: https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=f38ca0d5ab46d44943e8acb086bf633e https://play.rust-lang.org/?version=nightly&mode=debug&editi...