RFC: std.sumtype (adding sumtype to Phobos)

[bachmeier]

On Sunday, 22 November 2020 at 13:25:37 UTC, Paul Backus wrote:
> Following the recent 1.0.0 release [1], I have decided to 
> submit sumtype [2] for inclusion in Phobos, D's standard 
> library. The PR can be found here:
>
> https://github.com/dlang/phobos/pull/7702
>
> This thread is for you, the D community, to give your feedback, 
> comments, reviews, and constructive criticism regarding both 
> sumtype itself, and my proposal to include it in D's standard 
> library. Please keep your replies on-topic. If you are unsure 
> what to include in your comments, the Boost reviewer guidelines 
> [3] have some good advice.
>
> THIS IS NOT A VOTING THREAD. IF YOU WISH TO SHOW 
> SUPPORT/OPPOSIION, GIVE THE PR A "THUMBS UP" OR "THUMBS DOWN" 
> ON GITHUB.
>
> [1] 
> https://forum.dlang.org/post/zagxftjoxxzirneavymj@forum.dlang.org
> [2] https://code.dlang.org/packages/sumtype
> [3] https://www.boost.org/community/reviews.html#Comments

The "Basic Usage" examples show functions preceded by "pure @safe 
@nogc nothrow". Is that required? If so, do we want to go down 
the path of adding that kind of verbosity/complexity to Phobos 
libraries? That would be a substantial change from what we have 
now. It would definitely make the language less appealing 
(particularly with two starting with @ and two not).