[arinlen]

> I mean, have you looked at them?

Last time I looked at Rust's std::Result, it's implemented as a tagged union.

Most of C++'s implementations of a Result data type are implemented as tagged unions as well.

What's your point?

> This isn't a criticism of the team behind this code, it's just what it takes to do this in C++.

The only conceivable argument you can possibly make is argue that Rust might support tagged unions as language primitives, but that would be totally pointless as Result types are relevant for the interfaces and higher level abstraction they provide, not your personal opinion of how hard someone else had to work to implement them.

I've developed Result and Either types in a few languages, including C++, and the only hard thing about C++ is doing the usual homework to handle lvalur/revalue/revalue well.