> I was hoping someone could prove this, actually.
Maybe this presentation by Jason Turner from CppCon 2016 can illustrate just what can be done in C++17. His target in the presentation is a C64, but I think it illustrates well just what you can do with the language, and hence what tools are available for writing fast code.
Go has boxing?
> Because C++17 code if written well is likely to be much faster.
I was hoping someone could prove this, actually. I don't have the means or the knowledge.