[Patch] Implement std::experimental::variant

[Jonathan Wakely]

On 08/06/16 22:12 -0700, Tim Shen wrote:
>I just realized that <type_traits> doesn't define aliases like
>is_same_v, is_default_constructible_v, etc. Are they going to be in
>C++17? Should I add them to <type_traits> as well?

Yes, C++17 adds those to namespace std.

I think Ville was talking about doing some of that work, please
co-ordinate with him so you don't duplicate effort - thanks!