[Bug libstdc++/66693] [C++17] std::tuple_size fails with const std::array

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66693

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-06-28
          Component|c++                         |libstdc++
     Ever confirmed|0                           |1

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I think we should move those metafunctions out of <tuple> into a common header
that can be used in <tuple>, <utility> and <array>.