[Bug c++/63437] [4.9/5 regression][C++14] Parenthesized "movable but not copyable" object doesn't compile in return statement

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63437

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
in C++14 (a) means the same as static_cast<typeof(a) &>(a).

So it is a reference at this point which means const & is better than &&.

Or at least that is how I understand this.  Does clang implement the C++11 ()
rule correctly?