[Bug c++/60955] Erroneous warning about taking address of register with std=c++1y

[harald at gigawatt dot nl]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60955

Harald van Dijk <harald at gigawatt dot nl> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |harald at gigawatt dot nl

--- Comment #2 from Harald van Dijk <harald at gigawatt dot nl> ---
This is caused by the implementation of C++1y decltype(auto), where seemingly
redundant parentheses around an identifier must not simply be removed, because
they may be significant.

int a;
decltype(auto) b = a; // means int b = a;
decltype(auto) c = (a); // means int &c = a;

GCC implements this by transforming (a) into static_cast<int &>(a)
(force_paren_expr in gcc/cp/semantics.c), which would normally be a no-op, but
causes the warning when a is declared using the "register" keyword.