[Bug libstdc++/55993] tuple_cat not a constant expression for result size >= 3

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55993



--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> 2013-01-15 
17:28:42 UTC ---

#include <tuple>

struct A {};

constexpr auto t = std::make_tuple( A(), A() );

constexpr auto a = std::get<0>( t );



t.cc:4:35: error: accessing value of 't' through a 'const A' glvalue in a

constant expression

 constexpr auto a = std::get<0>( t );

                                   ^



Huh?