[Bug c++/35722] [C++0x] Variadic templates expansion into non-variadic class template

["jack dot q dot word at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

------- Comment #11 from jack dot q dot word at gmail dot com  2009-08-13 05:14 -------
(From update of attachment 18348)
template< class cT, class... vT >
struct VarTypeNav
{
        typedef cT T;
        typedef VarTypeNav< vT..., void > Next;
        struct scT { cT v; };
        static const size_t Size =
                sizeof(scT) + Next::Size;
        static const size_t Count =
                1 + Next::Count;
};

template< class... vT >
struct VarTypeNav< void, vT... >
{
        typedef void T; 
        typedef void Next;
        static const size_t Size = 0;
        static const size_t Count = 0;
};

template< const size_t nIndex, class cT, class... vT >
struct VarTypeSelect
{
        typedef VarTypeSelect< nIndex-1, vT... >::T T;
        struct scT { T v; };
        static const size_t Offset =
                sizeof(scT) + VarTypeSelect< nIndex-1, vT... >::Offset;
};

template< class cT, class... vT >
struct VarTypeSelect< 0, cT, vT... >
{
        typedef cT T;
        static const size_t Offset = 0;
};

template< class cT, class... vT >
struct Tuple
{
        char Data[VarTypeNav<cT,vT...>::Size];
        template< const size_t index >
        VarTypeSelect< index, vT... >::T & operator [] ( const size_t index )
        {
                static_assert(!(index > VarTypeNav< vT... >::Count ), "Index
out of bounds");
                char * pThisChars = (char *) this;
                return *(
                        (VarTypeSelect< index, vT... >::T *)
                                pThisChars[ VarTypeSelect< index, vT...
>::Offset ]));
        }
        template< const size_t index >
        const VarTypeSelect< index, vT... >::T & operator [] ( const size_t
index ) const
        {
                static_assert(!(index > VarTypeNav< vT... >::Count ), "Index
out of bounds");
                const char * pThisChars = (const char *) this;
                return *(
                        (const VarTypeSelect< index, vT... >::T *)
                                pThisChars[ VarTypeSelect< index, vT...
>::Offset ]));
        }
};

int main() {
        Tuple< size_t, char * > x; /* = { 32, new char[32] }; *//* ? */
        x[0] = 32;
        x[1] = new char[32];
        x[1][31] = 0;
        return (int) &x[1][0] != 0;
}


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35722