On 17/08/18 19:01 +0100, Jonathan Wakely wrote:
On 17/08/18 18:52 +0100, Jonathan Wakely wrote:
+ // The tag parameter ensures that in nested tuples each __tuple_base
+ // is a different type and can use the empty base-class optimisation.
+ template<typename _Tag>
+ class __tuple_base
Specifically, this would fail if __tuple_base was not a class
template:
static_assert(sizeof(tuple<tuple<int>>) == sizeof(int), "");
And also:
struct empty {};
static_assert(sizeof(tuple<tuple<empty>, tuple<empty>>) == 2, "");
In fact, it's just occurred to me that we don't really need the
__tuple_base class template at all. We can make _Tuple_impl
non-assignable (adding _M_assign members for the required
functionality). Then we don't need an extra base class.
