<
_CheckArgsConstructor<
_Dummy
- >::template __enable_implicit<_Tp...>(),
+ >::template __enable_implicit<_Tp const&...>(),
bool
>::type = false
>
<
_CheckArgsConstructor<
_Dummy
- >::template __enable_explicit<_Tp...>(),
+ >::template __enable_explicit<_Tp const&...>(),
bool
>::type = false
>
<
_CheckArgsConstructor<
_Dummy
- >::template __enable_implicit<_Tp...>(),
+ >::template __enable_implicit<_Tp const&...>(),
bool
>::type = false
>
<
_CheckArgsConstructor<
_Dummy
- >::template __enable_explicit<_Tp...>(),
+ >::template __enable_explicit<_Tp const&...>(),
bool
>::type = false
>
}
};
+// move_only type which triggers the empty base optimization
+struct move_only_ebo {
+ move_only_ebo() = default;
+ move_only_ebo(move_only_ebo&&) = default;
+};
+
+// a move_only type which does not trigger the empty base optimization
+struct move_only_large final {
+ move_only_large() : value(42) {}
+ move_only_large(move_only_large&&) = default;
+ int value;
+};
+
+template <class Elem>
+void test_sfinae() {
+ using Tup = std::tuple<Elem>;
+ using Alloc = std::allocator<void>;
+ using Tag = std::allocator_arg_t;
+ // special members
+ {
+ static_assert(std::is_default_constructible<Tup>::value, "");
+ static_assert(std::is_move_constructible<Tup>::value, "");
+ static_assert(!std::is_copy_constructible<Tup>::value, "");
+ static_assert(!std::is_constructible<Tup, Tup&>::value, "");
+ }
+ // args constructors
+ {
+ static_assert(std::is_constructible<Tup, Elem&&>::value, "");
+ static_assert(!std::is_constructible<Tup, Elem const&>::value, "");
+ static_assert(!std::is_constructible<Tup, Elem&>::value, "");
+ }
+ // uses-allocator special member constructors
+ {
+ static_assert(std::is_constructible<Tup, Tag, Alloc>::value, "");
+ static_assert(std::is_constructible<Tup, Tag, Alloc, Tup&&>::value, "");
+ static_assert(!std::is_constructible<Tup, Tag, Alloc, Tup const&>::value, "");
+ static_assert(!std::is_constructible<Tup, Tag, Alloc, Tup &>::value, "");
+ }
+ // uses-allocator args constructors
+ {
+ static_assert(std::is_constructible<Tup, Tag, Alloc, Elem&&>::value, "");
+ static_assert(!std::is_constructible<Tup, Tag, Alloc, Elem const&>::value, "");
+ static_assert(!std::is_constructible<Tup, Tag, Alloc, Elem &>::value, "");
+ }
+}
+
int main()
{
{
d_t d((ConstructsWithTupleLeaf()));
d_t d2(static_cast<d_t &&>(d));
}
+ {
+ test_sfinae<move_only_ebo>();
+ test_sfinae<move_only_large>();
+ }
}