[ 2022-08-23; Reflector poll ]
Set priority to 3 after reflector poll.
"The constraint should just be move_constructible."
This wording is relative to N4910.
Modify [ranges.syn], header <ranges> synopsis, as indicated:
namespace std::ranges {
[…]
// [range.zip], zip view
template<class Ref>
concept tuple-constructible-reference = see below; // exposition only
template<input_range... Views>
requires (view<Views> && ...) && (sizeof...(Views) > 0) &&
(tuple-constructible-reference<range_reference_t<Views>> && ...)
class zip_view;
[…]
// [range.adjacent], adjacent view
template<forward_range V, size_t N>
requires view<V> && (N > 0) &&
tuple-constructible-reference<range_reference_t<V>>
class adjacent_view;
}
[…]
Modify [range.zip.view] as indicated:
namespace std::ranges {
template<class Ref>
concept tuple-constructible-reference = // exposition only
is_reference_v<Ref> || move_constructible<Ref>;
[…]
template<input_range... Views>
requires (view<Views> && ...) && (sizeof...(Views) > 0) &&
(tuple-constructible-reference<range_reference_t<Views>> && ...)
class zip_view : public view_interface<zip_view<Views...>> {
[…]
};
[…]
}
Modify [range.adjacent.view] as indicated:
namespace std::ranges {
template<forward_range V, size_t N>
requires view<V> && (N > 0) &&
tuple-constructible-reference<range_reference_t<V>>
class adjacent_view : public view_interface<adjacent_view<V, N>> {
[…]
};
[…]
}