[PATCH 1/3] libstdc++: Fix elements_view::operator* and operator[] [LWG 3502]

[Jonathan Wakely]

On 29/03/21 14:49 -0400, Patrick Palka via Libstdc++ wrote:
>While we're modifying elements_view, this also implements the one-line
>resolution of LWG 3492.
>
>libstdc++-v3/ChangeLog:
>
>	* include/std/ranges (__detail::__returnable_element): New
>	concept.
>	(elements_view): Use this concept in its constraints.  Add
>	missing private access specifier.
>	(elements_view::_S_get_element): Define as per LWG 3502.
>	(elements_view::operator*, elements_view::operator[]): Use
>	_S_get_element.
>	(elements_view::operator++): Remove unnecessary constraint
>	as per LWG 3492.
>	* testsuite/std/ranges/adaptors/elements.cc (test05): New test.

OK, thanks.