[PATCH] libstdc++: LWG 3313 join_view::iterator::operator-- is incorrectly constrained

[Jonathan Wakely]

On 24/02/20 18:26 -0500, Patrick Palka wrote:
>libstdc++-v3/ChangeLog:
>
>	LWG 3313 join_view::_Iterator::operator-- is incorrectly constrained
>	* include/std/ranges (join_view::_Iterator::operator--): Require that
>	range_reference_t<_Base> models common_range.
>	* testsuite/std/ranges/adaptors/lwg3313_neg.cc: New test.

OK.