US268 23.03.7.4 iter_swap should be callable with rvalue iterators P1878

[wg21bot]

The indirectly_swappable concept is over-constrained: it requires only that iter_swap is callable with lvalue iterators. It should be possible to call iter_swap with rvalues as well.

See discussion at ericniebler/stl2#578.

Proposed change:
Change the concept to require iter_swap to be callable with both lvalue and rvalue iterators.

[JeffGarland]

This is covered by paper http://wg21.link/P1878

[JeffGarland]

Reviewed Monday in LWG small group.

[JeffGarland]

Reviewed P1878 and adopted by large group on Wed in Belfast.

straw polls to adopt for C++20
F N A
13 0 1

[jensmaurer]

Accepted.