[Bug libstdc++/78231] New: Should std::sort use unqualifed iter_swap?

[correaa at llnl dot gov]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78231

            Bug ID: 78231
           Summary: Should std::sort use unqualifed iter_swap?
           Product: gcc
           Version: 6.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: correaa at llnl dot gov
  Target Milestone: ---

Currently `std::sort` uses `std::iter_swap` internally. I think it is more
correct to use an unqualified `iter_swap` (after a `using std::swap_iter`
line).
This way, special iterators can be specialize the way they are value-swapped in
`std::sort` without touching the namespace `std`. (analogous to the case of
`std::swap` vs `swap`).

It sounds that the standard is vague regarding this issue.

See for example, line 1411 in
https://gcc.gnu.org/onlinedocs/libstdc++/libstdc++-html-USERS-4.4/a01347.html

note: this may be related to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=20577