libstdc++: ranges::rotate should not use 'auto' with ranges::iter_move [PR121913]

The r16-3835-g7801236069a95c change to use ranges::iter_move should also
have used iter_value_t<_Iter> to ensure we get an object of the value
type, not a proxy reference.

libstdc++-v3/ChangeLog:

	PR libstdc++/121913
	* include/bits/ranges_algo.h (__rotate_fn::operator()): Use
	auto_value_t<_Iter> instead of deduced type.

Reviewed-by: Patrick Palka <ppalka@redhat.com>

diff --git a/libstdc++-v3/include/bits/ranges_algo.h b/libstdc++-v3/include/bits/ranges_algo.h
index ea933be2f604e58e49599cce7b880c3a0e548c1b..4025bba9f2048cc1f7db98d0c6f4467eac2f5c83 100644 (file)
--- a/libstdc++-v3/include/bits/ranges_algo.h
+++ b/libstdc++-v3/include/bits/ranges_algo.h
@@ -1685,7 +1685,7 @@ namespace ranges
                        {
                          auto __mid = ranges::next(__p, __n - 1);
                          auto __end = ranges::next(__mid);
-                         auto __t = ranges::iter_move(__p);
+                         iter_value_t<_Iter> __t(ranges::iter_move(__p));
                          ranges::move(ranges::next(__p), __end, __p);
                          *__mid = std::move(__t);
                          return {std::move(__ret), std::move(__lasti)};
@@ -1713,7 +1713,7 @@ namespace ranges
                        {
                          auto __mid = ranges::next(__p, __n - 1);
                          auto __end = ranges::next(__mid);
-                         auto __t = ranges::iter_move(__mid);
+                         iter_value_t<_Iter> __t(ranges::iter_move(__mid));
                          ranges::move_backward(__p, __mid, __end);
                          *__p = std::move(__t);
                          return {std::move(__ret), std::move(__lasti)};