[PATCH 1/2] libstdc++: Use ranges::iter_move in ranges::unique [PR120789]

[Patrick Palka]

Tested on x86_64-pc-linux-gnu, does this look OK for trunk and perhaps
15/14?

-- >8 --

        PR libstdc++/120789

libstdc++-v3/ChangeLog:

        * include/bits/ranges_algo.h (__unique_fn::operator()): Use
        ranges::iter_move(iter) instead of std::move(*iter).
        * testsuite/25_algorithms/unique/120789.cc: New test.
---
 libstdc++-v3/include/bits/ranges_algo.h       |  2 +-
 .../testsuite/25_algorithms/unique/120789.cc  | 36 +++++++++++++++++++
 2 files changed, 37 insertions(+), 1 deletion(-)
 create mode 100644 libstdc++-v3/testsuite/25_algorithms/unique/120789.cc

diff --git a/libstdc++-v3/include/bits/ranges_algo.h 
b/libstdc++-v3/include/bits/ranges_algo.h
index 83eaa7da28b9..3590c501c4cd 100644
--- a/libstdc++-v3/include/bits/ranges_algo.h
+++ b/libstdc++-v3/include/bits/ranges_algo.h
@@ -1454,7 +1454,7 @@ namespace ranges
          if (!std::__invoke(__comp,
                             std::__invoke(__proj, *__dest),
                             std::__invoke(__proj, *__first)))
-           *++__dest = std::move(*__first);
+           *++__dest = ranges::iter_move(__first);
        return {++__dest, __first};
       }
 
diff --git a/libstdc++-v3/testsuite/25_algorithms/unique/120789.cc 
b/libstdc++-v3/testsuite/25_algorithms/unique/120789.cc
new file mode 100644
index 000000000000..24b107132473
--- /dev/null
+++ b/libstdc++-v3/testsuite/25_algorithms/unique/120789.cc
@@ -0,0 +1,36 @@
+// PR libstdc++/120789 - ranges::unique should use ranges::iter_move
+// { dg-do compile { target c++20 } }
+
+#include <algorithm>
+
+struct A
+{
+  bool operator==(const A&) const;
+};
+
+struct B
+{
+  B(B&&) = delete;
+  B& operator=(const A&) const;
+
+  operator A() const;
+  bool operator==(const B&) const;
+};
+
+struct I
+{
+  using value_type = A;
+  using difference_type = int;
+  B operator*() const;
+  I& operator++();
+  I operator++(int);
+  bool operator==(const I&) const;
+  friend A iter_move(const I&);
+};
+
+void
+test01()
+{
+  std::ranges::subrange<I, I> r;
+  auto [begin, end] = std::ranges::unique(r);
+}
-- 
2.50.0.131.gcf6f63ea6b