libstdc++: Use ranges::iter_move in ranges::unique [PR120789]

	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.

Reviewed-by: Tomasz Kamiński <tkaminsk@redhat.com>
Reviewed-by: Jonathan Wakely <jwakely@redhat.com>

2 files changed, 37 insertions, 1 deletions

diff --git a/libstdc++-v3/include/bits/ranges_algo.h b/libstdc++-v3/include/bits/ranges_algo.h
index 2df730e..7aea5c9 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 0000000..24b1071
--- /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);
+}