1 files changed, 30 insertions, 0 deletions
diff --git a/libstdc++-v3/testsuite/std/ranges/subrange/lwg3589.cc b/libstdc++-v3/testsuite/std/ranges/subrange/lwg3589.cc
new file mode 100644
index 0000000..1ccc52d
--- /dev/null
+++ b/libstdc++-v3/testsuite/std/ranges/subrange/lwg3589.cc
@@ -0,0 +1,30 @@
+// { dg-do compile { target c++20 } }
+
+// LWG 3589. The const lvalue reference overload of get for subrange does not
+// constrain I to be copyable when N == 0
+
+#include <ranges>
+#include <testsuite_iterators.h>
+
+void
+test_lwg3589()
+{
+  int a[2]{};
+  __gnu_test::test_range<int, __gnu_test::input_iterator_wrapper_nocopy> r(a);
+
+  // Use a generic lambda so we have a dependent context.
+  auto test = [](auto& x)
+    {
+      // This was wrong before the LWG 3589 change:
+      if constexpr (requires { std::ranges::get<0>(x); })
+	(void) std::ranges::get<0>(x);
+
+      // These always worked unconditionally:
+      (void) std::ranges::get<1>(x);
+      (void) std::ranges::get<0>(std::move(x));
+      (void) std::ranges::get<1>(std::move(x));
+    };
+
+  std::ranges::subrange sr(r.begin(), r.end());
+  test(sr);
+}