1 files changed, 60 insertions, 1 deletions
diff --git a/libcxx/test/std/numerics/numeric.ops/inner.product/inner_product_comp.pass.cpp b/libcxx/test/std/numerics/numeric.ops/inner.product/inner_product_comp.pass.cpp
index 3f9ed7ee8951..be325b65ec29 100644
--- a/libcxx/test/std/numerics/numeric.ops/inner.product/inner_product_comp.pass.cpp
+++ b/libcxx/test/std/numerics/numeric.ops/inner.product/inner_product_comp.pass.cpp
@@ -21,11 +21,65 @@
 
 #include <numeric>
 #include <functional>
+#include <string>
 #include <cassert>
 
 #include "test_macros.h"
 #include "test_iterators.h"
 
+#if TEST_STD_VER > 17
+struct do_nothing_op
+{
+    template<class T>
+    T operator()(T a, T)
+    { return a; }
+};
+
+struct rvalue_addable
+{
+    bool correctOperatorUsed = false;
+
+    rvalue_addable operator*(rvalue_addable const&) { return *this; }
+
+    // make sure the predicate is passed an rvalue and an lvalue (so check that the first argument was moved)
+    rvalue_addable operator()(rvalue_addable&& r, rvalue_addable const&) {
+        r.correctOperatorUsed = true;
+        return std::move(r);
+    }
+};
+
+rvalue_addable operator+(rvalue_addable& lhs, rvalue_addable const&)
+{
+    lhs.correctOperatorUsed = false;
+    return lhs;
+}
+
+rvalue_addable operator+(rvalue_addable&& lhs, rvalue_addable const&)
+{
+    lhs.correctOperatorUsed = true;
+    return std::move(lhs);
+}
+
+void
+test_use_move()
+{
+    rvalue_addable arr[100];
+    auto res1 = std::inner_product(arr, arr + 100, arr, rvalue_addable());
+    auto res2 = std::inner_product(arr, arr + 100, arr, rvalue_addable(), /*predicate=*/rvalue_addable(), do_nothing_op());
+
+    assert(res1.correctOperatorUsed);
+    assert(res2.correctOperatorUsed);
+}
+#endif // TEST_STD_VER > 17
+
+void
+test_string()
+{
+    std::string sa[] = {"a", "b", "c"};
+    assert(std::accumulate(sa, sa + 3, std::string()) == "abc");
+    assert(std::accumulate(sa, sa + 3, std::string(), std::plus<std::string>()) == "abc");
+}
+
 template <class Iter1, class Iter2, class T>
 void
 test(Iter1 first1, Iter1 last1, Iter2 first2, T init, T x)
@@ -83,5 +137,10 @@ int main(int, char**)
     test<const int*, random_access_iterator<const int*> >();
     test<const int*, const int*>();
 
-  return 0;
+#if TEST_STD_VER > 17
+    test_use_move();
+#endif // TEST_STD_VER > 17
+    test_string();
+
+    return 0;
 }