Mark LWG 2716 as complete - shuffle and sample disallows lvalue URNGs.

Libc++'s implementation of shuffle and sample already support lvalue and rvalue
RNG's. This patch adds tests for both categories and marks the issue as complete.

This patch also contains drive-by change for std::experimental::sample which
improves the diagnostics produced when the correct iterator categories are
not supplied.

llvm-svn: 279947

3 files changed, 13 insertions, 10 deletions

diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle_urng.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle_urng.pass.cpp
index 0c35ed73ee4..512acc392de 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle_urng.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.random.shuffle/random_shuffle_urng.pass.cpp
@@ -29,7 +29,7 @@ int main()
     std::shuffle(ia, ia+sa, g);
     LIBCPP_ASSERT(std::equal(ia, ia+sa, ia1));
     assert(std::is_permutation(ia, ia+sa, ia1));
-    std::shuffle(ia, ia+sa, g);
+    std::shuffle(ia, ia+sa, std::move(g));
     LIBCPP_ASSERT(std::equal(ia, ia+sa, ia2));
     assert(std::is_permutation(ia, ia+sa, ia2));
 }
diff --git a/libcxx/test/std/experimental/algorithms/alg.random.sample/sample.fail.cpp b/libcxx/test/std/experimental/algorithms/alg.random.sample/sample.fail.cpp
index eeb43737932..b27135ac7c0 100644
--- a/libcxx/test/std/experimental/algorithms/alg.random.sample/sample.fail.cpp
+++ b/libcxx/test/std/experimental/algorithms/alg.random.sample/sample.fail.cpp
@@ -32,5 +32,8 @@ template <class PopulationIterator, class SampleIterator> void test() {
 }
 
 int main() {
+  // expected-error@experimental/algorithm:* {{static_assert failed "SampleIterator must meet the requirements of RandomAccessIterator"}}
+  // expected-error@experimental/algorithm:* 2 {{does not provide a subscript operator}}
+  // expected-error@experimental/algorithm:* {{invalid operands}}
   test<input_iterator<int *>, output_iterator<int *> >();
 }
diff --git a/libcxx/test/std/experimental/algorithms/alg.random.sample/sample.pass.cpp b/libcxx/test/std/experimental/algorithms/alg.random.sample/sample.pass.cpp
index 1a9f9b099b2..531731791c5 100644
--- a/libcxx/test/std/experimental/algorithms/alg.random.sample/sample.pass.cpp
+++ b/libcxx/test/std/experimental/algorithms/alg.random.sample/sample.pass.cpp
@@ -46,8 +46,8 @@ template <>
 struct TestExpectations<std::input_iterator_tag>
     : public ReservoirSampleExpectations {};
 
-template <template<class> class PopulationIteratorType, class PopulationItem,
-          template<class> class SampleIteratorType, class SampleItem>
+template <template<class...> class PopulationIteratorType, class PopulationItem,
+          template<class...> class SampleIteratorType, class SampleItem>
 void test() {
   typedef PopulationIteratorType<PopulationItem *> PopulationIterator;
   typedef SampleIteratorType<SampleItem *> SampleIterator;
@@ -68,13 +68,13 @@ void test() {
   assert(std::equal(oa, oa + os, oa1));
   end = std::experimental::sample(PopulationIterator(ia),
                                   PopulationIterator(ia + is),
-                                  SampleIterator(oa), os, g);
+                                  SampleIterator(oa), os, std::move(g));
   assert(end.base() - oa == std::min(os, is));
   assert(std::equal(oa, oa + os, oa2));
 }
 
-template <template<class> class PopulationIteratorType, class PopulationItem,
-          template<class> class SampleIteratorType, class SampleItem>
+template <template<class...> class PopulationIteratorType, class PopulationItem,
+          template<class...> class SampleIteratorType, class SampleItem>
 void test_empty_population() {
   typedef PopulationIteratorType<PopulationItem *> PopulationIterator;
   typedef SampleIteratorType<SampleItem *> SampleIterator;
@@ -88,8 +88,8 @@ void test_empty_population() {
   assert(end.base() == oa);
 }
 
-template <template<class> class PopulationIteratorType, class PopulationItem,
-          template<class> class SampleIteratorType, class SampleItem>
+template <template<class...> class PopulationIteratorType, class PopulationItem,
+          template<class...> class SampleIteratorType, class SampleItem>
 void test_empty_sample() {
   typedef PopulationIteratorType<PopulationItem *> PopulationIterator;
   typedef SampleIteratorType<SampleItem *> SampleIterator;
@@ -103,8 +103,8 @@ void test_empty_sample() {
   assert(end.base() == oa);
 }
 
-template <template<class> class PopulationIteratorType, class PopulationItem,
-          template<class> class SampleIteratorType, class SampleItem>
+template <template<class...> class PopulationIteratorType, class PopulationItem,
+          template<class...> class SampleIteratorType, class SampleItem>
 void test_small_population() {
   // The population size is less than the sample size.
   typedef PopulationIteratorType<PopulationItem *> PopulationIterator;