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

1 files changed, 3 insertions, 0 deletions

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 *> >();
 }