1//===----------------------------------------------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is dual licensed under the MIT and the University of Illinois Open
6// Source Licenses. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10// UNSUPPORTED: c++98, c++03, c++11
11// <optional>
12
13// A program that necessitates the instantiation of template optional for a
14// reference type is ill-formed.
15
16#include <experimental/optional>
17
18int main()
19{
20    using std::experimental::optional;
21
22    optional<const int&> opt;
23}
24