1 // RUN: %clang_cc1 -fsyntax-only %s -std=c++98 -verify
2 // expected-no-diagnostics
3 
4 // This is a test for a hack in Clang that works around an issue with libc++
5 // 3.1's std::move and std::forward implementation. When emulating these
6 // functions in C++98 mode, libc++ 3.1 has a "fake rvalue reference" type, and
7 // std::move will return by value when given an instance of that type.
8 
9 namespace std {
10   struct rv {};
11 
12   template<bool B, typename T> struct enable_if;
13   template<typename T> struct enable_if<true, T> { typedef T type; };
14 
15   template<typename T> typename enable_if<__is_convertible(T, rv), T>::type move(T &);
16   template<typename T> typename enable_if<!__is_convertible(T, rv), T&>::type move(T &);
17 
18   template<typename U, typename T> typename enable_if<__is_convertible(T, rv), U>::type forward(T &);
19   template<typename U, typename T> typename enable_if<!__is_convertible(T, rv), U&>::type forward(T &);
20 }
21 
22 struct A {};
23 void f(A a, std::rv rv) {
24   a = std::move(a);
25   rv = std::move(rv);
26 
27   a = std::forward<A>(a);
28   rv = std::forward<std::rv>(rv);
29 
30   a = std::forward<A&>(a);
31   rv = std::forward<std::rv&>(rv);
32 }
33