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      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 // type_traits
     11 
     12 // void_t
     13 
     14 // UNSUPPORTED: c++98, c++03, c++11, c++14
     15 
     16 // XFAIL: gcc-5.1, gcc-5.2
     17 
     18 #include <type_traits>
     19 
     20 template <class T>
     21 void test1()
     22 {
     23     static_assert( std::is_same<void, std::void_t<T>>::value, "");
     24     static_assert( std::is_same<void, std::void_t<const T>>::value, "");
     25     static_assert( std::is_same<void, std::void_t<volatile T>>::value, "");
     26     static_assert( std::is_same<void, std::void_t<const volatile T>>::value, "");
     27 }
     28 
     29 template <class T, class U>
     30 void test2()
     31 {
     32     static_assert( std::is_same<void, std::void_t<T, U>>::value, "");
     33     static_assert( std::is_same<void, std::void_t<const T, U>>::value, "");
     34     static_assert( std::is_same<void, std::void_t<volatile T, U>>::value, "");
     35     static_assert( std::is_same<void, std::void_t<const volatile T, U>>::value, "");
     36 
     37     static_assert( std::is_same<void, std::void_t<T, const U>>::value, "");
     38     static_assert( std::is_same<void, std::void_t<const T, const U>>::value, "");
     39     static_assert( std::is_same<void, std::void_t<volatile T, const U>>::value, "");
     40     static_assert( std::is_same<void, std::void_t<const volatile T, const U>>::value, "");
     41 }
     42 
     43 class Class
     44 {
     45 public:
     46     ~Class();
     47 };
     48 
     49 int main()
     50 {
     51     static_assert( std::is_same<void, std::void_t<>>::value, "");
     52 
     53     test1<void>();
     54     test1<int>();
     55     test1<double>();
     56     test1<int&>();
     57     test1<Class>();
     58     test1<Class[]>();
     59     test1<Class[5]>();
     60 
     61     test2<void, int>();
     62     test2<double, int>();
     63     test2<int&, int>();
     64     test2<Class&, bool>();
     65     test2<void *, int&>();
     66 
     67     static_assert( std::is_same<void, std::void_t<int, double const &, Class, volatile int[], void>>::value, "");
     68 }
     69