libcxx/test/std/utilities/meta/meta.unary.prop.query/void_t.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // type_traits
  10
  11 // void_t
  12
  13 // UNSUPPORTED: c++03, c++11, c++14
  14
  15 #include <type_traits>
  16
  17 #include "test_macros.h"
  18
  19 template <class T>
  20 void test1()
  21 {
  22     ASSERT_SAME_TYPE(void, std::void_t<T>);
  23     ASSERT_SAME_TYPE(void, std::void_t<const T>);
  24     ASSERT_SAME_TYPE(void, std::void_t<volatile T>);
  25     ASSERT_SAME_TYPE(void, std::void_t<const volatile T>);
  26 }
  27
  28 template <class T, class U>
  29 void test2()
  30 {
  31     ASSERT_SAME_TYPE(void, std::void_t<T, U>);
  32     ASSERT_SAME_TYPE(void, std::void_t<const T, U>);
  33     ASSERT_SAME_TYPE(void, std::void_t<volatile T, U>);
  34     ASSERT_SAME_TYPE(void, std::void_t<const volatile T, U>);
  35
  36     ASSERT_SAME_TYPE(void, std::void_t<U, T>);
  37     ASSERT_SAME_TYPE(void, std::void_t<U, const T>);
  38     ASSERT_SAME_TYPE(void, std::void_t<U, volatile T>);
  39     ASSERT_SAME_TYPE(void, std::void_t<U, const volatile T>);
  40
  41     ASSERT_SAME_TYPE(void, std::void_t<T, const U>);
  42     ASSERT_SAME_TYPE(void, std::void_t<const T, const U>);
  43     ASSERT_SAME_TYPE(void, std::void_t<volatile T, const U>);
  44     ASSERT_SAME_TYPE(void, std::void_t<const volatile T, const U>);
  45 }
  46
  47 class Class
  48 {
  49 public:
  50     ~Class();
  51 };
  52
  53 int main(int, char**)
  54 {
  55     ASSERT_SAME_TYPE(void, std::void_t<>);
  56
  57     test1<void>();
  58     test1<int>();
  59     test1<double>();
  60     test1<int&>();
  61     test1<Class>();
  62     test1<Class[]>();
  63     test1<Class[5]>();
  64
  65     test2<void, int>();
  66     test2<double, int>();
  67     test2<int&, int>();
  68     test2<Class&, bool>();
  69     test2<void *, int&>();
  70
  71     ASSERT_SAME_TYPE(void, std::void_t<int, double const &, Class, volatile int[], void>);
  72
  73   return 0;
  74 }