libcxx/test/std/utilities/variant/variant.variant/variant.dtor/dtor.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 // UNSUPPORTED: c++03, c++11, c++14
  10
  11 // <variant>
  12
  13 // template <class ...Types> class variant;
  14
  15 // ~variant();
  16
  17 #include <cassert>
  18 #include <type_traits>
  19 #include <variant>
  20
  21 #include "test_macros.h"
  22
  23 struct NonTDtor {
  24   int* count;
  25   constexpr NonTDtor(int* a, int*) : count(a) {}
  26   TEST_CONSTEXPR_CXX20 ~NonTDtor() { ++*count; }
  27 };
  28 static_assert(!std::is_trivially_destructible<NonTDtor>::value, "");
  29
  30 struct NonTDtor1 {
  31   int* count;
  32   constexpr NonTDtor1(int*, int* b) : count(b) {}
  33   TEST_CONSTEXPR_CXX20 ~NonTDtor1() { ++*count; }
  34 };
  35 static_assert(!std::is_trivially_destructible<NonTDtor1>::value, "");
  36
  37 struct TDtor {
  38   constexpr TDtor() = default;
  39   constexpr TDtor(const TDtor&) {} // non-trivial copy
  40   TEST_CONSTEXPR_CXX20 ~TDtor() = default;
  41 };
  42 static_assert(!std::is_trivially_copy_constructible<TDtor>::value, "");
  43 static_assert(std::is_trivially_destructible<TDtor>::value, "");
  44
  45 TEST_CONSTEXPR_CXX20 bool test() {
  46   {
  47     using V = std::variant<int, long, TDtor>;
  48     static_assert(std::is_trivially_destructible<V>::value, "");
  49     [[maybe_unused]] V v(std::in_place_index<2>);
  50   }
  51   {
  52     using V = std::variant<NonTDtor, int, NonTDtor1>;
  53     static_assert(!std::is_trivially_destructible<V>::value, "");
  54     {
  55       int count0 = 0;
  56       int count1 = 0;
  57       {
  58         V v(std::in_place_index<0>, &count0, &count1);
  59         assert(count0 == 0);
  60         assert(count1 == 0);
  61       }
  62       assert(count0 == 1);
  63       assert(count1 == 0);
  64     }
  65     {
  66       int count0 = 0;
  67       int count1 = 0;
  68       { V v(std::in_place_index<1>); }
  69       assert(count0 == 0);
  70       assert(count1 == 0);
  71     }
  72     {
  73       int count0 = 0;
  74       int count1 = 0;
  75       {
  76         V v(std::in_place_index<2>, &count0, &count1);
  77         assert(count0 == 0);
  78         assert(count1 == 0);
  79       }
  80       assert(count0 == 0);
  81       assert(count1 == 1);
  82     }
  83   }
  84
  85   return true;
  86 }
  87
  88 int main(int, char**) {
  89   test();
  90
  91 #if TEST_STD_VER >= 20
  92   static_assert(test());
  93 #endif
  94
  95   return 0;
  96 }