libcxx/test/std/utilities/expected/expected.void/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, c++17, c++20
  10
  11 // constexpr ~expected();
  12 //
  13 // Effects: If has_value() is false, destroys unex.
  14 //
  15 // Remarks: If is_trivially_destructible_v<E> is true, then this destructor is a trivial destructor.
  16
  17 #include <cassert>
  18 #include <expected>
  19 #include <type_traits>
  20 #include <utility>
  21
  22 #include "test_macros.h"
  23
  24 // Test Remarks: If is_trivially_destructible_v<E> is true, then this destructor is a trivial destructor.
  25 struct NonTrivial {
  26   ~NonTrivial() {}
  27 };
  28
  29 static_assert(std::is_trivially_destructible_v<std::expected<void, int>>);
  30 static_assert(!std::is_trivially_destructible_v<std::expected<void, NonTrivial>>);
  31
  32 struct TrackedDestroy {
  33   bool& destroyed;
  34   constexpr TrackedDestroy(bool& b) : destroyed(b) {}
  35   constexpr ~TrackedDestroy() { destroyed = true; }
  36 };
  37
  38 constexpr bool test() {
  39   // has value
  40   { [[maybe_unused]] std::expected<void, TrackedDestroy> e(std::in_place); }
  41
  42   // has error
  43   {
  44     bool errorDestroyed = false;
  45     { [[maybe_unused]] std::expected<void, TrackedDestroy> e(std::unexpect, errorDestroyed); }
  46     assert(errorDestroyed);
  47   }
  48
  49   return true;
  50 }
  51
  52 int main(int, char**) {
  53   test();
  54   static_assert(test());
  55   return 0;
  56 }