libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/nullopt_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 // UNSUPPORTED: c++03, c++11, c++14
  10 // <optional>
  11
  12 // constexpr optional(nullopt_t) noexcept;
  13
  14 #include <optional>
  15 #include <type_traits>
  16 #include <cassert>
  17
  18 #include "archetypes.h"
  19
  20 #include "test_macros.h"
  21
  22 using std::optional;
  23 using std::nullopt_t;
  24 using std::nullopt;
  25
  26 template <class Opt>
  27 void
  28 test_constexpr()
  29 {
  30     static_assert(std::is_nothrow_constructible<Opt, nullopt_t&>::value, "");
  31     static_assert(std::is_trivially_destructible<Opt>::value, "");
  32     static_assert(std::is_trivially_destructible<typename Opt::value_type>::value, "");
  33
  34     constexpr Opt opt(nullopt);
  35     static_assert(static_cast<bool>(opt) == false, "");
  36
  37     struct test_constexpr_ctor
  38         : public Opt
  39     {
  40         constexpr test_constexpr_ctor() {}
  41     };
  42 }
  43
  44 template <class Opt>
  45 void
  46 test()
  47 {
  48     static_assert(std::is_nothrow_constructible<Opt, nullopt_t&>::value, "");
  49     static_assert(!std::is_trivially_destructible<Opt>::value, "");
  50     static_assert(!std::is_trivially_destructible<typename Opt::value_type>::value, "");
  51     {
  52     Opt opt(nullopt);
  53     assert(static_cast<bool>(opt) == false);
  54     }
  55     {
  56     const Opt opt(nullopt);
  57     assert(static_cast<bool>(opt) == false);
  58     }
  59     struct test_constexpr_ctor
  60         : public Opt
  61     {
  62         constexpr test_constexpr_ctor() {}
  63     };
  64 }
  65
  66 int main(int, char**)
  67 {
  68     test_constexpr<optional<int>>();
  69     test_constexpr<optional<int*>>();
  70     test_constexpr<optional<ImplicitTypes::NoCtors>>();
  71     test_constexpr<optional<NonTrivialTypes::NoCtors>>();
  72     test_constexpr<optional<NonConstexprTypes::NoCtors>>();
  73     test<optional<NonLiteralTypes::NoCtors>>();
  74
  75   return 0;
  76 }