libcxx/test/std/utilities/optional/optional.object/optional.object.observe/op_arrow_const.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 const T* optional<T>::operator->() const;
  13
  14 #include <optional>
  15 #include <type_traits>
  16 #include <cassert>
  17
  18 #include "test_macros.h"
  19
  20 using std::optional;
  21
  22 struct X
  23 {
  24     constexpr int test() const {return 3;}
  25 };
  26
  27 struct Y
  28 {
  29     int test() const noexcept {return 2;}
  30 };
  31
  32 struct Z
  33 {
  34     const Z* operator&() const;
  35     constexpr int test() const {return 1;}
  36 };
  37
  38 int main(int, char**)
  39 {
  40     {
  41         const std::optional<X> opt; ((void)opt);
  42         ASSERT_SAME_TYPE(decltype(opt.operator->()), X const*);
  43         ASSERT_NOEXCEPT(opt.operator->());
  44     }
  45     {
  46         constexpr optional<X> opt(X{});
  47         static_assert(opt->test() == 3, "");
  48     }
  49     {
  50         constexpr optional<Y> opt(Y{});
  51         assert(opt->test() == 2);
  52     }
  53     {
  54         constexpr optional<Z> opt(Z{});
  55         static_assert(opt->test() == 1, "");
  56     }
  57
  58     return 0;
  59 }