libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const.compile.fail.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>::value() const &;
  13
  14 #include <optional>
  15 #include <type_traits>
  16 #include <cassert>
  17
  18 using std::optional;
  19
  20 struct X
  21 {
  22     constexpr int test() const {return 3;}
  23     int test() {return 4;}
  24 };
  25
  26 int main(int, char**)
  27 {
  28     {
  29         constexpr optional<X> opt;
  30         static_assert(opt.value().test() == 3, "");
  31     }
  32
  33   return 0;
  34 }