ceph/src/boost/libs/asio/test/properties/cpp14/require_concept_free.cpp

   1 //
   2 // cpp14/require_concept_free.cpp
   3 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2022 Christopher M. Kohlhoff (chris at kohlhoff dot com)
   6 //
   7 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   9 //
  10
  11 #include <boost/asio/require_concept.hpp>
  12 #include <cassert>
  13
  14 template <int>
  15 struct prop
  16 {
  17   template <typename> static constexpr bool is_applicable_property_v = true;
  18   static constexpr bool is_requirable_concept = true;
  19 };
  20
  21 template <int>
  22 struct object
  23 {
  24   template <int N>
  25   friend constexpr object<N> require_concept(const object&, prop<N>)
  26   {
  27     return object<N>();
  28   }
  29 };
  30
  31 int main()
  32 {
  33   object<1> o1 = {};
  34   object<2> o2 = boost::asio::require_concept(o1, prop<2>());
  35   (void)o2;
  36
  37   const object<1> o3 = {};
  38   object<2> o4 = boost::asio::require_concept(o3, prop<2>());
  39   (void)o4;
  40
  41   constexpr object<2> o5 = boost::asio::require_concept(object<1>(), prop<2>());
  42   (void)o5;
  43 }