ceph/src/boost/libs/variant2/test/variant_default_construct.cpp

   1
   2 // Copyright 2017 Peter Dimov.
   3 //
   4 // Distributed under the Boost Software License, Version 1.0.
   5 //
   6 // See accompanying file LICENSE_1_0.txt or copy at
   7 // http://www.boost.org/LICENSE_1_0.txt
   8
   9 #include <boost/variant2/variant.hpp>
  10 #include <boost/core/lightweight_test.hpp>
  11 #include <boost/core/lightweight_test_trait.hpp>
  12 #include <type_traits>
  13 #include <utility>
  14 #include <string>
  15
  16 using namespace boost::variant2;
  17
  18 struct X
  19 {
  20     X();
  21 };
  22
  23 struct Y
  24 {
  25     Y() = delete;
  26 };
  27
  28 int main()
  29 {
  30     {
  31         variant<int> v;
  32
  33         BOOST_TEST_EQ( v.index(), 0 );
  34         BOOST_TEST_EQ( get<0>(v), 0 );
  35     }
  36
  37     {
  38         variant<int const> v;
  39
  40         BOOST_TEST_EQ( v.index(), 0 );
  41         BOOST_TEST_EQ( get<0>(v), 0 );
  42     }
  43
  44     {
  45         variant<int, float, std::string> v;
  46
  47         BOOST_TEST_EQ( v.index(), 0 );
  48         BOOST_TEST_EQ( get<0>(v), 0 );
  49     }
  50
  51     {
  52         variant<int, int, std::string> v;
  53
  54         BOOST_TEST_EQ( v.index(), 0 );
  55         BOOST_TEST_EQ( get<0>(v), 0 );
  56     }
  57
  58     {
  59         variant<std::string> v;
  60
  61         BOOST_TEST_EQ( v.index(), 0 );
  62         BOOST_TEST_EQ( get<0>(v), std::string() );
  63     }
  64
  65     {
  66         variant<std::string const> v;
  67
  68         BOOST_TEST_EQ( v.index(), 0 );
  69         BOOST_TEST_EQ( get<0>(v), std::string() );
  70     }
  71
  72     {
  73         variant<std::string, int, float> v;
  74
  75         BOOST_TEST_EQ( v.index(), 0 );
  76         BOOST_TEST_EQ( get<0>(v), std::string() );
  77     }
  78
  79     {
  80         variant<std::string, std::string, float> v;
  81
  82         BOOST_TEST_EQ( v.index(), 0 );
  83         BOOST_TEST_EQ( get<0>(v), std::string() );
  84     }
  85
  86     {
  87         BOOST_TEST_TRAIT_TRUE((std::is_nothrow_default_constructible<variant<int>>));
  88         BOOST_TEST_TRAIT_TRUE((std::is_nothrow_default_constructible<variant<int const>>));
  89         BOOST_TEST_TRAIT_TRUE((std::is_nothrow_default_constructible<variant<int, X>>));
  90         BOOST_TEST_TRAIT_TRUE((std::is_nothrow_default_constructible<variant<int, float, X>>));
  91         BOOST_TEST_TRAIT_TRUE((std::is_nothrow_default_constructible<variant<int, int, X>>));
  92         BOOST_TEST_TRAIT_TRUE((std::is_nothrow_default_constructible<variant<int, X, X>>));
  93
  94         BOOST_TEST_TRAIT_FALSE((std::is_nothrow_default_constructible<variant<X>>));
  95         BOOST_TEST_TRAIT_FALSE((std::is_nothrow_default_constructible<variant<X, int>>));
  96         BOOST_TEST_TRAIT_FALSE((std::is_nothrow_default_constructible<variant<X, int, float>>));
  97
  98         BOOST_TEST_TRAIT_TRUE((std::is_default_constructible<variant<int, Y>>));
  99         BOOST_TEST_TRAIT_FALSE((std::is_default_constructible<variant<Y, int>>));
 100     }
 101
 102     return boost::report_errors();
 103 }