ceph/src/boost/libs/hana/test/map/cnstr.trap.cpp

   1 // Copyright Louis Dionne 2013-2017
   2 // Distributed under the Boost Software License, Version 1.0.
   3 // (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
   4
   5 #include <boost/hana/bool.hpp>
   6 #include <boost/hana/detail/wrong.hpp>
   7 #include <boost/hana/fwd/hash.hpp>
   8 #include <boost/hana/map.hpp>
   9 #include <boost/hana/pair.hpp>
  10 #include <boost/hana/type.hpp>
  11
  12 #include <utility>
  13 namespace hana = boost::hana;
  14
  15
  16 // This test makes sure that we do not instantiate rogue constructors when
  17 // doing copies and moves
  18
  19 template <int i>
  20 struct Trap {
  21     Trap() = default;
  22     Trap(Trap const&) = default;
  23     Trap(Trap&) = default;
  24     Trap(Trap&&) = default;
  25
  26     template <typename X>
  27     Trap(X&&) {
  28         static_assert(hana::detail::wrong<X>{},
  29         "this constructor must not be instantiated");
  30     }
  31 };
  32
  33 template <int i, int j>
  34 constexpr auto operator==(Trap<i> const&, Trap<j> const&)
  35 { return hana::bool_c<i == j>; }
  36
  37 template <int i, int j>
  38 constexpr auto operator!=(Trap<i> const&, Trap<j> const&)
  39 { return hana::bool_c<i != j>; }
  40
  41 namespace boost { namespace hana {
  42     template <int i>
  43     struct hash_impl<Trap<i>> {
  44         static constexpr auto apply(Trap<i> const&)
  45         { return hana::type_c<Trap<i>>; };
  46     };
  47 }}
  48
  49 int main() {
  50     {
  51         auto expr = hana::make_map(
  52             hana::make_pair(Trap<0>{}, Trap<0>{})
  53         );
  54         auto implicit_copy = expr;
  55         decltype(expr) explicit_copy(expr);
  56
  57         (void)implicit_copy;
  58         (void)explicit_copy;
  59     }
  60     {
  61         auto expr = hana::make_map(
  62             hana::make_pair(Trap<0>{}, Trap<0>{})
  63         );
  64         auto implicit_move = std::move(expr);
  65         decltype(expr) explicit_move(std::move(implicit_move));
  66
  67         (void)implicit_move;
  68         (void)explicit_move;
  69     }
  70 }