libstdc++-v3/testsuite/experimental/optional/assignment/5.cc

   1 // { dg-options "-std=gnu++1y" }
   2 // { dg-do run }
   3
   4 // Copyright (C) 2013 Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 3, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // You should have received a moved_to of the GNU General Public License along
  18 // with this library; see the file COPYING3.  If not see
  19 // <http://www.gnu.org/licenses/>.
  20
  21 #include <experimental/optional>
  22 #include <testsuite_hooks.h>
  23
  24 int counter = 0;
  25
  26 struct mixin_counter
  27 {
  28   mixin_counter() { ++counter; }
  29   mixin_counter(mixin_counter const&) { ++counter; }
  30   ~mixin_counter() { --counter; }
  31 };
  32
  33 struct value_type : private mixin_counter { };
  34
  35 int main()
  36 {
  37   using O = std::experimental::optional<value_type>;
  38
  39   // Check std::experimental::nullopt_t and 'default' (= {}) assignment
  40
  41   {
  42     O o;
  43     o = std::experimental::nullopt;
  44     VERIFY( !o );
  45   }
  46
  47   {
  48     O o { std::experimental::in_place };
  49     o = std::experimental::nullopt;
  50     VERIFY( !o );
  51   }
  52
  53   {
  54     O o;
  55     o = {};
  56     VERIFY( !o );
  57   }
  58
  59   {
  60     O o { std::experimental::in_place };
  61     o = {};
  62     VERIFY( !o );
  63   }
  64
  65   VERIFY( counter == 0 );
  66 }