// { dg-do run { target c++14 } } // Copyright (C) 2013-2019 Free Software Foundation, Inc. // // This file is part of the GNU ISO C++ Library. This library is free // software; you can redistribute it and/or modify it under the // terms of the GNU General Public License as published by the // Free Software Foundation; either version 3, or (at your option) // any later version. // This library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // You should have received a copy of the GNU General Public License along // with this library; see the file COPYING3. If not see // . #include #include int counter = 0; struct mixin_counter { mixin_counter() { ++counter; } mixin_counter(mixin_counter const&) { ++counter; } ~mixin_counter() { --counter; } }; struct value_type : private mixin_counter { value_type() = default; value_type(int) : state(1) { } value_type(std::initializer_list, const char*) : state(2) { } int state = 0; }; int main() { using O = std::experimental::optional; // Check emplace { O o; o.emplace(); VERIFY( o && o->state == 0 ); } { O o { std::experimental::in_place, 0 }; o.emplace(); VERIFY( o && o->state == 0 ); } { O o; o.emplace(0); VERIFY( o && o->state == 1 ); } { O o { std::experimental::in_place }; o.emplace(0); VERIFY( o && o->state == 1 ); } { O o; o.emplace({ 'a' }, ""); VERIFY( o && o->state == 2 ); } { O o { std::experimental::in_place }; o.emplace({ 'a' }, ""); VERIFY( o && o->state == 2 ); } static_assert( !std::is_constructible, int>(), "" ); VERIFY( counter == 0 ); }