// Copyright (C) 2019-2021 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 // . // { dg-options "-std=gnu++2a" } // { dg-do run { target c++2a } } #include #include void test01() { struct Visitor { int operator()(int, void*) const { return 0; } int operator()(char& c, void* p) const { return &c == p; } int operator()(int i, const char* s) const { return s[i] == '\0'; } int operator()(char c, const char* s) const { return c == *s; } }; std::variant v1{'c'}; std::variant v2{"chars"}; auto res = std::visit(Visitor{}, v1, v2); static_assert(std::is_same_v); VERIFY( res == true ); static_assert(std::is_void_v(Visitor{}, v1, v2))>); } void test02() { struct Visitor { int operator()(double) {return 42;} double operator()(int) {return 0.02;} }; std::variant v; std::visit(Visitor(), v); std::visit(Visitor(), v); } int main() { test01(); test02(); }