libstdc++-v3/testsuite/20_util/tuple/tuple_element_t.cc

   1 // { dg-options "-std=gnu++14" }
   2 // { dg-do compile }
   3
   4 // Copyright (C) 2014 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 copy 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 <tuple>
  22
  23 using namespace std;
  24
  25 struct foo
  26 { };
  27
  28 int
  29 main()
  30 {
  31   // As foo isn't constructible from anything else, this
  32   // lets us check if the alias is returning foo when it should
  33   foo q1;
  34   tuple_element_t<0,tuple<foo,void,int> > q2(q1);
  35   tuple_element_t<2,tuple<void,int,foo> > q3(q1);
  36 }