libstdc++-v3/testsuite/20_util/reference_wrapper/83427.cc

   1 // Copyright (C) 2017-2020 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // { dg-options "-std=gnu++17" }
  19 // { dg-do compile { target c++17 } }
  20
  21 #include <functional>
  22
  23 // PR libstdc++/83427
  24
  25 int f(short) noexcept { return 0; }
  26 std::reference_wrapper<decltype(f)> r(f);
  27 static_assert(std::is_same_v<decltype(r)::result_type, int>);
  28 static_assert(std::is_same_v<decltype(r)::argument_type, short>);
  29
  30 auto* p = &f;
  31 std::reference_wrapper<decltype(&f)> r2(p);
  32 static_assert(std::is_same_v<decltype(r2)::result_type, int>);
  33 static_assert(std::is_same_v<decltype(r2)::argument_type, short>);
  34
  35 struct X { long f() const & noexcept { return 0L; } };
  36 auto m = &X::f;
  37 std::reference_wrapper<decltype(m)> r3(m);
  38 static_assert(std::is_same_v<decltype(r3)::result_type, long>);
  39 static_assert(std::is_same_v<decltype(r3)::argument_type, const X*>);