libstdc++-v3/testsuite/20_util/remove_cvref/value.cc

// { dg-options "-std=gnu++2a" }
// { dg-do compile { target c++2a } }

// Copyright (C) 2018-2023 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
// <http://www.gnu.org/licenses/>.

#include <type_traits>
#include <testsuite_tr1.h>

void test01()
{
  using std::remove_cvref;
  using std::is_same;
  using namespace __gnu_test;

  static_assert(is_same<remove_cvref<const volatile int>::type,
			int>::value, "");
  static_assert(is_same<remove_cvref<const volatile int*>::type,
			const volatile int*>::value, "");
  static_assert(is_same<typename remove_cvref<const volatile int&>::type,
			int>::value, "");
  static_assert(is_same<typename remove_cvref<const volatile int&&>::type,
			int>::value, "");
  static_assert(is_same<remove_cvref<const volatile ClassType>::type,
			ClassType>::value, "");
  static_assert(is_same<remove_cvref<const volatile ClassType*>::type,
			const volatile ClassType*>::value, "");
  static_assert(is_same<typename remove_cvref<const volatile ClassType&>::type,
			ClassType>::value, "");
  static_assert(is_same<typename remove_cvref<const volatile ClassType&&>::type,
			ClassType>::value, "");
  static_assert(is_same<typename remove_cvref<const int(&)[3]>::type,
			int[3]>::value, "");
  static_assert(is_same<typename remove_cvref<const int(&)()>::type,
			const int()>::value, "");
}

// Declare using nested name of class template
template<typename T> T func(typename std::remove_cvref<T>::type);
// Define using alias
template<typename T> T func(std::remove_cvref_t<T> t) { return t; }
// Call must not be ambiguous
int i = func<int>(1);