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// Copyright (C) 2019-2020 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/>.
// { dg-options "-std=gnu++2a" }
// { dg-do run { target c++2a } }
#include <ranges>
#include <testsuite_hooks.h>
#include <testsuite_iterators.h>
struct R1
{
int i = 0;
int j = 0;
const int* rbegin() const { return &i; }
friend const int* rbegin(const R1&& r) { return &r.j; }
};
struct R1V // view on an R1
{
R1& r;
friend const long* rbegin(R1V&); // this is not defined
friend const int* rbegin(const R1V& rv) noexcept { return rv.r.rbegin(); }
};
// Allow ranges::end to work with R1V&&
template<> constexpr bool std::ranges::enable_borrowed_range<R1V> = true;
void
test01()
{
R1 r;
const R1& c = r;
VERIFY( std::ranges::crbegin(r) == std::ranges::rbegin(c) );
VERIFY( std::ranges::crbegin(c) == std::ranges::rbegin(c) );
R1V v{r};
const R1V cv{r};
VERIFY( std::ranges::crbegin(std::move(v)) == std::ranges::rbegin(c) );
VERIFY( std::ranges::crbegin(std::move(cv)) == std::ranges::rbegin(c) );
}
struct R2
{
int a[2] = { };
long l[2] = { };
const int* begin() const { return a; }
const int* end() const { return a + 2; }
friend const long* begin(const R2&&); // not defined
friend const long* end(const R2&&); // not defined
};
// N.B. this is a lie, rbegin on an R2 rvalue will return a dangling pointer.
template<> constexpr bool std::ranges::enable_borrowed_range<R2> = true;
void
test02()
{
R2 r;
const R2& c = r;
VERIFY( std::ranges::crbegin(r) == std::ranges::rbegin(c) );
VERIFY( std::ranges::crbegin(c) == std::ranges::rbegin(c) );
VERIFY( std::ranges::crbegin(std::move(r)) == std::ranges::rbegin(c) );
VERIFY( std::ranges::crbegin(std::move(c)) == std::ranges::rbegin(c) );
}
int
main()
{
test01();
test02();
}
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