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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14, c++17
// constexpr auto end() requires (!simple-view<V> && !common_range<V>)
// constexpr auto end() requires (!simple-view<V> && common_range<V>)
// constexpr auto end() const requires range<const V>
// constexpr auto end() const requires common_range<const V>
#include <cassert>
#include <iterator>
#include <ranges>
#include <type_traits>
#include <utility>
#include "types.h"
// | simple | common | v.end() | as_const(v)
// | | | | .end()
// |--------|--------|------------------|---------------
// | Y | Y | iterator<true> | iterator<true>
// | Y | N | sentinel<true> | sentinel<true>
// | N | Y | iterator<false> | iterator<true>
// | N | N | sentinel<false> | sentinel<true>
// !range<const V>
template <class T>
concept HasEnd = requires(T t) { t.end(); };
template <class T>
concept HasConstEnd = requires(const T ct) { ct.end(); };
struct NoConstEndView : TupleBufferView {
using TupleBufferView::TupleBufferView;
constexpr std::tuple<int>* begin() { return buffer_; }
constexpr std::tuple<int>* end() { return buffer_ + size_; }
};
static_assert(HasEnd<std::ranges::elements_view<NoConstEndView, 0>>);
static_assert(!HasConstEnd<std::ranges::elements_view<NoConstEndView, 0>>);
constexpr bool test() {
std::tuple<int> buffer[] = {{1}, {2}, {3}};
// simple-view && common_view
{
SimpleCommon v{buffer};
auto ev = std::views::elements<0>(v);
auto it = ev.begin();
decltype(auto) st = ev.end();
assert(st == it + 3);
auto const_it = std::as_const(ev).begin();
decltype(auto) const_st = std::as_const(ev).end();
assert(const_st == const_it + 3);
// Both iterator<true>
static_assert(std::same_as<decltype(st), decltype(const_st)>);
static_assert(std::same_as<decltype(st), decltype(it)>);
static_assert(std::same_as<decltype(const_st), decltype(const_it)>);
}
// simple-view && !common_view
{
SimpleNonCommon v{buffer};
auto ev = std::views::elements<0>(v);
auto it = ev.begin();
decltype(auto) st = ev.end();
assert(st == it + 3);
auto const_it = std::as_const(ev).begin();
decltype(auto) const_st = std::as_const(ev).end();
assert(const_st == const_it + 3);
// Both iterator<true>
static_assert(std::same_as<decltype(st), decltype(const_st)>);
static_assert(!std::same_as<decltype(st), decltype(it)>);
static_assert(!std::same_as<decltype(const_st), decltype(const_it)>);
}
// !simple-view && common_view
{
NonSimpleCommon v{buffer};
auto ev = std::views::elements<0>(v);
auto it = ev.begin();
decltype(auto) st = ev.end();
assert(st == it + 3);
auto const_it = std::as_const(ev).begin();
decltype(auto) const_st = std::as_const(ev).end();
assert(const_st == const_it + 3);
// iterator<false> and iterator<true>
static_assert(!std::same_as<decltype(st), decltype(const_st)>);
static_assert(std::same_as<decltype(st), decltype(it)>);
static_assert(std::same_as<decltype(const_st), decltype(const_it)>);
}
// !simple-view && !common_view
{
NonSimpleNonCommon v{buffer};
auto ev = std::views::elements<0>(v);
auto it = ev.begin();
decltype(auto) st = ev.end();
assert(st == it + 3);
auto const_it = std::as_const(ev).begin();
decltype(auto) const_st = std::as_const(ev).end();
assert(const_st == const_it + 3);
// sentinel<false> and sentinel<true>
static_assert(!std::same_as<decltype(st), decltype(const_st)>);
static_assert(!std::same_as<decltype(st), decltype(it)>);
static_assert(!std::same_as<decltype(const_st), decltype(const_it)>);
}
// LWG 3406 elements_view::begin() and elements_view::end() have incompatible constraints
{
std::tuple<int, int> x[] = {{0, 0}};
std::ranges::subrange r = {std::counted_iterator(x, 1), std::default_sentinel};
auto v = r | std::views::elements<0>;
assert(v.begin() != v.end());
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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