1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9// UNSUPPORTED: c++03, c++11, c++14, c++17
10
11// constexpr V base() const & requires copy_constructible<V> { return base_; }
12// constexpr V base() && { return std::move(base_); }
13
14#include <cassert>
15#include <ranges>
16#include <tuple>
17#include <type_traits>
18#include <utility>
19
20#include "MoveOnly.h"
21
22struct View : std::ranges::view_base {
23 int i;
24 std::tuple<int>* begin() const;
25 std::tuple<int>* end() const;
26};
27
28struct MoveOnlyView : View {
29 MoveOnly mo;
30};
31
32template <class T>
33concept HasBase = requires(T&& t) { std::forward<T>(t).base(); };
34
35static_assert(HasBase<std::ranges::elements_view<View, 0> const&>);
36static_assert(HasBase<std::ranges::elements_view<View, 0>&&>);
37
38static_assert(!HasBase<std::ranges::elements_view<MoveOnlyView, 0> const&>);
39static_assert(HasBase<std::ranges::elements_view<MoveOnlyView, 0>&&>);
40
41constexpr bool test() {
42 // const &
43 {
44 const std::ranges::elements_view<View, 0> ev{View{{}, 5}};
45 std::same_as<View> decltype(auto) v = ev.base();
46 assert(v.i == 5);
47 }
48
49 // &
50 {
51 std::ranges::elements_view<View, 0> ev{View{{}, 5}};
52 std::same_as<View> decltype(auto) v = ev.base();
53 assert(v.i == 5);
54 }
55
56 // &&
57 {
58 std::ranges::elements_view<View, 0> ev{View{{}, 5}};
59 std::same_as<View> decltype(auto) v = std::move(ev).base();
60 assert(v.i == 5);
61 }
62
63 // const &&
64 {
65 const std::ranges::elements_view<View, 0> ev{View{{}, 5}};
66 std::same_as<View> decltype(auto) v = std::move(ev).base();
67 assert(v.i == 5);
68 }
69
70 // move only
71 {
72 std::ranges::elements_view<MoveOnlyView, 0> ev{MoveOnlyView{{}, 5}};
73 std::same_as<MoveOnlyView> decltype(auto) v = std::move(ev).base();
74 assert(v.mo.get() == 5);
75 }
76
77 return true;
78}
79
80int main(int, char**) {
81 test();
82 static_assert(test());
83 return 0;
84}
85

source code of libcxx/test/std/ranges/range.adaptors/range.elements/base.pass.cpp