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 <type_traits>
17 #include <utility>
18
19 #include "MoveOnly.h"
20
21 struct View : std::ranges::view_base {
22 int i;
23 int* begin() const;
24 int* end() const;
25 };
26
27 struct MoveOnlyView : View {
28 MoveOnly mo;
29 };
30
31 template <class T>
32 concept HasBase = requires(T&& t) { std::forward<T>(t).base(); };
33
34 static_assert(HasBase<std::ranges::split_view<View, View> const&>);
35 static_assert(HasBase<std::ranges::split_view<View, View>&&>);
36
37 static_assert(!HasBase<std::ranges::split_view<MoveOnlyView, View> const&>);
38 static_assert(HasBase<std::ranges::split_view<MoveOnlyView, View>&&>);
39
test()40 constexpr bool test() {
41 // const &
42 {
43 const std::ranges::split_view<View, View> sv{View{{}, 5}, View{{}, 0}};
44 std::same_as<View> decltype(auto) v = sv.base();
45 assert(v.i == 5);
46 }
47
48 // &
49 {
50 std::ranges::split_view<View, View> sv{View{{}, 5}, View{{}, 0}};
51 std::same_as<View> decltype(auto) v = sv.base();
52 assert(v.i == 5);
53 }
54
55 // &&
56 {
57 std::ranges::split_view<View, View> sv{View{{}, 5}, View{{}, 0}};
58 std::same_as<View> decltype(auto) v = std::move(sv).base();
59 assert(v.i == 5);
60 }
61
62 // const &&
63 {
64 std::ranges::split_view<View, View> sv{View{{}, 5}, View{{}, 0}};
65 std::same_as<View> decltype(auto) v = std::move(sv).base();
66 assert(v.i == 5);
67 }
68
69 // move only
70 {
71 std::ranges::split_view<MoveOnlyView, View> sv{MoveOnlyView{{}, 5}, View{{}, 0}};
72 std::same_as<MoveOnlyView> decltype(auto) v = std::move(sv).base();
73 assert(v.mo.get() == 5);
74 }
75
76 // LWG 3590 split_view::base() const & is overconstrained
77 {
78 struct CopyCtorButNotAssignable : std::ranges::view_base {
79 int i;
80 constexpr CopyCtorButNotAssignable(int ii) : i(ii) {}
81 constexpr CopyCtorButNotAssignable(const CopyCtorButNotAssignable&) = default;
82 constexpr CopyCtorButNotAssignable(CopyCtorButNotAssignable&&) = default;
83 constexpr CopyCtorButNotAssignable& operator=(CopyCtorButNotAssignable&&) = default;
84 constexpr CopyCtorButNotAssignable& operator=(const CopyCtorButNotAssignable&) = delete;
85 constexpr int* begin() const { return nullptr; }
86 constexpr int* end() const { return nullptr; }
87 };
88 static_assert(std::copy_constructible<CopyCtorButNotAssignable>);
89 static_assert(!std::copyable<CopyCtorButNotAssignable>);
90 const std::ranges::split_view<CopyCtorButNotAssignable, CopyCtorButNotAssignable> sv{
91 CopyCtorButNotAssignable{5}, CopyCtorButNotAssignable{5}};
92 std::same_as<CopyCtorButNotAssignable> decltype(auto) v = sv.base();
93 assert(v.i == 5);
94 }
95
96 return true;
97 }
98
main(int,char **)99 int main(int, char**) {
100 test();
101 static_assert(test());
102 return 0;
103 }
104