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 struct Pred {
operator ()Pred35 constexpr bool operator()(int i) const { return i > 5; }
36 };
37
38 static_assert(HasBase<std::ranges::drop_while_view<View, Pred> const&>);
39 static_assert(HasBase<std::ranges::drop_while_view<View, Pred>&&>);
40
41 static_assert(!HasBase<std::ranges::drop_while_view<MoveOnlyView, Pred> const&>);
42 static_assert(HasBase<std::ranges::drop_while_view<MoveOnlyView, Pred>&&>);
43
test()44 constexpr bool test() {
45 // const &
46 {
47 const std::ranges::drop_while_view<View, Pred> dwv{View{{}, 5}, {}};
48 std::same_as<View> decltype(auto) v = dwv.base();
49 assert(v.i == 5);
50 }
51
52 // &
53 {
54 std::ranges::drop_while_view<View, Pred> dwv{View{{}, 5}, {}};
55 std::same_as<View> decltype(auto) v = dwv.base();
56 assert(v.i == 5);
57 }
58
59 // &&
60 {
61 std::ranges::drop_while_view<View, Pred> dwv{View{{}, 5}, {}};
62 std::same_as<View> decltype(auto) v = std::move(dwv).base();
63 assert(v.i == 5);
64 }
65
66 // const &&
67 {
68 const std::ranges::drop_while_view<View, Pred> dwv{View{{}, 5}, {}};
69 std::same_as<View> decltype(auto) v = std::move(dwv).base();
70 assert(v.i == 5);
71 }
72
73 // move only
74 {
75 std::ranges::drop_while_view<MoveOnlyView, Pred> dwv{MoveOnlyView{{}, 5}, {}};
76 std::same_as<MoveOnlyView> decltype(auto) v = std::move(dwv).base();
77 assert(v.mo.get() == 5);
78 }
79 return true;
80 }
81
main(int,char **)82 int main(int, char**) {
83 test();
84 static_assert(test());
85 return 0;
86 }
87