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
21struct View : std::ranges::view_base {
22 int i;
23 int* begin() const;
24 int* end() const;
25};
26
27struct MoveOnlyView : View {
28 MoveOnly mo;
29};
30
31template <class T>
32concept HasBase = requires(T&& t) { std::forward<T>(t).base(); };
33
34struct Pred {
35 constexpr bool operator()(int i) const { return i > 5; }
36};
37
38static_assert(HasBase<std::ranges::drop_while_view<View, Pred> const&>);
39static_assert(HasBase<std::ranges::drop_while_view<View, Pred>&&>);
40
41static_assert(!HasBase<std::ranges::drop_while_view<MoveOnlyView, Pred> const&>);
42static_assert(HasBase<std::ranges::drop_while_view<MoveOnlyView, Pred>&&>);
43
44constexpr 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
82int main(int, char**) {
83 test();
84 static_assert(test());
85 return 0;
86}
87

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