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// elements_view() requires default_initializable<V> = default;
12
13#include <cassert>
14#include <ranges>
15#include <tuple>
16#include <type_traits>
17
18template <bool DefaultInitializable>
19struct View : std::ranges::view_base {
20 int i = 42;
21 constexpr explicit View()
22 requires DefaultInitializable
23 = default;
24 std::tuple<int>* begin() const;
25 std::tuple<int>* end() const;
26};
27
28
29// clang-format off
30static_assert( std::is_default_constructible_v<std::ranges::elements_view<View<true >, 0>>);
31static_assert(!std::is_default_constructible_v<std::ranges::elements_view<View<false>, 0>>);
32// clang-format on
33
34constexpr bool test() {
35 {
36 std::ranges::elements_view<View<true>, 0> ev = {};
37 assert(ev.base().i == 42);
38 }
39
40 return true;
41}
42
43int main(int, char**) {
44 test();
45 static_assert(test());
46 return 0;
47}
48

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