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clang-p2996/libcxx/test/std/ranges/range.adaptors/range.elements/ctor.view.pass.cpp
Hui Xie 94461822c7 [libc++][ranges] implement std::views::elements_view
`subrange` is also a `tuple-like`. To avoid the add entire `subrange` dependencies to `tuple-like`, we need forward declaration of `subrange`. However, the class template constraints of `subrange` currently requires `__iterator/concepts.h`, which requires `<concepts>`. The problem is that currently `tuple-like` is used in several different places, including libc++ extension for pair constructors. we don't want to add `<concepts>` to pair and other stuff. So this change also created several small headers that `subrange`'s declaration needed inside `__iterator/concepts/`

Differential Revision: https://reviews.llvm.org/D136268
2023-01-15 17:36:10 +00:00

45 lines
1.1 KiB
C++

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14, c++17
// constexpr explicit elements_view(V base);
#include <cassert>
#include <ranges>
#include <tuple>
#include <type_traits>
#include <utility>
#include "MoveOnly.h"
struct View : std::ranges::view_base {
MoveOnly mo;
std::tuple<int>* begin() const;
std::tuple<int>* end() const;
};
// Test Explicit
static_assert(std::is_constructible_v<std::ranges::elements_view<View, 0>, View>);
static_assert(!std::is_convertible_v<View, std::ranges::elements_view<View, 0>>);
constexpr bool test() {
{
std::ranges::elements_view<View, 0> ev{View{{}, MoveOnly{5}}};
assert(std::move(ev).base().mo.get() == 5);
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}