third_party/llvm-project/libcxx/test/std/ranges/range.adaptors/range.join.view/base.pass.cpp

//===----------------------------------------------------------------------===//
//
// 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
// UNSUPPORTED: !c++experimental

// constexpr V base() const& requires copy_constructible<V>;
// constexpr V base() &&;

#include <cassert>
#include <ranges>

#include "test_macros.h"
#include "types.h"

constexpr bool hasLValueQualifiedBase(auto&& view) {
    return requires { view.base(); };
}

constexpr bool test() {
  int buffer[4][4] = {{1111, 2222, 3333, 4444}, {555, 666, 777, 888}, {99, 1010, 1111, 1212}, {13, 14, 15, 16}};

  {
    ChildView children[4] = {ChildView(buffer[0]), ChildView(buffer[1]), ChildView(buffer[2]), ChildView(buffer[3])};
    auto jv = std::ranges::join_view(ParentView{children});
    assert(std::move(jv).base().ptr_ == children);

    static_assert(!hasLValueQualifiedBase(jv));
    ASSERT_SAME_TYPE(decltype(std::move(jv).base()), ParentView<ChildView>);
  }

  {
    std::ranges::join_view jv(buffer);
    assert(jv.base().base() == buffer + 0);

    static_assert(hasLValueQualifiedBase(jv));
    ASSERT_SAME_TYPE(decltype(jv.base()), std::ranges::ref_view<int [4][4]>);
  }

  {
    const std::ranges::join_view jv(buffer);
    assert(jv.base().base() == buffer + 0);

    static_assert(hasLValueQualifiedBase(jv));
    ASSERT_SAME_TYPE(decltype(jv.base()), std::ranges::ref_view<int [4][4]>);
  }

  return true;
}

int main(int, char**) {
  test();
  static_assert(test());

  return 0;
}