llvm-project/libcxx/test/std/ranges/range.adaptors/range.lazy.split/range.lazy.split.outer.value/begin.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: libcpp-has-no-incomplete-ranges

// std::ranges::lazy_split_view::outer-iterator::value_type::begin()

#include <ranges>

#include <cassert>
#include "../types.h"

constexpr bool test() {
  // `View` is a forward range.
  {
    CopyableView input("a");

    // Non-const.
    {
      SplitViewCopyable v(input, "b");
      auto val = *v.begin();
      assert(val.begin().base() == input.begin());
    }

    // Const.
    {
      SplitViewCopyable v(input, "b");
      const auto val = *v.begin();
      assert(val.begin().base() == input.begin());
    }
  }

  // `View` is an input range.
  {
    InputView input("a");

    // Non-const.
    {
      SplitViewInput v(input, 'b');
      auto val = *v.begin();
      // Copies of `InputView` are independent and the iterators won't compare the same.
      assert(*val.begin().base() == *input.begin());
    }

    // Const.
    {
      SplitViewInput v(input, 'b');
      const auto val = *v.begin();
      // Copies of `InputView` are independent and the iterators won't compare the same.
      assert(*val.begin().base() == *input.begin());
    }
  }

  return true;
}

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

  return 0;
}