libcxx/test/std/ranges/range.adaptors/range.reverse/adaptor.nodiscard.verify.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-no-concepts
// UNSUPPORTED: libcpp-has-no-incomplete-ranges
// REQUIRES: libc++

// Test the libc++ extension that std::views::reverse is marked as [[nodiscard]] to avoid
// the potential for user mistakenly thinking they're calling an algorithm.

#include <ranges>

void test() {
  int range[] = {1, 2, 3};

  std::views::reverse(range); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
  range | std::views::reverse; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
  std::views::reverse | std::views::reverse; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
}