llvm/libcxx/test/libcxx/ranges/range.adaptors/range.transform/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

// Test the libc++ extension that std::views::transform is marked as [[nodiscard]].

#include <ranges>

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

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