libcxx/test/std/containers/container.node/node_handle.nodiscard.verify.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // UNSUPPORTED: c++03
  10 // UNSUPPORTED: (c++11 || c++14 || c++17) && !stdlib=libc++
  11
  12 // Make sure the various node handles mark their .empty() method with
  13 // [[nodiscard]] starting with C++20
  14
  15 #include <map>
  16 #include <set>
  17 #include <unordered_map>
  18 #include <unordered_set>
  19
  20 #include "test_macros.h"
  21
  22 void test() {
  23 #if TEST_STD_VER >= 17
  24     {
  25         std::map<int, int>::node_type node;
  26         node.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
  27     }
  28     {
  29         std::multimap<int, int>::node_type node;
  30         node.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
  31     }
  32 #endif // TEST_STD_VER >= 17
  33     {
  34         std::set<int> node;
  35         node.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
  36     }
  37     {
  38         std::multiset<int> node;
  39         node.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
  40     }
  41     {
  42         std::unordered_map<int, int> node;
  43         node.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
  44     }
  45     {
  46         std::unordered_multimap<int, int> node;
  47         node.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
  48     }
  49     {
  50         std::unordered_set<int> node;
  51         node.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
  52     }
  53     {
  54         std::unordered_multiset<int> node;
  55         node.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
  56     }
  57 }