libcxx/test/std/containers/container.node/node_handle.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

// Make sure the various node handles mark their .empty() method with
// [[nodiscard]] starting with C++20

#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>

void test() {
    {
        std::map<int, int>::node_type node;
        node.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
    }
    {
        std::multimap<int, int>::node_type node;
        node.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
    }
    {
        std::set<int> node;
        node.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
    }
    {
        std::multiset<int> node;
        node.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
    }
    {
        std::unordered_map<int, int> node;
        node.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
    }
    {
        std::unordered_multimap<int, int> node;
        node.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
    }
    {
        std::unordered_set<int> node;
        node.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
    }
    {
        std::unordered_multiset<int> node;
        node.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
    }
}