xref: /llvm-project/libcxx/test/std/iterators/iterator.container/empty.container.verify.cpp (revision 72f0edf3f4291d2614719a8c8af21a7a62ed5d74)
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 // <iterator>
10 
11 // <iterator>
12 // template <class C> constexpr auto empty(const C& c) -> decltype(c.empty());
13 
14 // UNSUPPORTED: c++03, c++11, c++14, c++17
15 
16 #include <vector>
17 #include <iterator>
18 
f()19 void f() {
20     std::vector<int> c;
21     std::empty(c); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
22 }
23