llvm-project/libcxx/test/std/ranges/range.adaptors/range.all/all.nodiscard.verify.cpp

27 lines
1.2 KiB
C++

//===----------------------------------------------------------------------===//
//
// 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::all is marked as [[nodiscard]].
#include <ranges>
void test() {
int range[] = {1, 2, 3};
auto f = [](int i) { return i; };
std::views::all(range); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
range | std::views::all; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
std::views::transform(f) | std::views::all; // 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}}
}