53 lines · 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-exception6//7//===----------------------------------------------------------------------===//8 9// UNSUPPORTED: c++03, c++11, c++14, c++1710 11// constexpr auto size()12// requires sized_range<V>13// constexpr auto size() const14// requires sized_range<const V>15 16#include <ranges>17 18#include "test_macros.h"19#include "types.h"20 21template<class T>22concept SizeInvocable = requires(std::ranges::drop_view<T> t) { t.size(); };23 24constexpr bool test() {25 // sized_range<V>26 std::ranges::drop_view dropView1(MoveOnlyView(), 4);27 assert(dropView1.size() == 4);28 29 // sized_range<V>30 std::ranges::drop_view dropView2(MoveOnlyView(), 0);31 assert(dropView2.size() == 8);32 33 // sized_range<const V>34 const std::ranges::drop_view dropView3(MoveOnlyView(), 8);35 assert(dropView3.size() == 0);36 37 // sized_range<const V>38 const std::ranges::drop_view dropView4(MoveOnlyView(), 10);39 assert(dropView4.size() == 0);40 41 // Because ForwardView is not a sized_range.42 static_assert(!SizeInvocable<ForwardView>);43 44 return true;45}46 47int main(int, char**) {48 test();49 static_assert(test());50 51 return 0;52}53