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, c++11, c++14, c++17 10 // UNSUPPORTED: libcpp-no-concepts 11 // UNSUPPORTED: gcc-10 12 13 // constexpr iterator<false> begin(); 14 // constexpr iterator<true> begin() const 15 // requires range<const V> && 16 // regular_invocable<const F&, range_reference_t<const V>>; 17 18 #include <ranges> 19 20 #include "test_macros.h" 21 #include "types.h" 22 23 template<class T> 24 concept BeginInvocable = requires(T t) { t.begin(); }; 25 26 constexpr bool test() { 27 int buff[8] = {0, 1, 2, 3, 4, 5, 6, 7}; 28 29 { 30 std::ranges::transform_view transformView(ContiguousView{buff}, Increment{}); 31 assert(transformView.begin().base() == buff); 32 assert(*transformView.begin() == 1); 33 } 34 35 { 36 std::ranges::transform_view transformView(ForwardView{buff}, Increment{}); 37 assert(transformView.begin().base().base() == buff); 38 assert(*transformView.begin() == 1); 39 } 40 41 { 42 std::ranges::transform_view transformView(InputView{buff}, Increment{}); 43 assert(transformView.begin().base().base() == buff); 44 assert(*transformView.begin() == 1); 45 } 46 47 { 48 const std::ranges::transform_view transformView(ContiguousView{buff}, IncrementConst{}); 49 assert(*transformView.begin() == 1); 50 } 51 52 static_assert(!BeginInvocable<const std::ranges::transform_view<ContiguousView, Increment>>); 53 54 return true; 55 } 56 57 int main(int, char**) { 58 test(); 59 static_assert(test()); 60 61 return 0; 62 } 63