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 // projected
14 
15 #include <iterator>
16 
17 #include <concepts>
18 #include <functional>
19 
20 #include "test_iterators.h"
21 
22 using IntPtr = std::projected<int const*, std::identity>;
23 static_assert(std::same_as<IntPtr::value_type, int>);
24 static_assert(std::same_as<decltype(*std::declval<IntPtr>()), int const&>);
25 static_assert(std::same_as<std::iter_difference_t<IntPtr>, std::ptrdiff_t>);
26 
27 struct S { };
28 
29 using Cpp17InputIterator = std::projected<cpp17_input_iterator<S*>, int S::*>;
30 static_assert(std::same_as<Cpp17InputIterator::value_type, int>);
31 static_assert(std::same_as<decltype(*std::declval<Cpp17InputIterator>()), int&>);
32 static_assert(std::same_as<std::iter_difference_t<Cpp17InputIterator>, std::ptrdiff_t>);
33 
34 using Cpp20InputIterator = std::projected<cpp20_input_iterator<S*>, int S::*>;
35 static_assert(std::same_as<Cpp20InputIterator::value_type, int>);
36 static_assert(std::same_as<decltype(*std::declval<Cpp20InputIterator>()), int&>);
37 static_assert(std::same_as<std::iter_difference_t<Cpp20InputIterator>, std::ptrdiff_t>);
38 
39 using ForwardIterator = std::projected<forward_iterator<S*>, int (S::*)()>;
40 static_assert(std::same_as<ForwardIterator::value_type, int>);
41 static_assert(std::same_as<decltype(*std::declval<ForwardIterator>()), int>);
42 static_assert(std::same_as<std::iter_difference_t<ForwardIterator>, std::ptrdiff_t>);
43 
44 using BidirectionalIterator = std::projected<bidirectional_iterator<S*>, S* (S::*)() const>;
45 static_assert(std::same_as<BidirectionalIterator::value_type, S*>);
46 static_assert(std::same_as<decltype(*std::declval<BidirectionalIterator>()), S*>);
47 static_assert(std::same_as<std::iter_difference_t<BidirectionalIterator>, std::ptrdiff_t>);
48 
49 using RandomAccessIterator = std::projected<random_access_iterator<S*>, S && (S::*)()>;
50 static_assert(std::same_as<RandomAccessIterator::value_type, S>);
51 static_assert(std::same_as<decltype(*std::declval<RandomAccessIterator>()), S&&>);
52 static_assert(std::same_as<std::iter_difference_t<RandomAccessIterator>, std::ptrdiff_t>);
53 
54 using ContiguousIterator = std::projected<contiguous_iterator<S*>, S& (S::*)() const>;
55 static_assert(std::same_as<ContiguousIterator::value_type, S>);
56 static_assert(std::same_as<decltype(*std::declval<ContiguousIterator>()), S&>);
57 static_assert(std::same_as<std::iter_difference_t<ContiguousIterator>, std::ptrdiff_t>);
58 
59 template <class I, class F>
60 constexpr bool projectable = requires {
61   typename std::projected<I, F>;
62 };
63 
64 static_assert(!projectable<int, void (*)(int)>); // int isn't indirectly_readable
65 static_assert(!projectable<S, void (*)(int)>);   // S isn't weakly_incrementable
66 static_assert(!projectable<int*, void(int)>);    // void(int) doesn't satisfy indirectly_regular_unary_invcable
67