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 
12 // projected
13 
14 #include <iterator>
15 
16 #include <concepts>
17 #include <functional>
18 
19 #include "test_iterators.h"
20 
21 using IntPtr = std::projected<int const*, std::identity>;
22 static_assert(std::same_as<IntPtr::value_type, int>);
23 static_assert(std::same_as<decltype(*std::declval<IntPtr>()), int const&>);
24 static_assert(std::same_as<std::iter_difference_t<IntPtr>, std::ptrdiff_t>);
25 
26 struct S { };
27 
28 using Cpp17InputIterator = std::projected<cpp17_input_iterator<S*>, int S::*>;
29 static_assert(std::same_as<Cpp17InputIterator::value_type, int>);
30 static_assert(std::same_as<decltype(*std::declval<Cpp17InputIterator>()), int&>);
31 static_assert(std::same_as<std::iter_difference_t<Cpp17InputIterator>, std::ptrdiff_t>);
32 
33 using Cpp20InputIterator = std::projected<cpp20_input_iterator<S*>, int S::*>;
34 static_assert(std::same_as<Cpp20InputIterator::value_type, int>);
35 static_assert(std::same_as<decltype(*std::declval<Cpp20InputIterator>()), int&>);
36 static_assert(std::same_as<std::iter_difference_t<Cpp20InputIterator>, std::ptrdiff_t>);
37 
38 using ForwardIterator = std::projected<forward_iterator<S*>, int (S::*)()>;
39 static_assert(std::same_as<ForwardIterator::value_type, int>);
40 static_assert(std::same_as<decltype(*std::declval<ForwardIterator>()), int>);
41 static_assert(std::same_as<std::iter_difference_t<ForwardIterator>, std::ptrdiff_t>);
42 
43 using BidirectionalIterator = std::projected<bidirectional_iterator<S*>, S* (S::*)() const>;
44 static_assert(std::same_as<BidirectionalIterator::value_type, S*>);
45 static_assert(std::same_as<decltype(*std::declval<BidirectionalIterator>()), S*>);
46 static_assert(std::same_as<std::iter_difference_t<BidirectionalIterator>, std::ptrdiff_t>);
47 
48 using RandomAccessIterator = std::projected<random_access_iterator<S*>, S && (S::*)()>;
49 static_assert(std::same_as<RandomAccessIterator::value_type, S>);
50 static_assert(std::same_as<decltype(*std::declval<RandomAccessIterator>()), S&&>);
51 static_assert(std::same_as<std::iter_difference_t<RandomAccessIterator>, std::ptrdiff_t>);
52 
53 using ContiguousIterator = std::projected<contiguous_iterator<S*>, S& (S::*)() const>;
54 static_assert(std::same_as<ContiguousIterator::value_type, S>);
55 static_assert(std::same_as<decltype(*std::declval<ContiguousIterator>()), S&>);
56 static_assert(std::same_as<std::iter_difference_t<ContiguousIterator>, std::ptrdiff_t>);
57 
58 template <class I, class F>
59 constexpr bool projectable = requires {
60   typename std::projected<I, F>;
61 };
62 
63 static_assert(!projectable<int, void (*)(int)>); // int isn't indirectly_readable
64 static_assert(!projectable<S, void (*)(int)>);   // S isn't weakly_incrementable
65 static_assert(!projectable<int*, void(int)>);    // void(int) doesn't satisfy indirectly_regular_unary_invcable
66