| 1 | //===----------------------------------------------------------------------===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |
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| 9 | // UNSUPPORTED: c++03, c++11, c++14, c++17 |
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| 10 | |
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| 11 | // template<class F, class I> |
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| 12 | // concept indirect_unary_predicate; |
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| 13 | |
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| 14 | #include <iterator> |
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| 15 | #include <type_traits> |
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| 16 | |
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| 17 | #include "indirectly_readable.h" |
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| 18 | #include "test_macros.h" |
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| 19 | |
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| 20 | using It = IndirectlyReadable<struct Token>; |
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| 21 | |
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| 22 | template <class I> |
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| 23 | struct GoodPredicate { |
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| 24 | bool operator()(std::iter_reference_t<I>) const; |
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| 25 | bool operator()(std::iter_value_t<I>&) const; |
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| 26 | bool operator()(std::iter_common_reference_t<I>) const; |
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| 27 | }; |
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| 28 | |
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| 29 | // Should work when all constraints are satisfied |
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| 30 | static_assert(std::indirect_unary_predicate<GoodPredicate<It>, It>); |
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| 31 | static_assert(std::indirect_unary_predicate<bool(*)(int), int*>); |
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| 32 | [[maybe_unused]] auto lambda = [](int i) { return i % 2 == 0; }; |
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| 33 | static_assert(std::indirect_unary_predicate<decltype(lambda), int*>); |
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| 34 | |
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| 35 | // Should fail when the iterator is not indirectly_readable |
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| 36 | struct NotIndirectlyReadable { }; |
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| 37 | static_assert(!std::indirect_unary_predicate<GoodPredicate<NotIndirectlyReadable>, NotIndirectlyReadable>); |
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| 38 | |
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| 39 | // Should fail when the predicate is not copy constructible |
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| 40 | struct BadPredicate1 { |
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| 41 | BadPredicate1(BadPredicate1 const&) = delete; |
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| 42 | template <class T> bool operator()(T const&) const; |
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| 43 | }; |
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| 44 | static_assert(!std::indirect_unary_predicate<BadPredicate1, It>); |
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| 45 | |
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| 46 | // Should fail when the predicate can't be called with std::iter_value_t<It>& |
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| 47 | struct BadPredicate2 { |
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| 48 | template <class T> bool operator()(T const&) const; |
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| 49 | bool operator()(std::iter_value_t<It>&) const = delete; |
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| 50 | }; |
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| 51 | static_assert(!std::indirect_unary_predicate<BadPredicate2, It>); |
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| 52 | |
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| 53 | // Should fail when the predicate can't be called with std::iter_reference_t<It> |
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| 54 | struct BadPredicate3 { |
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| 55 | template <class T> bool operator()(T const&) const; |
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| 56 | bool operator()(std::iter_reference_t<It>) const = delete; |
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| 57 | }; |
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| 58 | static_assert(!std::indirect_unary_predicate<BadPredicate3, It>); |
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| 59 | |
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| 60 | // This case was made valid by P2997R1. |
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| 61 | struct GoodPredicate4 { |
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| 62 | template <class T> |
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| 63 | bool operator()(T const&) const; |
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| 64 | bool operator()(std::iter_common_reference_t<It>) const = delete; |
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| 65 | }; |
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| 66 | static_assert(std::indirect_unary_predicate<GoodPredicate4, It>); |
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| 67 | |
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| 68 | // Test ADL-proofing (P2538R1) |
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| 69 | #if TEST_STD_VER >= 26 || defined(_LIBCPP_VERSION) |
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| 70 | struct Incomplete; |
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| 71 | template<class T> struct Holder { T t; }; |
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| 72 | struct HolderIncompletePred { bool operator()(Holder<Incomplete>*) const; }; |
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| 73 | static_assert(std::indirect_unary_predicate<HolderIncompletePred, Holder<Incomplete>**>); |
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| 74 | static_assert(!std::indirect_unary_predicate<Holder<Incomplete>*, Holder<Incomplete>**>); |
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| 75 | #endif |
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| 76 | |
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