| 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... Args> |
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| 12 | // concept predicate; |
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| 13 | |
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| 14 | #include <concepts> |
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| 15 | #include <type_traits> |
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| 16 | |
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| 17 | static_assert(std::predicate<bool()>); |
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| 18 | static_assert(std::predicate<bool (*)()>); |
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| 19 | static_assert(std::predicate<bool (&)()>); |
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| 20 | |
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| 21 | static_assert(!std::predicate<void()>); |
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| 22 | static_assert(!std::predicate<void (*)()>); |
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| 23 | static_assert(!std::predicate<void (&)()>); |
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| 24 | |
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| 25 | struct S {}; |
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| 26 | |
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| 27 | static_assert(!std::predicate<S(int), int>); |
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| 28 | static_assert(!std::predicate<S(double), double>); |
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| 29 | static_assert(std::predicate<int S::*, S*>); |
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| 30 | static_assert(std::predicate<int (S::*)(), S*>); |
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| 31 | static_assert(std::predicate<int (S::*)(), S&>); |
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| 32 | static_assert(!std::predicate<void (S::*)(), S*>); |
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| 33 | static_assert(!std::predicate<void (S::*)(), S&>); |
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| 34 | |
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| 35 | static_assert(!std::predicate<bool(S)>); |
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| 36 | static_assert(!std::predicate<bool(S&), S>); |
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| 37 | static_assert(!std::predicate<bool(S&), S const&>); |
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| 38 | static_assert(std::predicate<bool(S&), S&>); |
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| 39 | |
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| 40 | struct Predicate { |
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| 41 | bool operator()(int, double, char); |
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| 42 | }; |
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| 43 | static_assert(std::predicate<Predicate, int, double, char>); |
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| 44 | static_assert(std::predicate<Predicate&, int, double, char>); |
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| 45 | static_assert(!std::predicate<const Predicate, int, double, char>); |
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| 46 | static_assert(!std::predicate<const Predicate&, int, double, char>); |
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| 47 | |
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| 48 | constexpr bool check_lambda(auto) { return false; } |
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| 49 | |
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| 50 | constexpr bool check_lambda(std::predicate auto) { return true; } |
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| 51 | |
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| 52 | static_assert(check_lambda([] { return std::true_type(); })); |
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| 53 | static_assert(check_lambda([]() -> int* { return nullptr; })); |
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| 54 | |
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| 55 | struct boolean { |
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| 56 | operator bool() const noexcept; |
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| 57 | }; |
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| 58 | static_assert(check_lambda([] { return boolean(); })); |
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| 59 | |
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| 60 | struct explicit_bool { |
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| 61 | explicit operator bool() const noexcept; |
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| 62 | }; |
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| 63 | static_assert(!check_lambda([] { return explicit_bool(); })); |
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| 64 | |
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