| 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 | // ranges::prev |
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| 12 | // Make sure we're SFINAE-friendly when the template argument constraints are not met. |
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| 13 | |
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| 14 | #include <iterator> |
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| 15 | |
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| 16 | #include <cstddef> |
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| 17 | #include <utility> |
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| 18 | #include "test_iterators.h" |
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| 19 | |
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| 20 | template <class ...Args> |
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| 21 | concept has_ranges_prev = requires (Args&& ...args) { |
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| 22 | { std::ranges::prev(std::forward<Args>(args)...) }; |
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| 23 | }; |
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| 24 | |
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| 25 | using It = forward_iterator<int*>; |
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| 26 | static_assert(!has_ranges_prev<It>); |
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| 27 | static_assert(!has_ranges_prev<It, std::ptrdiff_t>); |
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| 28 | static_assert(!has_ranges_prev<It, std::ptrdiff_t, It>); |
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| 29 | |
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| 30 | // Test the test |
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| 31 | using It2 = bidirectional_iterator<int*>; |
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| 32 | static_assert(has_ranges_prev<It2>); |
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| 33 | static_assert(has_ranges_prev<It2, std::ptrdiff_t>); |
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| 34 | static_assert(has_ranges_prev<It2, std::ptrdiff_t, It2>); |
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| 35 | |
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