| 1 | // Copyright Louis Dionne 2013-2022 |
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| 2 | // Distributed under the Boost Software License, Version 1.0. |
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| 3 | // (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt) |
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| 4 | |
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| 5 | #include <boost/hana/at.hpp> |
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| 6 | #include <boost/hana/first.hpp> |
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| 7 | #include <boost/hana/pair.hpp> |
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| 8 | #include <boost/hana/second.hpp> |
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| 9 | #include <boost/hana/tuple.hpp> |
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| 10 | namespace hana = boost::hana; |
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| 11 | |
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| 12 | |
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| 13 | // This test makes sure that tuples containing pairs behave properly. It is |
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| 14 | // useful to test this specific case because tuple and pair (may) share a lot |
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| 15 | // of implementation details (for EBO), and that can easily lead to subtle bugs. |
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| 16 | // For example, if both pair and tuple inherit from similar base classes for |
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| 17 | // EBO, accessing a tuple of pairs or a pair of tuples (which requires some |
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| 18 | // base class casting magic) can lead to ambiguous overloads. |
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| 19 | |
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| 20 | int main() { |
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| 21 | struct empty1 { }; |
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| 22 | struct empty2 { }; |
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| 23 | |
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| 24 | { |
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| 25 | hana::tuple<hana::pair<empty1, empty2>> t{}; |
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| 26 | hana::first(hana::at_c<0>(xs&: t)); |
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| 27 | hana::second(hana::at_c<0>(xs&: t)); |
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| 28 | } |
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| 29 | { |
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| 30 | hana::tuple<hana::pair<int, empty2>> t{}; |
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| 31 | hana::first(hana::at_c<0>(xs&: t)); |
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| 32 | hana::second(hana::at_c<0>(xs&: t)); |
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| 33 | } |
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| 34 | { |
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| 35 | hana::tuple<hana::pair<int, int>> t{}; |
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| 36 | hana::first(hana::at_c<0>(xs&: t)); |
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| 37 | hana::second(hana::at_c<0>(xs&: t)); |
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| 38 | } |
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| 39 | { |
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| 40 | hana::tuple<hana::pair<empty1, int>> t{}; |
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| 41 | hana::first(hana::at_c<0>(xs&: t)); |
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| 42 | hana::second(hana::at_c<0>(xs&: t)); |
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| 43 | } |
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| 44 | |
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| 45 | { |
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| 46 | hana::pair<hana::tuple<>, hana::tuple<>> p{}; |
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| 47 | hana::first(p); |
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| 48 | hana::second(p); |
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| 49 | } |
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| 50 | { |
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| 51 | hana::pair<hana::tuple<int>, hana::tuple<int>> p{}; |
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| 52 | hana::first(p); |
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| 53 | hana::second(p); |
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| 54 | } |
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| 55 | { |
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| 56 | hana::pair<hana::tuple<>, hana::tuple<int>> p{}; |
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| 57 | hana::first(p); |
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| 58 | hana::second(p); |
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| 59 | } |
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| 60 | { |
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| 61 | hana::pair<hana::tuple<empty1>, hana::tuple<empty2>> p{}; |
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| 62 | hana::first(p); |
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| 63 | hana::second(p); |
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| 64 | } |
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| 65 | { |
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| 66 | hana::pair<hana::tuple<empty1, empty2>, hana::tuple<empty2>> p{}; |
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| 67 | hana::first(p); |
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| 68 | hana::second(p); |
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| 69 | } |
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| 70 | { |
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| 71 | hana::pair<hana::tuple<empty1, empty2>, hana::tuple<empty1, empty2>> p{}; |
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| 72 | hana::first(p); |
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| 73 | hana::second(p); |
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| 74 | } |
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| 75 | } |
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| 76 | |
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