76 lines
2.2 KiB
C++
76 lines
2.2 KiB
C++
// Copyright Louis Dionne 2013-2016
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
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#include <boost/hana/at.hpp>
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#include <boost/hana/first.hpp>
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#include <boost/hana/pair.hpp>
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#include <boost/hana/second.hpp>
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#include <boost/hana/tuple.hpp>
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namespace hana = boost::hana;
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// This test makes sure that tuples containing pairs behave properly. It is
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// useful to test this specific case because tuple and pair (may) share a lot
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// of implementation details (for EBO), and that can easily lead to subtle bugs.
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// For example, if both pair and tuple inherit from similar base classes for
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// EBO, accessing a tuple of pairs or a pair of tuples (which requires some
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// base class casting magic) can lead to ambiguous overloads.
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int main() {
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struct empty1 { };
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struct empty2 { };
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{
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hana::tuple<hana::pair<empty1, empty2>> t{};
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hana::first(hana::at_c<0>(t));
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hana::second(hana::at_c<0>(t));
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}
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{
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hana::tuple<hana::pair<int, empty2>> t{};
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hana::first(hana::at_c<0>(t));
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hana::second(hana::at_c<0>(t));
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}
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{
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hana::tuple<hana::pair<int, int>> t{};
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hana::first(hana::at_c<0>(t));
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hana::second(hana::at_c<0>(t));
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}
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{
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hana::tuple<hana::pair<empty1, int>> t{};
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hana::first(hana::at_c<0>(t));
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hana::second(hana::at_c<0>(t));
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}
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{
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hana::pair<hana::tuple<>, hana::tuple<>> p{};
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hana::first(p);
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hana::second(p);
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}
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{
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hana::pair<hana::tuple<int>, hana::tuple<int>> p{};
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hana::first(p);
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hana::second(p);
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}
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{
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hana::pair<hana::tuple<>, hana::tuple<int>> p{};
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hana::first(p);
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hana::second(p);
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}
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{
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hana::pair<hana::tuple<empty1>, hana::tuple<empty2>> p{};
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hana::first(p);
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hana::second(p);
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}
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{
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hana::pair<hana::tuple<empty1, empty2>, hana::tuple<empty2>> p{};
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hana::first(p);
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hana::second(p);
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}
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{
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hana::pair<hana::tuple<empty1, empty2>, hana::tuple<empty1, empty2>> p{};
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hana::first(p);
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hana::second(p);
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}
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}
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