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ea571a11fc
- Apparently std::array operator[] returns an lvalue reference when unpacking
a temporary std::array. Using std::get<n> returns the
proper reference type in the case of rvalues.
- Adds test by ldionne
44 lines
1.1 KiB
C++
44 lines
1.1 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/ext/std/array.hpp>
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#include <boost/hana/assert.hpp>
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#include <boost/hana/at.hpp>
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#include <laws/base.hpp> // for move_only
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#include <array>
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namespace hana = boost::hana;
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int main() {
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// Check non-const lvalue reference
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{
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std::array<int, 2> arr = {{999, 888}};
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int& i = hana::at_c<0>(arr);
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BOOST_HANA_RUNTIME_CHECK(i == 999);
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arr[0] = 333;
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BOOST_HANA_RUNTIME_CHECK(i == 333);
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i = 444;
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BOOST_HANA_RUNTIME_CHECK(arr[0] == 444);
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}
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// Check const lvalue reference
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{
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std::array<int, 2> arr = {{999, 888}};
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int const& i = hana::at_c<0>(static_cast<std::array<int, 2> const&>(arr));
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BOOST_HANA_RUNTIME_CHECK(i == 999);
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arr[0] = 333;
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BOOST_HANA_RUNTIME_CHECK(i == 333);
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}
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// Check move-only types
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{
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std::array<hana::test::move_only, 2> arr{};
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hana::test::move_only m = hana::at_c<0>(std::move(arr));
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(void)m;
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}
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}
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