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42 lines
1.3 KiB
C++
42 lines
1.3 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef SUPPORT_TEST_CONVERTIBLE_H
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#define SUPPORT_TEST_CONVERTIBLE_H
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// "test_convertible<Tp, Args...>()" is a metafunction used to check if 'Tp'
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// is implicitly convertible from 'Args...' for any number of arguments,
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// Unlike 'std::is_convertible' which only allows checking for single argument
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// conversions.
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#include <type_traits>
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#include "test_macros.h"
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#if TEST_STD_VER < 11
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#error test_convertible.h requires C++11 or newer
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#endif
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namespace detail {
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template <class Tp> void eat_type(Tp);
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template <class Tp, class ...Args>
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constexpr auto test_convertible_imp(int)
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-> decltype(eat_type<Tp>({std::declval<Args>()...}), true)
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{ return true; }
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template <class Tp, class ...Args>
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constexpr auto test_convertible_imp(long) -> bool { return false; }
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}
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template <class Tp, class ...Args>
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constexpr bool test_convertible()
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{ return detail::test_convertible_imp<Tp, Args...>(0); }
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#endif // SUPPORT_TEST_CONVERTIBLE_H
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