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1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef SUPPORT_TEST_CONVERTIBLE_H10#define SUPPORT_TEST_CONVERTIBLE_H11 12// "test_convertible<Tp, Args...>()" is a metafunction used to check if 'Tp'13// is implicitly convertible from 'Args...' for any number of arguments,14// Unlike 'std::is_convertible' which only allows checking for single argument15// conversions.16 17#include <utility>18 19#include "test_macros.h"20 21#if TEST_STD_VER < 1122#error test_convertible.h requires C++11 or newer23#endif24 25namespace detail {26 template <class Tp> void eat_type(Tp);27 28 template <class Tp, class ...Args>29 constexpr auto test_convertible_imp(int)30 -> decltype(eat_type<Tp>({std::declval<Args>()...}), true)31 { return true; }32 33 template <class Tp, class ...Args>34 constexpr auto test_convertible_imp(long) -> bool { return false; }35}36 37template <class Tp, class ...Args>38constexpr bool test_convertible()39{ return detail::test_convertible_imp<Tp, Args...>(0); }40 41#endif // SUPPORT_TEST_CONVERTIBLE_H42