1 //===----------------------------------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 #ifndef SUPPORT_TEST_CONVERTIBLE_HPP 11 #define SUPPORT_TEST_CONVERTIBLE_HPP 12 13 // "test_convertible<Tp, Args...>()" is a metafunction used to check if 'Tp' 14 // is implicitly convertible from 'Args...' for any number of arguments, 15 // Unlike 'std::is_convertible' which only allows checking for single argument 16 // conversions. 17 18 #include <type_traits> 19 20 #include "test_macros.h" 21 22 #if TEST_STD_VER < 11 23 #error test_convertible.hpp requires C++11 or newer 24 #endif 25 26 namespace detail { 27 template <class Tp> void eat_type(Tp); 28 29 template <class Tp, class ...Args> 30 constexpr auto test_convertible_imp(int) 31 -> decltype(eat_type<Tp>({std::declval<Args>()...}), true) 32 { return true; } 33 34 template <class Tp, class ...Args> 35 constexpr auto test_convertible_imp(long) -> bool { return false; } 36 } 37 38 template <class Tp, class ...Args> 39 constexpr bool test_convertible() 40 { return detail::test_convertible_imp<Tp, Args...>(0); } 41 42 #endif // SUPPORT_TEST_CONVERTIBLE_HPP
