1 // -*- C++ -*- 2 //===----------------------------------------------------------------------===// 3 // 4 // The LLVM Compiler Infrastructure 5 // 6 // This file is dual licensed under the MIT and the University of Illinois Open 7 // Source Licenses. See LICENSE.TXT for details. 8 // 9 //===----------------------------------------------------------------------===// 10 11 // UNSUPPORTED: c++98, c++03, c++11, c++14 12 13 // <variant> 14 15 // template <class ...Types> class variant; 16 17 #include <limits> 18 #include <type_traits> 19 #include <utility> 20 #include <variant> 21 22 template <class Sequence> 23 struct make_variant_imp; 24 25 template <size_t ...Indices> 26 struct make_variant_imp<std::integer_sequence<size_t, Indices...>> { 27 using type = std::variant<decltype((Indices, char(0)))...>; 28 }; 29 30 template <size_t N> 31 using make_variant_t = typename make_variant_imp<std::make_index_sequence<N>>::type; 32 33 constexpr bool ExpectEqual = 34 #ifdef _LIBCPP_ABI_VARIANT_INDEX_TYPE_OPTIMIZATION 35 false; 36 #else 37 true; 38 #endif 39 40 template <class IndexType> 41 void test_index_type() { 42 using Lim = std::numeric_limits<IndexType>; 43 using T1 = make_variant_t<Lim::max() - 1>; 44 using T2 = make_variant_t<Lim::max()>; 45 static_assert((sizeof(T1) == sizeof(T2)) == ExpectEqual, ""); 46 } 47 48 template <class IndexType> 49 void test_index_internals() { 50 using Lim = std::numeric_limits<IndexType>; 51 static_assert(std::__choose_index_type(Lim::max() -1) != 52 std::__choose_index_type(Lim::max()), ""); 53 static_assert(std::is_same_v< 54 std::__variant_index_t<Lim::max()-1>, 55 std::__variant_index_t<Lim::max()> 56 > == ExpectEqual, ""); 57 using IndexT = std::__variant_index_t<Lim::max()-1>; 58 using IndexLim = std::numeric_limits<IndexT>; 59 static_assert(std::__variant_npos<IndexT> == IndexLim::max(), ""); 60 } 61 62 int main() { 63 test_index_type<unsigned char>(); 64 // This won't compile due to template depth issues. 65 //test_index_type<unsigned short>(); 66 test_index_internals<unsigned char>(); 67 test_index_internals<unsigned short>(); 68 } 69
