Author: ericwf
Date: Thu Mar 22 15:32:55 2018
New Revision: 328261
URL: http://llvm.org/viewvc/llvm-project?rev=328261&view=rev
Log:
Workaround GCC bug PR78489 - SFINAE order is not respected.
This patch works around variant test failures which are new to
GCC 8. GCC 8 either doesn't perform SFINAE in lexical order, or
it doesn't halt after encountering the first failure. This
causes hard error to occur instead of substitution failure.
See gcc.gnu.org/PR78489
Modified:
libcxx/trunk/include/variant
libcxx/trunk/test/std/utilities/variant/variant.variant/variant.ctor/in_place_index_init_list_args.pass.cpp
Modified: libcxx/trunk/include/variant
URL:
http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/variant?rev=328261&r1=328260&r2=328261&view=diff
==============================================================================
--- libcxx/trunk/include/variant (original)
+++ libcxx/trunk/include/variant Thu Mar 22 15:32:55 2018
@@ -1156,29 +1156,24 @@ public:
: __impl(in_place_index<_Ip>, _VSTD::forward<_Arg>(__arg)) {}
template <size_t _Ip, class... _Args,
- class = enable_if_t<(_Ip < sizeof...(_Types)), int>,
- class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,
- enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>
+ enable_if_t<(_Ip < sizeof...(_Types)), size_t> _Ip2 = _Ip,
+ class _Tp = variant_alternative_t<_Ip2, variant<_Types...>>,
+ enable_if_t<is_constructible<_Tp, _Args...>::value, int> = 0>
inline _LIBCPP_INLINE_VISIBILITY
- explicit constexpr variant(
- in_place_index_t<_Ip>,
- _Args&&... __args) noexcept(is_nothrow_constructible_v<_Tp, _Args...>)
+ explicit constexpr variant(in_place_index_t<_Ip>,
+ _Args&&... __args)
+ noexcept(is_nothrow_constructible_v<_Tp, _Args...>)
: __impl(in_place_index<_Ip>, _VSTD::forward<_Args>(__args)...) {}
- template <
- size_t _Ip,
- class _Up,
- class... _Args,
- enable_if_t<(_Ip < sizeof...(_Types)), int> = 0,
- class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,
+ template <size_t _Ip, class _Up, class... _Args,
+ enable_if_t<(_Ip < sizeof...(_Types)), size_t> _Ip2 = _Ip,
+ class _Tp = variant_alternative_t<_Ip2, variant<_Types...>>,
enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>,
int> = 0>
inline _LIBCPP_INLINE_VISIBILITY
- explicit constexpr variant(
- in_place_index_t<_Ip>,
- initializer_list<_Up> __il,
- _Args&&... __args) noexcept(
- is_nothrow_constructible_v<_Tp, initializer_list<_Up>&, _Args...>)
+ explicit constexpr variant(in_place_index_t<_Ip>, initializer_list<_Up> __il,
+ _Args&&... __args)
+ noexcept(is_nothrow_constructible_v<_Tp, initializer_list<_Up>&,
_Args...>)
: __impl(in_place_index<_Ip>, __il, _VSTD::forward<_Args>(__args)...) {}
template <
Modified:
libcxx/trunk/test/std/utilities/variant/variant.variant/variant.ctor/in_place_index_init_list_args.pass.cpp
URL:
http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/utilities/variant/variant.variant/variant.ctor/in_place_index_init_list_args.pass.cpp?rev=328261&r1=328260&r2=328261&view=diff
==============================================================================
---
libcxx/trunk/test/std/utilities/variant/variant.variant/variant.ctor/in_place_index_init_list_args.pass.cpp
(original)
+++
libcxx/trunk/test/std/utilities/variant/variant.variant/variant.ctor/in_place_index_init_list_args.pass.cpp
Thu Mar 22 15:32:55 2018
@@ -73,6 +73,12 @@ void test_ctor_sfinae() {
!std::is_constructible<V, std::in_place_index_t<2>, IL>::value, "");
static_assert(!test_convertible<V, std::in_place_index_t<2>, IL>(), "");
}
+ { // index not in variant
+ using V = std::variant<InitList, InitListArg, int>;
+ static_assert(
+ !std::is_constructible<V, std::in_place_index_t<3>, IL>::value, "");
+ static_assert(!test_convertible<V, std::in_place_index_t<3>, IL>(), "");
+ }
}
void test_ctor_basic() {
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