Revert r289727 due to PR31384
This patch reverts the changes to tuple which fixed construction from
types derived from tuple. It breaks the code mentioned in llvm.org/PR31384.
I'll follow this commit up with a test case.
llvm-svn: 289773
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 347a1cc2212abd771ae9cc2e202ddd78704242cc
diff --git a/include/__tuple b/include/__tuple
index 8e6d2bd..775d734 100644
--- a/include/__tuple
+++ b/include/__tuple
@@ -453,57 +453,19 @@
#endif // _LIBCPP_HAS_NO_VARIADICS
#ifndef _LIBCPP_CXX03_LANG
+template <bool _IsTuple, class _SizeTrait, size_t _Expected>
+struct __tuple_like_with_size_imp : false_type {};
-template <class _Tp, size_t _TSize, bool _Good = true>
-struct __lookup_result {
- using type = _Tp;
- static constexpr bool _Success = _Good;
- static constexpr size_t _Size = _TSize;
-};
-using __lookup_failure = __lookup_result<void, (size_t)-1, false>;
+template <class _SizeTrait, size_t _Expected>
+struct __tuple_like_with_size_imp<true, _SizeTrait, _Expected>
+ : integral_constant<bool, _SizeTrait::value == _Expected> {};
-template <class ..._Args>
-auto __deduce_tuple_type_ovl(tuple<_Args...>&)
- -> __lookup_result<tuple<_Args...>, sizeof...(_Args)>;
-
-template <class _T1, class _T2>
-auto __deduce_tuple_type_ovl(pair<_T1, _T2>&)
- -> __lookup_result<pair<_T1, _T2>, 2>;
-
-template <class _Tp, size_t _Size>
-auto __deduce_tuple_type_ovl(array<_Tp, _Size>&)
- -> __lookup_result<array<_Tp, _Size>, _Size>;
-
-template <class _Tp>
-auto __deduce_tuple_type_imp(int)
- -> decltype(__deduce_tuple_type_ovl(_VSTD::declval<__uncvref_t<_Tp>&>()));
-template <class> __lookup_failure __deduce_tuple_type_imp(...);
-
-// __deduce_tuple_like - Given a type determine if it is, or is derived from,
-// a tuple-like type. This trait is used to support constructing and assigning
-// to std::tuple from user-types derived from a tuple-like type.
-template <class _TupleLike,
- class _Result = decltype(__deduce_tuple_type_imp<_TupleLike>(0)),
- bool _Good = _Result::_Success>
-struct __deduce_tuple_like {
- static_assert(_Good, "incorrect specialization choosen");
- static constexpr bool _Success = true;
- static constexpr size_t _Size = _Result::_Size;
- using _RawType = typename _Result::type;
- using _QualType =
- typename __propagate_value_category<_TupleLike>::template __apply<_RawType>;
-};
-
-template <class _TupleLike, class _Result>
-struct __deduce_tuple_like<_TupleLike, _Result, /*_Good=*/false> {
- static constexpr bool _Success = false;
- static constexpr size_t _Size = (size_t)-1;
-};
-
-template <class _TupleLike, size_t _ExpectedSize,
- class _Deduced = __deduce_tuple_like<_TupleLike>>
-using __tuple_like_with_size = integral_constant<bool,
- _Deduced::_Success && _Deduced::_Size == _ExpectedSize>;
+template <class _Tuple, size_t _ExpectedSize,
+ class _RawTuple = typename __uncvref<_Tuple>::type>
+using __tuple_like_with_size = __tuple_like_with_size_imp<
+ __tuple_like<_RawTuple>::value,
+ tuple_size<_RawTuple>, _ExpectedSize
+ >;
struct _LIBCPP_TYPE_VIS __check_tuple_constructor_fail {
template <class ...>