Fix PR39619 - iterator_traits isn't SFINAE-friendly enough. Thanks to Eric for the report
llvm-svn: 346738
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: d4fa0381e35b68fccff8070764282f07b3eb7711
diff --git a/include/iterator b/include/iterator
index aed0525..bda177e 100644
--- a/include/iterator
+++ b/include/iterator
@@ -438,6 +438,23 @@
struct _LIBCPP_TEMPLATE_VIS random_access_iterator_tag : public bidirectional_iterator_tag {};
template <class _Tp>
+struct __has_iterator_typedefs
+{
+private:
+ struct __two {char __lx; char __lxx;};
+ template <class _Up> static __two __test(...);
+ template <class _Up> static char __test(typename std::__void_t<typename _Up::iterator_category>::type* = 0,
+ typename std::__void_t<typename _Up::difference_type>::type* = 0,
+ typename std::__void_t<typename _Up::value_type>::type* = 0,
+ typename std::__void_t<typename _Up::reference>::type* = 0,
+ typename std::__void_t<typename _Up::pointer>::type* = 0
+ );
+public:
+ static const bool value = sizeof(__test<_Tp>(0,0,0,0,0)) == 1;
+};
+
+
+template <class _Tp>
struct __has_iterator_category
{
private:
@@ -479,7 +496,7 @@
template <class _Iter>
struct _LIBCPP_TEMPLATE_VIS iterator_traits
- : __iterator_traits<_Iter, __has_iterator_category<_Iter>::value> {};
+ : __iterator_traits<_Iter, __has_iterator_typedefs<_Iter>::value> {};
template<class _Tp>
struct _LIBCPP_TEMPLATE_VIS iterator_traits<_Tp*>