@@ 1,122 0,0 @@
-From 0487cca29e352e8f16bbd91fda38e76e39a0ed28 Mon Sep 17 00:00:00 2001
-From: Louis Dionne <ldionne.2@gmail.com>
-Date: Tue, 15 Jun 2021 14:40:01 -0400
-Subject: [PATCH] Work around broken integration with latest libc++. (#1635)
-
-* Work around broken integration with latest libc++.
-
-In newer versions of libc++, the base template of std::iterator_traits
-provides a member typedef called __primary_template which is an alias
-to the std::iterator_traits specialization itself. This fix works with
-both the old version of libc++ and the new one.
-
-Fixes issue #1633.
-
-* Fix is_std_iterator_traits_specialized_v on MSVC
-
-It used to pretend that std::iterator_traits<T*> is a user-defined
-specialization, which isn't the case. This is due to MSVC's
-iterator_traits<T*> specialization not posing as the base template.
----
- include/std/detail/associated_types.hpp | 22 +++++++++++-----
- test/CMakeLists.txt                     |  1 +
- test/bug1633.cpp                        | 34 +++++++++++++++++++++++++
- 3 files changed, 51 insertions(+), 6 deletions(-)
- create mode 100644 test/bug1633.cpp
-
-diff --git a/include/std/detail/associated_types.hpp b/include/std/detail/associated_types.hpp
-index b642166d4..449a3f91c 100644
---- a/include/std/detail/associated_types.hpp
-+++ b/include/std/detail/associated_types.hpp
-@@ -265,11 +265,22 @@ namespace ranges
-         template<typename I>
-         char is_std_iterator_traits_specialized_impl_(void *);
- #elif defined(_LIBCPP_VERSION)
--        template<typename I, bool B>
--        char (
--            &is_std_iterator_traits_specialized_impl_(std::__iterator_traits<I, B> *))[2];
-+        // In older versions of libc++, the base template inherits from std::__iterator_traits<typename, bool>.
-+        template<template<typename, bool> class IteratorTraitsBase, typename I, bool B>
-+        char (&libcpp_iterator_traits_base_impl(IteratorTraitsBase<I, B> *))[2];
-+        template<template<typename, bool> class IteratorTraitsBase, typename I>
-+        char libcpp_iterator_traits_base_impl(void *);
-+
-+        // In newer versions, the base template has only one template parameter and provides the
-+        // __primary_template typedef which aliases the iterator_traits specialization.
-+        template<template<typename> class, typename I>
-+        char (&libcpp_iterator_traits_base_impl(typename std::iterator_traits<I>::__primary_template *))[2];
-+        template<template<typename> class, typename I>
-+        char libcpp_iterator_traits_base_impl(void *);
-+
-         template<typename I>
--        char is_std_iterator_traits_specialized_impl_(void *);
-+        auto is_std_iterator_traits_specialized_impl_(std::iterator_traits<I>* traits)
-+            -> decltype(libcpp_iterator_traits_base_impl<std::__iterator_traits, I>(traits));
- #elif defined(_MSVC_STL_VERSION)
-         template<typename I>
-         char (&is_std_iterator_traits_specialized_impl_(
-@@ -287,14 +298,13 @@ namespace ranges
-         RANGES_INLINE_VAR constexpr bool is_std_iterator_traits_specialized_v =
-             1 == sizeof(is_std_iterator_traits_specialized_impl_<I>(
-                      static_cast<std::iterator_traits<I> *>(nullptr)));
--
-+#endif
-         // The standard iterator_traits<T *> specialization(s) do not count
-         // as user-specialized. This will no longer be necessary in C++20.
-         // This helps with `T volatile*` and `void *`.
-         template<typename T>
-         RANGES_INLINE_VAR constexpr bool is_std_iterator_traits_specialized_v<T *> =
-             false;
--#endif
-     } // namespace detail
-     /// \endcond
- } // namespace ranges
-diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
-index 889f314af..2c2b7c09c 100644
---- a/test/CMakeLists.txt
-+++ b/test/CMakeLists.txt
-@@ -19,3 +19,4 @@ rv3_add_test(test.bug474 bug474 bug474.cpp)
- rv3_add_test(test.bug566 bug566 bug566.cpp)
- rv3_add_test(test.bug1322 bug1322 bug1322.cpp)
- rv3_add_test(test.bug1335 bug1335 bug1335.cpp)
-+rv3_add_test(test.bug1633 bug1633 bug1633.cpp)
-diff --git a/test/bug1633.cpp b/test/bug1633.cpp
-new file mode 100644
-index 000000000..be52420ad
---- /dev/null
-+++ b/test/bug1633.cpp
-@@ -0,0 +1,34 @@
-+// Range v3 library
-+//
-+//  Use, modification and distribution is subject to the
-+//  Boost Software License, Version 1.0. (See accompanying
-+//  file LICENSE_1_0.txt or copy at
-+//  http://www.boost.org/LICENSE_1_0.txt)
-+//
-+// Project home: https://github.com/ericniebler/range-v3
-+
-+#include <cstddef>
-+#include <iterator>
-+#include <range/v3/iterator.hpp>
-+
-+struct X { };
-+
-+namespace std {
-+    template<> struct iterator_traits<X> { };
-+}
-+
-+struct Y {
-+    using difference_type = std::ptrdiff_t;
-+    using value_type = int;
-+    using pointer = int*;
-+    using reference = int&;
-+    using iterator_category = std::forward_iterator_tag;
-+};
-+
-+static_assert(ranges::detail::is_std_iterator_traits_specialized_v<X>, "");
-+static_assert(!ranges::detail::is_std_iterator_traits_specialized_v<Y>, "");
-+static_assert(!ranges::detail::is_std_iterator_traits_specialized_v<int*>, "");
-+
-+int main()
-+{
-+}