From 37f08bb8188e3af81869ee5c12ba5bee30d2101a Mon Sep 17 00:00:00 2001
From: Hanos-Puskai Peter <peter.hanos-puskai@intel.com>
Date: Tue, 10 Aug 2021 17:58:37 +0300
Subject: [PATCH] Fix ambiguity of std::begin/end

- this patch should restore the range-based for functionality for
  pull-type coroutines
- it also keeps the behaviour when using std::begin / std::end
  if some standard container's header is included
- it also eliminates the possible undefined behaviour / ill-formedness
  caused by the custom overload of std::begin / std::end
---
 .../coroutine2/detail/pull_coroutine.hpp      | 24 +++++++------------
 1 file changed, 8 insertions(+), 16 deletions(-)

diff --git a/include/boost/coroutine2/detail/pull_coroutine.hpp b/include/boost/coroutine2/detail/pull_coroutine.hpp
index 96d10d6..767a388 100644
--- a/include/boost/coroutine2/detail/pull_coroutine.hpp
+++ b/include/boost/coroutine2/detail/pull_coroutine.hpp
@@ -130,6 +130,9 @@ public:
     };
 
     friend class iterator;
+
+    iterator begin() { return iterator (this); }
+    iterator end() { return iterator(); }
 };
 
 template< typename T >
@@ -238,6 +241,9 @@ public:
     };
 
     friend class iterator;
+
+    iterator begin() { return iterator (this); }
+    iterator end() { return iterator(); }
 };
 
 template<>
@@ -278,6 +284,8 @@ public:
     explicit operator bool() const noexcept;
 
     bool operator!() const noexcept;
+
+
 };
 
 template< typename T >
@@ -294,22 +302,6 @@ end( pull_coroutine< T > &) {
 
 }}}
 
-namespace std {
-
-template< typename T >
-typename boost::coroutines2::detail::pull_coroutine< T >::iterator
-begin( boost::coroutines2::detail::pull_coroutine< T > & c) {
-    return boost::coroutines2::detail::begin( c);
-}
-
-template< typename T >
-typename boost::coroutines2::detail::pull_coroutine< T >::iterator
-end( boost::coroutines2::detail::pull_coroutine< T > & c) {
-    return boost::coroutines2::detail::end( c);
-}
-
-}
-
 #ifdef BOOST_HAS_ABI_HEADERS
 #  include BOOST_ABI_SUFFIX
 #endif