From 0105146915c62f732841bb63d5c2046ed7cb3864 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Sat, 10 Nov 2018 09:11:38 +0100
Subject: [PATCH] Fix warning in c++03

---
 Eigen/src/Core/StlIterators.h | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/Eigen/src/Core/StlIterators.h b/Eigen/src/Core/StlIterators.h
index 131a95085..4f25a60c4 100644
--- a/Eigen/src/Core/StlIterators.h
+++ b/Eigen/src/Core/StlIterators.h
@@ -23,8 +23,9 @@ protected:
   typedef indexed_based_stl_iterator_base<typename traits::non_const_iterator> non_const_iterator;
   typedef indexed_based_stl_iterator_base<typename traits::const_iterator> const_iterator;
   typedef typename internal::conditional<internal::is_const<XprType>::value,non_const_iterator,const_iterator>::type other_iterator;
-  friend const_iterator;
-  friend non_const_iterator;
+  // NOTE: in C++03 we cannot declare friend classes through typedefs because we need to write friend class:
+  friend class indexed_based_stl_iterator_base<typename traits::const_iterator>;
+  friend class indexed_based_stl_iterator_base<typename traits::non_const_iterator>;
 public:
   typedef Index difference_type;
   typedef std::random_access_iterator_tag iterator_category;
@@ -99,8 +100,9 @@ class pointer_based_stl_iterator
   typedef pointer_based_stl_iterator<typename internal::remove_const<XprType>::type> non_const_iterator;
   typedef pointer_based_stl_iterator<typename internal::add_const<XprType>::type> const_iterator;
   typedef typename internal::conditional<internal::is_const<XprType>::value,non_const_iterator,const_iterator>::type other_iterator;
-  friend const_iterator;
-  friend non_const_iterator;
+  // NOTE: in C++03 we cannot declare friend classes through typedefs because we need to write friend class:
+  friend class pointer_based_stl_iterator<typename internal::add_const<XprType>::type>;
+  friend class pointer_based_stl_iterator<typename internal::remove_const<XprType>::type>;
 public:
   typedef Index difference_type;
   typedef typename XprType::Scalar value_type;