From 7dad5f797e8c270be5f32aee154f6660df2242f5 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Tue, 16 Dec 2014 13:33:43 +0100
Subject: [PATCH] bug #821: workaround MSVC 2013 issue with using
 Base::Base::operator=

---
 Eigen/src/Core/MapBase.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/Eigen/src/Core/MapBase.h b/Eigen/src/Core/MapBase.h
index 3c67edae5..5d51548cd 100644
--- a/Eigen/src/Core/MapBase.h
+++ b/Eigen/src/Core/MapBase.h
@@ -243,7 +243,11 @@ template<typename Derived> class MapBase<Derived, WriteAccessors>
       return derived();
     }
 
-    using Base::Base::operator=;
+    // In theory MapBase<Derived, ReadOnlyAccessors> should not make a using Base::operator=,
+    // and thus we should directly do: using Base::Base::operator=;
+    // However, this would confuse recent MSVC 2013 (bug 821), and since MapBase<Derived, ReadOnlyAccessors>
+    // has operator= to make ICC 11 happy, we can also make MSVC 2013 happy as follow:
+    using Base::operator=;
 };
 
 #undef EIGEN_STATIC_ASSERT_INDEX_BASED_ACCESS