diff --git a/Eigen/src/Core/Assign.h b/Eigen/src/Core/Assign.h
index e025fa355..a389b3c06 100644
--- a/Eigen/src/Core/Assign.h
+++ b/Eigen/src/Core/Assign.h
@@ -536,4 +536,11 @@ EIGEN_STRONG_INLINE Derived& MatrixBase<Derived>::operator=(const MatrixBase& ot
   return ei_assign_selector<Derived,Derived>::run(derived(), other.derived());
 }
 
+template<typename Derived>
+template <typename OtherDerived>
+EIGEN_STRONG_INLINE Derived& MatrixBase<Derived>::operator=(const MatrixBase<OtherDerived>& other)
+{
+  return ei_assign_selector<Derived,OtherDerived>::run(derived(), other.derived());
+}
+
 #endif // EIGEN_ASSIGN_H
diff --git a/Eigen/src/Core/MatrixBase.h b/Eigen/src/Core/MatrixBase.h
index 1829ece7a..7fc5774ad 100644
--- a/Eigen/src/Core/MatrixBase.h
+++ b/Eigen/src/Core/MatrixBase.h
@@ -153,6 +153,9 @@ template<typename Derived> class MatrixBase
       */
     Derived& operator=(const MatrixBase& other);
 
+    template <typename OtherDerived>
+    Derived& operator=(const MatrixBase<OtherDerived>& other);
+
 #ifndef EIGEN_PARSED_BY_DOXYGEN
     template<typename ProductDerived, typename Lhs, typename Rhs>
     Derived& lazyAssign(const ProductBase<ProductDerived, Lhs,Rhs>& other);