diff --git a/Eigen/src/Core/util/ForwardDeclarations.h b/Eigen/src/Core/util/ForwardDeclarations.h
index c755ea3c1..b114b3745 100644
--- a/Eigen/src/Core/util/ForwardDeclarations.h
+++ b/Eigen/src/Core/util/ForwardDeclarations.h
@@ -282,8 +282,6 @@ struct stem_function
 };
 }
 
-// KroneckerProduct module
-template<typename Lhs, typename Rhs> class KroneckerProductSparse;
 
 #ifdef EIGEN2_SUPPORT
 template<typename ExpressionType> class Cwise;
diff --git a/Eigen/src/SparseCore/SparseMatrixBase.h b/Eigen/src/SparseCore/SparseMatrixBase.h
index 0e431815f..2ef841616 100644
--- a/Eigen/src/SparseCore/SparseMatrixBase.h
+++ b/Eigen/src/SparseCore/SparseMatrixBase.h
@@ -259,9 +259,6 @@ template<typename Derived> class SparseMatrixBase : public EigenBase<Derived>
     template<typename Lhs, typename Rhs>
     inline Derived& operator=(const SparseSparseProduct<Lhs,Rhs>& product);
 
-    template<typename Lhs, typename Rhs>
-    inline Derived& operator=(const KroneckerProductSparse<Lhs,Rhs>& product);
-
     friend std::ostream & operator << (std::ostream & s, const SparseMatrixBase& m)
     {
       typedef typename Derived::Nested Nested;
diff --git a/unsupported/Eigen/KroneckerProduct b/unsupported/Eigen/KroneckerProduct
index baddc3837..796e386ad 100644
--- a/unsupported/Eigen/KroneckerProduct
+++ b/unsupported/Eigen/KroneckerProduct
@@ -2,7 +2,6 @@
 #define EIGEN_KRONECKER_PRODUCT_MODULE_H
 
 #include "../../Eigen/Core"
-#include "../../Eigen/SparseCore"
 
 #include "../../Eigen/src/Core/util/DisableStupidWarnings.h"
 
diff --git a/unsupported/Eigen/src/KroneckerProduct/KroneckerTensorProduct.h b/unsupported/Eigen/src/KroneckerProduct/KroneckerTensorProduct.h
index 5c2841dbd..a313eade3 100644
--- a/unsupported/Eigen/src/KroneckerProduct/KroneckerTensorProduct.h
+++ b/unsupported/Eigen/src/KroneckerProduct/KroneckerTensorProduct.h
@@ -12,12 +12,10 @@
 #ifndef KRONECKER_TENSOR_PRODUCT_H
 #define KRONECKER_TENSOR_PRODUCT_H
 
-#define EIGEN_SIZE_PRODUCT(a,b) (!((int)a && (int)b) ? 0 \
-                : ((int)a == Dynamic || (int)b == Dynamic) ? Dynamic \
-                : (int)a * (int)b)
-
 namespace Eigen { 
 
+template<typename Scalar, int Options, typename Index> class SparseMatrix;
+
 /*!
  * \brief Kronecker tensor product helper class for dense matrices
  *
@@ -79,12 +77,12 @@ class KroneckerProduct : public ReturnByValue<KroneckerProduct<Lhs,Rhs> >
  * \tparam Rhs  Type of the rignt-hand side, a matrix expression.
  */
 template<typename Lhs, typename Rhs>
-class KroneckerProductSparse : public SparseMatrixBase<KroneckerProductSparse<Lhs,Rhs> >
+class KroneckerProductSparse : public EigenBase<KroneckerProductSparse<Lhs,Rhs> >
 {
-  public:
-    typedef SparseMatrixBase<KroneckerProductSparse> Base;
-    EIGEN_DENSE_PUBLIC_INTERFACE(KroneckerProductSparse)
+  private:
+    typedef typename internal::traits<KroneckerProductSparse>::Index Index;
 
+  public:
     /*! \brief Constructor. */
     KroneckerProductSparse(const Lhs& A, const Rhs& B)
       : m_A(A), m_B(B)
@@ -96,6 +94,14 @@ class KroneckerProductSparse : public SparseMatrixBase<KroneckerProductSparse<Lh
     inline Index rows() const { return m_A.rows() * m_B.rows(); }
     inline Index cols() const { return m_A.cols() * m_B.cols(); }
 
+    template<typename Scalar, int Options, typename Index>
+    operator SparseMatrix<Scalar, Options, Index>()
+    {
+      SparseMatrix<Scalar, Options, Index> result;
+      evalTo(result.derived());
+      return result;
+    }
+
   private:
     typename Lhs::Nested m_A;
     typename Rhs::Nested m_B;
@@ -151,10 +157,10 @@ struct traits<KroneckerProduct<_Lhs,_Rhs> >
   typedef typename scalar_product_traits<typename Lhs::Scalar, typename Rhs::Scalar>::ReturnType Scalar;
 
   enum {
-    Rows = EIGEN_SIZE_PRODUCT(traits<Lhs>::RowsAtCompileTime, traits<Rhs>::RowsAtCompileTime),
-    Cols = EIGEN_SIZE_PRODUCT(traits<Lhs>::ColsAtCompileTime, traits<Rhs>::ColsAtCompileTime),
-    MaxRows = EIGEN_SIZE_PRODUCT(traits<Lhs>::MaxRowsAtCompileTime, traits<Rhs>::MaxRowsAtCompileTime),
-    MaxCols = EIGEN_SIZE_PRODUCT(traits<Lhs>::MaxColsAtCompileTime, traits<Rhs>::MaxColsAtCompileTime),
+    Rows = size_at_compile_time<traits<Lhs>::RowsAtCompileTime, traits<Rhs>::RowsAtCompileTime>::ret,
+    Cols = size_at_compile_time<traits<Lhs>::ColsAtCompileTime, traits<Rhs>::ColsAtCompileTime>::ret,
+    MaxRows = size_at_compile_time<traits<Lhs>::MaxRowsAtCompileTime, traits<Rhs>::MaxRowsAtCompileTime>::ret,
+    MaxCols = size_at_compile_time<traits<Lhs>::MaxColsAtCompileTime, traits<Rhs>::MaxColsAtCompileTime>::ret,
     CoeffReadCost = Lhs::CoeffReadCost + Rhs::CoeffReadCost + NumTraits<Scalar>::MulCost
   };
 
@@ -168,17 +174,17 @@ struct traits<KroneckerProductSparse<_Lhs,_Rhs> >
   typedef typename remove_all<_Lhs>::type Lhs;
   typedef typename remove_all<_Rhs>::type Rhs;
   typedef typename scalar_product_traits<typename Lhs::Scalar, typename Rhs::Scalar>::ReturnType Scalar;
-  typedef Sparse StorageKind;
+  typedef typename promote_storage_type<typename traits<Lhs>::StorageKind, typename traits<Rhs>::StorageKind>::ret StorageKind;
   typedef typename promote_index_type<typename Lhs::Index, typename Rhs::Index>::type Index;
 
   enum {
     LhsFlags = Lhs::Flags,
     RhsFlags = Rhs::Flags,
 
-    RowsAtCompileTime = EIGEN_SIZE_PRODUCT(traits<Lhs>::RowsAtCompileTime, traits<Rhs>::RowsAtCompileTime),
-    ColsAtCompileTime = EIGEN_SIZE_PRODUCT(traits<Lhs>::ColsAtCompileTime, traits<Rhs>::ColsAtCompileTime),
-    MaxRowsAtCompileTime = EIGEN_SIZE_PRODUCT(traits<Lhs>::MaxRowsAtCompileTime, traits<Rhs>::MaxRowsAtCompileTime),
-    MaxColsAtCompileTime = EIGEN_SIZE_PRODUCT(traits<Lhs>::MaxColsAtCompileTime, traits<Rhs>::MaxColsAtCompileTime),
+    RowsAtCompileTime = size_at_compile_time<traits<Lhs>::RowsAtCompileTime, traits<Rhs>::RowsAtCompileTime>::ret,
+    ColsAtCompileTime = size_at_compile_time<traits<Lhs>::ColsAtCompileTime, traits<Rhs>::ColsAtCompileTime>::ret,
+    MaxRowsAtCompileTime = size_at_compile_time<traits<Lhs>::MaxRowsAtCompileTime, traits<Rhs>::MaxRowsAtCompileTime>::ret,
+    MaxColsAtCompileTime = size_at_compile_time<traits<Lhs>::MaxColsAtCompileTime, traits<Rhs>::MaxColsAtCompileTime>::ret,
 
     EvalToRowMajor = (LhsFlags & RhsFlags & RowMajorBit),
     RemovedBits = ~(EvalToRowMajor ? 0 : RowMajorBit),
@@ -233,14 +239,6 @@ KroneckerProductSparse<A,B> kroneckerProduct(const EigenBase<A>& a, const EigenB
   return KroneckerProductSparse<A,B>(a.derived(), b.derived());
 }
 
-template<typename Derived>
-template<typename Lhs, typename Rhs>
-Derived& SparseMatrixBase<Derived>::operator=(const KroneckerProductSparse<Lhs,Rhs>& product)
-{
-  product.evalTo(derived());
-  return derived();
-}
-
 } // end namespace Eigen
 
 #endif // KRONECKER_TENSOR_PRODUCT_H