diff --git a/Eigen/src/Core/DenseStorageBase.h b/Eigen/src/Core/DenseStorageBase.h
index 302da2b19..94f565b1f 100644
--- a/Eigen/src/Core/DenseStorageBase.h
+++ b/Eigen/src/Core/DenseStorageBase.h
@@ -612,7 +612,7 @@ struct ei_matrix_swap_impl<MatrixTypeA, MatrixTypeB, true>
 {
   static inline void run(MatrixTypeA& a, MatrixTypeB& b)
   {
-    static_cast<MatrixTypeA::Base&>(a).m_storage.swap(static_cast<MatrixTypeB::Base&>(b).m_storage);
+    static_cast<typename MatrixTypeA::Base&>(a).m_storage.swap(static_cast<typename MatrixTypeB::Base&>(b).m_storage);
   }
 };