Avoid mixing types in CompressedStorage.h

Eigen/src/SparseCore/CompressedStorage.h

diff --git a/Eigen/src/SparseCore/CompressedStorage.h b/Eigen/src/SparseCore/CompressedStorage.h
index 733b1aa..81d7cb0 100644
--- a/Eigen/src/SparseCore/CompressedStorage.h
+++ b/Eigen/src/SparseCore/CompressedStorage.h
@@ -92,7 +92,7 @@
     {
       if (m_allocatedSize<size)
       {
-        Index realloc_size = (std::min<Index>)(NumTraits<StorageIndex>::highest(),  size + Index(reserveSizeFactor*double(size)));
+        Index realloc_size = (std::min<Index>)(NumTraits<Index>::highest(),  size + Index(reserveSizeFactor*double(size)));
         if(realloc_size<size)
           internal::throw_std_bad_alloc();
         reallocate(realloc_size);