diff --git a/Eigen/src/SparseCore/SparseMap.h b/Eigen/src/SparseCore/SparseMap.h
index d76f3b68f..f99be3379 100644
--- a/Eigen/src/SparseCore/SparseMap.h
+++ b/Eigen/src/SparseCore/SparseMap.h
@@ -186,7 +186,7 @@ class SparseMapBase<Derived,WriteAccessors>
       Index end = Base::isCompressed() ? Base::m_outerIndex[outer+1] : start + Base::m_innerNonZeros[outer];
       eigen_assert(end>=start && "you probably called coeffRef on a non finalized matrix");
       eigen_assert(end>start && "coeffRef cannot be called on a zero coefficient");
-      Index* r = std::lower_bound(&Base::m_innerIndices[start],&Base::m_innerIndices[end],inner);
+      StorageIndex* r = std::lower_bound(&Base::m_innerIndices[start],&Base::m_innerIndices[end],inner);
       const Index id = r - &Base::m_innerIndices[0];
       eigen_assert((*r==inner) && (id<end) && "coeffRef cannot be called on a zero coefficient");
       return const_cast<Scalar*>(Base::m_values)[id];
diff --git a/test/sparse_basic.cpp b/test/sparse_basic.cpp
index 77523bab5..10309b3a9 100644
--- a/test/sparse_basic.cpp
+++ b/test/sparse_basic.cpp
@@ -317,6 +317,17 @@ template<typename SparseMatrixType> void sparse_basic(const SparseMatrixType& re
       VERIFY_IS_APPROX(mapMat2+mapMat3, refMat2+refMat3);
       VERIFY_IS_APPROX(mapMat2+mapMat3, refMat2+refMat3);
     }
+
+    Index i = internal::random<Index>(0,rows-1);
+    Index j = internal::random<Index>(0,cols-1);
+    m2.coeffRef(i,j) = 123;
+    if(internal::random<bool>())
+      m2.makeCompressed();
+    Map<SparseMatrixType> mapMat2(rows, cols, m2.nonZeros(), m2.outerIndexPtr(), m2.innerIndexPtr(), m2.valuePtr(),  m2.innerNonZeroPtr());
+    VERIFY_IS_EQUAL(m2.coeff(i,j),Scalar(123));
+    VERIFY_IS_EQUAL(mapMat2.coeff(i,j),Scalar(123));
+    mapMat2.coeffRef(i,j) = -123;
+    VERIFY_IS_EQUAL(m2.coeff(i,j),Scalar(-123));
   }
 
   // test triangularView