diff --git a/test/conservative_resize.cpp b/test/conservative_resize.cpp
index f0aff37b9..f428021dd 100644
--- a/test/conservative_resize.cpp
+++ b/test/conservative_resize.cpp
@@ -32,7 +32,7 @@ template <typename Scalar, int Storage>
 void run_matrix_tests()
 {
   typedef Matrix<Scalar, Eigen::Dynamic, Eigen::Dynamic, Storage> MatrixType;
-  typedef MatrixType::Index Index;
+  typedef typename MatrixType::Index Index;
 
   MatrixType m, n;