diff --git a/gm/refine.cc b/gm/refine.cc
index 7ea02bdbb178d42b977aa6f158189bc39a8fcdc4..2b5083b928642ab1fad0cd717645922d58d3f764 100644
--- a/gm/refine.cc
+++ b/gm/refine.cc
@@ -2977,7 +2977,7 @@ static void CheckElementContextConsistency(ELEMENT *theElement,
                                            ELEMENTCONTEXT theElementContext)
 {
   int i;
-  int errorflag = 0;
+  DUNE_UNUSED int errorflag = 0;
   int errortype[MAX_CORNERS_OF_ELEM+MAX_NEW_CORNERS_DIM];
   int correcttype[MAX_CORNERS_OF_ELEM+MAX_NEW_CORNERS_DIM];