diff --git a/src/App/Expression.h b/src/App/Expression.h
index 410f4eb38e..e21f7415cc 100644
--- a/src/App/Expression.h
+++ b/src/App/Expression.h
@@ -503,7 +503,7 @@ public:
   double fvalue;
   struct {
     std::string name;
-    double fvalue;
+    double fvalue = 0;
   } constant;
   std::vector<Expression*> arguments;
   std::vector<Expression*> list;