diff --git a/data_structures/query_node.hpp b/data_structures/query_node.hpp
index 48bf2edf0..7705df008 100644
--- a/data_structures/query_node.hpp
+++ b/data_structures/query_node.hpp
@@ -78,7 +78,7 @@ struct QueryNode
             break;
         }
         BOOST_ASSERT_MSG(false, "should not happen");
-        return std::numeric_limits<unsigned>::max();
+        return std::numeric_limits<int>::lowest();
     }
 };