diff --git a/src/util/lp/factorization.h b/src/util/lp/factorization.h
index fd2974f9b..878bf6416 100644
--- a/src/util/lp/factorization.h
+++ b/src/util/lp/factorization.h
@@ -23,7 +23,7 @@
 
 namespace nla {
 
-class factorization_factory;
+struct factorization_factory;
 typedef unsigned lpvar;
 
 class factorization {