diff --git a/src/frontend/numparam/xpressn.c b/src/frontend/numparam/xpressn.c
index a99d18c15..85875c044 100644
--- a/src/frontend/numparam/xpressn.c
+++ b/src/frontend/numparam/xpressn.c
@@ -1309,7 +1309,7 @@ formula(tdico *dico, char *s, bool *perror)
                 topop = level;
         }
 
-        if (state > 0)
+        if (state != 0)
             oldstate = state;
     }