1 files changed, 1 insertions, 0 deletions
diff --git a/awk.h b/awk.h
index 0c42f2e7..220dba95 100644
--- a/awk.h
+++ b/awk.h
@@ -1182,6 +1182,7 @@ extern void r_unref(NODE *tmp);
 static inline void
 DEREF(NODE *r)
 {
+	assert(r->valref > 0);
 	if (--r->valref == 0)
 		r_unref(r);
 }