diff --git a/src/tree_schema_free.c b/src/tree_schema_free.c
index 071de57..8bcfb5a 100644
--- a/src/tree_schema_free.c
+++ b/src/tree_schema_free.c
@@ -987,9 +987,11 @@
 }
 
 API void
-lysc_extension_instance_free(struct ly_ctx *ctx, struct lysc_ext_substmt *substmts)
+lysc_extension_instance_substatements_free(struct ly_ctx *ctx, struct lysc_ext_substmt *substmts)
 {
-    for (LY_ARRAY_COUNT_TYPE u = 0; substmts[u].stmt; ++u) {
+    LY_ARRAY_COUNT_TYPE u;
+
+    LY_ARRAY_FOR(substmts, u) {
         if (!substmts[u].storage) {
             continue;
         }
@@ -1012,6 +1014,8 @@
                 FREE_ARRAY(ctx, types, lysc_type2_free);
             }
             break;
+        case LY_STMT_DESCRIPTION:
+        case LY_STMT_REFERENCE:
         case LY_STMT_UNITS:
             if (substmts[u].cardinality < LY_STMT_CARD_SOME) {
                 /* single item */
@@ -1054,6 +1058,8 @@
             LOGINT(ctx);
         }
     }
+
+    LY_ARRAY_FREE(substmts);
 }
 
 void