diff --git a/qobject/json-parser.c b/qobject/json-parser.c
index e3ee2a273a..685e9dac24 100644
--- a/qobject/json-parser.c
+++ b/qobject/json-parser.c
@@ -544,6 +544,7 @@ QObject *json_parser_parse(GQueue *tokens, va_list *ap, Error **errp)
     QObject *result;
 
     result = parse_value(&ctxt, ap);
+    assert(ctxt.err || g_queue_is_empty(ctxt.buf));
 
     error_propagate(errp, ctxt.err);