diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
index d6a4012f78..6451a21a28 100644
--- a/qapi/qapi-visit-core.c
+++ b/qapi/qapi-visit-core.c
@@ -263,8 +263,17 @@ void visit_type_int64(Visitor *v, int64_t *obj, const char *name, Error **errp)
 
 void visit_type_size(Visitor *v, uint64_t *obj, const char *name, Error **errp)
 {
+    int64_t value;
     if (!error_is_set(errp)) {
-        (v->type_size ? v->type_size : v->type_uint64)(v, obj, name, errp);
+        if (v->type_size) {
+            v->type_size(v, obj, name, errp);
+        } else if (v->type_uint64) {
+            v->type_uint64(v, obj, name, errp);
+        } else {
+            value = *obj;
+            v->type_int(v, &value, name, errp);
+            *obj = value;
+        }
     }
 }