I suggest you provide a set of SQL commands that provoke some wrong behavior with the original code, and show that they generate good behavior after the patch. Otherwise, it's hard to evaluate the usefulness of this.
-- Álvaro Herrera Breisgau, Deutschland — https://www.EnterpriseDB.com/ "Puedes vivir sólo una vez, pero si lo haces bien, una vez es suficiente"
Toggling enable_seqscan on / off using the example from `parenting a PK constraint to a self-FK one` thread, it can be shown that different constraint Id would be detached which is incorrect.
However, I am not sure whether toggling enable_seqscan mid-test is legitimate.