While working on something else, I noticed $SUBJECT added by commit 86dc90056:
* For UPDATE and DELETE queries, the targetlist must also contain "junk" * tlist entries needed to allow the executor to identify the rows to be * updated or deleted; for example, the ctid of a heap row. (The planner * adds these; they're not in what we receive from the planner/rewriter.)
I think that “planner/rewriter” should be parser/rewriter. Attached is a patch for that.