Alexander Korotkov <aekorotkov@gmail.com> writes:
> Please, consider my additions to the comment. They explain why we use
> ChangeVarNodes_walker() instead of expression_tree_walker(), and gives
> a bit more details about difference in processing of top-level Query
> and subquery.
I'm fine with this, although in
+ * ... We invoke ChangeVarNodes_walker directly rather than
+ * expression_tree_walker
I would write "rather than via expression_tree_walker".
regards, tom lane