Re: cannot restore schema with is not distinct from on hstore since PG 9.6.8

[ just to tie back to this old thread ]

I wrote:
> I poked into this area for awhile, and it turns out to be even a
> worse can of worms than I thought.  I looked through gram.y and
> parse_expr.c, and identified several distinct classes of issue.
> (I'm not promising that I found everything.)

In fact, the thread at [1] identifies an essentially similar class
of issue that I missed: JOIN ... USING (x) also implicitly looks up
an equality operator by seeing what "tab1.x = tab2.x" resolves as.
This is much like the CASE situation, in that there's no
SQL-standard-compliant way to reverse-list a view containing
such a construct while showing how it was resolved.  We'd need
to invent some new syntax if we want to make this safer.

            regards, tom lane

[1] https://www.postgresql.org/message-id/flat/CAC35HNnNGavaZ%3DP%3DrUcwTwYEhfoyXDg32REXCRDgxBmC3No3nA%40mail.gmail.com