I wonder if the right answer to that is "let's enhance the I/O functions for those types". But whether that helps or not, it's v18-or-later material for sure.
That was Stephen's take as well, and I agreed given that I had to throw the kitchen-sink of source-side oid mappings (attname, types, collatons, operators) into the JSON to work around the limitation.
I can't quibble with that view of what has priority. I'm just suggesting that redesigning what pg_upgrade does in this area should come later than doing something about extended stats.
I mostly agree, with the caveat that pg_upgrade's existing message saying that optimizer stats were not carried over wouldn't be 100% true anymore.
