Re: [HACKERS][BUG] Cache invalidation for queries that contains constof temporary composite type

I have tested the following case:

create type pair as (x int, y int);
prepare test as select json_populate_record(null::pair, '{"x": 1, "y": 2}'::json);
drop type pair cascade;

execute test;

-- The following output is obtained before patch
ERROR:  cache lookup failed for type 16419

-- After applying patch
ERROR:  type "pair" does not exist

But after recreating 'pair' type I'll get the following message:
ERROR:  cached plan must not change result type

I don't know whether it's right behavior. Anyhow your point is a good motivation to experiment and investigate different scenarios of work with cached plan that depends on non-stable type. Thanks for that.