json/jsonb/hstore operator precedence

Fwiw I'm finding myself repeatedly caught up by the operator
precedence rules when experimenting with jsonb:

stark=***# select  segment->'id' as id from flight_segments where
segment->>'marketing_airline_code' <>
segment->>'operating_airline_code' ;
ERROR:  42883: operator does not exist: text <> jsonb
LINE 2: ...segments where segment->>'marketing_airline_code' <> segment...
             ^
 
HINT:  No operator matches the given name and argument type(s). You
might need to add explicit type casts.
LOCATION:  op_error, parse_oper.c:722
Time: 0.407 ms
stark=***# select  segment->'id' as id from flight_segments where
(segment->>'marketing_airline_code') <>
(segment->>'operating_airline_code') ;    id
-------------"45866185""95575359"
....

I don't think this is related to the jsonb patch -- json and hstore
have the same behaviour so jsonb is obviously going to follow suit.
The only option right now would be to use a higher precedence operator
like % or ^ for all of these data types which I'm not for. I suspect
it's a pipe dream to think we might be able to override the '.' and
changing the precedence of -> and ->> would be fraught...

I think the best we can do is to highlight it in the docs.

Incidentally it's a good thing there wasn't an implicit cast
text->jsonb. In this case it would have resulted in just a confusing
error of jsonb->>boolean not existing.


-- 
greg