Unexpected syntax error when using JSON -> in 9.3.5

hi all,

This part looks correct and expected:

> $ psql foobar
> psql (9.3.5)
> Type "help" for help.
>
> foobar=# select coalesce('{}'::json->'a', 1);
> ERROR: COALESCE types json and integer cannot be matched
> LINE 1: select coalesce('{}'::json->'a', 1);
> ^

but check it out when I use a string instead of an integer:

> foobar=# select coalesce('{}'::json->'a', 'b');
> ERROR: invalid input syntax for type json
> LINE 1: select coalesce('{}'::json->'a', 'b');
> ^
> DETAIL: Token "b" is invalid.
> CONTEXT: JSON data, line 1: b

That seems like the wrong error - shouldn't it be the equiv of "[...]
json and string cannot be matched"?

Thanks,
Seamus

--
Seamus Abshere, SCEA
https://github.com/seamusabshere