Tom Dunstan <pgsql(at)tomd(dot)cc> writes:
> Tom Lane wrote:
>>> ... could we
>>> have a special rule that would look for e.g. a regtype as the first
>>> parameter if the return type is generic and there are no generic parameters?
>>
>> I thought about that too but don't like it much. The problem is mainly
>> that it can only work for a constant regtype parameter.
> OK, I give up. :) Why?
Because the whole point is that the type has to be known at parse time.
I've got it working with get_fn_expr_argtype and it seems fairly
reasonable.
regards, tom lane