p:data and error codes

Again, about p:data (sorry...)

I think we should throw a dynamic error if the resource referenced by
p:data does not exist or cannot be accessed (similar to XD0012 in
p:document).

I also wonder whether p:data and p:document shouldn't behave the same as
p:load and report different dynamic errors if the URI scheme is not
supported (see XC0007) or if the pipeline is not allowed to read from
the specified location (see XC0011).

Regards,
Vojtech