Can a step have both primary document and parameter input ports?

The text in the draft says:

> A document that reads:
>  <p:pipeline some-attributes> some-content </p:pipeline>
> can be interpreted as if it read:
> <p:declare-step some-attributes>
> <p:input port='source' primary='true'/>
> <p:input port='parameters' kind='parameter' primary='true'/>
> <p:output port='result' primary='true'/>
> some-content
> </p:declare-step>
>
With both the document and parameter input ports explicitly marked primary,
whereas this fails on Calabash with:

> Error  : Pipeline failed: err:XS0030: null  It is a static error to specify
> that more than one input port is the primary.
>

Does 'primary' mean primary port of that kind, or primary port in that
direction, period?
-Leif