[news.eclipse.modeling.gmt] OAW - Type Casting with XTend

[Alexander Nyßen <any@xxxxxxxxxxxxxxxxxx>]

I have specified the following in my Extension:

cached int getConnectorCount(uml::ConnectorEnd e) :
uml::MultiplicityElement.isInstance(e.role) ?
 e.getPartWithPortMultiplicity() * e.upper() * 
((uml::MultiplicityElement)e.role).upper()
    : e.getPartWithPortMultiplicity() * e.upper()
;

The cast of e.role into MultiplicityElemenet is acknowledged by the OAW 
environement with the error "cannot cast from uml::ConnectableElement into 
uml::MultiplicityElement". The dynamic type of e.role may however by a 
MultiplicityElement. What am I doing wrong?