UMLR — Section 9.3.4 Collaboration Use, 2nd constraint creates unneces

Assuming one Collaboration represents mandatory features and another Collaboration wants to extend that. It seems natural to express only the differences in the second Collaboration and to use roleBinding to between properties of the extending Collaboration to properties of a CollaborationUse of the first. The implication is that properties of the first collaboration are included as part of the second collaboration, since the CollaborationUse is essentially an instantiation of the first Collaboration in the context of the second. The roleBindings indicate were instances of the properties of first are constrained to be instances of the second Collaboration.

This usage would require that the 2nd constraint be modified and that properties of the CollaborationUse of the first Collaboration are interpreted as being incorporated into the second Collaboration except when there is a roleBinding between the properties of the first and second Collaborations.