Denotes the first subtype of the incomplete class-wide type rooted at
T. The completion of T shall declare a tagged type. Such
an attribute reference shall occur in the same library unit as the incomplete_type_declaration.
This subclause is new. This feature was moved here because the tagged
incomplete type provides a better way to provide this capability (it
doesn't put requirements on the completion based on uses that could be
anywhere). Pity we didn't think of it in 1994.
Ada 2005 and 2012 Editions sponsored in part by Ada-Europe