typ'Type_Class for any type or subtype typ yields
the value of the type class for the full type of typ. If
typ is a generic formal type, the value is the value for the
corresponding actual subtype. The value of this attribute is of type
System.Aux_DEC.Type_Class, which has the following definition:
type Type_Class is (Type_Class_Enumeration, Type_Class_Integer, Type_Class_Fixed_Point, Type_Class_Floating_Point, Type_Class_Array, Type_Class_Record, Type_Class_Access, Type_Class_Task, Type_Class_Address);
Protected types yield the value Type_Class_Task, which thus
applies to all concurrent types. This attribute is designed to
be compatible with the DEC Ada 83 attribute of the same name.