J.4 The Constrained Attribute
Static Semantics
For every private subtype
S, the following attribute is defined:
Yields the value False if S denotes an unconstrained nonformal private
subtype with discriminants; also yields the value False if S denotes
a generic formal private subtype, and the associated actual subtype is
either an unconstrained subtype with discriminants or an unconstrained
array subtype; yields the value True otherwise. The value of this attribute
is of the predefined subtype Boolean.