The Unrestricted_Access attribute is similar to Access
except that all accessibility and aliased view checks are omitted. This
is a user-beware attribute. It is similar to
Address, for which it is a desirable replacement where the value
desired is an access type. In other words, its effect is identical to
first applying the Address attribute and then doing an unchecked
conversion to a desired access type. In GNAT, but not necessarily in
other implementations, the use of static chains for inner level
subprograms means that Unrestricted_Access applied to a
subprogram yields a value that can be called as long as the subprogram
is in scope (normal Ada accessibility rules restrict this usage).
It is possible to use Unrestricted_Access for any type, but care
must be exercised if it is used to create pointers to unconstrained
objects. In this case, the resulting pointer has the same scope as the
context of the attribute, and may not be returned to some enclosing
scope. For instance, a function cannot use Unrestricted_Access
to create a unconstrained pointer and then return that value to the
caller.