preventing inheritance

[Tom Moran <tmoran@bix.com>]

Given
type T is tagged ...
procedure A(X:T)
function  B(X:T) return ...
procedure C(X:T)
  and
Type U is new T with ...
procedure D(X:T)
procedure E(X:T)
function  F(X:T) return ...

  BUT
B(X:U) is, for reasons beyond my control, illegal.

  What is the best way to prevent/catch B(X:U)?

Currently I replace the inherited B(X:U) with
function  B(X:U) return ... is
begin
  raise this_is_a_no_no;
  return 0; -- all functions need at least one return
end B;