          else
                Result := b /= Void and then
                            a.standard_is_equal (b)
            end
        ensure
            definition: Result = (a = Void and b = Void) or else
                        ((a /= Void and b /= Void) and then
                        a.standard_is_equal (b))
        end

    frozen is_deep_equal (other: like Current): BOOLEAN
            -- Are `Current' and `other' attached to isomorphic object structures?
        require
            ot