        ensure
            deep_equal: deep_equal (other, Result)
        end

    frozen deep_copy (other: like Current)
            -- Effect equivalent to that of:
            --      `copy' (`other' . `deep_twin')
        require
            other_not_void: other /= Void
        do
            copy (other.deep_twin)
        ensure
            deep_equal: deep_equal (Current, other)
        end

feature {NONE} -- Retrieval

    frozen internal_correct_mismatch
            -- Called from