* erasure).
     * @param s a signature (possible raw, could be subjected to
     * erasure).
     * @return true if either argument is a sub signature of the other.
     */
    public boolean overrideEquivalent(Type t, Type s) {
        return hasSameArgs(t, s) ||
            hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
    }