public R visitClass(ClassTree node, P p) {
        R r = scan(node.getModifiers(), p);
        r = scanAndReduce(node.getTypeParameters(), p, r);
        r = scanAndReduce(node.getExtendsClause(), p, r);
        r = scanAndReduce(node.getImplementsClause(), p, r);
        r = scanAndReduce(node.getMembers(), p, r);
        return r;
    }