public Type superclass(final Type type) {
		final TypeNode node = getExtendsNode(type);

		if (node != null) {
			final Collection succs = extendsGraph.succs(node);

			final Iterator iter = succs.iterator();

			if (iter.hasNext()) {
				final TypeNode v = (TypeNode) iter.next();
				return v.type;
			}
		}

		return null;
	}