public void addFollowLink(int ruleIndex, ATNState right) {
		// add follow edge from end of invoked rule
		RuleStopState stop = atn.ruleToStopState[ruleIndex];
//        System.out.println("add follow link from "+ruleIndex+" to "+right);
		epsilon(stop, right);
	}
For reference to rule {@code r}, build

<pre>
 o-&gt;(r)  o
</pre>

where {@code (r)} is the start of rule {@code r} and the trailing
{@code o} is not linked to from rule ref state directly (uses
{@link RuleTransition#followState}).
tool/src/org/antlr/v4/automata/ParserATNFactory.java