public LabelElementPair getAnyLabelDef(String x) {
		List<LabelElementPair> labels = getElementLabelDefs().get(x);
		if ( labels!=null ) return labels.get(0);
		return null;
	}
$x.y	Attribute: x is surrounding rule, label ref (in any alts)
tool/src/org/antlr/v4/tool/Rule.java