@Override
	public List<AltAST> getUnlabeledAltASTs() {
		List<AltAST> alts = new ArrayList<AltAST>();
		for (LeftRecursiveRuleAltInfo altInfo : recPrimaryAlts) {
			if (altInfo.altLabel == null) alts.add(altInfo.originalAltAST);
		}
		for (int i = 0; i < recOpAlts.size(); i++) {
			LeftRecursiveRuleAltInfo altInfo = recOpAlts.getElement(i);
			if ( altInfo.altLabel==null ) alts.add(altInfo.originalAltAST);
		}
		if ( alts.isEmpty() ) return null;
		return alts;
	}
Did we delete any labels on direct left-recur refs? Points at ID of ^(= ID el)
tool/src/org/antlr/v4/tool/LeftRecursiveRule.java