@Override
	public void reset() {
		super.reset();
		overrideDecisionRoot = null;
	}
Cache {@link LeftRecursiveRule#getPrimaryAlts()} and
 {@link LeftRecursiveRule#getRecursiveOpAlts()} for states in
 {@link #decisionStatesThatSetOuterAltNumInContext}. It only
 caches decisions in left-recursive rules.
tool/src/org/antlr/v4/tool/GrammarParserInterpreter.java