public List<String> getRuleInvocationStack() {
		return getRuleInvocationStack(_ctx);
	}
Return List&lt;String&gt; of the rule names in your parser instance
 leading up to a call to the current rule.  You could override if
 you want more details such as the file/line info of where
 in the ATN a rule is invoked.

 This is very useful for error messages.
runtime/Java/src/org/antlr/v4/runtime/Parser.java