@Override
	public boolean resolvesToAttributeDict(String x, ActionAST node) {
		if ( resolvesToToken(x, node) ) return true;
        if ( ruleRefs.get(x)!=null ) return true; // rule ref in this alt?
        LabelElementPair anyLabelDef = getAnyLabelDef(x);
        if ( anyLabelDef!=null && anyLabelDef.type==LabelType.RULE_LABEL ) return true;
		return false;
	}
Track all executable actions other than named actions like @init
 and catch/finally (not in an alt). Also tracks predicates, rewrite actions.
 We need to examine these actions before code generation so
 that we can detect refs to $rule.attr etc...

 This tracks per alt
tool/src/org/antlr/v4/tool/Alternative.java