public AttributeDict getPredefinedScope(LabelType ltype) {
        String grammarLabelKey = g.getTypeString() + ":" + ltype;
        return Grammar.grammarAndLabelRefTypeToScope.get(grammarLabelKey);
    }
$x.y	Attribute: x is surrounding rule, label ref (in any alts)
tool/src/org/antlr/v4/tool/Rule.java