@Override
	public boolean equals(Object obj) {
		if (this == obj) {
			return true;
		}

		if (!(obj instanceof Rule)) {
			return false;
		}

		return name.equals(((Rule)obj).name);
	}
$x.y	Attribute: x is surrounding rule, label ref (in any alts)
tool/src/org/antlr/v4/tool/Rule.java