code: private static boolean isLocalDefaultValueAssignment(Node targetNode, Node valueNode) {
      return valueNode.isOr()
          && targetNode.isQualifiedName()
          && valueNode.getFirstChild().isEquivalentTo(targetNode)
          && NodeUtil.evaluatesToLocalValue(valueNode.getLastChild());
    }
docs: True if targetNode is a qualified name and the valueNode is of the form `targetQualifiedName ||
  localValue`.