anchor.diff:    @override
     void registerNodeProcessors(
         NodeLintRegistry registry, LinterContext context) {
  +    if (!isInLibDir(context.currentUnit.unit, context.package)) {
  +      return;
  +    }
  +
       final visitor = _Visitor(this, context);
       registry.addClassDeclaration(this, visitor);
       registry.addClassTypeAlias(this, visitor);
  
positive.code: 
    @override
    void visitCompilationUnit(CompilationUnit node) {
      // Ignore this compilation unit if it's not in the lib/ folder.
      isInLibFolder = isInLibDir(node, context.package);
      if (!isInLibFolder) return;
  
      final getters = <String, FunctionDeclaration>{};
      final setters = <FunctionDeclaration>[];
  
  
negative.code: 
    @override
    void visitEnumDeclaration(EnumDeclaration node) {
      if (!isPrivate(node.name)) {
        check(node);
      }
  