# File lib/rake/task_manager.rb, line 54
    def [](task_name, scopes=nil)
      task_name = task_name.to_s
      self.lookup(task_name, scopes) or
        enhance_with_matching_rule(task_name) or
        synthesize_file_task(task_name) or
        fail generate_message_for_undefined_task(task_name)
    end