# File lib/capistrano/configuration/alias_task.rb, line 13
      def alias_task(new_name, old_name)
        if !new_name.respond_to?(:to_sym) or !old_name.respond_to?(:to_sym)
          raise ArgumentError, "expected a valid task name"
        end

        original_task = find_task(old_name) or raise NoSuchTaskError, "the task `#{old_name}' does not exist"
        task = original_task.dup # Dup. task to avoid modify original task
        task.name = new_name

        define_task(task)
      end