# File lib/sass/environment.rb, line 55
    def push_frame(frame_info)
      if stack.last && stack.last[:prepared]
        stack.last.delete(:prepared)
        stack.last.merge!(frame_info)
      else
        stack.push(frame_info)
      end
      mixins_in_use << stack.last[:mixin] if stack.last[:mixin] && !stack.last[:prepared]
    end