# File lib/sass/tree/visitors/cssize.rb, line 113
  def visit_extend(node)
    node.resolved_selector.members.each do |seq|
      if seq.members.size > 1
        raise Sass::SyntaxError.new("Can't extend #{seq.to_a.join}: can't extend nested selectors")
      end

      sseq = seq.members.first
      if !sseq.is_a?(Sass::Selector::SimpleSequence)
        raise Sass::SyntaxError.new("Can't extend #{seq.to_a.join}: invalid selector")
      elsif sseq.members.any? {|ss| ss.is_a?(Sass::Selector::Parent)}
        raise Sass::SyntaxError.new("Can't extend #{seq.to_a.join}: can't extend parent selectors")
      end

      sel = sseq.members
      parent.resolved_rules.members.each do |seq|
        if !seq.members.last.is_a?(Sass::Selector::SimpleSequence)
          raise Sass::SyntaxError.new("#{seq} can't extend: invalid selector")
        end

        @extends[sel] = Extend.new(seq, sel, node, @parent_directives.dup, :not_found)
      end
    end

    []
  end