class Sass::Tree::Visitors::Perform

def visit_content(node)
  content, content_env = @environment.content
  return [] unless content
  @environment.stack.with_mixin(node.filename, node.line, '@content') do
    trace_node = Sass::Tree::TraceNode.from_node('@content', node)
    content_env = Sass::Environment.new(content_env)
    content_env.caller = Sass::Environment.new(@environment)
    with_environment(content_env) do
      trace_node.children = content.map {|c| visit(c.dup)}.flatten
    end
    trace_node
  end
rescue Sass::SyntaxError => e
  e.modify_backtrace(:mixin => '@content', :line => node.line)
  e.add_backtrace(:line => node.line)
  raise e
end