# File lib/rubygems/specification.rb, line 591
  def self.outdated
    outdateds = []

    # TODO: maybe we should switch to rubygems' version service?
    fetcher = Gem::SpecFetcher.fetcher

    latest_specs.each do |local|
      dependency = Gem::Dependency.new local.name, ">= #{local.version}"
      remotes    = fetcher.find_matching dependency
      remotes    = remotes.map { |(_, version, _), _| version }
      latest     = remotes.sort.last

      outdateds << local.name if latest and local.version < latest
    end

    outdateds
  end