# File lib/rubygems/source_index.rb, line 251
    def outdated
      dep = Gem::Dependency.new '', Gem::Requirement.default

      remotes = Gem::SourceInfoCache.search dep, true

      outdateds = []

      latest_specs.each do |local|
        name = local.name
        remote = remotes.select  { |spec| spec.name == name }.
                         sort_by { |spec| spec.version.to_ints }.
                         last
        outdateds << name if remote and local.version < remote.version
      end

      outdateds
    end