# File lib/rdoc/options.rb, line 344
  def check_files
    @files.delete_if do |file|
      if File.exist? file then
        if File.readable? file then
          false
        else
          warn "file '#{file}' not readable"

          true
        end
      else
        warn "file '#{file}' not found"

        true
      end
    end
  end