# File lib/rubygems.rb, line 871
  def self.ruby_version
    return @ruby_version if defined? @ruby_version
    version = RUBY_VERSION.dup

    if defined?(RUBY_PATCHLEVEL) && RUBY_PATCHLEVEL != -1 then
      version << ".#{RUBY_PATCHLEVEL}"
    elsif defined?(RUBY_REVISION) then
      version << ".dev.#{RUBY_REVISION}"
    end

    @ruby_version = Gem::Version.new version
  end