# File lib/rspec/expectations/deprecation.rb, line 19
      def deprecate(deprecated, options={})
        call_site = caller.find { |line| line !~ LIB_REGEX }

        message = "DEPRECATION: #{deprecated} is deprecated."
        message << " Use #{options[:replacement]} instead." if options[:replacement]
        message << " Called from #{call_site}."
        warn message
      end