extract_source_fragment_lines

# File actionpack/lib/action_dispatch/middleware/exception_wrapper.rb, line 335
      def extract_source_fragment_lines(source_lines, line)
        start = [line - 3, 0].max
        lines = source_lines.drop(start).take(6)
        Hash[*(start + 1..(lines.count + start)).zip(lines).flatten]
      end