def scan_for_line_warnings(line, filename)
      warnings = scan_for_warnings(using & LineWarning.all_warnings, line, filename)
      filtered_warnings_from_line(line, warnings)
    end
def scan_for_line_warnings(line, filename)
      warnings = scan_for_warnings(using & LineWarning.all_warnings, line, filename)
      filtered_warnings_from_line(line, warnings)
    end
Goes through all line warning subclasses and checks if we got some new
 warnings for a given line