if (width == -1 && f.contains(Flags.LEFT_JUSTIFY))
throw new MissingFormatWidthException(toString());
break;
case Conversion.LINE_SEPARATOR:
if (width != -1)
throw new IllegalFormatWidthException(width);
if (f.valueOf() != Flags.NONE.valueOf())
throw new IllegalFormatFlagsException(f.toString());
break;
default:
assert false;