// Erroneous cases.
	{"%[d", SE{2, 1}, "%!d(BADINDEX)"},
	{"%]d", SE{2, 1}, "%!](int=2)d%!(EXTRA int=1)"},
	{"%[]d", SE{2, 1}, "%!d(BADINDEX)"},
	{"%[-3]d", SE{2, 1}, "%!d(BADINDEX)"},
	{"%[99]d", SE{2, 1}, "%!d(BADINDEX)"},
	{"%[3]", SE{2, 1}, "%!(NOVERB)"},
	{"%[1].2d", SE{5, 6}, "%!d(BADINDEX)"},
	{"%[1]2d", SE{2, 1}, "%!d(BADINDEX)"},
	{"%3.[2]d", SE{7}, "%!d(BADINDEX)"},
	{"%.[2]d", SE{7}, "%!d(BADINDEX)"},

		s.refillAllocCache(whichByte)
		aCache = s.allocCache
		bitIndex = sys.TrailingZeros64(aCache)
		// nothing available in cached bits
		// grab the next 8 bytes and try again.
	}
	result := sfreeindex + uint16(bitIndex)
	if result >= snelems {
		s.freeindex = snelems
		return snelems
	}

	s.allocCache >>= uint(bitIndex + 1)
	sfreeindex = result + 1