return labels;
}

// Generate new unnamed labels for the expression.
// For example, if we have GenerateLabels(2, {'b', 'c', 'd'}) for "...xy"
// We will have "dcxy" for the ellipsis expression since it's rank 4,
// we will have dcbxy if it's rank 5.
std::string GenerateLabels(int count,
                           const llvm::SetVector<char>& available_labels) {
  std::string new_labels(count, 0);

	{`a(b*)`, "abbaab", build(3, 0, 3, 1, 3, 3, 4, 4, 4, 4, 6, 5, 6)},

	// fixed bugs
	{`ab$`, "cab", build(1, 1, 3)},
	{`axxb$`, "axxcb", nil},
	{`data`, "daXY data", build(1, 5, 9)},
	{`da(.)a$`, "daXY data", build(1, 5, 9, 7, 8)},
	{`zx+`, "zzx", build(1, 1, 3)},
	{`ab$`, "abcab", build(1, 3, 5)},
	{`(aa)*$`, "a", build(1, 1, 1, -1, -1)},
	{`(?:.|(?:.a))`, "", nil},