}
break;
}
case Union: {
RegExUnion u = (RegExUnion) r;
<BUG>HashSet<SuccinctRegExMatch> firstResults, secondResults;
firstResults = regexConcat(u.getFirst(), rightMatch);

secondResults = regexConcat(u.getSecond(), rightMatch);

concatResults = regexUnion(firstResults, secondResults);</BUG>
break;

}
switch (r.getRegExType()) {
case Blank: {
break;
}
