Program: 168807
Project: 168807
Buggy source:
@Override protected void initialize(){
  String sqlQuery;
  List<Query> participatingQueries=new ArrayList<Query>();
  List<Query> cteQueries=new ArrayList<Query>();
  if (leftMostQuery instanceof CustomSQLQuery) {
    CustomSQLQuery customQuery=(CustomSQLQuery)leftMostQuery;
    List<Query> customQueryParticipants=customQuery.getParticipatingQueries();
    participatingQueries.addAll(customQueryParticipants);
    sqlQuery=customQuery.getSql();
  }
 else   if (leftMostQuery instanceof CustomSQLTypedQuery<?>) {
    CustomSQLTypedQuery<?> customQuery=(CustomSQLTypedQuery<?>)leftMostQuery;
    List<Query> customQueryParticipants=customQuery.getParticipatingQueries();
    participatingQueries.addAll(customQueryParticipants);
    sqlQuery=customQuery.getSql();
  }
 else {
    participatingQueries.add(baseQuery);
    sqlQuery=extendedQuerySupport.getSql(em,baseQuery);
  }
  int size=sqlQuery.length() + 10;
  List<String> setOperands=new ArrayList<String>();
  setOperands.add(sqlQuery);
  for (  Query q : this.setOperands) {
    String setOperandSql;
    if (q instanceof CustomSQLQuery) {
      CustomSQLQuery customQuery=(CustomSQLQuery)q;
      List<Query> customQueryParticipants=customQuery.getParticipatingQueries();
      participatingQueries.addAll(customQueryParticipants);
      setOperandSql=customQuery.getSql();
    }
 else     if (q instanceof CustomSQLTypedQuery<?>) {
      CustomSQLTypedQuery<?> customQuery=(CustomSQLTypedQuery<?>)q;
      List<Query> customQueryParticipants=customQuery.getParticipatingQueries();
      participatingQueries.addAll(customQueryParticipants);
      setOperandSql=customQuery.getSql();
    }
 else {
      setOperandSql=extendedQuerySupport.getSql(em,q);
      participatingQueries.add(q);
    }
    setOperands.add(setOperandSql);
    size+=setOperandSql.length() + 30;
  }
  StringBuilder sqlSb=new StringBuilder(size);
  dbmsDialect.appendSet(sqlSb,operator,nested,setOperands,orderByElements,limit,offset);
  StringBuilder withClause=applyCtes(sqlSb,baseQuery,cteQueries);
  Map<String,String> addedCtes=applyExtendedSql(sqlSb,false,false,withClause,null,null);
  cteQueries.addAll(participatingQueries);
  participatingQueries=cteQueries;
  this.sql=sqlSb.toString();
  this.participatingQueries=participatingQueries;
  this.addedCtes=addedCtes;
  this.dirty=false;
}

Fixed version (ground truth):
@Override protected void initialize(){
  String sqlQuery;
  List<Query> participatingQueries=new ArrayList<Query>();
  List<Query> cteQueries=new ArrayList<Query>();
  if (leftMostQuery instanceof CustomSQLQuery) {
    CustomSQLQuery customQuery=(CustomSQLQuery)leftMostQuery;
    List<Query> customQueryParticipants=customQuery.getParticipatingQueries();
    participatingQueries.addAll(customQueryParticipants);
    sqlQuery=customQuery.getSql();
  }
 else   if (leftMostQuery instanceof CustomSQLTypedQuery<?>) {
    CustomSQLTypedQuery<?> customQuery=(CustomSQLTypedQuery<?>)leftMostQuery;
    List<Query> customQueryParticipants=customQuery.getParticipatingQueries();
    participatingQueries.addAll(customQueryParticipants);
    sqlQuery=customQuery.getSql();
  }
 else {
    participatingQueries.add(baseQuery);
    sqlQuery=extendedQuerySupport.getSql(em,baseQuery);
  }
  int size=sqlQuery.length() + 10;
  List<String> setOperands=new ArrayList<String>();
  setOperands.add(sqlQuery);
  for (  Query q : this.setOperands) {
    String setOperandSql;
    if (q instanceof CustomSQLQuery) {
      CustomSQLQuery customQuery=(CustomSQLQuery)q;
      List<Query> customQueryParticipants=customQuery.getParticipatingQueries();
      participatingQueries.addAll(customQueryParticipants);
      setOperandSql=customQuery.getSql();
    }
 else     if (q instanceof CustomSQLTypedQuery<?>) {
      CustomSQLTypedQuery<?> customQuery=(CustomSQLTypedQuery<?>)q;
      List<Query> customQueryParticipants=customQuery.getParticipatingQueries();
      participatingQueries.addAll(customQueryParticipants);
      setOperandSql=customQuery.getSql();
    }
 else {
      setOperandSql=extendedQuerySupport.getSql(em,q);
      participatingQueries.add(q);
    }
    setOperands.add(setOperandSql);
    size+=setOperandSql.length() + 30;
  }
  StringBuilder sqlSb=new StringBuilder(size);
  dbmsDialect.appendSet(sqlSb,operator,nested,setOperands,orderByElements,limit,offset);
  StringBuilder withClause=applyCtes(sqlSb,baseQuery,cteQueries);
  Map<String,String> addedCtes=dbmsDialect.appendExtendedSql(sqlSb,statementType,false,false,withClause,null,null,null,null);
  cteQueries.addAll(participatingQueries);
  participatingQueries=cteQueries;
  this.sql=sqlSb.toString();
  this.participatingQueries=participatingQueries;
  this.addedCtes=addedCtes;
  this.dirty=false;
}