Program: 15778
Project: 15778
Buggy source:
private TemplateModel dealWithRangeKey(TemplateModel targetModel,Range range,Environment env) throws TemplateException {
  int start=EvaluationUtil.getNumber(range.left,env).intValue();
  int end=0;
  boolean hasRhs=range.hasRhs();
  if (hasRhs) {
    end=EvaluationUtil.getNumber(range.right,env).intValue();
  }
  if (targetModel instanceof TemplateSequenceModel) {
    TemplateSequenceModel sequence=(TemplateSequenceModel)targetModel;
    if (!hasRhs)     end=sequence.size() - 1;
    if (start < 0) {
      throw range.left.newTemplateException("String_Node_Str" + start + "String_Node_Str");
    }
    if (end < 0) {
      throw range.right.newTemplateException("String_Node_Str" + end + "String_Node_Str");
    }
    if (start >= sequence.size()) {
      throw range.left.newTemplateException("String_Node_Str" + start + "String_Node_Str"+ sequence.size()+ "String_Node_Str"+ "String_Node_Str");
    }
    if (end >= sequence.size()) {
      throw range.right.newTemplateException("String_Node_Str" + end + "String_Node_Str"+ sequence.size()+ "String_Node_Str"+ "String_Node_Str");
    }
    ArrayList list=new ArrayList(1 + Math.abs(start - end));
    if (start > end) {
      for (int i=start; i >= end; i--) {
        list.add(sequence.get(i));
      }
    }
 else {
      for (int i=start; i <= end; i++) {
        list.add(sequence.get(i));
      }
    }
    return new SimpleSequence(list);
  }
  try {
    String s=target.getStringValue(env);
    if (!hasRhs)     end=s.length() - 1;
    if (start < 0) {
      throw range.left.newTemplateException("String_Node_Str" + start + "String_Node_Str");
    }
    if (end < 0) {
      throw range.right.newTemplateException("String_Node_Str" + end + "String_Node_Str");
    }
    if (start > s.length()) {
      String msg="String_Node_Str" + start + "String_Node_Str"+ targetModel+ "String_Node_Str"+ s.length()+ "String_Node_Str";
      throw range.left.newTemplateException(msg);
    }
    if (end > s.length()) {
      String msg="String_Node_Str" + end + "String_Node_Str"+ targetModel+ "String_Node_Str"+ s.length()+ "String_Node_Str";
      throw range.right.newTemplateException(msg);
    }
    try {
      return new SimpleScalar(s.substring(start,end + 1));
    }
 catch (    RuntimeException re) {
      throw this.newTemplateException(re);
    }
  }
 catch (  NonStringException e) {
    throw target.newUnexpectedTypeException(target.getAsTemplateModel(env),MessageUtil.TYPES_USABLE_WHERE_STRING_IS_EXPECTED + "String_Node_Str");
  }
}

Fixed version (ground truth):
private TemplateModel dealWithRangeKey(TemplateModel targetModel,Range range,Environment env) throws TemplateException {
  int start=EvaluationUtil.getNumber(range.left,env).intValue();
  int end=0;
  boolean hasRhs=range.hasRhs();
  if (hasRhs) {
    end=EvaluationUtil.getNumber(range.right,env).intValue();
  }
  if (targetModel instanceof TemplateSequenceModel) {
    TemplateSequenceModel sequence=(TemplateSequenceModel)targetModel;
    if (!hasRhs)     end=sequence.size() - 1;
    if (start < 0) {
      throw range.left.newTemplateException("String_Node_Str" + start + "String_Node_Str");
    }
    if (end < 0) {
      throw range.right.newTemplateException("String_Node_Str" + end + "String_Node_Str");
    }
    if (start >= sequence.size()) {
      throw range.left.newTemplateException("String_Node_Str" + start + "String_Node_Str"+ sequence.size()+ "String_Node_Str"+ "String_Node_Str");
    }
    if (end >= sequence.size()) {
      throw range.right.newTemplateException("String_Node_Str" + end + "String_Node_Str"+ sequence.size()+ "String_Node_Str"+ "String_Node_Str");
    }
    ArrayList list=new ArrayList(1 + Math.abs(start - end));
    if (start > end) {
      for (int i=start; i >= end; i--) {
        list.add(sequence.get(i));
      }
    }
 else {
      for (int i=start; i <= end; i++) {
        list.add(sequence.get(i));
      }
    }
    return new SimpleSequence(list);
  }
  try {
    String s=target.getCoercedStringValue(env);
    if (!hasRhs)     end=s.length() - 1;
    if (start < 0) {
      throw range.left.newTemplateException("String_Node_Str" + start + "String_Node_Str");
    }
    if (end < 0) {
      throw range.right.newTemplateException("String_Node_Str" + end + "String_Node_Str");
    }
    if (start > s.length()) {
      String msg="String_Node_Str" + start + "String_Node_Str"+ targetModel+ "String_Node_Str"+ s.length()+ "String_Node_Str";
      throw range.left.newTemplateException(msg);
    }
    if (end > s.length()) {
      String msg="String_Node_Str" + end + "String_Node_Str"+ targetModel+ "String_Node_Str"+ s.length()+ "String_Node_Str";
      throw range.right.newTemplateException(msg);
    }
    try {
      return new SimpleScalar(s.substring(start,end + 1));
    }
 catch (    RuntimeException re) {
      throw this.newTemplateException(re);
    }
  }
 catch (  NonStringException e) {
    throw target.newUnexpectedTypeException(target.getAsTemplateModel(env),MessageUtil.TYPES_USABLE_WHERE_STRING_IS_EXPECTED + "String_Node_Str");
  }
}