Program: 11104
Project: 11104
Buggy source:
public OperatorResolution resolveOperator(CallContext callContext,ConversionMap conversionMap){
  OperatorEntry entry=getEntry(callContext.getOperatorName());
  List<OperatorResolution> results=entry.resolve(callContext,conversionMap);
  OperatorResolution result=null;
  if (results != null) {
    int lowestScore=Integer.MAX_VALUE;
    for (    OperatorResolution resolution : results) {
      Iterator<DataType> operands=resolution.getOperator().getSignature().getOperandTypes().iterator();
      Iterator<DataType> callOperands=callContext.getSignature().getOperandTypes().iterator();
      Iterator<Conversion> conversions=resolution.hasConversions() ? resolution.getConversions().iterator() : null;
      int score=0;
      while (operands.hasNext()) {
        DataType operand=operands.next();
        DataType callOperand=callOperands.next();
        Conversion conversion=conversions != null ? conversions.next() : null;
        if (operand.equals(callOperand)) {
          score+=0;
        }
 else         if (operand.isSuperTypeOf(callOperand)) {
          score+=1;
        }
 else         if (conversion != null) {
          score+=2;
        }
      }
      if (score < lowestScore) {
        lowestScore=score;
        result=resolution;
      }
 else       if (score == lowestScore) {
        throw new IllegalArgumentException(String.format("String_Node_Str",callContext.getOperatorName(),callContext.getSignature(),result.getOperator().getSignature(),resolution.getOperator().getSignature()));
      }
    }
  }
  return result;
}

Fixed version (ground truth):
public OperatorResolution resolveOperator(CallContext callContext,ConversionMap conversionMap){
  OperatorEntry entry=getEntry(callContext.getOperatorName());
  List<OperatorResolution> results=entry.resolve(callContext,conversionMap);
  OperatorResolution result=null;
  if (results != null) {
    int lowestScore=Integer.MAX_VALUE;
    List<OperatorResolution> lowestScoringResults=new ArrayList<>();
    for (    OperatorResolution resolution : results) {
      Iterator<DataType> operands=resolution.getOperator().getSignature().getOperandTypes().iterator();
      Iterator<DataType> callOperands=callContext.getSignature().getOperandTypes().iterator();
      Iterator<Conversion> conversions=resolution.hasConversions() ? resolution.getConversions().iterator() : null;
      int score=0;
      while (operands.hasNext()) {
        DataType operand=operands.next();
        DataType callOperand=callOperands.next();
        Conversion conversion=conversions != null ? conversions.next() : null;
        if (operand.equals(callOperand)) {
          score+=0;
        }
 else         if (operand.isSuperTypeOf(callOperand)) {
          score+=1;
        }
 else         if (conversion != null) {
          score+=2;
        }
      }
      if (score < lowestScore) {
        lowestScore=score;
        lowestScoringResults.clear();
        lowestScoringResults.add(resolution);
      }
 else       if (score == lowestScore) {
        lowestScoringResults.add(resolution);
      }
    }
    if (lowestScoringResults.size() > 1) {
      StringBuilder message=new StringBuilder("String_Node_Str").append(callContext.getOperatorName()).append(callContext.getSignature()).append("String_Node_Str");
      for (      OperatorResolution resolution : lowestScoringResults) {
        message.append("String_Node_Str").append(resolution.getOperator().getName()).append(resolution.getOperator().getSignature());
      }
      throw new IllegalArgumentException(message.toString());
    }
 else {
      result=lowestScoringResults.get(0);
    }
  }
  return result;
}