Program: 84571
Project: 84571
Buggy source:
@Override public int getSignatureMatch(Name name,IValue instance,IArguments arguments){
  if (name != null && name != this.name) {
    return 0;
  }
  if ((this.modifiers & Modifiers.SYNTHETIC) != 0) {
    return 0;
  }
  if (arguments == null) {
    return 1;
  }
  if (instance == null && this.modifiers == Modifiers.PREFIX) {
    int m=arguments.getFirstValue().getTypeMatch(this.theClass.getType());
    if (m == 0) {
      return 0;
    }
    return 1 + m;
  }
  int parIndex=0;
  int match=1;
  int len=arguments.size();
  int mods=this.modifiers & Modifiers.INFIX;
  if (instance != null && mods == Modifiers.INFIX) {
    IType t2=this.parameters[0].getType();
    int m=instance.getTypeMatch(t2);
    if (m == 0) {
      return 0;
    }
    match+=m;
    parIndex=1;
  }
  if ((this.modifiers & Modifiers.VARARGS) != 0) {
    int parCount=this.parameterCount - 1;
    if (len <= parCount) {
      return 0;
    }
    int m;
    IParameter varParam=this.parameters[parCount];
    for (int i=parIndex; i < parCount; i++) {
      IParameter par=this.parameters[i + parIndex];
      m=arguments.getTypeMatch(i,par);
      if (m == 0) {
        return 0;
      }
      match+=m;
    }
    for (int i=parCount + parIndex; i < len; i++) {
      m=arguments.getVarargsTypeMatch(i,varParam);
      if (m == 0) {
        return 0;
      }
      match+=m;
    }
    return match;
  }
 else   if (len > this.parameterCount) {
    return 0;
  }
  for (int i=0; parIndex < this.parameterCount; parIndex++, i++) {
    IParameter par=this.parameters[parIndex];
    int m=arguments.getTypeMatch(i,par);
    if (m == 0) {
      return 0;
    }
    match+=m;
  }
  return match;
}

Fixed version (ground truth):
@Override public int getSignatureMatch(Name name,IValue instance,IArguments arguments){
  if (name != null && name != this.name) {
    return 0;
  }
  if ((this.modifiers & Modifiers.SYNTHETIC) != 0) {
    return 0;
  }
  if (arguments == null) {
    return 1;
  }
  if (instance == null && this.modifiers == Modifiers.PREFIX) {
    int m=arguments.getFirstValue().getTypeMatch(this.theClass.getType());
    if (m == 0) {
      return 0;
    }
    return 1 + m;
  }
  int parIndex=0;
  int match=1;
  int len=arguments.size();
  if (instance != null) {
    int mod=(this.modifiers & Modifiers.INFIX);
    if (mod != 0 && instance.valueTag() == IValue.CLASS_ACCESS) {
      instance=null;
    }
 else     if (mod == Modifiers.INFIX) {
      IType t2=this.parameters[0].getType();
      int m=instance.getTypeMatch(t2);
      if (m == 0) {
        return 0;
      }
      match+=m;
      parIndex=1;
    }
  }
  if ((this.modifiers & Modifiers.VARARGS) != 0) {
    int parCount=this.parameterCount - 1;
    if (len <= parCount) {
      return 0;
    }
    int m;
    IParameter varParam=this.parameters[parCount];
    for (int i=parIndex; i < parCount; i++) {
      IParameter par=this.parameters[i + parIndex];
      m=arguments.getTypeMatch(i,par);
      if (m == 0) {
        return 0;
      }
      match+=m;
    }
    for (int i=parCount + parIndex; i < len; i++) {
      m=arguments.getVarargsTypeMatch(i,varParam);
      if (m == 0) {
        return 0;
      }
      match+=m;
    }
    return match;
  }
 else   if (len > this.parameterCount) {
    return 0;
  }
  for (int i=0; parIndex < this.parameterCount; parIndex++, i++) {
    IParameter par=this.parameters[parIndex];
    int m=arguments.getTypeMatch(i,par);
    if (m == 0) {
      return 0;
    }
    match+=m;
  }
  return match;
}