anchor.diff:  }
   
   
  -bool isIfThenElseIntRes(x) {
  +int isIfThenElseIntRes(x) {
     return x is int ?  1 : 0;
   }
   
  
positive.code: bool isString(x) => x is String;
  
  
  bool isStringRes(x) {
    if (x is String) {
      return 1;
    } else {
  
negative.code: }
  
  
  int isNotStringRes(x) {
    if (x is! String) {
      return 1;
    } else {
  