anchor.diff:        return BoolState.from(_element == rightElement);
       }
       return BoolState.FALSE_STATE;
  -  }
  -
  -  @override
  -  BoolState lazyEqualEqual(
  -    TypeSystemImpl typeSystem,
  -    InstanceState rightOperand,
  -  ) {
  -    return isIdentical(typeSystem, rightOperand);
     }
   
     @override
  
positive.code:   }
  
    @override
    BoolState lazyEqualEqual(
      TypeSystemImpl typeSystem,
      InstanceState rightOperand,
    ) {
      return isIdentical(typeSystem, rightOperand);
    }
  
    @override
    IntState stringLength() {
      if (value == null) {
        return IntState.UNKNOWN_VALUE;
  
negative.code:   }
  
    @override
    String toString() {
      StringBuffer buffer = StringBuffer();
      buffer.write('{');
  