anchor.diff:  
     /// Initialize a newly created variable element to have the given [name] and
     /// [offset].
  -  VariableElementImpl(String? name, int offset, {Reference? reference})
  -      : super(name, offset, reference: reference);
  -
  -  VariableElementImpl.forLinkedNode(
  -      ElementImpl enclosing, Reference? reference, AstNode linkedNode)
  -      : super.forLinkedNode(enclosing, reference, linkedNode);
  -
  -  /// Initialize using the given serialized information.
  -  VariableElementImpl.forSerialized(ElementImpl enclosingElement)
  -      : super.forSerialized(enclosingElement);
  +  VariableElementImpl(String? name, int offset) : super(name, offset);
   
     /// If this element represents a constant variable, and it has an initializer,
     /// a copy of the initializer for the constant.  Otherwise `null`.
  
positive.code: 
    @override
    List<ParameterElement> get parametersInternal {
      if (!identical(_parameters, _Sentinel.parameterElement)) {
        return _parameters;
      }
  
  
negative.code: 
    /// Return true if this parameter is explicitly marked as being covariant.
    bool get isExplicitlyCovariant {
      return hasModifier(Modifier.COVARIANT);
    }
  
  