anchor.diff:  function TNullableInteger.CheckIfDifferentAndAssign(const aValue: Variant): boolean;
   var
     tmpInt : integer;
  -begin
  +  SavedIsUnassigned : boolean;
  +begin
  +  SavedIsUnassigned:= IsUnassigned;
  +
     if VarIsNull(aValue) then
     begin
       Result := Self.NotNull;
  
positive.code: end;
  
  function TNullableString.CheckIfDifferentAndAssign(const aValue: Variant): boolean;
  begin
    if VarIsNull(aValue) then
    begin
      Result:= Self.NotNull;
      Self.IsNull:= true
    end
    else
    begin
  
negative.code: function TNullableBoolean.CheckIfDifferentAndAssign(const aValue: Variant): boolean;
  var
    tmpBool : boolean;
    SavedIsUnassigned : boolean;
  begin
    SavedIsUnassigned:= IsUnassigned;
    if VarIsNull(aValue) then
    begin
      Result := Self.NotNull;
  