limited agregate and limited components default initialization

[Jean-Claude Rostaing <00120260a@gmail.com>]

Why does a component declaration like that:
type Item_Accessor (Item: not null access Item_type) is limited record
      Ref: Item_access := SET(Item_Record'(Item => ITEM.all, others => <>));
   end record;
unconstrained subtype in component declaration
? ITEM is limited but IS constrained by the default initialisation
It forced me to add the function DEFAULT_INITIALIZATION as a parameter, which I would prefer to not to. But since the result is the same, I'll drop it.
Item (and the article it is in) is never meant to be left uninitialized.

Also, how to get rid of the problem with
function Set (Value: in Item_type) return Smart_Pointers is
     (Smart_Pointers'(Controlled with Node => new Accessor_type'(Data => new Item_type'(Value), Count => 1)));
which gives :Initialization not allowed for limited types.
So an aggregate like this is not counted as a "limited agregate" ??