unpack_items_imp uses same address

[KayRichter]

Unpacking a sequence of ref object in unpack_items_imp writes to same address.

The following code should echo 2 3 5 but echos 5 5 5:

import msgpack4nim, streams
import msgpack4nim / msgpack4collection
import lists

type Element = ref object
  value: int

proc newElement(value: int): Element =
  result = new Element
  result.value = value

var elementList = initDoublyLinkedList[Element]()
elementList.add(newElement(2))
elementList.add(newElement(3))
elementList.add(newElement(5))

var strm = MsgStream.init()
strm.pack(elementList)

var sstrm = MsgStream.init(strm.data)
var unpackedList: DoublyLinkedList[Element]
sstrm.unpack(unpackedList)

for e in unpackedList:
  echo e.value

Moving var x: T into the for loop in the unpack_items_imp template fixed the problem for me.