(use srfi-42)

(let ((table (make-hash-table)))
  (list-ec (: i 0 2) (: j 0 2)
            (hash-table-update!/default table (list i j)
                                (lambda (x)
                                  (append x (list j)))
                                (list j)))
           (hash-table->alist table))
;;; Result:   (((0 1) 1 1) ((1 0) 0 0) ((1 1) 1 1) ((0 0) 0 0))
;;; Expected: (((0 1) 1)   ((1 0) 0)   ((0 0) 0)   ((1 1) 1))