anchor.diff:      (condition-broadcast (queue-cvar queue)))
     nil)
   
  -(defun push-self (task &optional (queue *current-queue*))
  +(defun push-self (task &optional (queue (current-queue)))
     (declare (type queue queue)
              (type task-designator task))
     (assert (alive-p queue))
  
positive.code:           (t
             (enqueue task queue)))))
  
  (defun push-self-all (tasks &optional (queue *current-queue*))
    (declare (type queue queue))
    (assert (alive-p queue))
    (let ((id *worker-id*))
  
negative.code: (defvar *worker-hint* 0)
  (defvar *current-queue* nil)
  
  (declaim (inline current-queue))
  (defun current-queue ()
    (and *current-queue*
         (weak-pointer-value *current-queue*)))
  