anchor.diff:  (defun array-element-type (array)
     (check-type array array)
     (if (%array-header-p array)
  -      (cond ((or (null (%array-header-dimensions array))
  -		 (integerp (%array-header-storage array)))
  -	     ;; 0D and memory arrays store the type in the info slot.
  +      (cond ((integerp (%array-header-storage array))
  +	     ;; Memory arrays store the type in the info slot.
   	     (%array-header-info array))
   	    ((%array-header-info array)
   	     ;; Displaced arrays inherit the type of the array they displace on.
  
positive.code: (defun (setf %row-major-aref) (value array index)
    "(SETF ROW-MAJOR-AREF) with no bounds check."
    (if (%array-header-p array)
        (cond ((null (%array-header-dimensions array))
  	     ;; 0D array, value is stored in the storage slot.
  	     (unless (typep value (%array-header-info array))
  	       (error 'type-error
  		      :expected-type (%array-header-info array)
  		      :datum value))
  	     (setf (%array-header-storage array) value))
  	    ((null (%array-header-info array))
  	     ;; Normal array, must be backed by a simple array.
  	     (setf (%simple-array-aref (%array-header-storage array) index) value))
  	    ((fixnump (%array-header-info array))
  
negative.code: (defun %row-major-aref (array index)
    "ROW-MAJOR-AREF with no bounds check."
    (if (%array-header-p array)
        (cond ((null (%array-header-info array))
  	     ;; Normal array, must be backed by a simple array.
  	     (%simple-array-aref (%array-header-storage array) index))
  	    ((fixnump (%array-header-info array))
  