anchor.diff:  
   ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   ;;;
  -;;; Compile a FUNCTION-CALL-AST.
  +;;; Compile a CALL-AST.
   ;;;
   ;;; The first instruction generated is a PUT-ARGUMENTS-INSTRUCTION.
   ;;; This instruction supplies the arguments to the call.  Then the
  
positive.code:   (with-accessors ((results results)
  		   (successors successors))
        context
      (ecase (length successors)
        (1 (cond ((eq results t)
  		(sicl-mir:make-return-instruction (list ast)))
  	       ((null results)
  		(warn "variable compiled in a context with no values")
  		(car successors))
  	       ((eq ast (car results))
  		(nil-fill (cdr results) (car successors)))
  	       (t
  		(sicl-mir:make-assignment-instruction
  		 ast
  		 (car results) 
  		 (nil-fill (cdr results) (car successors))))))
        (2 (if (or (null results) (eq ast (car results)))
  	     (sicl-mir:make-test-instruction ast successors)
  	     (sicl-mir:make-assignment-instruction
  	      ast
  	      (car results)
  	      (sicl-mir:make-test-instruction ast successors)))))))
  
  (defun compile-toplevel (ast)
    (let ((*block-info* (make-hash-table :test #'eq))
  
negative.code: 		     :successors successors
  		     :false-required-p false-required-p)))
  
  (defmethod print-object ((obj context) stream)
    (print-unreadable-object (obj stream)
      (format stream " results: ~s" (results obj))
      (format stream " successors: ~s" (successors obj))
      (format stream " false-required-p: ~s" (false-required-p obj))))
  
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;
  ;;; Compile an abstract syntax tree in a compilation context.
  