anchor.diff:  			 collect (make-instance 'lexical-variable-entry
   						:name var))
   		   environment)))
  -    (let ((body (loop for form in (cddr lambda-form)
  -		      collect (convert form new-environment))))
  +    (let ((body (convert-sequence (cddr lambda-form) new-environment)))
         (make-instance 'close-ast
   		     ;; FIXME: Need to convert the lambda list first.
   		     :lambda-list parsed-lambda-list
  
positive.code:     (error 'progn-special-form-must-be-proper-list
  	   :expr form))
    (make-instance 'progn-ast
  		 :forms (loop for subform in (cdr form)
  			      collect (convert subform environment))))
  
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;
  
negative.code: ;;;
  ;;; Converting FUNCTION.
  
  (defclass close-ast (ast)
    ((%lambda-list :initarg :lambda-list :reader lambda-list)
     (%body :initarg :body :reader body)))
  