anchor.diff:                   (list (unwalk-form form))))
               arguments)))
   
  -(def (class* e) auxiliary-function-argument-form (function-argument-form)
  -  ((default-value nil)))
  -
  -(defun walk-auxiliary-argument (form parent env)
  -  (destructuring-bind (name &optional (default-value nil default-value-supplied?))
  -      (ensure-list form)
  -    (with-form-object (arg 'auxiliary-function-argument-form parent :name name)
  -      (when default-value-supplied?
  -        (setf (default-value-of arg) (walk-form default-value :parent arg :environment env))))))
  -
  -(def unwalker auxiliary-function-argument-form (name supplied-p-parameter)
  -  (bind ((default-value (awhen (default-value-of -form-)
  -                          (recurse it))))
  -    (cond ((and name default-value)
  -           `(,name ,default-value))
  -          (name name)
  -          (t (error "Invalid auxiliary argument")))))
  -
   ;;;; FLET/LABELS
   
   (def (class* e) function-binding-form (walked-form
  
positive.code:       (with-form-object (arg 'keyword-function-argument-form parent
                               :name name
                               :keyword-name keyword
                               :supplied-p-parameter supplied-p-parameter)
          (when default-value-supplied?
            (setf (default-value-of arg) (walk-form default-value :parent arg :environment env)))))))
  
  (def unwalker keyword-function-argument-form (keyword-name name default-value supplied-p-parameter)
    (bind ((default-value (awhen (default-value-of -form-)
                            (recurse it))))
      (cond ((and keyword-name name supplied-p-parameter)
             `((,keyword-name ,name) ,default-value ,supplied-p-parameter))
            ((and name supplied-p-parameter)
             `(,name ,default-value ,supplied-p-parameter))
            ((and name default-value)
             `(,name ,default-value))
            (name name)
  
negative.code: 
  (def unwalker rest-function-argument-form (name)
    name)
  
  (def (class* e) auxiliary-function-argument-form (function-argument-form-with-default-value)
    ())
  
  (defun walk-auxiliary-argument (form parent env)
    (destructuring-bind (name &optional (default-value nil default-value-supplied?))
        (ensure-list form)
      (with-form-object (arg 'auxiliary-function-argument-form parent :name name)
        (when default-value-supplied?
          (setf (default-value-of arg) (walk-form default-value :parent arg :environment env))))))
  
  (def unwalker auxiliary-function-argument-form (name supplied-p-parameter)
    (bind ((default-value (awhen (default-value-of -form-)
                            (recurse it))))
      (cond ((and name default-value)
             `(,name ,default-value))
            (name name)
            (t (error "Invalid auxiliary argument")))))
  
  (def (function e) unwalk-ordinary-lambda-list (arguments)
    (bind ((optional-seen? nil)
  