anchor.diff:                 (expand-in-env-1 (form &optional env)
                    "Like macroexpand-1, but handle local symbol macro bindings."
                    (if (symbolp form)
  -                     (let ((exp (assoc form symbol-macros)))
  +                     (let ((exp (assoc form *symbol-macros*)))
                          (if exp
                              (progn
                                (when (eql exp form)
  
positive.code:                          (unless exp?
                             (return (values form exps?))))))
                 (wrap-symbol-macros (form)
                   (if (null symbol-macros) form
                       `(symbol-macrolet ,symbol-macros
                          ,form)))
                 (step-expansion (form)
                   (multiple-value-bind (exp exp?)
  
negative.code:                  "Shorthand for recursing on an implicit `progn'."
                   `(progn ,@(mapcar #'expand-partially body)))
                 (symbol-macro (name exp)
                   (push (list name exp) *symbol-macros*))
                 (shadow-symbol-macro (name)
                   (removef *symbol-macros* name :key #'car))
                 (expansion-done (form)
                   (setf form (wrap-symbol-macros form))
                   (push form exprs)
  