anchor.diff:                                  :key (if *print-shortcut*
                                            #'modifier-shortcut
                                            #'modifier-string))))
  -    (coerce (str:concat (if (str:empty? modifiers) "" (str:concat modifiers "-"))
  -                        value)
  -            'keyspecs-type)))
  +    (the (values keyspecs-type &optional)
  +         (str:concat (if (str:empty? modifiers) "" (str:concat modifiers "-"))
  +                     value))))
   
   (declaim (ftype (function (list-of-keys) keyspecs-type) keys->keyspecs))
   (defun keys->keyspecs (keys)
     "Return the keyspecs (a list of `keyspec') for KEYS.
   See `key->keyspec' for the details."
  -  (coerce (str:join " " (mapcar #'key->keyspec keys)) 'keyspecs-type))
  +  (the (values keyspecs-type &optional)
  +       (str:join " " (mapcar #'key->keyspec keys))))
   
   (declaim (ftype (function (keymap &optional list-of-keymaps) fset:map) keymap->map*))
   (defun keymap->map* (keymap &optional visited)
  
positive.code: When multiple keymaps are provided, return the union of the `fset:map' of each arguments.
  Keymaps are ordered by precedence, highest precedence comes first."
    (let ((keymaps (reverse (cons keymap more-keymaps))))
      (coerce
       (fset:convert 'hash-table
                     (reduce #'fset:map-union
                             (mapcar #'keymap->map* keymaps)))
       'hash-table)))
  
  (declaim (ftype (function (keymap) hash-table) keymap-with-parents->map))
  (defun keymap-with-parents->map (keymap)
  
negative.code:              (setf list1 (delete list2-elt list1 :count 1)))))
      (if (fset:set? strings-or-modifiers)
          strings-or-modifiers
          (the (values fset:wb-set &optional)
               (fset:convert 'fset:set
                             (let* ((mods (mapcar #'modspec->modifier strings-or-modifiers))
                                    (no-dups-mods (delete-duplicates mods :test #'modifier=)))
                               (when (/= (length mods) (length no-dups-mods))
                                 (warn "Duplicate modifiers: ~a"
                                       (mapcar #'modifier-string
                                               (list-difference mods no-dups-mods))))
                               no-dups-mods))))))
  
  (declaim (ftype (function (&key (:code integer) (:value string)
                                  (:modifiers list) (:status keyword))
  