anchor.diff:  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)))
  +    (the (values hash-table &optional)
  +         (fset:convert 'hash-table
  +                       (reduce #'fset:map-union
  +                               (mapcar #'keymap->map* keymaps))))))
   
   (declaim (ftype (function (keymap) hash-table) keymap-with-parents->map))
   (defun keymap-with-parents->map (keymap)
  
positive.code:              (setf list1 (delete list2-elt list1 :count 1)))))
      (if (fset:set? strings-or-modifiers)
          strings-or-modifiers
          (coerce (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))
                  'fset:wb-set))))
  
  (declaim (ftype (function (&key (:code integer) (:value string)
                                  (:modifiers list) (:status keyword))
  
negative.code:                                                           subsym))
                                                  (keymap->map* sym (cons sym visited))))))
                   (fset:with result keyspec sym)))))
      (the (values fset:map &optional)
           (fset:reduce #'fold-keymap (entries keymap)
                        :initial-value (fset:empty-map)))))
  
  (declaim (ftype (function (keymap &rest keymap) hash-table) keymap->map))
  (defun keymap->map (keymap &rest more-keymaps)
  