anchor.diff:  (-> merge-tables (hash-table &rest hash-table)
       hash-table)
   
  -(defconst hash-table-default-size
  +(defconstant +hash-table-default-size+
     (hash-table-size (make-hash-table)))
   
   (deftype ok-hash-table-test ()
  
positive.code:     (with-gensyms (ht)
        `(let ((,ht (make-hash-table
                     :test ,test
                     :size ,(max hash-table-default-size
                                 (truncate (length keys-and-values)
                                           2)))))
           ,@(unsplice
  
negative.code: (export '(pophash swaphash
            dict dict* @ href href-default
            merge-tables flip-hash-table
            hash-fold maphash-return
            set-hash-table hash-table-set))
  
  (-> dict (&rest t) hash-table)
  