(let (foo1 foo2 hytmp)
  (require 'cl-lib)
  (cl-defstruct foo slot1 slot2)
  (setq foo1 (make-foo :slot1 "abc" :slot2 "cba"))
  (setq foo2 (make-foo :slot1 "abc" :slot2 "cba"))
  (equal foo1 foo2)
  (setq hytmp (make-hash-table :test 'equal))
  (puthash foo1 'foobar hytmp)
  (when (eq 'no (gethash foo2 hytmp 'no))
    (error "Problematic hash")))