Recursive fn defined in let block

recursive_let_fn.clj

(defmacro memoize-rec [form]
  (let [[fn* fname params & body] form
        params-with-fname (vec (cons fname params))]
    `(let [f# (memoize (fn ~params-with-fname
                         (let [~fname (partial ~fname ~fname)] ~@body)))]
       (partial f# f#))))

(let [fib (fn fib [n]
            (if (< n 2)
              n
              (+ (fib (- n 1))
                 (fib (- n 2)))))]
  (fib 42))

(let [fib (memoize-rec
            (fn fib [n]
              (if (< n 2)
                n
                (+ (fib (- n 1))
                   (fib (- n 2))))))]
  (fib 42))