Nested macro vs. macro plus function with eval

core.clj

;; This approach works as intended:

(defn- connect-fn [instance iface method args & code]
  (eval `(proxy [~iface] []
           (~(symbol (.getName method)) ~args
             ~@code))))

(defmacro connect [instance method args & code]
  `(let [functional-method# (first (clojure.lang.Reflector/getMethods (class ~instance) 1 ~(str "set" (camelcase (name method))) false))
         functional-para# (symbol (.getName (first (.getParameterTypes ^Method functional-method#))))]
     (~(symbol (str ".set" (camelcase (name method)))) ~instance
       (connect-fn ~instance functional-para# functional-method# '~args ~@code))))
     
;; This here, however, does not:

(defmacro connect
  "This macro is used to make use of functional interfaces."
  [instance method args & code]
  `(let [functional-method# (first (clojure.lang.Reflector/getMethods (class ~instance) 1 ~(str "set" (camelcase (name method))) false))
         functional-para# (symbol (.getName (first (.getParameterTypes ^Method functional-method#))))]
     (~(symbol (str ".set" (camelcase (name method)))) ~instance
        `(proxy [~functional-para#] []
           (~(symbol (.getName functional-method#)) ~'~args
             ~'~@code)))))