Warn if protocol impl methods do not match its protocol

Check if the provided method names exist and belong to the
associated protocol.

Author: bensu

src/main/clojure/cljs/core.cljc

@@ -1435,13 +1435,20 @@
   (core/when-not (= p 'Object)
     (core/let [var (ana/resolve-var (dissoc env :locals) p)
                minfo (core/-> var :protocol-info :methods)
-               ->name (comp symbol name first)
+               method-name (first method)
+               ->name (comp symbol name)
                [fname sigs] (if (core/vector? (second method))
-                              [(->name method) [(second method)]]
-                              [(->name method) (map first (rest method))])
+                              [(->name method-name) [(second method)]]
+                              [(->name method-name) (map first (rest method))])
                decmeths (core/get minfo fname ::not-found)]
       (core/when (= decmeths ::not-found)
         (ana/warning :protocol-invalid-method env {:protocol p :fname fname :no-such-method true}))
+      (core/when (namespace method-name)
+        (core/let [method-var (ana/resolve-var (dissoc env :locals) method-name
+                                ana/confirm-var-exist-warning)]
+          (core/when-not (= (:name var) (:protocol method-var))
+            (ana/warning :protocol-invalid-method env
+              {:protocol p :fname method-name :no-such-method true}))))
       (core/loop [sigs sigs seen #{}]
         (core/when (seq sigs)
           (core/let [sig (first sigs)