CLJS-3257: satisfies? produces an inference warning when given an unhinted argument

We're checking protocol methods so mark the symbol as such. Add test case.

Author: swannodette

src/main/clojure/cljs/core.cljc

@@ -2212,15 +2212,17 @@
       `(let [~xsym ~x]
          (if-not (nil? ~xsym)
            (if (or ~(if bit `(unsafe-bit-and (. ~xsym ~msym) ~bit) false)
-                    (identical? cljs.core/PROTOCOL_SENTINEL (. ~xsym ~(symbol (core/str "-" prefix)))))
+                    (identical? cljs.core/PROTOCOL_SENTINEL
+                      (. ~xsym ~(with-meta (symbol (core/str "-" prefix)) {:protocol-method true}))))
              true
              (if (coercive-not (. ~xsym ~msym))
                (cljs.core/native-satisfies? ~psym ~xsym)
                false))
            (cljs.core/native-satisfies? ~psym ~xsym)))
       `(if-not (nil? ~x)
          (if (or ~(if bit `(unsafe-bit-and (. ~x ~msym) ~bit) false)
-                  (identical? cljs.core/PROTOCOL_SENTINEL (. ~x ~(symbol (core/str "-" prefix)))))
+                  (identical? cljs.core/PROTOCOL_SENTINEL
+                    (. ~x ~(with-meta (symbol (core/str "-" prefix)) {:protocol-method true}))))
            true
            (if (coercive-not (. ~x ~msym))
              (cljs.core/native-satisfies? ~psym ~x)

src/test/clojure/cljs/externs_infer_tests.clj

@@ -398,6 +398,21 @@
                  :with-core? true}))]
     (is (empty? @ws))))
 
+(deftest test-cljs-3257
+  (let [ws  (atom [])
+        res (binding [ana/*cljs-static-fns* true]
+              (infer-test-helper
+                {:forms '[(ns app.core)
+                          (set! *warn-on-infer* true)
+                          (defprotocol IFoo
+                            (bar [this]))
+                          (defn not-ok? [v]
+                            (satisfies? IFoo v))]
+                 :warnings ws
+                 :warn true
+                 :with-core? true}))]
+    (is (empty? @ws))))
+
 (comment
   (binding [ana/*cljs-ns* ana/*cljs-ns*]
     (ana/no-warn