CLJS-2491: Inference warnings are not reported

Fix a mistake from last year - we cannot blindly rebind *cljs-warning* at
a lower level than analyze-file.

Add test case for `set! *warn-on-infer*` idiom

Author: swannodette

src/main/clojure/cljs/analyzer.cljc

@@ -3595,11 +3595,6 @@
         ast    (analyze-form env form name opts)]
     (reduce (fn [ast pass] (pass env ast opts)) ast passes)))
 
-(defn- warnings-for [form]
-  (if (analyzed? form)
-    (zipmap (keys *cljs-warnings*) (repeat false))
-    *cljs-warnings*))
-
 (defn analyze
   "Given an environment, a map containing {:locals (mapping of names to bindings), :context
   (one of :statement, :expr, :return), :ns (a symbol naming the
@@ -3615,9 +3610,10 @@
   ([env form name opts]
    (ensure
      (wrapping-errors env
-       (binding [*cljs-warnings* (warnings-for form)
-                 reader/*alias-map* (or reader/*alias-map* {})]
-         (analyze* env form name opts))))))
+       (binding [reader/*alias-map* (or reader/*alias-map* {})]
+         (if (analyzed? form)
+           (no-warn (analyze* env form name opts))
+           (analyze* env form name opts)))))))
 
 (defn add-consts
   "Given a compiler state and a map from fully qualified symbols to constant

src/test/clojure/cljs/analyzer_tests.clj

@@ -971,8 +971,7 @@
           (first @ws)
           "Adding extern to Object for property Component"))))
 
-(comment
-
+(deftest test-set-warn-on-infer
   (let [ws  (atom [])
         res (infer-test-helper
               {:forms '[(ns warn-on-infer-test.app)
@@ -982,6 +981,6 @@
                :externs ["src/test/externs/test.js"]
                :warnings ws
                :warn false})]
-    (println (pr-str res) @ws))
-
-  )
+    (is (string/blank? res))
+    (is (= 1 (count @ws)))
+    (is (string/starts-with? (first @ws) "Cannot infer target type"))))