CLJS-3284: Use of private deftype by public function in another namespace when inside an if causes warning

Suppress warnings in `type?` which are of private-var-access.  A lot of
type inference is automatic, and users don't necessarily know that it's
happening.  The type itself isn't secret in this context, even if the
library indicates the user shouldn't rely on the exact existence of the
type.

Author: SevereOverfl0w

src/main/clojure/cljs/analyzer.cljc

@@ -1361,7 +1361,8 @@
   [env t]
   ;; don't use resolve-existing-var to avoid warnings
   (when (and (some? t) (symbol? t))
-    (let [var (resolve-var env t)]
+    (let [var (binding [*private-var-access-nowarn* true]
+                (resolve-var env t))]
       (if-some [type (:type var)]
         type
           (if-some [type (-> var :info :type)]

src/test/cljs_build/cljs_3284/bean.cljs

@@ -0,0 +1,7 @@
+(ns cljs-3284.bean)
+
+(deftype ^:private SomeType [a])
+
+(defn some-type
+  [a]
+  (SomeType. a))

src/test/cljs_build/cljs_3284/core.cljs

@@ -0,0 +1,9 @@
+(ns cljs-3284.core
+  (:require
+    cljs-3284.bean))
+
+(defn maybe-bean
+  [x]
+  (if (object? x)
+    (cljs-3284.bean/some-type x)
+    x))

src/test/clojure/cljs/build_api_tests.clj

@@ -768,3 +768,17 @@
       (is (empty? @ws))))
   (.delete (io/file "package.json"))
   (test/delete-node-modules))
+
+(deftest test-cljs-3284
+  (testing "Type hint warnings don't fire just because of private types"
+    (let [ws (atom [])
+          out (.getPath (io/file (test/tmp-dir) "cljs-3235-out"))
+          {:keys [inputs opts]} {:inputs (str (io/file "src" "test" "cljs_build"))
+                                 :opts   {:main             'cljs-3284.core
+                                          :output-dir       out
+                                          :optimizations    :none}}
+          cenv (env/default-compiler-env opts)]
+      (test/delete-out-files out)
+      (ana/with-warning-handlers [(collecting-warning-handler ws)]
+        (build/build (build/inputs (io/file inputs "cljs_3284/core.cljs")) opts cenv))
+      (is (empty? @ws)))))