if we know some foreign js/foo is a fn from externs, annotate the AST with :js-fn-var

in infer-invoke, handle :js-fn-var case, in the case of an invoke we do not know anything
about set the :tag to 'js

Author: swannodette

src/main/clojure/cljs/analyzer.cljc

@@ -850,7 +850,8 @@
               :ns   'js
               :tag  (with-meta (or (js-tag pre) 'js) {:prefix pre})}
              (when-let [ret-tag (js-tag pre :ret-tag)]
-               {:ret-tag ret-tag}))))
+               {:js-fn-var true
+                :ret-tag ret-tag}))))
        (let [s  (str sym)
              lb (get locals sym)]
          (cond
@@ -1076,7 +1077,10 @@
 
 (defn infer-invoke [env e]
   (let [{info :info :as f} (:f e)]
-    (if-some [ret-tag (when (true? (:fn-var info)) (:ret-tag info))]
+    (if-some [ret-tag (if (or (true? (:fn-var info))
+                              (true? (:js-fn-var info)))
+                        (:ret-tag info)
+                        (when (= 'js (:ns info)) 'js))]
       ret-tag
       (let [args (:args e)
             me (assoc (find-matching-method f args) :op :method)]

src/test/clojure/cljs/analyzer_tests.clj

@@ -659,7 +659,17 @@
          (-> (binding [a/*cljs-ns* a/*cljs-ns*]
                (e/with-compiler-env externs-cenv
                  (a/analyze (a/empty-env) 'js/baz)))
-           :info :ret-tag))))
+           :info :ret-tag)))
+  (is (= 'js/Foo
+         (-> (binding [a/*cljs-ns* a/*cljs-ns*]
+               (e/with-compiler-env externs-cenv
+                 (a/analyze (a/empty-env) '(js/baz))))
+           :tag)))
+  (is (= 'js
+         (-> (binding [a/*cljs-ns* a/*cljs-ns*]
+               (e/with-compiler-env externs-cenv
+                 (a/analyze (a/empty-env) '(js/woz))))
+           :tag))))
 
 (comment
   (require '[cljs.compiler :as cc])
@@ -691,8 +701,7 @@
               a/*cljs-warnings* (assoc a/*cljs-warnings* :infer-warning true)]
       (e/with-compiler-env test-cenv
         (a/analyze-form-seq
-          '[(ns foo.core)
-            (js/console.log (.wozMethod (js/baz)))]))
+          '[(js/console.log (.wozMethod (js/baz)))]))
       (cc/emit-externs
         (reduce util/map-merge {}
           (map (comp :externs second)
@@ -706,8 +715,7 @@
               a/*cljs-warnings* (assoc a/*cljs-warnings* :infer-warning true)]
       (e/with-compiler-env test-cenv
         (a/analyze-form-seq
-          '[(ns foo.core)
-            (defn baz [^js/Foo x]
+          '[(defn afun [^js/Foo x]
               (.wozMethod x))]))
       (cc/emit-externs
         (reduce util/map-merge {}
@@ -722,8 +730,7 @@
               a/*cljs-warnings* (assoc a/*cljs-warnings* :infer-warning true)]
       (e/with-compiler-env test-cenv
         (a/analyze-form-seq
-          '[(ns foo.core)
-            (defn baz [^js/Foo a]
+          '[(defn baz [^js/Foo a]
               (.gozMethod a))]))
       (cc/emit-externs
         (reduce util/map-merge {}
@@ -738,8 +745,7 @@
               a/*cljs-warnings* (assoc a/*cljs-warnings* :infer-warning true)]
       (e/with-compiler-env test-cenv
         (a/analyze-form-seq
-          '[(ns foo.core)
-            (js/console.log (.gozMethod (js/baz)))]))
+          '[(.gozMethod (js/baz))]))
       (cc/emit-externs
         (reduce util/map-merge {}
           (map (comp :externs second)