warning for unresolveable properties on known extern types

Author: swannodette

src/main/clojure/cljs/analyzer.cljc

@@ -420,8 +420,11 @@
   (str name " is shadowed by a local"))
 
 (defmethod error-message :infer-warning
-  [warning-type {:keys [form]}]
-  (str "Cannot infer target type for " form ""))
+  [warning-type {:keys [warn-type form type property]}]
+  (case warn-type
+    :target   (str "Cannot infer target type in expression " form "")
+    :property (str "Cannot resolve property " property
+                   " for inferred type " type  " in expression " form)))
 
 (defn default-warning-handler [warning-type env extra]
   (when (warning-type *cljs-warnings*)
@@ -2623,11 +2626,19 @@
                               update-in [:prefix] (fnil conj '[Object]) prop))
                        nil)]
     (when (and (not (string/starts-with? (str prop) "cljs$"))
-               (not= 'js target-tag)
-               (get-in env [:locals target]))
-      (when (or (nil? target-tag)
-                ('#{any} target-tag))
-        (warning :infer-warning env {:form form})))
+               (not= 'js target-tag))
+      (when (and (get-in env [:locals target])
+                 (or (nil? target-tag)
+                     ('#{any} target-tag)))
+        (warning :infer-warning env
+          {:warn-type :target :form form}))
+      (let [[pre' pre] ((juxt (comp butlast butlast) identity) ;; drop prototype from pre'
+                         (-> tag meta :prefix))]
+        (when (and (has-extern? pre') (not (has-extern? pre)))
+          (warning :infer-warning env
+            {:warn-type :property :form form
+             :type (symbol "js" (string/join "." pre'))
+             :property prop}))))
     (when (js-tag? tag)
       (let [pre (-> tag meta :prefix)]
         (when-not (has-extern? pre)

src/test/clojure/cljs/analyzer_tests.clj

@@ -703,6 +703,18 @@
           (map (comp :externs second)
             (get @test-cenv ::a/namespaces))))))
 
+  (let [test-cenv (atom {::a/externs (externs/externs-map)})]
+    (binding [a/*cljs-ns* a/*cljs-ns*
+              a/*cljs-warnings* (assoc a/*cljs-warnings* :infer-warning true)]
+      (e/with-compiler-env test-cenv
+        (a/analyze-form-seq
+          '[(defn foo [^js/React.Component c]
+              (.render c))]))
+      (cc/emit-externs
+        (reduce util/map-merge {}
+          (map (comp :externs second)
+            (get @test-cenv ::a/namespaces))))))
+
   ;; works, does not generate extern
   (let [test-cenv (atom {::a/externs (externs/externs-map
                                        (closure/load-externs
@@ -761,19 +773,18 @@
           (map (comp :externs second)
             (get @test-cenv ::a/namespaces))))))
 
-  ;; works, generates externs
+  ;; known extern
   (let [test-cenv (atom {::a/externs (externs/externs-map
                                        (closure/load-externs
                                          {:externs ["src/test/externs/test.js"]}))})]
     (binding [a/*cljs-ns* a/*cljs-ns*
               a/*cljs-warnings* (assoc a/*cljs-warnings* :infer-warning true)]
       (e/with-compiler-env test-cenv
         (a/analyze-form-seq
-          '[(.gozMethod (js/woz))]))
+          '[(.gozMethod (js/baz))]))
       (cc/emit-externs
         (reduce util/map-merge {}
           (map (comp :externs second)
             (get @test-cenv ::a/namespaces))))))
 
-
   )