CLJS-712 & CLJS-2957: resolve-var for dot still wrong, externs inference regression

The AST alignment changes reveal that our handling of the dot form was still
incorrect. When resolve-var returns a dotted :var like foo.bar/baz.woz it gets
desugared. In this case of GCL import this would lead to malformed :host-field
AST nodes.

Now in resolve var if we have a dotted symbol first we check that the prefix
is *not* something that can be resolved. If can't be resolved then we don't
do anything other than convert the form from foo.bar.baz to foo.bar/baz.

Add tests cases for type inference, externs inference, and code gen.

Author: swannodette

src/main/clojure/cljs/analyzer.cljc

@@ -1156,8 +1156,11 @@
 (defn resolve-var
   "Resolve a var. Accepts a side-effecting confirm fn for producing
    warnings about unresolved vars."
-  ([env sym] (resolve-var env sym nil))
+  ([env sym]
+   (resolve-var env sym nil))
   ([env sym confirm]
+   (resolve-var env sym confirm true))
+  ([env sym confirm default?]
    (let [locals (:locals env)]
      (if #?(:clj  (= "js" (namespace sym))
             :cljs (identical? "js" (namespace sym)))
@@ -1209,21 +1212,15 @@
            (let [idx    (.indexOf s ".")
                  prefix (symbol (subs s 0 idx))
                  suffix (subs s (inc idx))]
-             (if-some [lb (handle-symbol-local prefix (get locals prefix))]
-               {:op :local
-                :name (symbol (str (:name lb) "." suffix))}
-               (if-some [full-ns (gets @env/*compiler* ::namespaces current-ns :imports prefix)]
-                 {:op :js-var
-                  :name (symbol (str full-ns) suffix)}
-                 (if-some [info (gets @env/*compiler* ::namespaces current-ns :defs prefix)]
-                   (merge info
-                     {:name (symbol (str current-ns) (str sym))
-                      :op :var
-                      :ns current-ns})
-                   (merge (gets @env/*compiler* ::namespaces prefix :defs (symbol suffix))
-                     {:name (if (= "" prefix) (symbol suffix) (symbol (str prefix) suffix))
-                      :op :var
-                      :ns prefix})))))
+             ;; check if prefix is some existing def
+             (if-let [resolved (resolve-var env prefix nil false)]
+               (update resolved :name #(symbol (str % "." suffix)))
+               (let [idx (.lastIndexOf s ".")
+                     pre (subs s 0 idx)
+                     suf (subs s (inc idx))]
+                 {:op   :var
+                  :name (symbol pre suf)
+                  :ns   (symbol pre)})))
 
            (some? (gets @env/*compiler* ::namespaces current-ns :uses sym))
            (let [full-ns (gets @env/*compiler* ::namespaces current-ns :uses sym)]
@@ -1236,7 +1233,7 @@
              (resolve* env sym full-ns current-ns))
 
            (some? (gets @env/*compiler* ::namespaces current-ns :imports sym))
-           (recur env (gets @env/*compiler* ::namespaces current-ns :imports sym) confirm)
+           (recur env (gets @env/*compiler* ::namespaces current-ns :imports sym) confirm default?)
 
            (some? (gets @env/*compiler* ::namespaces current-ns :defs sym))
            (do
@@ -1260,7 +1257,7 @@
            (resolve-invokeable-ns s current-ns env)
 
            :else
-           (do
+           (when default?
              (when (some? confirm)
                (confirm env current-ns sym))
              (merge (gets @env/*compiler* ::namespaces current-ns :defs sym)

src/test/clojure/cljs/analyzer_tests.clj

@@ -12,7 +12,6 @@
     [cljs.analyzer.api :as ana-api]
     [cljs.compiler :as comp]
     [cljs.env :as env]
-    [cljs.js-deps :as deps]
     [cljs.test-util :refer [unsplit-lines]]
     [cljs.util :as util]
     [clojure.java.io :as io]

src/test/clojure/cljs/compiler_tests.clj

@@ -32,6 +32,17 @@
 (def aenv (assoc-in (ana/empty-env) [:ns :name] 'cljs.user))
 (def cenv (env/default-compiler-env))
 
+(defn compile-form-seq
+  ([forms]
+   (compile-form-seq forms
+     (when env/*compiler*
+       (:options @env/*compiler*))))
+  ([forms opts]
+   (with-out-str
+     (binding [ana/*cljs-ns* 'cljs.user]
+       (doseq [form forms]
+         (comp/emit (ana/analyze (ana/empty-env) form)))))))
+
 #_(deftest should-recompile
   (let [src (File. "test/hello.cljs")
         dst (File/createTempFile "compilertest" ".cljs")
@@ -331,6 +342,22 @@
     (is (not (str/includes? snippet3 "(function (x){")))
     ))
 
+(deftest test-goog-ctor-import-gen
+  (is (true? (str/includes?
+               (env/with-compiler-env (env/default-compiler-env)
+                 (compile-form-seq
+                   '[(ns test.foo
+                       (:import [goog.history Html5History]))
+                     (defn bar [] Html5History)]))
+               "return goog.history.Html5History;")))
+  (is (true? (str/includes?
+               (env/with-compiler-env (env/default-compiler-env)
+                 (compile-form-seq
+                   '[(ns test.foo
+                       (:import [goog.history Html5History]))
+                     (def hist (Html5History.))]))
+               "(new goog.history.Html5History());"))))
+
 ;; CLJS-1225
 
 (comment

src/test/clojure/cljs/externs_infer_tests.clj

@@ -383,10 +383,7 @@
                  :warnings ws
                  :warn true
                  :with-core? true}))]
-    (is (empty? @ws))
-    ;; TODO:
-    ;; test that the ctor returns the expected type in a let
-    ))
+    (is (empty? @ws))))
 
 (comment
   (binding [ana/*cljs-ns* ana/*cljs-ns*]

src/test/clojure/cljs/type_inference_tests.clj

@@ -357,9 +357,20 @@
   )
 
 (deftest test-ctor-infer
-  (is (= (env/with-compiler-env test-cenv
-           (ana/no-warn
-             (:tag (analyze test-cenv
-                     '(let [g (Foo.)]
-                        q)))))
-         'cljs.core/Foo)))
+  (is (= 'cljs.core/Foo
+         (:tag
+           (env/with-compiler-env test-cenv
+             (ana/no-warn
+               (analyze test-env
+                 '(let [g (Foo.)]
+                    g))))))))
+
+(deftest test-goog-import-ctor-infer
+  (is (= 'goog.history/Html5History
+         (:tag
+           (env/with-compiler-env (env/default-compiler-env)
+             (ana/analyze-form-seq
+               '[(ns test.foo
+                   (:import [goog.history Html5History]))
+                 (Html5History.)]
+               {} true))))))