CLJS-3086: Switch clj-nil to not be considered a numeric type

Author: roman01la

src/main/clojure/cljs/analyzer.cljc

@@ -3477,7 +3477,6 @@
   ;; warning without this - David
   (cond
     (nil? t) true
-    (= 'clj-nil t) true
     (js-tag? t) true ;; TODO: revisit
     :else
     (if (and (symbol? t) (some? (get NUMERIC_SET t)))

src/test/clojure/cljs/analyzer_tests.clj

@@ -1346,6 +1346,16 @@
          (env/with-compiler-env test-cenv
                               (:tag (analyze test-env '(demunge-str "")))))))
 
+(deftest test-cljs-3086
+  (let [ws (atom [])]
+    (try
+      (ana/with-warning-handlers [(collecting-warning-handler ws)]
+        (cljs.env/with-compiler-env test-cenv
+          (analyze (ana/empty-env)
+            '(+ nil 1))))
+      (catch Exception _))
+    (is (= ["cljs.core/+, all arguments must be numbers, got [clj-nil number] instead"] @ws))))
+
 (deftest test-cljs-3120
   (let [cenv (core-env)
         _ (analyze-forms cenv