[parser] parse `CalllExpression TemplateLiteral` production

test/mjsunit/es6/templates.js

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Flags: --harmony-unicode
 
 var num = 5;
 var str = "str";
 function fn() { return "result"; }
 var obj = {
@@ skipping 570 matching lines @@
   }
   assertEquals("test3", tag`test1``test2``test3`);
   assertEquals([
     "tag;test1",
     "tag;test2",
     "raw;test3"
   ], raw);
 })();
 
 
+(function testReturnValueAsTagFn() {
+  "use strict";
+  var i = 0;
+  function makeTag() {
+    return function tag(cs) {
+      var args = Array.prototype.slice.call(arguments, 1);
+      var rcs = [];
+      rcs.raw = cs.map(function(s) {
+        return '!' + s + '!';
+      });
+      args.unshift(rcs);
+      return String.raw.apply(null, args);
+    }
+  }
+  assertEquals('!hi!', makeTag()`hi`);
+  assertEquals('!test!0!test!', makeTag()`test${0}test`);
+  assertEquals('!!', makeTag()``);
+});
+
+
 (function testToStringSubstitutions() {
   var a = {
     toString: function() { return "a"; },
     valueOf: function() { return "-a-"; }
   };
   var b = {
     toString: function() { return "b"; },
     valueOf: function() { return "-b-"; }
   };
   assertEquals("a", `${a}`);
@@ skipping 71 matching lines @@
   assertEquals("-1-2-3-", tag`-${subs[0]}-${subs[1]}-${subs[2]}-`);
   assertArrayEquals(["get0", "get1", "get2"], log);
   assertArrayEquals([1, 2, 3], tagged);
 
   tagged.length = 0;
   log.length = 0;
   assertEquals("-1-", tag`-${subs[0]}-`);
   assertArrayEquals(["get0"], log);
   assertArrayEquals([1], tagged);
 })();