@@ -184,6 +184,10 @@ export function stringify(token: any): string {
     return `${token.name}`;
   }
 
+  if (!token.toString) {
+    return 'object';
+  }
+
   // WARNING: do not try to `JSON.stringify(token)` here
   // see https://github.com/angular/angular/issues/23440
   const res = token.toString();
 
@@ -6,8 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {fakeAsync} from '@angular/core/testing/src/fake_async';
-import {SyncAsync, escapeRegExp, splitAtColon, utf8Encode} from '../src/util';
+import {escapeRegExp, splitAtColon, stringify, utf8Encode} from '../src/util';
 
 {
   describe('util', () => {
@@ -75,5 +74,10 @@ import {SyncAsync, escapeRegExp, splitAtColon, utf8Encode} from '../src/util';
             ([input, output]: [string, string]) => { expect(utf8Encode(input)).toEqual(output); });
       });
     });
+
+    describe('stringify()', () => {
+      it('should handle objects with no prototype.',
+         () => { expect(stringify(Object.create(null))).toEqual('object'); });
+    });
   });
 }