Require legacy form of type parameters in factories and report errors if a factory class does not...

frog/leg/util/link_implementation.dart

Index: frog/leg/util/link_implementation.dart
===================================================================
--- frog/leg/util/link_implementation.dart	(revision 1435)
+++ frog/leg/util/link_implementation.dart	(working copy)
@@ -2,7 +2,10 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-class LinkFactory {
+// TODO(regis): Move type parameter <T> from the class declaration to the
+// factory declarations after the new factory syntax is implemented.
+// See issues 226, 5257789, 5408808.
+class LinkFactory<T> {
   factory Link(head, [Link tail]) {
     return new LinkEntry(head, (tail === null) ? const LinkTail() : tail);
   }