Resolve type Dynamic and implement black listing.

dart/frog/leg/warnings.dart

Index: dart/frog/leg/warnings.dart
diff --git a/dart/frog/leg/warnings.dart b/dart/frog/leg/warnings.dart
index e2e4137d66aea6a7fc4793c3f2c3bca6f54223b8..22f6629e79ac4d0611e2cc28d263f65f81e45042 100644
--- a/dart/frog/leg/warnings.dart
+++ b/dart/frog/leg/warnings.dart
@@ -151,6 +151,13 @@ class MessageKind {
       "cyclic reference to type variable #{1}");
   static final TYPE_NAME_EXPECTED = const MessageKind(
       "class or interface name exptected");
+
+  static final CANNOT_EXTEND = const MessageKind(
+      "#{1} cannot be extended");
+
+  static final CANNOT_IMPLEMENT = const MessageKind(
+      "#{1} cannot be implemented");
+
   toString() => template;
 }