Checked mode throws a TypeError.

tests/language/inferrer_synthesized_constructor_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // 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.
 
 // Regression test for dart2js's type inferrer that used to not
 // propagate default types in synthesized calls.
 
 import "package:expect/expect.dart";
 
 class A {
   final x;
   A([this.x = 'foo']);
 }
 
 class B extends A {
   // The synthesized constructor was not saying that it would call
   // [A]'s constructor with its default type.
 }
 
 main() {
   // By calling [B]'s constructor with an int parameter, the inferrer
   // used to only see this call and consider the [A.x] field to always
   // be int.
   Expect.equals(84, new A(42).x + 42);
-  Expect.throws(() => new B().x + 42, (e) => e is ArgumentError);
+  Expect.throws(() => new B().x + 42,
+                (e) => e is ArgumentError || e is TypeError);
 }