Infer AsExpression types.

pkg/front_end/testcases/inference/type_cast.dart

Index: pkg/front_end/testcases/inference/type_cast.dart
diff --git a/pkg/front_end/testcases/inference/infer_type_cast.dart b/pkg/front_end/testcases/inference/type_cast.dart
similarity index 80%
rename from pkg/front_end/testcases/inference/infer_type_cast.dart
rename to pkg/front_end/testcases/inference/type_cast.dart
index 836e79ef3cae74debd12da592eb22583799b8dd9..f653d5678cedee58810ac6560c2325335bc1e72f 100644
--- a/pkg/front_end/testcases/inference/infer_type_cast.dart
+++ b/pkg/front_end/testcases/inference/type_cast.dart
@@ -13,6 +13,8 @@ class B<T> extends A<T> {
 
 A<num> a = new B<int>();
 var /*@topType=B<int>*/ b = (a as B<int>);
+
 main() {
-  b.foo();
+  A<num> a = new B<int>();
+  var /*@type=B<int>*/ b = (/*@promotedType=none*/ a as B<int>);
 }