Handle unresolved elements in the new IR

sdk/lib/_internal/compiler/implementation/dart_backend/dart_codegen.dart

Index: sdk/lib/_internal/compiler/implementation/dart_backend/dart_codegen.dart
diff --git a/sdk/lib/_internal/compiler/implementation/dart_backend/dart_codegen.dart b/sdk/lib/_internal/compiler/implementation/dart_backend/dart_codegen.dart
index f3177aedc6503c335c13bd0eb25aefccaff071aa..18687378ddbfb9befc7a03641820a392a5bb5b20 100644
--- a/sdk/lib/_internal/compiler/implementation/dart_backend/dart_codegen.dart
+++ b/sdk/lib/_internal/compiler/implementation/dart_backend/dart_codegen.dart
@@ -554,9 +554,8 @@ class ASTEmitter extends tree.Visitor<dynamic, Expression> {
       return new TypeAnnotation("dynamic")
           ..dartType = type;
     } else if (type is MalformedType) {
-      // treat malformed types as dynamic
-      return new TypeAnnotation("dynamic")
-          ..dartType = const DynamicType();
+      return new TypeAnnotation(type.name)
+          ..dartType = type;
     } else {
       throw "Unsupported type annotation: $type";
     }