Error recovery broke host checked mode, fix it.

dart/pkg/compiler/lib/src/elements/modelx.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.
 
 library elements.modelx;
 
 import 'elements.dart';
 import '../constants/expressions.dart';
 import '../helpers/helpers.dart';  // Included for debug helpers.
 import '../tree/tree.dart';
@@ skipping 312 matching lines @@
 
   String get message => '${messageKind.message(messageArguments)}';
 
   String toString() => '<$name: $message>';
 
   accept(ElementVisitor visitor) => visitor.visitErroneousElement(this);
 }
 
 /// A constructor that was synthesized to recover from a compile-time error.
 class ErroneousConstructorElementX extends ErroneousElementX
-    with PatchMixin<FunctionElement>
+    with PatchMixin<FunctionElement>, AnalyzableElementX
     implements ConstructorElementX {
   // TODO(ahe): Instead of subclassing [ErroneousElementX], this class should
   // be more like [ErroneousFieldElementX]. In particular, its kind should be
   // [ElementKind.GENERATIVE_CONSTRUCTOR], and it shouldn't throw as much.
 
   ErroneousConstructorElementX(
       MessageKind messageKind,
       Map messageArguments,
       String name,
       Element enclosing)
@@ skipping 202 matching lines @@
 }
 
 /// Element synthesized to recover from a duplicated member of an element.
 class DuplicatedElementX extends AmbiguousElementX {
   DuplicatedElementX(
       MessageKind messageKind,
       Map messageArguments,
       Element enclosingElement, Element existingElement, Element newElement)
       : super(messageKind, messageArguments, enclosingElement, existingElement,
               newElement);
+
+  bool get isErroneous => true;
 }
 
 class ScopeX {
   final Map<String, Element> contents = new Map<String, Element>();
 
   bool get isEmpty => contents.isEmpty;
   Iterable<Element> get values => contents.values;
 
   Element lookup(String name) {
     return contents[name];
@@ skipping 2476 matching lines @@
   AstElement get definingElement;
 
   bool get hasResolvedAst => definingElement.hasTreeElements;
 
   ResolvedAst get resolvedAst {
     return new ResolvedAst(declaration,
         definingElement.node, definingElement.treeElements);
   }
 
 }