Change ErrorNode to masquerade as a null literal.

dart/sdk/lib/_internal/compiler/implementation/tree/nodes.dart

 // Copyright (c) 2012, 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.
 
 part of tree;
 
 abstract class Visitor<R> {
   const Visitor();
 
   R visitNode(Node node);
@@ skipping 301 matching lines @@
   Statement();
 
   Statement asStatement() => this;
 
   // TODO(ahe): make class abstract instead of adding an abstract method.
   accept(Visitor visitor);
 
   bool isValidBreakTarget() => true;
 }
 
-/// Errorneous expression that behaves as a literal integer (0).
-class ErrorExpression extends LiteralInt {
+/// Errorneous expression that behaves as a literal null.
+class ErrorExpression extends LiteralNull {
   ErrorExpression(token)
-      : super(token, null);
+      : super(token);
 
   ErrorExpression asErrorExpression() => this;
-
-  int get value => 0;
 }
 
 /**
  * A message send aka method invocation. In Dart, most operations can
  * (and should) be considered as message sends. Getters and setters
  * are just methods with a special syntax. Consequently, we model
  * property access, assignment, operators, and method calls with this
  * one node.
  */
 class Send extends Expression {
@@ skipping 1767 matching lines @@
 }
 
 class IsInterpolationVisitor extends Visitor<bool> {
   const IsInterpolationVisitor();
   bool visitNode(Node node) => false;
   bool visitStringInterpolation(StringInterpolation node) => true;
   bool visitStringJuxtaposition(StringJuxtaposition node)
       => node.isInterpolation;
 }