Make hashCode a getter and not a method.

lib/compiler/implementation/dart_backend/placeholder_collector.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.
 
 class LocalPlaceholder {
   final String identifier;
   final Set<Node> nodes;
   LocalPlaceholder(this.identifier) : nodes = new Set<Node>();
-  int hashCode() => identifier.hashCode();
+  int get hashCode => identifier.hashCode;
   String toString() =>
       'local_placeholder[id($identifier), nodes($nodes)]';
 }
 
 class FunctionScope {
   final Set<String> parameterIdentifiers;
   final Set<LocalPlaceholder> localPlaceholders;
   FunctionScope()
       : parameterIdentifiers = new Set<String>(),
       localPlaceholders = new Set<LocalPlaceholder>();
@@ skipping 616 matching lines @@
 
   visitBlock(Block node) {
     for (Node statement in node.statements.nodes) {
       if (statement is VariableDefinitions) {
         makeVarDeclarationTypePlaceholder(statement);
       }
     }
     node.visitChildren(this);
   }
 }