dart2dart Fix renaming of top-level setters.

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 implements Hashable {
   final String identifier;
   final Set<Node> nodes;
   LocalPlaceholder(this.identifier) : nodes = new Set<Node>();
   int hashCode() => identifier.hashCode();
   String toString() =>
@@ skipping 285 matching lines @@
   visitSend(Send send) {
     new SendVisitor(this, treeElements).visitSend(send);
     send.visitChildren(this);
   }
 
   visitSendSet(SendSet send) {
     final element = treeElements[send];
     if (element !== null) {
       if (element.isInstanceMember()) {
         tryMakePrivateIdentifier(send.selector.asIdentifier());
+      } else if (element.isTopLevel()) {
+        assert(element is VariableElement || element.isSetter());
+        makeElementPlaceholder(send.selector, element);
       } else {
         assert(send.selector is Identifier);
         tryMakeLocalPlaceholder(element, send.selector);
       }
     }
     send.visitChildren(this);
   }
 
   static bool isPlainTypeName(TypeAnnotation typeAnnotation) {
     if (typeAnnotation.typeName is !Identifier) return false;
@@ skipping 96 matching lines @@
     makeElementPlaceholder(node.name, currentElement);
     node.visitChildren(this);
   }
 
   visitTypedef(Typedef node) {
     assert(currentElement is TypedefElement);
     makeElementPlaceholder(node.name, currentElement);
     node.visitChildren(this);
   }
 }