Fix issue https://code.google.com/p/dart/issues/detail?id=9251, by compiling for/in correctly.

sdk/lib/_internal/compiler/implementation/resolution/members.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 resolution;
 
 abstract class TreeElements {
   Element get currentElement;
   Set<Node> get superUses;
 
@@ skipping 2717 matching lines @@
         compiler.reportErrorCode(first, MessageKind.INVALID_FOR_IN);
       } else {
         loopVariableSelector = new Selector.setter(identifier.source, library);
         loopVariable = mapping[identifier];
       }
     } else {
       compiler.reportErrorCode(declaration, MessageKind.INVALID_FOR_IN);
     }
     if (loopVariableSelector != null) {
       mapping.setSelector(declaration, loopVariableSelector);
+      registerSend(loopVariableSelector, loopVariable);
     } else {
       // The selector may only be null if we reported an error.
       assert(invariant(declaration, compiler.compilationFailed));
     }
     if (loopVariable != null) {
       // loopVariable may be null if it could not be resolved.
       mapping[declaration] = loopVariable;
     }
     visitLoopBodyIn(node, node.body, blockScope);
   }
@@ skipping 1128 matching lines @@
     return e;
   }
 
   /// Assumed to be called by [resolveRedirectingFactory].
   Element visitReturn(Return node) {
     Node expression = node.expression;
     return finishConstructorReference(visit(expression),
                                       expression, expression);
   }
 }