Big merge from experimental to bleeding edge.

sdk/lib/_internal/compiler/implementation/closure.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.
 
 library closureToClassMapper;
 
 import "elements/elements.dart";
 import "dart2jslib.dart";
 import "scanner/scannerlib.dart" show Token;
 import "tree/tree.dart";
@@ skipping 596 matching lines @@
 
     ClosureClassMap savedClosureData = closureData;
     bool savedInsideClosure = insideClosure;
 
     // Restore old values.
     insideClosure = oldInsideClosure;
     closureData = oldClosureData;
     currentElement = oldFunctionElement;
 
     // Mark all free variables as captured and use them in the outer function.
-    List<Element> freeVariables = savedClosureData.freeVariableMapping.keys;
+    Iterable<Element> freeVariables = savedClosureData.freeVariableMapping.keys;
     assert(freeVariables.isEmpty || savedInsideClosure);
     for (Element freeElement in freeVariables) {
       if (capturedVariableMapping[freeElement] != null &&
           capturedVariableMapping[freeElement] != freeElement) {
         compiler.internalError('In closure analyzer', node: node);
       }
       capturedVariableMapping[freeElement] = freeElement;
       useLocal(freeElement);
     }
   }
@@ skipping 23 matching lines @@
   }
 
   visitTryStatement(TryStatement node) {
     // TODO(ngeoffray): implement finer grain state.
     bool oldInTryStatement = inTryStatement;
     inTryStatement = true;
     node.visitChildren(this);
     inTryStatement = oldInTryStatement;
   }
 }