Support parameter access in analyzer2dart.

sdk/lib/_internal/compiler/implementation/inferrer/node_tracer.dart

 // Copyright (c) 2013, 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 type_graph_inferrer;
 
 // A set of selectors we know do not escape the elements inside the
 // list.
 Set<String> doesNotEscapeListSet = new Set<String>.from(
   const <String>[
@@ skipping 350 matching lines @@
       bailout('Returned from a closure');
     }
     if (!inferrer.compiler.backend
         .canBeUsedForGlobalOptimizations(info.element)) {
       bailout('Escape to code that has special backend treatment');
     }
     addNewEscapeInformation(info);
   }
 
   void visitParameterTypeInformation(ParameterTypeInformation info) {
-    Element element = info.element;
-    if (inferrer.isNativeElement(element.enclosingElement)) {
+    ParameterElement element = info.element;
+    if (inferrer.isNativeElement(element.functionDeclaration)) {
       bailout('Passed to a native method');
     }
     if (!inferrer.compiler.backend
         .canBeUsedForGlobalOptimizations(info.element)) {
       bailout('Escape to code that has special backend treatment');
     }
     if (isParameterOfListAddingMethod(info.element) ||
         isParameterOfMapAddingMethod(info.element)) {
       // These elements are being handled in
       // [visitDynamicCallSiteTypeInformation].
       return;
     }
     addNewEscapeInformation(info);
   }
 }