Support is/as expressions in analyzer2dart.

pkg/analyzer2dart/lib/src/tree_shaker.dart

 // Copyright (c) 2014, 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 analyzer2dart.treeShaker;
 
 import 'dart:collection';
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/src/generated/element.dart';
@@ skipping 26 matching lines @@
   final List<PropertyInducingElement> accesses = <PropertyInducingElement>[];
 
   /**
    * The selectors used by the method to perform dynamic invocation.
    */
   final List<Selector> invokes = <Selector>[];
 
   /**
    * The classes that are instantiated by the method.
    */
+  // TODO(johnniwinther,paulberry): Register instantiated types.
+  // TODO(johnniwinther,paulberry): Register checked types from is/as checks,
+  // catch clauses and (checked) type annotations.
   final List<ClassElement> instantiates = <ClassElement>[];
 
   MethodAnalysis(this.declaration);
 }
 
 /**
  * The result of performing local reachability analysis on a class.
  *
  * TODO(paulberry): Do we need to do any other analysis of classes?  (For
  * example, detect annotations that are relevant to mirrors, detect that a
@@ skipping 328 matching lines @@
     // null, because that would have been detected by the analyzer and
     // reported as a compile time error.
     analysis.calls.add(node.staticElement);
   }
 
   @override
   void handleAssignmentExpression(AssignmentExpression node) {
     // Don't special-case assignment expressions.
   }
 }