fix #27631, get/set methods no longer shadow index operator

pkg/dev_compiler/lib/src/compiler/code_generator.dart

 // Copyright (c) 2015, 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.
 
 import 'dart:collection' show HashMap, HashSet;
 import 'dart:math' show min, max;
 
 import 'package:analyzer/analyzer.dart' hide ConstantEvaluator;
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 1470 matching lines @@
   List<JS.Method> _emitVirtualFieldAccessor(VariableDeclaration field,
       Map<FieldElement, JS.TemporaryId> virtualFields) {
     var virtualField = virtualFields[field.element];
     var result = <JS.Method>[];
     var name = _emitMemberName(field.element.name,
         type: (field.element.enclosingElement as ClassElement).type);
     var getter = js.call('function() { return this[#]; }', [virtualField]);
     result.add(new JS.Method(name, getter, isGetter: true));
 
     if (field.isFinal) {
+      // TODO(jmesserly): vsm@ commented that this seems unnecessary if we
+      // don't have a super setter. I'm not sure either why this code was
+      // introduced.
       var setter = js.call('function(value) { super[#] = value; }', [name]);
       result.add(new JS.Method(name, setter, isSetter: true));
     } else {
       var setter =
           js.call('function(value) { this[#] = value; }', [virtualField]);
       result.add(new JS.Method(name, setter, isSetter: true));
     }
 
     return result;
   }
@@ skipping 4022 matching lines @@
 }
 
 bool isLibraryPrefix(Expression node) =>
     node is SimpleIdentifier && node.staticElement is PrefixElement;
 
 LibraryElement _getLibrary(AnalysisContext c, String uri) =>
     c.computeLibraryElement(c.sourceFactory.forUri(uri));
 
 bool _isDartRuntime(LibraryElement l) =>
     l.isInSdk && l.source.uri.toString() == 'dart:_runtime';