anchor.diff:  /// The state is kept in the finalizer so that this scan could be extended to
   /// look for other deferred expressions in one pass.
   class _DeferredHolderExpressionCollectorVisitor extends js.BaseVisitorVoid {
  -  String resourceName;
  +  String? resourceName;
     final DeferredHolderExpressionFinalizer _finalizer;
   
     _DeferredHolderExpressionCollectorVisitor(this._finalizer);
  
positive.code:     var holderArray =
          js.js.statement('var holders = #', js.ArrayInitializer(holderUses));
  
      mainHolderResource.statement =
          js.Block([holderCode.statement, holderArray]);
    }
  
    /// Initializes local names for [Holder] objects, and also performs frequency
  
negative.code: // Copyright (c) 2021, 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 'package:js_ast/src/precedence.dart' as js show PRIMARY;
  import 'package:front_end/src/api_unstable/dart2js.dart' show $A;
  