Code clean-up

pkg/analysis_server/lib/src/services/refactoring/extract_local.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 services.src.refactoring.extract_local;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
@@ skipping 495 matching lines @@
   void _invalidSelection(String message, Location location) {
     status.addFatalError(message, location);
     reset();
   }
 
   bool _isFirstSelectedNode(AstNode node) => node == firstSelectedNode;
 }
 
 
 class _HasStatementVisitor extends GeneralizingAstVisitor {
-  final List<bool> result;
+  bool result = false;
 
-  _HasStatementVisitor(this.result);
+  _HasStatementVisitor();
 
   @override
   visitStatement(Statement node) {
-    result[0] = true;
+    result = true;
   }
 }
 
 
 class _OccurrencesVisitor extends GeneralizingAstVisitor<Object> {
   final ExtractLocalRefactoringImpl ref;
   final List<SourceRange> occurrences;
   final String selectionSource;
 
   _OccurrencesVisitor(this.ref, this.occurrences, this.selectionSource);
@@ skipping 39 matching lines @@
 
   void _addOccurrence(SourceRange range) {
     if (range.intersects(ref.selectionRange)) {
       occurrences.add(ref.selectionRange);
     } else {
       occurrences.add(range);
     }
   }
 
   bool _hasStatements(AstNode root) {
-    List<bool> result = [false];
-    root.accept(new _HasStatementVisitor(result));
-    return result[0];
+    _HasStatementVisitor visitor = new _HasStatementVisitor();
+    root.accept(visitor);
+    return visitor.result;
   }
 
   void _tryToFindOccurrence(Expression node) {
     String nodeSource = ref.utils.getNodeText(node);
     List<Token> nodeTokens = TokenUtils.getTokens(nodeSource);
     nodeSource = ref._encodeExpressionTokens(node, nodeTokens);
     if (nodeSource == selectionSource) {
       SourceRange occuRange = rangeNode(node);
       _addOccurrence(occuRange);
     }
@@ skipping 35 matching lines @@
 
   _TokenLocalElementVisitor(this.map);
 
   visitSimpleIdentifier(SimpleIdentifier node) {
     Element element = node.staticElement;
     if (element is LocalVariableElement) {
       map[node.token] = element;
     }
   }
 }