Issue 18926. Rename refactoring for labels.

pkg/analysis_server/lib/src/services/refactoring/refactoring.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.refactoring;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol.dart' show
     RefactoringMethodParameter, SourceChange;
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/refactoring/extract_local.dart';
 import 'package:analysis_server/src/services/refactoring/extract_method.dart';
 import 'package:analysis_server/src/services/refactoring/inline_local.dart';
 import 'package:analysis_server/src/services/refactoring/inline_method.dart';
 import 'package:analysis_server/src/services/refactoring/rename_class_member.dart';
 import 'package:analysis_server/src/services/refactoring/rename_constructor.dart';
 import 'package:analysis_server/src/services/refactoring/rename_import.dart';
+import 'package:analysis_server/src/services/refactoring/rename_label.dart';
 import 'package:analysis_server/src/services/refactoring/rename_library.dart';
 import 'package:analysis_server/src/services/refactoring/rename_local.dart';
 import 'package:analysis_server/src/services/refactoring/rename_unit_member.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
 
 
 /**
  * [Refactoring] to extract an expression into a local variable declaration.
@@ skipping 285 matching lines @@
     }
     if (element.enclosingElement is CompilationUnitElement) {
       return new RenameUnitMemberRefactoringImpl(searchEngine, element);
     }
     if (element is ConstructorElement) {
       return new RenameConstructorRefactoringImpl(searchEngine, element);
     }
     if (element is ImportElement) {
       return new RenameImportRefactoringImpl(searchEngine, element);
     }
+    if (element is LabelElement) {
+      return new RenameLabelRefactoringImpl(searchEngine, element);
+    }
     if (element is LibraryElement) {
       return new RenameLibraryRefactoringImpl(searchEngine, element);
     }
     if (element is LocalElement) {
       return new RenameLocalRefactoringImpl(searchEngine, element);
     }
     if (element.enclosingElement is ClassElement) {
       return new RenameClassMemberRefactoringImpl(searchEngine, element);
     }
     return null;
@@ skipping 19 matching lines @@
    * Validates that the [newName] is a valid identifier and is appropriate for
    * the type of the [Element] being renamed.
    *
    * It does not perform all the checks (such as checking for conflicts with any
    * existing names in any of the scopes containing the current name), as many
    * of these checkes require search engine. Use [checkFinalConditions] for this
    * level of checking.
    */
   RefactoringStatus checkNewName();
 }