When user renames 'prefix' in 'prefix.Class' she actually wants to rename ImportElement.

pkg/analysis_server/test/services/refactoring/abstract_rename.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 test.services.refactoring.rename;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/services/correction/change.dart';
+import 'package:analysis_server/src/services/correction/namespace.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:unittest/unittest.dart';
 
 import 'abstract_refactoring.dart';
 
 
@@ skipping 74 matching lines @@
     expect(actualCode, expectedCode);
   }
 
   /**
    * Creates a new [RenameRefactoring] in [refactoring] for the [Element] of
    * the [SimpleIdentifier] at the given [search] pattern.
    */
   void createRenameRefactoringAtString(String search) {
     SimpleIdentifier identifier = findIdentifier(search);
     Element element = identifier.bestElement;
-    // TODO(scheglov) uncomment later
-//    if (element instanceof PrefixElement) {
-//      element = IndexContributor.getImportElement(identifier);
-//    }
+    if (element is PrefixElement) {
+      element = getImportElement(identifier);
+    }
     createRenameRefactoringForElement(element);
   }
 
   /**
    * Creates a new [RenameRefactoring] in [refactoring] for [element].
    * Fails if no [RenameRefactoring] can be created.
    */
   void createRenameRefactoringForElement(Element element) {
     refactoring = new RenameRefactoring(searchEngine, element);
     expect(refactoring, isNotNull, reason: "No refactoring for '$element'.");
@@ skipping 27 matching lines @@
 //  void assertChangeResult(Change change, Source source, String expected)
 //       {
 //    SourceChange sourceChange = getSourceChange(compositeChange, source);
 //    assertNotNull("No change for: " + source.toString(), sourceChange);
 //    String sourceResult = getChangeResult(context, source, sourceChange);
 //    assertEquals(expected, sourceResult);
 ////    AnalysisContext context = getAnalysisContext();
 ////    assertChangeResult(context, compositeChange, source, expected);
 //  }
 }