Report a fatal error on attempt to rename an element declared in SDK.

pkg/analysis_server/lib/src/services/refactoring/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 services.src.refactoring.rename;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
 import 'package:analysis_server/src/services/correction/source_range.dart';
 import 'package:analysis_server/src/services/correction/status.dart';
+import 'package:analysis_server/src/services/correction/util.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring_internal.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/engine.dart';
+import 'package:analyzer/src/generated/java_core.dart';
 import 'package:analyzer/src/generated/source.dart';
 
 /**
  * Returns `true` if two given [Element]s are [LocalElement]s and have
  * intersecting with visibility ranges.
  */
 bool haveIntersectingRanges(LocalElement localElement, Element element) {
   if (element is! LocalElement) {
     return false;
   }
@@ skipping 102 matching lines @@
   void addReferenceEdits(List<SearchMatch> matches) {
     List<SourceReference> references = getSourceReferences(matches);
     for (SourceReference reference in references) {
       reference.addEdit(change, newName);
     }
   }
 
   @override
   Future<RefactoringStatus> checkInitialConditions() {
     RefactoringStatus result = new RefactoringStatus();
+    if (element.source.isInSystemLibrary) {
+      String message = format(
+          "The {0} '{1}' is defined in the SDK, so cannot be renamed.",
+          getElementKindName(element),
+          getElementQualifiedName(element));
+      result.addFatalError(message);
+    }
     return new Future.value(result);
   }
 
   @override
   RefactoringStatus checkNewName() {
     RefactoringStatus result = new RefactoringStatus();
     if (newName == oldName) {
       result.addFatalError(
           "The new name must be different than the current name.");
     }
@@ skipping 22 matching lines @@
     if (element is ImportElement) {
       PrefixElement prefix = element.prefix;
       if (prefix != null) {
         return prefix.displayName;
       }
       return '';
     }
     return element.displayName;
   }
 }