Use Element.nameLength where possible.

pkg/analyzer/lib/src/generated/error.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 engine.error;
 
 import 'dart:collection';
 
 import 'ast.dart' show AstNode;
 import 'element.dart';
@@ skipping 2551 matching lines @@
    * Report the given [error].
    */
   void reportError(AnalysisError error) {
     _errorListener.onError(error);
   }
 
   /**
    * Report an error with the given [errorCode] and [arguments]. The [element]
    * is used to compute the location of the error.
    */
-  void reportErrorForElement(
-      ErrorCode errorCode, Element element, List<Object> arguments) {
-    String displayName = element.displayName;
+  void reportErrorForElement(ErrorCode errorCode, Element element,
+      [List<Object> arguments]) {
     int length = 0;
-    if (displayName != null) {
-      length = displayName.length;
-    } else if (element is ImportElement) {
+    if (element is ImportElement) {
       length = 6; // 'import'.length
     } else if (element is ExportElement) {
       length = 6; // 'export'.length
+    } else {
+      length = element.nameLength;
     }
     reportErrorForOffset(errorCode, element.nameOffset, length, arguments);
   }
 
   /**
    * Report an error with the given [errorCode] and [arguments].
    * The [node] is used to compute the location of the error.
    *
    * If the arguments contain the names of two or more types, the method
    * [reportTypeErrorForNode] should be used and the types
@@ skipping 2407 matching lines @@
    * Initialize a newly created error code to have the given [name].
    */
   const TodoCode(String name) : super(name, "{0}");
 
   @override
   ErrorSeverity get errorSeverity => ErrorSeverity.INFO;
 
   @override
   ErrorType get type => ErrorType.TODO;
 }