Fix for issue 20930

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 4821 matching lines @@
    */
   static const StaticWarningCode TYPE_ANNOTATION_DEFERRED_CLASS =
       const StaticWarningCode(
           'TYPE_ANNOTATION_DEFERRED_CLASS',
           "The deferred type '{0}' cannot be used in a declaration, cast or type test");
 
   /**
    * 12.31 Type Test: It is a static warning if <i>T</i> does not denote a type
    * available in the current lexical scope.
    */
-  static const StaticWarningCode TYPE_TEST_NON_TYPE = const StaticWarningCode(
-      'TYPE_TEST_NON_TYPE',
+  static const StaticWarningCode TYPE_TEST_WITH_NON_TYPE = const StaticWarningCode(
+      'TYPE_TEST_WITH_NON_TYPE',
       "The name '{0}' is not a type and cannot be used in an 'is' expression");
 
   /**
+   * 12.31 Type Test: It is a static warning if <i>T</i> does not denote a type
+   * available in the current lexical scope.
+   */
+  static const StaticWarningCode TYPE_TEST_WITH_UNDEFINED_NAME = const StaticWarningCode(
+      'TYPE_TEST_WITH_UNDEFINED_NAME',
+      "The name '{0}' is not defined and cannot be used in an 'is' expression");
+
+  /**
    * 10 Generics: However, a type parameter is considered to be a malformed type
    * when referenced by a static member.
    *
    * 15.1 Static Types: Any use of a malformed type gives rise to a static
    * warning. A malformed type is then interpreted as dynamic by the static type
    * checker and the runtime.
    */
   static const StaticWarningCode TYPE_PARAMETER_REFERENCED_BY_STATIC =
       const StaticWarningCode(
           'TYPE_PARAMETER_REFERENCED_BY_STATIC',
@@ skipping 141 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;
 }