Add an error when a type parameter from a generic function is used in an is test

pkg/analyzer/lib/src/error/codes.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 analyzer.src.error.codes;
 
 import 'package:analyzer/error/error.dart';
 
 export 'package:analyzer/src/analysis_options/error/option_codes.dart';
 export 'package:analyzer/src/dart/error/hint_codes.dart';
@@ skipping 4419 matching lines @@
    *    annotation
    */
   static const StaticWarningCode TYPE_ANNOTATION_DEFERRED_CLASS =
       const StaticWarningCode(
           'TYPE_ANNOTATION_DEFERRED_CLASS',
           "The deferred type '{0}' can't be used in a declaration, cast or type test.",
           "Try using a different type, or "
           "changing the import to not be deferred.");
 
   /**
+   * Not yet spec'd.
+   *
+   * Parameters:
+   * 0: the name of the generic function's type parameter that is being used in
+   *    an `is` expression
+   */
+  static const StaticWarningCode TYPE_ANNOTATION_GENERIC_FUNCTION_PARAMETER =
+      const StaticWarningCode(
+          'TYPE_ANNOTATION_GENERIC_FUNCTION_PARAMETER',
+          "The type parameter '{0}' can't be used in a type test.",
+          "Try using a different type.");
+
+  /**
    * 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_NON_TYPE =
       const StaticWarningCode(
           'TYPE_TEST_WITH_NON_TYPE',
           "The name '{0}' isn't a type and can't be used in an 'is' expression.",
           "Try correcting the name to match an existing type.");
 
   /**
@@ skipping 453 matching lines @@
    * created from the optional [correction] template.
    */
   const StrongModeCode(ErrorType type, String name, String message,
       [String correction])
       : type = type,
         super('STRONG_MODE_$name', message, correction);
 
   @override
   ErrorSeverity get errorSeverity => type.severity;
 }