In the analysis server API, change RequestError.code to an enum.

pkg/analysis_server/test/integration/protocol_matchers.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.
 //
 // This file has been automatically generated.  Please do not edit it manually.
 // To regenerate the file, use the script
 // "pkg/analysis_server/spec/generate_files".
 
 /**
  * Matchers for data types defined in the analysis server API
@@ skipping 1063 matching lines @@
   "TYPE_PARAMETER",
   "UNIT_TEST_GROUP",
   "UNIT_TEST_TEST",
   "UNKNOWN"
 ]);
 
 /**
  * Error
  *
  * {
- *   "code": String
+ *   "code": RequestErrorCode
  *   "message": String
  *   "data": optional object
  * }
  */
 final Matcher isError = new LazyMatcher(() => new MatchesJsonObject(
   "Error", {
-    "code": isString,
+    "code": isRequestErrorCode,
     "message": isString
   }, optionalFields: {
     "data": isObject
   }));
 
 /**
  * ErrorFixes
  *
  * {
  *   "error": AnalysisError
@@ skipping 503 matching lines @@
  * {
  *   "type": "remove"
  * }
  */
 final Matcher isRemoveContentOverlay = new LazyMatcher(() => new MatchesJsonObject(
   "RemoveContentOverlay", {
     "type": equals("remove")
   }));
 
 /**
+ * RequestErrorCode
+ *
+ * enum {
+ *   GET_ERRORS_ERROR
+ *   INVALID_PARAMETER
+ *   INVALID_REQUEST
+ *   SERVER_ALREADY_STARTED
+ *   UNANALYZED_PRIORITY_FILES
+ *   UNKNOWN_REQUEST
+ *   UNSUPPORTED_FEATURE
+ * }
+ */
+final Matcher isRequestErrorCode = new MatchesEnum("RequestErrorCode", [
+  "GET_ERRORS_ERROR",
+  "INVALID_PARAMETER",
+  "INVALID_REQUEST",
+  "SERVER_ALREADY_STARTED",
+  "UNANALYZED_PRIORITY_FILES",
+  "UNKNOWN_REQUEST",
+  "UNSUPPORTED_FEATURE"
+]);
+
+/**
  * SearchId
  *
  * String
  */
 final Matcher isSearchId = isString;
 
 /**
  * SearchResult
  *
  * {
@@ skipping 268 matching lines @@
  *
  * {
  *   "newName": String
  * }
  */
 final Matcher isRenameOptions = new LazyMatcher(() => new MatchesJsonObject(
   "rename options", {
     "newName": isString
   }));