Issue 22845. Rename should prevent the use of invalid identifiers.

pkg/analysis_server/test/services/refactoring/naming_conventions_test.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 test.services.refactoring.naming_conventions;
 
 import 'package:analysis_server/src/protocol.dart'
     show RefactoringProblemSeverity;
 import 'package:analysis_server/src/services/refactoring/naming_conventions.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
@@ skipping 461 matching lines @@
         validateMethodName("NewName"), RefactoringProblemSeverity.WARNING,
         expectedMessage: "Method name should start with a lowercase letter.");
   }
 
   void test_validateMethodName_empty() {
     assertRefactoringStatus(
         validateMethodName(""), RefactoringProblemSeverity.FATAL,
         expectedMessage: "Method name must not be empty.");
   }
 
+  void test_validateMethodName_keyword() {
+    assertRefactoringStatus(
+        validateMethodName("for"), RefactoringProblemSeverity.FATAL,
+        expectedMessage: "Method name must not be a keyword.");
+  }
+
   void test_validateMethodName_leadingBlanks() {
     assertRefactoringStatus(
         validateMethodName(" newName"), RefactoringProblemSeverity.FATAL,
         expectedMessage: "Method name must not start or end with a blank.");
   }
 
   void test_validateMethodName_notIdentifierMiddle() {
     assertRefactoringStatus(
         validateMethodName("new-Name"), RefactoringProblemSeverity.FATAL,
         expectedMessage: "Method name must not contain '-'.");
@@ skipping 134 matching lines @@
   void test_validateVariableName_OK_middleUnderscore() {
     assertRefactoringStatusOK(validateVariableName("new_name"));
   }
 
   void test_validateVariableName_trailingBlanks() {
     assertRefactoringStatus(
         validateVariableName("newName "), RefactoringProblemSeverity.FATAL,
         expectedMessage: "Variable name must not start or end with a blank.");
   }
 }