improve keyword suggestions - fixes #24016

pkg/analysis_server/test/services/completion/completion_test_util.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.completion.util;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/protocol.dart' as protocol
@@ skipping 4273 matching lines @@
     // SwitchStatement  Block  BlockFunctionBody  MethodDeclaration
     addTestSource('class A {String g(int x) {switch(x) {c^}}}');
     computeFast();
     return computeFull((bool result) {
       assertNoSuggestions();
     });
   }
 
   test_SwitchStatement_case() {
     // SwitchStatement  Block  BlockFunctionBody  MethodDeclaration
-    addTestSource('class A {String g(int x) {switch(x) {case 0: ^}}}');
+    addTestSource('class A {String g(int x) {var t; switch(x) {case 0: ^}}}');
     computeFast();
     return computeFull((bool result) {
       assertSuggestLocalClass('A');
       assertSuggestLocalMethod('g', 'A', 'String');
+      assertSuggestLocalVariable('t', null);
       assertSuggestImportedClass('String');
     });
   }
 
   test_SwitchStatement_empty() {
     // SwitchStatement  Block  BlockFunctionBody  MethodDeclaration
     addTestSource('class A {String g(int x) {switch(x) {^}}}');
     computeFast();
     return computeFull((bool result) {
       assertNoSuggestions();
@@ skipping 389 matching lines @@
       assertNotSuggested('bar2');
       assertNotSuggested('_B');
       assertSuggestLocalClass('Y');
       assertSuggestLocalClass('C');
       assertSuggestLocalVariable('f', null);
       assertNotSuggested('x');
       assertNotSuggested('e');
     });
   }
 }