Handle invalid default cases.

pkg/compiler/lib/src/resolution/members.dart

 // Copyright (c) 2012, 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 dart2js.resolution.members;
 
 import '../common.dart';
 import '../common/names.dart' show Selectors;
 import '../common/resolution.dart' show Resolution;
 import '../compile_time_constants.dart';
@@ skipping 4584 matching lines @@
         LabelDefinition labelElement = targetElement.addLabel(label, labelName);
         registry.defineLabel(label, labelElement);
         continueLabels[labelName] = labelElement;
       }
       cases = cases.tail;
       // Test that only the last case, if any, is a default case.
       if (switchCase.defaultKeyword != null && !cases.isEmpty) {
         reporter.reportErrorMessage(
             switchCase, MessageKind.INVALID_CASE_DEFAULT);
       }
-      if (cases.isNotEmpty) {
+      if (cases.isNotEmpty && switchCase.statements.isNotEmpty) {
         Node last = switchCase.statements.last;
         if (last.asBreakStatement() == null &&
             last.asContinueStatement() == null &&
             last.asThrow() == null &&
             last.asReturn() == null) {
           registry.registerFeature(Feature.FALL_THROUGH_ERROR);
         }
       }
     }
 
@@ skipping 124 matching lines @@
     }
     return const NoneResult();
   }
 }
 
 /// Looks up [name] in [scope] and unwraps the result.
 Element lookupInScope(
     DiagnosticReporter reporter, Node node, Scope scope, String name) {
   return Elements.unwrap(scope.lookup(name), reporter, node);
 }