Ensure that lists are reified.

test/parse_test.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.
 
 import 'package:test/test.dart';
 import 'package:args/args.dart';
 import 'utils.dart';
 
 void main() {
   group('ArgParser.parse()', () {
@@ skipping 143 matching lines @@
 
       test('for multiple present, allowMultiple, options are invoked with '
           'value as a list', () {
         var a;
         var parser = new ArgParser();
         parser.addOption('a',
             allowMultiple: true, callback: (value) => a = value);
 
         parser.parse(['--a=v', '--a=x']);
         expect(a, equals(['v', 'x']));
+
+        // This reified type is important in strong mode so that people can
+        // safely write "as List<String>".
+        expect(a, new isInstanceOf<List<String>>());
       });
 
       test('for single present, allowMultiple, options are invoked with '
           ' value as a single element list', () {
         var a;
         var parser = new ArgParser();
         parser.addOption('a',
             allowMultiple: true, callback: (value) => a = value);
 
         parser.parse(['--a=v']);
@@ skipping 322 matching lines @@
         var parser = new ArgParser();
         parser.addFlag('woof');
 
         var results = parser.parse(['--woof', 'stop', '--', 'arg']);
         expect(results['woof'], isTrue);
         expect(results.rest, equals(['stop', '--', 'arg']));
       });
     });
   });
 }