Added the continueParsing option to ArgParser.

sdk/lib/_internal/dartdoc/bin/dartdoc.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.
 
 /**
  * To generate docs for a library, run this script with the path to an
  * entrypoint .dart file, like:
  *
  *     $ dart dartdoc.dart foo.dart
  *
@@ skipping 189 matching lines @@
 
   if (args.isEmpty) {
     print('No arguments provided.');
     print(USAGE);
     print(argParser.getUsage());
     exit(1);
   }
 
   final entrypoints = <Uri>[];
   try {
-    final option = argParser.parse(args);
+    final option = argParser.parse(args, allowTrailingOptions: true);
 
     // This checks to see if the root of all entrypoints is the same.
     // If it is not, then we display a warning, as package imports might fail.
     var entrypointRoot;
     for (final entrypoint in option.rest) {
       var uri = Uri.parse(entrypoint);
       if (uri.scheme == '') uri = path.toUri(entrypoint);
       entrypoints.add(uri);
 
       if (uri.scheme != 'file') continue;
@@ skipping 60 matching lines @@
   // If there is not, then check if the entrypoint is somewhere in a `lib`
   // directory.
   var parts = path.split(path.dirname(script));
   var libDir = parts.lastIndexOf('lib');
   if (libDir > 0) {
     return path.join(path.joinAll(parts.take(libDir)), 'packages');
   } else {
     return null;
   }
 }