在升级到当前的聚合物0.16和当前的纸元素和核心元件包之前，我有一个工作应用程序。现在，当我运行index.html时，我收到以下错误。
浏览器输出
404 Not Found
Could not find asset web/index.html in package polymer_snippet.
控制台输出
Serving polymer_snippet web on http://localhost:8080
Build error:
Transform polymer (PolymerBootstrapTransformer) on polymer_snippet|web/index.html threw error: Bad state: No element
dart:collection/list.dart 133 Object&ListMixin.firstWhere
package:initialize/transformer.dart 452 InitializerData.annotationNode
package:web_components/build/html_import_annotation_recorder.dart 30 HtmlImportAnnotationRecorder.shouldApply
package:initialize/transformer.dart 279 _BootstrapFileBuilder._buildNewEntryPoint.<fn>
dart:collection/list.dart 127 Object&ListMixin.firstWhere
package:initialize/transformer.dart 279 _BootstrapFileBuilder._buildNewEntryPoint
package:initialize/transformer.dart 195 _BootstrapFileBuilder.run
package:initialize/transformer.dart 35 generateBootstrapFile
package:web_components/build/web_components.dart 32 generateWebComponentsBootstrap
package:polymer/src/build/polymer_bootstrap.dart 55 PolymerBootstrapTransformer.apply.<fn>.<fn>
dart:async/zone.dart 1155 _RootZone.runUnary
dart:async/future_impl.dart 484 _Future._propagateToListeners.handleValueCallback
dart:async/future_impl.dart 567 _Future._propagateToListeners
dart:async/future_impl.dart 550 _Future._propagateToListeners.handleWhenCompleteCallback.<fn>
dart:async/zone.dart 1155 _RootZone.runUnary
dart:async/future_impl.dart 484 _Future._propagateToListeners.handleValueCallback
dart:async/future_impl.dart 567 _Future._propagateToListeners
dart:async/future_impl.dart 358 _Future._completeWithValue
dart:async/future_impl.dart 412 _Future._asyncComplete.<fn>
dart:async/schedule_microtask.dart 41 _asyncRunCallbackLoop
dart:async/schedule_microtask.dart 48 _asyncRunCallback
dart:isolate-patch/isolate_patch.dart 96 _runPendingImmediateCallback
dart:isolate-patch/isolate_patch.dart 143 _RawReceivePortImpl._handleMessage
dart:collection Object&ListMixin.firstWhere
package:initialize/transformer.dart 452 InitializerData.annotationNode
package:web_components/build/html_import_annotation_recorder.dart 30 HtmlImportAnnotationRecorder.shouldApply
package:initialize/transformer.dart 279 _BootstrapFileBuilder._buildNewEntryPoint.<fn>
dart:collection Object&ListMixin.firstWhere
package:initialize/transformer.dart 279 _BootstrapFileBuilder._buildNewEntryPoint
package:initialize/transformer.dart 195 _BootstrapFileBuilder.run
package:initialize/transformer.dart 35 generateBootstrapFile
package:web_components/build/web_components.dart 32 generateWebComponentsBootstrap
package:polymer/src/build/polymer_bootstrap.dart 55 PolymerBootstrapTransformer.apply.<fn>.<fn>
dart:isolate _RawReceivePortImpl._handleMessage
Build completed with 1 errors.
[web] GET /index.html => Could not find asset polymer_snippet|web/index.html.
[web] GET /favicon.ico => polymer_snippet|web/favicon.ico
的index.html
<!DOCTYPE html>
<!--
Copyright (c) 2014, <your name>. All rights reserved. Use of this source code
is governed by a BSD-style license that can be found in the LICENSE file.
-->
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta name="scaffolded-by" content="https://github.com/google/stagehand">
<title>polymer_snippet</title>
<!-- Add to homescreen for Chrome on Android -->
<meta name="mobile-web-app-capable" content="yes">
<link rel="icon" sizes="192x192" href="images/touch/chrome-touch-icon-192x192.png">
<!-- Add to homescreen for Safari on iOS -->
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black">
<meta name="apple-mobile-web-app-title" content="Web Starter Kit">
<link rel="apple-touch-icon-precomposed" href="apple-touch-icon-precomposed.png">
<!-- Tile icon for Win8 (144x144 + tile color) -->
<meta name="msapplication-TileImage" content="images/touch/ms-touch-icon-144x144-precomposed.png">
<meta name="msapplication-TileColor" content="#3372DF">
<!-- example of using a paper element -->
<link rel="import" href="packages/paper_elements/roboto.html">
<!-- example of your own custom element -->
<link rel="import" href="packages/polymer_snippet/main_app.html">
<link rel="import" href='../lib/main_app.html'>
<link rel="stylesheet" href="styles.css">
<link href='packages/core_elements/core_icon.html' rel='import'>
<link href='packages/bwu_fontawesome_iconset_svg/bwu_fontawesome_iconset_svg.html' rel='import' >
<link href='packages/bwu_emojione_iconset_svg/emojione_emoticons.html' rel='import'>
<link href='packages/bwu_emojione_iconset_svg/emojione_dingbats.html' rel='import'>
<link href='packages/bwu_emojione_iconset_svg/emojione_enclosed_characters.html' rel='import'>
<link href='packages/bwu_emojione_iconset_svg/emojione_transport_and_map.html' rel='import'>
<link href='packages/bwu_emojione_iconset_svg/emojione_uncategorized.html' rel='import'>
</head>
<body unresolved>
<bwu-fontawesome-iconset-svg></bwu-fontawesome-iconset-svg>
<emojione-emoticons></emojione-emoticons>
<emojione-dingbats></emojione-dingbats>
<emojione-enclosed-characters></emojione-enclosed-characters>
<emojione-transport-and-map></emojione-transport-and-map>
<emojione-uncategorized></emojione-uncategorized> <main-app></main-app>
<script type="application/dart">export 'package:polymer/init.dart';</script>
</body>
</html>
问题 - 聚合物0.16向后兼容0.15吗？ - 或者我必须使用@HtmlImport而不是previos样式吗？