<p dir="auto">This bug is filed to track a suboptimal hot reload experience during a step in our primary codelab (<a href="https://codelabs.developers.google.com/codelabs/flutter/" rel="nofollow">https://codelabs.developers.google.com/codelabs/flutter/</a>). Other similar bugs exist for other steps.</p>
<p dir="auto">This bug tracks step 5, part I (Add an interactive text input field).</p>
<p dir="auto">Before code:</p>
<div class="highlight highlight-source-dart notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="import 'package:flutter/material.dart';

void main() {
  runApp(new FriendlychatApp());
}

class FriendlychatApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: &quot;Friendlychat&quot;,
      home: new ChatScreen(),
    );
  }
}

class ChatScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(title: new Text(&quot;Friendlychat&quot;)),
    );
  }
}
"><pre class="notranslate"><span class="pl-k">import</span> <span class="pl-s">'package:flutter/material.dart'</span>;

<span class="pl-k">void</span> <span class="pl-en">main</span>() {
  <span class="pl-en">runApp</span>(<span class="pl-k">new</span> <span class="pl-c1">FriendlychatApp</span>());
}

<span class="pl-k">class</span> <span class="pl-c1">FriendlychatApp</span> <span class="pl-k">extends</span> <span class="pl-c1">StatelessWidget</span> {
  <span class="pl-k">@override</span>
  <span class="pl-c1">Widget</span> <span class="pl-en">build</span>(<span class="pl-c1">BuildContext</span> context) {
    <span class="pl-k">return</span> <span class="pl-k">new</span> <span class="pl-c1">MaterialApp</span>(
      title<span class="pl-k">:</span> <span class="pl-s">"Friendlychat"</span>,
      home<span class="pl-k">:</span> <span class="pl-k">new</span> <span class="pl-c1">ChatScreen</span>(),
    );
  }
}

<span class="pl-k">class</span> <span class="pl-c1">ChatScreen</span> <span class="pl-k">extends</span> <span class="pl-c1">StatelessWidget</span> {
  <span class="pl-k">@override</span>
  <span class="pl-c1">Widget</span> <span class="pl-en">build</span>(<span class="pl-c1">BuildContext</span> context) {
    <span class="pl-k">return</span> <span class="pl-k">new</span> <span class="pl-c1">Scaffold</span>(
      appBar<span class="pl-k">:</span> <span class="pl-k">new</span> <span class="pl-c1">AppBar</span>(title<span class="pl-k">:</span> <span class="pl-k">new</span> <span class="pl-c1">Text</span>(<span class="pl-s">"Friendlychat"</span>)),
    );
  }
}
</pre></div>
<p dir="auto">After code:</p>
<div class="highlight highlight-source-dart notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="import 'package:flutter/material.dart';

void main() {
  runApp(new FriendlychatApp());
}

class FriendlychatApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: &quot;Friendlychat&quot;,
      home: new ChatScreen(),
    );
  }
}

class ChatScreen extends StatefulWidget {
  @override
  State createState() =&gt; new ChatScreenState();
}

class ChatScreenState extends State&lt;ChatScreen&gt; {
  final TextEditingController _textController = new TextEditingController();

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(title: new Text(&quot;Friendlychat&quot;)),
      body: _buildTextComposer(),
    );
  }

  Widget _buildTextComposer() {
    return new Container(
      margin: const EdgeInsets.symmetric(horizontal: 8.0),
      child: new TextField(
        controller: _textController,
        onSubmitted: _handleSubmitted,
        decoration: new InputDecoration.collapsed(hintText: &quot;Send a message&quot;),
      ),
    );
  }

  void _handleSubmitted(String text) {
    _textController.clear();
  }
}
"><pre class="notranslate"><span class="pl-k">import</span> <span class="pl-s">'package:flutter/material.dart'</span>;

<span class="pl-k">void</span> <span class="pl-en">main</span>() {
  <span class="pl-en">runApp</span>(<span class="pl-k">new</span> <span class="pl-c1">FriendlychatApp</span>());
}

<span class="pl-k">class</span> <span class="pl-c1">FriendlychatApp</span> <span class="pl-k">extends</span> <span class="pl-c1">StatelessWidget</span> {
  <span class="pl-k">@override</span>
  <span class="pl-c1">Widget</span> <span class="pl-en">build</span>(<span class="pl-c1">BuildContext</span> context) {
    <span class="pl-k">return</span> <span class="pl-k">new</span> <span class="pl-c1">MaterialApp</span>(
      title<span class="pl-k">:</span> <span class="pl-s">"Friendlychat"</span>,
      home<span class="pl-k">:</span> <span class="pl-k">new</span> <span class="pl-c1">ChatScreen</span>(),
    );
  }
}

<span class="pl-k">class</span> <span class="pl-c1">ChatScreen</span> <span class="pl-k">extends</span> <span class="pl-c1">StatefulWidget</span> {
  <span class="pl-k">@override</span>
  <span class="pl-c1">State</span> <span class="pl-en">createState</span>() <span class="pl-k">=&gt;</span> <span class="pl-k">new</span> <span class="pl-c1">ChatScreenState</span>();
}

<span class="pl-k">class</span> <span class="pl-c1">ChatScreenState</span> <span class="pl-k">extends</span> <span class="pl-c1">State</span>&lt;<span class="pl-c1">ChatScreen</span>&gt; {
  <span class="pl-k">final</span> <span class="pl-c1">TextEditingController</span> _textController <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-c1">TextEditingController</span>();

  <span class="pl-k">@override</span>
  <span class="pl-c1">Widget</span> <span class="pl-en">build</span>(<span class="pl-c1">BuildContext</span> context) {
    <span class="pl-k">return</span> <span class="pl-k">new</span> <span class="pl-c1">Scaffold</span>(
      appBar<span class="pl-k">:</span> <span class="pl-k">new</span> <span class="pl-c1">AppBar</span>(title<span class="pl-k">:</span> <span class="pl-k">new</span> <span class="pl-c1">Text</span>(<span class="pl-s">"Friendlychat"</span>)),
      body<span class="pl-k">:</span> <span class="pl-en">_buildTextComposer</span>(),
    );
  }

  <span class="pl-c1">Widget</span> <span class="pl-en">_buildTextComposer</span>() {
    <span class="pl-k">return</span> <span class="pl-k">new</span> <span class="pl-c1">Container</span>(
      margin<span class="pl-k">:</span> <span class="pl-k">const</span> <span class="pl-c1">EdgeInsets</span>.<span class="pl-en">symmetric</span>(horizontal<span class="pl-k">:</span> <span class="pl-c1">8.0</span>),
      child<span class="pl-k">:</span> <span class="pl-k">new</span> <span class="pl-c1">TextField</span>(
        controller<span class="pl-k">:</span> _textController,
        onSubmitted<span class="pl-k">:</span> _handleSubmitted,
        decoration<span class="pl-k">:</span> <span class="pl-k">new</span> <span class="pl-c1">InputDecoration</span>.<span class="pl-en">collapsed</span>(hintText<span class="pl-k">:</span> <span class="pl-s">"Send a message"</span>),
      ),
    );
  }

  <span class="pl-k">void</span> <span class="pl-en">_handleSubmitted</span>(<span class="pl-c1">String</span> text) {
    _textController.<span class="pl-en">clear</span>();
  }
}
</pre></div>
<p dir="auto">Result:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="Reloaded 1 of 470 libraries in 372ms.
══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
type 'ChatScreen' is not a subtype of type 'StatelessWidget' of 'function result' where
ChatScreen is from
/Users/mit/Library/Developer/CoreSimulator/Devices/F49C5FF1-1784-4AC6-ACFD-C1D4222F3EDB/data/Containers/Data/Application/C52A7C9F-3328-4505-AE73-1A410B47A6C0/tmp/test011WLnNZ/test01/lib/main.dart
StatelessWidget is from package:flutter/src/widgets/framework.dart
Either the assertion indicates an error in the framework itself, or we should provide substantially
more information in this error message to help you determine and fix the underlying cause.
In either case, please report this assertion by filing a bug on GitHub:
https://github.com/flutter/flutter/issues/new
When the exception was thrown, this was the stack:
Reloaded 1 of 470 libraries in 689ms.
Some program elements were changed during reload but did not run when the view was reassembled;
you may need to restart the app for the changes to have an effect.
• ChatScreenState (lib/main.dart:22)
• ChatScreen.createState (lib/main.dart:19)"><pre class="notranslate"><code class="notranslate">Reloaded 1 of 470 libraries in 372ms.
══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
type 'ChatScreen' is not a subtype of type 'StatelessWidget' of 'function result' where
ChatScreen is from
/Users/mit/Library/Developer/CoreSimulator/Devices/F49C5FF1-1784-4AC6-ACFD-C1D4222F3EDB/data/Containers/Data/Application/C52A7C9F-3328-4505-AE73-1A410B47A6C0/tmp/test011WLnNZ/test01/lib/main.dart
StatelessWidget is from package:flutter/src/widgets/framework.dart
Either the assertion indicates an error in the framework itself, or we should provide substantially
more information in this error message to help you determine and fix the underlying cause.
In either case, please report this assertion by filing a bug on GitHub:
https://github.com/flutter/flutter/issues/new
When the exception was thrown, this was the stack:
Reloaded 1 of 470 libraries in 689ms.
Some program elements were changed during reload but did not run when the view was reassembled;
you may need to restart the app for the changes to have an effect.
• ChatScreenState (lib/main.dart:22)
• ChatScreen.createState (lib/main.dart:19)
</code></pre></div>
<p dir="auto">Root causes:</p>
<ul dir="auto">
<li>Changing from Stateless to Stateful widget</li>
</ul>
<h2 dir="auto">Steps to Reproduce</h2>
<p dir="auto">Make a class that extends <code class="notranslate">StatelessWidget</code>.<br>
flutter run<br>
Change your class to extend <code class="notranslate">StatefulWidget</code><br>
Hot-reload</p>
<p dir="auto">Result: Assertion failure in <code class="notranslate">StatelessElement.widget</code> (or <code class="notranslate">StatefulElement.update</code> if you're going the other direction). Hot-restarting fixes the issue.</p>
<p dir="auto">Suggestion: We should detect this case and show a helpful error message that suggests hot-restarting, or ideally just rebuild the parts of the app that need to be rebuilt.</p>
<p dir="auto">/cc <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/Hixie/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/Hixie">@Hixie</a> <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/jason-simmons/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/jason-simmons">@jason-simmons</a> <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/sethladd/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/sethladd">@sethladd</a><br>
Related bugs: <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="226112558" data-permission-text="Title is private" data-url="https://github.com/flutter/flutter/issues/9771" data-hovercard-type="issue" data-hovercard-url="/flutter/flutter/issues/9771/hovercard" href="https://github.com/flutter/flutter/issues/9771">#9771</a> <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="226069042" data-permission-text="Title is private" data-url="https://github.com/flutter/flutter/issues/9761" data-hovercard-type="issue" data-hovercard-url="/flutter/flutter/issues/9761/hovercard" href="https://github.com/flutter/flutter/issues/9761">#9761</a></p>
<h2 dir="auto">Logs</h2>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
The following assertion was thrown building _ModalScopeStatus(active):
type 'MyHomePage' is not a subtype of type 'StatelessWidget' of 'function result' where
The following assertion was thrown building _ModalScopeStatus(active):
  MyHomePage is from
type 'MyHomePage' is not a subtype of type 'StatelessWidget' of 'function result' where
  /Users/jackson/Library/Developer/CoreSimulator/Devices/5F90A4C3-6F80-446A-88CB-5394635BF8EF/data/Containers/Data/Application/03A8AB58-F47E-454A-8742-818E868A855D/tmp/scope_exampleCOE3SC/scope_example/lib/main.dart
  MyHomePage is from
  StatelessWidget is from package:flutter/src/widgets/framework.dart
  /Users/jackson/Library/Developer/CoreSimulator/Devices/5F90A4C3-6F80-446A-88CB-5394635BF8EF/data/Containers/Data/Application/03A8AB58-F47E-454A-8742-818E868A855D/tmp/scope_exampleCOE3SC/scope_example/lib/main.dart
  StatelessWidget is from package:flutter/src/widgets/framework.dart
Either the assertion indicates an error in the framework itself, or we should provide substantially
more information in this error message to help you determine and fix the underlying cause.
In either case, please report this assertion by filing a bug on GitHub:
Either the assertion indicates an error in the framework itself, or we should provide substantially
more information in this error message to help you determine and fix the underlying cause.
  https://github.com/flutter/flutter/issues/new
In either case, please report this assertion by filing a bug on GitHub:
  https://github.com/flutter/flutter/issues/new
When the exception was thrown, this was the stack:
#0      StatelessElement.widget (package:flutter/src/widgets/framework.dart:3196:39)
#1      Element.updateChild (package:flutter/src/widgets/framework.dart:2290:17)
#2      ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#3      Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#2      ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#3      Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#4      ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#5      Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#6      ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#7      Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#8      StatelessElement.update (package:flutter/src/widgets/framework.dart:3206:5)
#9      Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#10     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#9      Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#11     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#12     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#10     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#13     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#11     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#12     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#14     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#13     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#15     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#16     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#14     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#17     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#15     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#16     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#18     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#19     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#17     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#20     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#18     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#21     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#19     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#22     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#20     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#23     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#21     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#22     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#24     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#23     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#25     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#26     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#24     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#25     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#27     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#26     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#28     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#29     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#27     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#30     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#28     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#31     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#32     StatelessElement.update (package:flutter/src/widgets/framework.dart:3206:5)
#29     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#33     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#30     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#34     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#35     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#31     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#32     StatelessElement.update (package:flutter/src/widgets/framework.dart:3206:5)
#36     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#33     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#34     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#37     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#35     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#38     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#36     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#39     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#37     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#40     ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#38     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#41     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#42     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#39     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#40     ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#43     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#44     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#41     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#45     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#42     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#46     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#43     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#47     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#44     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#48     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#49     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#45     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#50     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#46     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#51     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#47     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#52     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#53     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#48     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#54     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#49     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#55     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#56     RenderObjectElement.updateChildren (package:flutter/src/widgets/framework.dart:3818:32)
#50     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#57     MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4200:17)
#51     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#58     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#52     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#53     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#59     _TheatreElement.update (package:flutter/src/widgets/overlay.dart:507:16)
#60     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#54     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#61     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#55     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#62     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#56     RenderObjectElement.updateChildren (package:flutter/src/widgets/framework.dart:3818:32)
#63     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#57     MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4200:17)
#64     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#58     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#65     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#59     _TheatreElement.update (package:flutter/src/widgets/overlay.dart:507:16)
#66     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#60     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#67     ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#61     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#68     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#62     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#69     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#70     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#63     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#64     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#71     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#65     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#72     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#73     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#66     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#74     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#67     ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#75     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#76     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#68     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#69     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#77     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#70     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#78     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#71     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#79     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#80     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#72     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#73     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#81     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#74     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#82     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#75     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#83     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#76     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#84     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#85     StatelessElement.update (package:flutter/src/widgets/framework.dart:3206:5)
#77     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#86     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#78     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#87     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#88     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#79     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#89     ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#80     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#90     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#91     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#81     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#92     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#93     ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#82     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#94     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#83     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#95     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#96     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#84     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#97     ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#98     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#85     StatelessElement.update (package:flutter/src/widgets/framework.dart:3206:5)
#99     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#86     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#100    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#87     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#88     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#101    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#102    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#89     ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#103    StatelessElement.update (package:flutter/src/widgets/framework.dart:3206:5)
#90     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#104    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#105    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#91     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#106    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#107    StatelessElement.update (package:flutter/src/widgets/framework.dart:3206:5)
#92     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#108    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#93     ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#109    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#94     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#110    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#95     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#111    StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#112    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#96     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#113    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#97     ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#114    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#115    ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#98     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#116    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#99     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#117    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#100    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#118    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#119    StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#101    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#120    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#102    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#121    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#122    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#103    StatelessElement.update (package:flutter/src/widgets/framework.dart:3206:5)
#123    ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#124    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#104    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#125    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#126    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#105    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#127    StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#128    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#106    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#129    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#130    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#107    StatelessElement.update (package:flutter/src/widgets/framework.dart:3206:5)
#131    BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:1898:33)
#108    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#132    BindingBase&amp;SchedulerBinding&amp;GestureBinding&amp;ServicesBinding&amp;RendererBinding&amp;WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:360:20)
#133    BindingBase&amp;SchedulerBinding&amp;GestureBinding&amp;ServicesBinding&amp;RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:170:5)
#109    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#134    BindingBase&amp;SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:685:15)
#135    BindingBase&amp;SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:633:9)
#110    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#136    BindingBase&amp;SchedulerBinding&amp;GestureBinding&amp;ServicesBinding&amp;RendererBinding.scheduleWarmUpFrame.&lt;anonymous closure&gt; (package:flutter/src/rendering/binding.dart:247:20)
#111    StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#138    _Timer._runTimers (dart:isolate-patch/timer_impl.dart:366)
#112    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#139    _Timer._handleMessage (dart:isolate-patch/timer_impl.dart:394)
#113    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#140    _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:151)
#114    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#115    ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
(elided one frame from package dart:async-patch)
#116    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
════════════════════════════════════════════════════════════════════════════════════════════════════
#117    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#118    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#119    StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#120    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#121    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#122    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#123    ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#124    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#125    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#126    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#127    StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#128    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#129    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#130    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#131    BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:1898:33)
#132    BindingBase&amp;SchedulerBinding&amp;GestureBinding&amp;ServicesBinding&amp;RendererBinding&amp;WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:360:20)
#133    BindingBase&amp;SchedulerBinding&amp;GestureBinding&amp;ServicesBinding&amp;RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:170:5)
#134    BindingBase&amp;SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:685:15)
#135    BindingBase&amp;SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:633:9)
#136    BindingBase&amp;SchedulerBinding&amp;GestureBinding&amp;ServicesBinding&amp;RendererBinding.scheduleWarmUpFrame.&lt;anonymous closure&gt; (package:flutter/src/rendering/binding.dart:247:20)
#138    _Timer._runTimers (dart:isolate-patch/timer_impl.dart:366)
#139    _Timer._handleMessage (dart:isolate-patch/timer_impl.dart:394)
#140    _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:151)
(elided one frame from package dart:async-patch)
════════════════════════════════════════════════════════════════════════════════════════════════════
Another exception was thrown: type 'MyHomePage' is not a subtype of type 'StatelessWidget' of 'function result' where
Another exception was thrown: type 'MyHomePage' is not a subtype of type 'StatelessWidget' of 'function result' where
Another exception was thrown: type 'MyHomePage' is not a subtype of type 'StatelessWidget' of 'function result' where
Another exception was thrown: 'package:flutter/src/widgets/framework.dart': Failed assertion: line 4112 pos 12: 'renderObject.child == child': is not true.
Another exception was thrown: 'package:flutter/src/widgets/framework.dart': Failed assertion: line 1896 pos 16: '!_dirtyElements[index]._active || _dirtyElements[index]._debugIsInScope(context)': is not true.
Reloaded 1 of 427 libraries in 788ms."><pre class="notranslate"><code class="notranslate">══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
The following assertion was thrown building _ModalScopeStatus(active):
type 'MyHomePage' is not a subtype of type 'StatelessWidget' of 'function result' where
The following assertion was thrown building _ModalScopeStatus(active):
  MyHomePage is from
type 'MyHomePage' is not a subtype of type 'StatelessWidget' of 'function result' where
  /Users/jackson/Library/Developer/CoreSimulator/Devices/5F90A4C3-6F80-446A-88CB-5394635BF8EF/data/Containers/Data/Application/03A8AB58-F47E-454A-8742-818E868A855D/tmp/scope_exampleCOE3SC/scope_example/lib/main.dart
  MyHomePage is from
  StatelessWidget is from package:flutter/src/widgets/framework.dart
  /Users/jackson/Library/Developer/CoreSimulator/Devices/5F90A4C3-6F80-446A-88CB-5394635BF8EF/data/Containers/Data/Application/03A8AB58-F47E-454A-8742-818E868A855D/tmp/scope_exampleCOE3SC/scope_example/lib/main.dart
  StatelessWidget is from package:flutter/src/widgets/framework.dart
Either the assertion indicates an error in the framework itself, or we should provide substantially
more information in this error message to help you determine and fix the underlying cause.
In either case, please report this assertion by filing a bug on GitHub:
Either the assertion indicates an error in the framework itself, or we should provide substantially
more information in this error message to help you determine and fix the underlying cause.
  https://github.com/flutter/flutter/issues/new
In either case, please report this assertion by filing a bug on GitHub:
  https://github.com/flutter/flutter/issues/new
When the exception was thrown, this was the stack:
#0      StatelessElement.widget (package:flutter/src/widgets/framework.dart:3196:39)
#1      Element.updateChild (package:flutter/src/widgets/framework.dart:2290:17)
#2      ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#3      Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#2      ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#3      Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#4      ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#5      Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#6      ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#7      Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#8      StatelessElement.update (package:flutter/src/widgets/framework.dart:3206:5)
#9      Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#10     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#9      Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#11     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#12     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#10     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#13     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#11     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#12     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#14     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#13     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#15     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#16     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#14     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#17     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#15     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#16     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#18     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#19     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#17     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#20     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#18     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#21     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#19     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#22     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#20     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#23     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#21     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#22     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#24     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#23     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#25     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#26     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#24     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#25     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#27     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#26     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#28     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#29     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#27     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#30     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#28     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#31     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#32     StatelessElement.update (package:flutter/src/widgets/framework.dart:3206:5)
#29     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#33     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#30     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#34     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#35     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#31     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#32     StatelessElement.update (package:flutter/src/widgets/framework.dart:3206:5)
#36     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#33     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#34     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#37     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#35     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#38     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#36     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#39     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#37     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#40     ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#38     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#41     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#42     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#39     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#40     ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#43     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#44     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#41     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#45     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#42     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#46     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#43     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#47     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#44     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#48     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#49     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#45     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#50     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#46     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#51     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#47     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#52     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#53     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#48     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#54     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#49     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#55     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#56     RenderObjectElement.updateChildren (package:flutter/src/widgets/framework.dart:3818:32)
#50     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#57     MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4200:17)
#51     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#58     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#52     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#53     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#59     _TheatreElement.update (package:flutter/src/widgets/overlay.dart:507:16)
#60     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#54     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#61     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#55     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#62     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#56     RenderObjectElement.updateChildren (package:flutter/src/widgets/framework.dart:3818:32)
#63     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#57     MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4200:17)
#64     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#58     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#65     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#59     _TheatreElement.update (package:flutter/src/widgets/overlay.dart:507:16)
#66     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#60     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#67     ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#61     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#68     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#62     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#69     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#70     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#63     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#64     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#71     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#65     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#72     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#73     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#66     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#74     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#67     ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#75     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#76     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#68     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#69     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#77     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#70     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#78     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#71     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#79     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#80     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#72     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#73     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#81     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#74     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#82     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#75     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#83     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#76     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#84     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#85     StatelessElement.update (package:flutter/src/widgets/framework.dart:3206:5)
#77     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#86     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#78     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#87     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#88     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#79     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#89     ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#80     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#90     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#91     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#81     StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#92     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#93     ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#82     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#94     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#83     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#95     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#96     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#84     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#97     ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#98     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#85     StatelessElement.update (package:flutter/src/widgets/framework.dart:3206:5)
#99     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#86     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#100    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#87     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#88     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#101    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#102    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#89     ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#103    StatelessElement.update (package:flutter/src/widgets/framework.dart:3206:5)
#90     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#104    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#105    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#91     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#106    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#107    StatelessElement.update (package:flutter/src/widgets/framework.dart:3206:5)
#92     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#108    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#93     ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#109    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#94     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#110    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#95     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#111    StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#112    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#96     Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#113    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#97     ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#114    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#115    ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#98     Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#116    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#99     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4092:14)
#117    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#100    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#118    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#119    StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#101    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#120    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#102    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#121    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#122    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#103    StatelessElement.update (package:flutter/src/widgets/framework.dart:3206:5)
#123    ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#124    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#104    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#125    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#126    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#105    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#127    StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#128    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#106    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#129    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#130    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#107    StatelessElement.update (package:flutter/src/widgets/framework.dart:3206:5)
#131    BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:1898:33)
#108    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#132    BindingBase&amp;SchedulerBinding&amp;GestureBinding&amp;ServicesBinding&amp;RendererBinding&amp;WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:360:20)
#133    BindingBase&amp;SchedulerBinding&amp;GestureBinding&amp;ServicesBinding&amp;RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:170:5)
#109    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#134    BindingBase&amp;SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:685:15)
#135    BindingBase&amp;SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:633:9)
#110    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#136    BindingBase&amp;SchedulerBinding&amp;GestureBinding&amp;ServicesBinding&amp;RendererBinding.scheduleWarmUpFrame.&lt;anonymous closure&gt; (package:flutter/src/rendering/binding.dart:247:20)
#111    StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#138    _Timer._runTimers (dart:isolate-patch/timer_impl.dart:366)
#112    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#139    _Timer._handleMessage (dart:isolate-patch/timer_impl.dart:394)
#113    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#140    _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:151)
#114    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#115    ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
(elided one frame from package dart:async-patch)
#116    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
════════════════════════════════════════════════════════════════════════════════════════════════════
#117    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#118    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#119    StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#120    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#121    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#122    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#123    ProxyElement.update (package:flutter/src/widgets/framework.dart:3392:5)
#124    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#125    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#126    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#127    StatefulElement.update (package:flutter/src/widgets/framework.dart:3281:5)
#128    Element.updateChild (package:flutter/src/widgets/framework.dart:2298:15)
#129    ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3156:16)
#130    Element.rebuild (package:flutter/src/widgets/framework.dart:3045:5)
#131    BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:1898:33)
#132    BindingBase&amp;SchedulerBinding&amp;GestureBinding&amp;ServicesBinding&amp;RendererBinding&amp;WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:360:20)
#133    BindingBase&amp;SchedulerBinding&amp;GestureBinding&amp;ServicesBinding&amp;RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:170:5)
#134    BindingBase&amp;SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:685:15)
#135    BindingBase&amp;SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:633:9)
#136    BindingBase&amp;SchedulerBinding&amp;GestureBinding&amp;ServicesBinding&amp;RendererBinding.scheduleWarmUpFrame.&lt;anonymous closure&gt; (package:flutter/src/rendering/binding.dart:247:20)
#138    _Timer._runTimers (dart:isolate-patch/timer_impl.dart:366)
#139    _Timer._handleMessage (dart:isolate-patch/timer_impl.dart:394)
#140    _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:151)
(elided one frame from package dart:async-patch)
════════════════════════════════════════════════════════════════════════════════════════════════════
Another exception was thrown: type 'MyHomePage' is not a subtype of type 'StatelessWidget' of 'function result' where
Another exception was thrown: type 'MyHomePage' is not a subtype of type 'StatelessWidget' of 'function result' where
Another exception was thrown: type 'MyHomePage' is not a subtype of type 'StatelessWidget' of 'function result' where
Another exception was thrown: 'package:flutter/src/widgets/framework.dart': Failed assertion: line 4112 pos 12: 'renderObject.child == child': is not true.
Another exception was thrown: 'package:flutter/src/widgets/framework.dart': Failed assertion: line 1896 pos 16: '!_dirtyElements[index]._active || _dirtyElements[index]._debugIsInScope(context)': is not true.
Reloaded 1 of 427 libraries in 788ms.
</code></pre></div>
<p dir="auto">Run <code class="notranslate">flutter analyze</code> and attach any output of that command also.</p>
<h2 dir="auto">Flutter Doctor</h2>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="[✓] Flutter (on Mac OS X 10.12.4 16E195, channel unknown)
    • Flutter at /Users/jackson/git/flutter
    • Framework revision 1d726bbeb5 (2 days ago), 2017-05-02 12:53:03 -0700
    • Engine revision da8ebf40bd
    • Tools Dart version 1.23.0-dev.11.11

[✓] Android toolchain - develop for Android devices (Android SDK 25.0.2)
    • Android SDK at /Users/jackson/Library/Android/sdk/
    • Platform android-25, build-tools 25.0.2
    • ANDROID_HOME = /Users/jackson/Library/Android/sdk/
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version: OpenJDK Runtime Environment (build 1.8.0_112-release-b06)

[-] iOS toolchain - develop for iOS devices (Xcode 8.3.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 8.3.1, Build version 8E1000a
    • ios-deploy 1.9.1
    ✗ libimobiledevice is incompatible with the installed Xcode version. To update, run:
        brew update
        brew uninstall --ignore-dependencies libimobiledevice
        brew install --HEAD libimobiledevice
    • CocoaPods version 1.0.1

[✓] Android Studio (version 2.3)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Gradle version 3.2
    • Java version: OpenJDK Runtime Environment (build 1.8.0_112-release-b06)

[✓] IntelliJ IDEA Community Edition (version 2016.3.4)
    • Dart plugin version 163.13137
    • Flutter plugin version 0.1.11.2

[✓] Connected devices
    •               • 14710ae2e8497590643751c5532d907ed1ff2eed • ios • iOS  ()
    • iPhone 7 Plus • 5F90A4C3-6F80-446A-88CB-5394635BF8EF     • ios • iOS 10.3 (simulator)"><pre class="notranslate"><code class="notranslate">[✓] Flutter (on Mac OS X 10.12.4 16E195, channel unknown)
    • Flutter at /Users/jackson/git/flutter
    • Framework revision 1d726bbeb5 (2 days ago), 2017-05-02 12:53:03 -0700
    • Engine revision da8ebf40bd
    • Tools Dart version 1.23.0-dev.11.11

[✓] Android toolchain - develop for Android devices (Android SDK 25.0.2)
    • Android SDK at /Users/jackson/Library/Android/sdk/
    • Platform android-25, build-tools 25.0.2
    • ANDROID_HOME = /Users/jackson/Library/Android/sdk/
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version: OpenJDK Runtime Environment (build 1.8.0_112-release-b06)

[-] iOS toolchain - develop for iOS devices (Xcode 8.3.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 8.3.1, Build version 8E1000a
    • ios-deploy 1.9.1
    ✗ libimobiledevice is incompatible with the installed Xcode version. To update, run:
        brew update
        brew uninstall --ignore-dependencies libimobiledevice
        brew install --HEAD libimobiledevice
    • CocoaPods version 1.0.1

[✓] Android Studio (version 2.3)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Gradle version 3.2
    • Java version: OpenJDK Runtime Environment (build 1.8.0_112-release-b06)

[✓] IntelliJ IDEA Community Edition (version 2016.3.4)
    • Dart plugin version 163.13137
    • Flutter plugin version 0.1.11.2

[✓] Connected devices
    •               • 14710ae2e8497590643751c5532d907ed1ff2eed • ios • iOS  ()
    • iPhone 7 Plus • 5F90A4C3-6F80-446A-88CB-5394635BF8EF     • ios • iOS 10.3 (simulator)
</code></pre></div>