<h2 dir="auto">Steps to Reproduce</h2>
<p dir="auto"><code class="notranslate">flutter run --preview-dart-2</code></p>
<p dir="auto">Make any tiny tweak to <code class="notranslate">widget_inspector.dart</code> or any other file in package:flutter</p>
<p dir="auto">Trigger hot reload</p>
<p dir="auto">See the warning:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="   Some program elements were changed during reload but did not run when the view was reassembled;
           you may need to restart the app (by pressing &quot;R&quot;) for the changes to have an effect.
             • _RenderSliverPersistentHeaderForWidgetsMixin.handleEvent (package:flutter/src/widgets/sliver_persistent_header.dart:253)
             • #errors (file:///)
             • #errors (file:///)
             • _RenderSliverPinnedPersistentHeader.handleEvent (package:flutter/src/widgets/sliver_persistent_header.dart:309)

"><pre class="notranslate"><code class="notranslate">   Some program elements were changed during reload but did not run when the view was reassembled;
           you may need to restart the app (by pressing "R") for the changes to have an effect.
             • _RenderSliverPersistentHeaderForWidgetsMixin.handleEvent (package:flutter/src/widgets/sliver_persistent_header.dart:253)
             • #errors (file:///)
             • #errors (file:///)
             • _RenderSliverPinnedPersistentHeader.handleEvent (package:flutter/src/widgets/sliver_persistent_header.dart:309)


</code></pre></div>
<h2 dir="auto">Steps to Reproduce</h2>
<p dir="auto">I was working through the <a href="https://flutter.io/get-started/codelab/" rel="nofollow">Write Your First App</a> tutorial. I received warnings that some program elements didn't run when the view was reassembled, but the UI seemed to be updated correctly.</p>
<p dir="auto">For example, when I changed my code from <a href="https://gist.githubusercontent.com/Sfshaza/bb51e3b7df4ebbf3dfd02a4a38db2655/raw/57c25b976ec34d56591cb898a3df0b320e903b99/main.dart" rel="nofollow">step 2</a> to <a href="https://gist.githubusercontent.com/Sfshaza/d7f13ddd8888556232476be8578efe40/raw/329c397b97309ce99f834bf70ebb90778baa5cfe/main.dart" rel="nofollow">step 3</a>, I received the following message:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="Performing hot reload...
Reloaded 1 of 430 libraries in 627ms.

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.
  • RandomWordsState.didUpdateWidget (lib/main.dart:28)
  • RandomWordsState._widget= (lib/main.dart:28)"><pre class="notranslate"><code class="notranslate">Performing hot reload...
Reloaded 1 of 430 libraries in 627ms.

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.
  • RandomWordsState.didUpdateWidget (lib/main.dart:28)
  • RandomWordsState._widget= (lib/main.dart:28)
</code></pre></div>
<p dir="auto">In addition to the UI appeared to be fine, I didn't know how relevant RandomWordsState.didUpdateWidget and RandomWordsState._widget were to me, since these two methods were not actually in the code I wrote.</p>
<p dir="auto">Then, when I changed my code from <a href="https://gist.githubusercontent.com/Sfshaza/d7f13ddd8888556232476be8578efe40/raw/329c397b97309ce99f834bf70ebb90778baa5cfe/main.dart" rel="nofollow">step 3</a> to <a href="https://gist.githubusercontent.com/Sfshaza/d6f9460a04d3a429eb6ac0b0f07da564/raw/34fe240f4122435c871bb737708ee0357741801c/main.dart" rel="nofollow">step 4</a>, I got the following message:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="Initializing hot reload...
Reloaded 1 of 430 libraries in 915ms.

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.
  • RandomWordsState._suggestions (lib/main.dart:22)
  • RandomWordsState._biggerFont (lib/main.dart:24)"><pre class="notranslate"><code class="notranslate">Initializing hot reload...
Reloaded 1 of 430 libraries in 915ms.

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.
  • RandomWordsState._suggestions (lib/main.dart:22)
  • RandomWordsState._biggerFont (lib/main.dart:24)
</code></pre></div>
<p dir="auto">Again, the UI seemed to be functioning correctly, including the font size, which the message says the relevant code didn't run.</p>
<h2 dir="auto">Flutter Doctor</h2>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="[✓] Flutter (Channel master, v0.2.9-pre.9, on Mac OS X 10.13.3 17D102, locale en-US)
    • Flutter version 0.2.9-pre.9 at /Users/taodong/Code/flutter_repos/flutter
    • Framework revision 5e9424419e (35 minutes ago), 2018-04-03 10:35:07 -0700
    • Engine revision 04f3c6557c
    • Dart version 2.0.0-dev.43.0.flutter-52afcba357

[!] Android toolchain - develop for Android devices (Android SDK 27.0.0)
    • Android SDK at /Users/taodong/Library/Android/sdk
    • Android NDK location not configured (optional; useful for native profiling support)
    • Platform android-27, build-tools 27.0.0
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b01)
    ✗ Android license status unknown.

[✓] iOS toolchain - develop for iOS devices (Xcode 9.2)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 9.2, Build version 9C40b
    • ios-deploy 1.9.2
    • CocoaPods version 1.4.0

[✓] Android Studio (version 3.1)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b01)

[✓] IntelliJ IDEA Community Edition (version 2018.1)
    • IntelliJ at /Applications/IntelliJ IDEA CE.app
    • Flutter plugin installed
    • Dart plugin version 181.4203.498

[✓] VS Code (version 1.20.1)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Dart Code extension version 2.9.0

[✓] Connected devices (1 available)
    • iPhone SE • AD00445E-9D4A-454D-892F-1419FF77D3A1 • ios • iOS 11.2 (simulator)

! Doctor found issues in 1 category."><pre class="notranslate"><code class="notranslate">[✓] Flutter (Channel master, v0.2.9-pre.9, on Mac OS X 10.13.3 17D102, locale en-US)
    • Flutter version 0.2.9-pre.9 at /Users/taodong/Code/flutter_repos/flutter
    • Framework revision 5e9424419e (35 minutes ago), 2018-04-03 10:35:07 -0700
    • Engine revision 04f3c6557c
    • Dart version 2.0.0-dev.43.0.flutter-52afcba357

[!] Android toolchain - develop for Android devices (Android SDK 27.0.0)
    • Android SDK at /Users/taodong/Library/Android/sdk
    • Android NDK location not configured (optional; useful for native profiling support)
    • Platform android-27, build-tools 27.0.0
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b01)
    ✗ Android license status unknown.

[✓] iOS toolchain - develop for iOS devices (Xcode 9.2)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 9.2, Build version 9C40b
    • ios-deploy 1.9.2
    • CocoaPods version 1.4.0

[✓] Android Studio (version 3.1)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b01)

[✓] IntelliJ IDEA Community Edition (version 2018.1)
    • IntelliJ at /Applications/IntelliJ IDEA CE.app
    • Flutter plugin installed
    • Dart plugin version 181.4203.498

[✓] VS Code (version 1.20.1)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Dart Code extension version 2.9.0

[✓] Connected devices (1 available)
    • iPhone SE • AD00445E-9D4A-454D-892F-1419FF77D3A1 • ios • iOS 11.2 (simulator)

! Doctor found issues in 1 category.
</code></pre></div>
<blockquote>
<p dir="auto">For more information about diagnosing and reporting Flutter bugs, please see <a href="https://flutter.io/bug-reports/" rel="nofollow">https://flutter.io/bug-reports/</a>.</p>
</blockquote>