Migrate to Microsoft.VisualStudio.Threading

build/Rulesets/Roslyn_BuildRules.ruleset

@@ -158,4 +158,12 @@ collection.
     <Rule Id="VSSDK001" Action="Warning" /> <!-- Derive from AsyncPackage -->
     <Rule Id="VSSDK003" Action="Warning" /> <!-- Support async tool windows -->
   </Rules>
+  <Rules AnalyzerId="Microsoft.VisualStudio.Threading.Analyzers" RuleNamespace="Microsoft.VisualStudio.Threading.Analyzers">
+    <Rule Id="VSTHRD001" Action="None" /> <!-- Avoid legacy thread switching APIs -->
+    <Rule Id="VSTHRD002" Action="None" /> <!-- Avoid problematic synchronous waits -->
+    <Rule Id="VSTHRD101" Action="None" /> <!-- Avoid unsupported async delegates -->
+    <Rule Id="VSTHRD103" Action="None" /> <!-- Call async methods when in an async method -->
+    <Rule Id="VSTHRD110" Action="None" /> <!-- Observe result of async calls -->
+    <Rule Id="VSTHRD200" Action="None" /> <!-- Use "Async" suffix for async methods -->
+  </Rules>
 </RuleSet>

build/Targets/Packages.props

@@ -134,6 +134,7 @@
     <MicrosoftVisualStudioTextManagerInterop100Version>10.0.30319</MicrosoftVisualStudioTextManagerInterop100Version>
     <MicrosoftVisualStudioTextManagerInterop120Version>12.0.30110</MicrosoftVisualStudioTextManagerInterop120Version>
     <MicrosoftVisualStudioTextManagerInterop121DesignTimeVersion>12.1.30328</MicrosoftVisualStudioTextManagerInterop121DesignTimeVersion>
+    <MicrosoftVisualStudioThreadingAnalyzersVersion>15.8.132</MicrosoftVisualStudioThreadingAnalyzersVersion>
     <MicrosoftVisualStudioThreadingVersion>15.3.23</MicrosoftVisualStudioThreadingVersion>
     <MicrosoftVisualStudioUtilitiesVersion>15.0.26730-alpha</MicrosoftVisualStudioUtilitiesVersion>
     <MicrosoftVisualStudioValidationVersion>15.3.23</MicrosoftVisualStudioValidationVersion>

build/Targets/Settings.props

@@ -134,6 +134,9 @@
              Condition="'$(OS)' == 'Windows_NT'" />
 
   <Import Project="$(RoslynDiagnosticsPropsFilePath)" Condition="'$(UseRoslynAnalyzers)' == 'true' AND Exists('$(RoslynDiagnosticsPropsFilePath)')" />
+  <ItemGroup>
+    <PackageReference Include="Microsoft.VisualStudio.Threading.Analyzers" Version="$(MicrosoftVisualStudioThreadingAnalyzersVersion)" />
+  </ItemGroup>
 
   <ImportGroup Label="WindowsImports" Condition="'$(OS)' == 'Windows_NT'">
     <Import 

src/EditorFeatures/Core.Wpf/NavigateTo/NavigateToItemProvider.Searcher.cs

@@ -59,7 +59,7 @@ public Searcher(
                 }
             }
 
-            internal async void Search()
+            internal async Task SearchAsync()
             {
                 try
                 {

src/EditorFeatures/Core.Wpf/NavigateTo/NavigateToItemProvider.cs

@@ -149,7 +149,7 @@ private void StartSearch(INavigateToCallback callback, string searchValue, IImmu
                 kinds,
                 _cancellationTokenSource.Token);
 
-            searcher.Search();
+            _ = searcher.SearchAsync();
         }
 
         private static INavigateToSearchService_RemoveInterfaceAboveAndRenameThisAfterInternalsVisibleToUsersUpdate TryGetNavigateToSearchService(Project project)

src/EditorFeatures/Core/FindReferences/FindReferencesCommandHandler.cs

@@ -5,6 +5,7 @@
 using System.ComponentModel.Composition;
 using System.Linq;
 using System.Threading;
+using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.Editor.FindUsages;
 using Microsoft.CodeAnalysis.Editor.Host;
 using Microsoft.CodeAnalysis.Editor.Shared.Extensions;
@@ -90,7 +91,7 @@ private bool TryExecuteCommand(int caretPosition, Document document, CommandExec
             // a presenter that can accept streamed results.
             if (streamingService != null && streamingPresenter != null)
             {
-                StreamingFindReferences(document, caretPosition, streamingService, streamingPresenter);
+                _ = StreamingFindReferencesAsync(document, caretPosition, streamingService, streamingPresenter);
                 return true;
             }
 
@@ -109,14 +110,14 @@ private IStreamingFindUsagesPresenter GetStreamingPresenter()
             }
         }
 
-        private async void StreamingFindReferences(
+        private async Task StreamingFindReferencesAsync(
             Document document, int caretPosition,
             IFindUsagesService findUsagesService,
             IStreamingFindUsagesPresenter presenter)
         {
             try
             {
-                using (var token = _asyncListener.BeginAsyncOperation(nameof(StreamingFindReferences)))
+                using (var token = _asyncListener.BeginAsyncOperation(nameof(StreamingFindReferencesAsync)))
                 {
                     // Let the presented know we're starting a search.  It will give us back
                     // the context object that the FAR service will push results into.

src/EditorFeatures/Core/Implementation/EditAndContinue/ActiveStatementTrackingService.cs

@@ -139,9 +139,11 @@ public void EndTracking()
             }
 
             private void DocumentOpened(object sender, DocumentEventArgs e)
-                => DocumentOpenedAsync(e.Document);
+            {
+                _ = DocumentOpenedAsync(e.Document);
+            }
 
-            private async void DocumentOpenedAsync(Document document)
+            private async Task DocumentOpenedAsync(Document document)
             {
                 try
                 {
@@ -232,12 +234,12 @@ private void TrackActiveSpansNoLock(
                         SetTrackingSpansNoLock(document.Id, null);
 
                         // fire and forget:
-                        RefreshTrackingSpansAsync(document, snapshot);
+                        _ = RefreshTrackingSpansAsync(document, snapshot);
                     }
                 }
             }
 
-            private async void RefreshTrackingSpansAsync(Document document, ITextSnapshot snapshot)
+            private async Task RefreshTrackingSpansAsync(Document document, ITextSnapshot snapshot)
             {
                 try
                 {

src/EditorFeatures/Core/Shared/Preview/PreviewSolutionCrawlerRegistrationService.cs

@@ -101,7 +101,12 @@ private async Task AnalyzeAsync()
                 }
             }
 
-            public async void Unregister(Workspace workspace, bool blockingShutdown = false)
+            public void Unregister(Workspace workspace, bool blockingShutdown = false)
+            {
+                _ = UnregisterAsync(workspace, blockingShutdown);
+            }
+
+            private async Task UnregisterAsync(Workspace workspace, bool blockingShutdown)
             {
                 Contract.ThrowIfFalse(workspace == _workspace);
                 _source.Cancel();

src/EditorFeatures/Core/Shared/Utilities/ResettableDelay.cs

@@ -31,11 +31,11 @@ public ResettableDelay(int delayInMilliseconds, TaskScheduler foregroundTaskSche
 
             if (foregroundTaskScheduler != null)
             {
-                Task.Factory.SafeStartNew(() => StartTimer(continueOnCapturedContext: true), CancellationToken.None, foregroundTaskScheduler);
+                Task.Factory.SafeStartNew(() => StartTimerAsync(continueOnCapturedContext: true), CancellationToken.None, foregroundTaskScheduler);
             }
             else
             {
-                StartTimer(continueOnCapturedContext: false);
+                _ = StartTimerAsync(continueOnCapturedContext: false);
             }
         }
 
@@ -48,7 +48,7 @@ public void Reset()
             _lastSetTime = Environment.TickCount;
         }
 
-        private async void StartTimer(bool continueOnCapturedContext)
+        private async Task StartTimerAsync(bool continueOnCapturedContext)
         {
             do
             {

src/Interactive/Features/Interactive/Core/InteractiveHost.RemoteService.cs

@@ -62,7 +62,12 @@ internal void HookAutoRestartEvent()
                 }
             }
 
-            private async void ProcessExitedHandler(object _, EventArgs __)
+            private void ProcessExitedHandler(object sender, EventArgs e)
+            {
+                _ = ProcessExitedHandlerAsync();
+            }
+
+            private async Task ProcessExitedHandlerAsync()
             {
                 try
                 {

src/Scripting/CSharpTest/ScriptTests.cs

@@ -169,7 +169,7 @@ public void TestRunVoidScript()
 
         [WorkItem(5279, "https://github.com/dotnet/roslyn/issues/5279")]
         [Fact]
-        public async void TestRunExpressionStatement()
+        public async Task TestRunExpressionStatement()
         {
             var state = await CSharpScript.RunAsync(
 @"int F() { return 1; }

src/Test/Utilities/Portable/Diagnostics/CommonDiagnosticAnalyzers.cs

@@ -598,7 +598,9 @@ public override void Initialize(AnalysisContext context)
                 context.RegisterCompilationAction(AsyncAction);
             }
 
+#pragma warning disable VSTHRD100 // Avoid async void methods
             private async void AsyncAction(CompilationAnalysisContext context)
+#pragma warning restore VSTHRD100 // Avoid async void methods
             {
                 context.ReportDiagnostic(Diagnostic.Create(Descriptor, Location.None));
                 await Task.FromResult(true);

src/Workspaces/Core/Portable/Utilities/TaskExtensions.cs

@@ -15,21 +15,6 @@ namespace Roslyn.Utilities
     [SuppressMessage("ApiDesign", "CA1068", Justification = "Matching TPL Signatures")]
     internal static partial class TaskExtensions
     {
-        /// <summary>
-        /// Use to explicitly indicate that you are not waiting for a task to complete
-        /// Observes the exceptions from it.
-        /// </summary>
-        public static async void FireAndForget(this Task task)
-        {
-            try
-            {
-                await task.ConfigureAwait(false);
-            }
-            catch (OperationCanceledException)
-            {
-            }
-        }
-
         public static T WaitAndGetResult<T>(this Task<T> task, CancellationToken cancellationToken)
         {
 #if DEBUG

src/Workspaces/MSBuildTest/MSBuildWorkspaceTests.cs

@@ -3251,7 +3251,7 @@ public async Task TestAddRemoveMetadataReference_GAC()
 
         [ConditionalFact(typeof(VisualStudioMSBuildInstalled))]
         [Trait(Traits.Feature, Traits.Features.MSBuildWorkspace)]
-        public async void TestAddRemoveMetadataReference_ReferenceAssembly()
+        public async Task TestAddRemoveMetadataReference_ReferenceAssembly()
         {
             CreateFiles(GetMultiProjectSolutionFiles()
                 .WithFile(@"CSharpProject\CSharpProject.csproj", Resources.ProjectFiles.CSharp.WithSystemNumerics));