build: Enable CS1998 as error

src/AddIns/Uno.UI.Lottie/LottieVisualSourceBase.cs

@@ -127,7 +127,7 @@ public Size Measure(Size availableSize)
 		private readonly Size CompositionSize = default;
 #pragma warning restore CA1805 // Do not initialize unnecessarily
 
-		private async Task InnerUpdate(CancellationToken ct)
+		private Task InnerUpdate(CancellationToken ct)
 		{
 			throw new NotSupportedException("Lottie on this platform is not supported yet.");
 		}
@@ -238,7 +238,7 @@ Size IAnimatedVisualSource.Measure(Size availableSize)
 
 		private async Task<IInputStream?> TryLoadDownloadJson(Uri uri, CancellationToken ct)
 		{
-			if(await TryLoadEmbeddedJson(uri, ct) is {} json)
+			if (TryLoadEmbeddedJson(uri, ct) is { } json)
 			{
 				return json;
 			}
@@ -262,7 +262,7 @@ Size IAnimatedVisualSource.Measure(Size availableSize)
 				: null;
 		}
 
-		private async Task<IInputStream?> TryLoadEmbeddedJson(Uri uri, CancellationToken ct)
+		private IInputStream? TryLoadEmbeddedJson(Uri uri, CancellationToken ct)
 		{
 			if (uri.Scheme != "embedded")
 			{

src/AddIns/Uno.UI.Lottie/ThemableLottieVisualSource.Android.cs

@@ -49,7 +49,7 @@ public partial class ThemableLottieVisualSource : LottieVisualSourceBase, IThema
 
 			_updateCallback = updateCallback;
 
-			var t = LoadAndUpdate(cts.Token, sourceCacheKey, sourceJson);
+			LoadAndUpdate(cts.Token, sourceCacheKey, sourceJson);
 
 			return Disposable.Create(() =>
 			{
@@ -58,7 +58,7 @@ public partial class ThemableLottieVisualSource : LottieVisualSourceBase, IThema
 			});
 		}
 
-		private async Task LoadAndUpdate(
+		private void LoadAndUpdate(
 			CancellationToken ct,
 			string sourceCacheKey,
 			IInputStream sourceJson)

src/AddIns/Uno.UI.Lottie/ThemableLottieVisualSource.cs

@@ -51,7 +51,7 @@ public Task LoadForTests(
 
 			_updateCallback = updateCallback;
 
-			var t = LoadAndUpdate(cts.Token, sourceCacheKey, sourceJson);
+			LoadAndUpdate(cts.Token, sourceCacheKey, sourceJson);
 
 			return Disposable.Create(() =>
 			{
@@ -60,7 +60,7 @@ public Task LoadForTests(
 			});
 		}
 
-		private async Task LoadAndUpdate(
+		private void LoadAndUpdate(
 			CancellationToken ct,
 			string sourceCacheKey,
 			IInputStream sourceJson)

src/Directory.Build.props

@@ -5,7 +5,6 @@
   <Import Project="$(MSBuildSDKExtrasTargets)" Condition="Exists('$(MSBuildSDKExtrasTargets)')" />
 
   <PropertyGroup>
-    <NoWarn>$(NoWarn);1998</NoWarn>
     <NoWarn>$(NoWarn);CA1416</NoWarn> <!-- Disable warning about cross platform call sites -->
     <NoWarn>$(NoWarn);MSB4011</NoWarn> <!-- Disable duplicate msbuild files imports message -->
     <DebugType>portable</DebugType>
@@ -168,7 +167,7 @@
     <IsTestProject>$(MSBuildProjectName.Contains('Test'))</IsTestProject>
     <IsSampleProject>$(MSBuildProjectName.Contains('Sample'))</IsSampleProject>
     <IsSampleProject Condition="'$(IsSampleProject)'=='false'">$(MSBuildProjectName.Contains('UnoIslands'))</IsSampleProject>
-    <WarningsAsErrors>$(WarningsAsErrors);nullable;CS8032</WarningsAsErrors>
+    <WarningsAsErrors>$(WarningsAsErrors);nullable;CS8032;CS1998</WarningsAsErrors>
   </PropertyGroup>
 
   <PropertyGroup>

src/SamplesApp/SamplesApp.Shared/App.xaml.cs

@@ -155,7 +155,7 @@ private void AppendRepositoryPathToTitleBar()
 		}
 #endif
 
-		private static async Task<bool> HandleSkiaAutoScreenshots(LaunchActivatedEventArgs e)
+		private static bool HandleSkiaAutoScreenshots(LaunchActivatedEventArgs e)
 		{
 #if __SKIA__ || __MACOS__
 			var runAutoScreenshotsParam =
@@ -185,7 +185,11 @@ private static async Task<bool> HandleSkiaAutoScreenshots(LaunchActivatedEventAr
 			return false;
 		}
 
-		private static async Task<bool> HandleSkiaRuntimeTests(LaunchActivatedEventArgs e)
+		private static
+#if __SKIA__ || __MACOS__
+			async
+#endif
+			Task<bool> HandleSkiaRuntimeTests(LaunchActivatedEventArgs e)
 		{
 #if __SKIA__ || __MACOS__
 			var runRuntimeTestsResultsParam =
@@ -207,8 +211,11 @@ await SampleControl.Presentation.SampleChooserViewModel.Instance.RunRuntimeTests
 
 				return true;
 			}
-#endif
+
 			return false;
+#else
+			return Task.FromResult(false);
+#endif
 		}
 
 #if __IOS__
@@ -318,7 +325,7 @@ private async void HandleLaunchArguments(LaunchActivatedEventArgs launchActivate
 		{
 			Console.WriteLine($"HandleLaunchArguments: {launchActivatedEventArgs.Arguments}");
 
-			if (await HandleSkiaAutoScreenshots(launchActivatedEventArgs))
+			if (HandleSkiaAutoScreenshots(launchActivatedEventArgs))
 			{
 				return;
 			}
@@ -328,7 +335,7 @@ private async void HandleLaunchArguments(LaunchActivatedEventArgs launchActivate
 				return;
 			}
 
-			if (await TryNavigateToLaunchSampleAsync(launchActivatedEventArgs))
+			if (TryNavigateToLaunchSample(launchActivatedEventArgs))
 			{
 				return;
 			}
@@ -340,7 +347,7 @@ private async void HandleLaunchArguments(LaunchActivatedEventArgs launchActivate
 			}
 		}
 
-		private async Task<bool> TryNavigateToLaunchSampleAsync(LaunchActivatedEventArgs launchActivatedEventArgs)
+		private bool TryNavigateToLaunchSample(LaunchActivatedEventArgs launchActivatedEventArgs)
 		{
 			const string samplePrefix = "sample=";
 			try
@@ -363,7 +370,7 @@ private async Task<bool> TryNavigateToLaunchSampleAsync(LaunchActivatedEventArgs
 				var category = pathParts[0];
 				var sampleName = pathParts[1];
 
-				await SampleControl.Presentation.SampleChooserViewModel.Instance.SetSelectedSample(CancellationToken.None, category, sampleName);
+				SampleControl.Presentation.SampleChooserViewModel.Instance.SetSelectedSample(CancellationToken.None, category, sampleName);
 				return true;
 			}
 			catch (Exception ex)

src/SamplesApp/SamplesApp.UITests/Extensions/QueryExtensions.async.cs

@@ -12,18 +12,24 @@ public static class AppExtensions
 	// Those are only mapping to the sync version but are needed to allow
 	// multi-targeting with **Runtime UI tests** engine which has only async versions.
 
-	public static async Task WaitForDependencyPropertyValueAsync(
+	public static Task WaitForDependencyPropertyValueAsync(
 		this IApp app,
 		QueryEx element,
 		string dependencyPropertyName,
 		string value)
-		=> app.WaitForDependencyPropertyValue(element, dependencyPropertyName, value);
+	{
+		app.WaitForDependencyPropertyValue(element, dependencyPropertyName, value);
+		return Task.CompletedTask;
+	}
 
-	public static async Task WaitForDependencyPropertyValueAsync<T>(
+	public static Task WaitForDependencyPropertyValueAsync<T>(
 		this IApp app,
 		Func<IAppQuery, IAppQuery> element,
 		string dependencyPropertyName,
 		T expectedValue)
-		=> app.WaitForDependencyPropertyValue<T>(element, dependencyPropertyName, expectedValue);
+	{
+		app.WaitForDependencyPropertyValue<T>(element, dependencyPropertyName, expectedValue);
+		return Task.CompletedTask;
+	}
 }
 #endif

src/SamplesApp/SamplesApp.UITests/SampleControlUITestBase.cs

@@ -337,8 +337,11 @@ private IEnumerable<Platform> GetActivePlatforms()
 			}
 		}
 
-		protected async Task RunAsync(string metadataName, bool waitForSampleControl = true, bool skipInitialScreenshot = false, int sampleLoadTimeout = 5)
-			=> Run(metadataName, waitForSampleControl, skipInitialScreenshot, sampleLoadTimeout);
+		protected Task RunAsync(string metadataName, bool waitForSampleControl = true, bool skipInitialScreenshot = false, int sampleLoadTimeout = 5)
+		{
+			Run(metadataName, waitForSampleControl, skipInitialScreenshot, sampleLoadTimeout);
+			return Task.CompletedTask;
+		}
 
 		protected void Run(string metadataName, bool waitForSampleControl = true, bool skipInitialScreenshot = false, int sampleLoadTimeout = 5)
 		{

src/SamplesApp/SamplesApp.UITests/Windows_UI_Xaml_Controls/TextBlockTests/TextBlockTests.cs

@@ -98,7 +98,7 @@ public void When_Foreground_Changed_With_Visibility()
 
 		[Test]
 		[AutoRetry]
-		public async Task When_TextDecoration_Changed()
+		public void When_TextDecoration_Changed()
 		{
 			Run("UITests.Shared.Windows_UI_Xaml_Controls.TextBlockControl.TextBlock_Decorations");
 

src/SamplesApp/SamplesApp.UITests/Windows_UI_Xaml_Input/Capture_Tests.cs

@@ -21,34 +21,34 @@ public partial class Capture_Tests : SampleControlUITestBase
 	[ActivePlatforms(Platform.iOS, Platform.Android)] // This fails with unit test
 	[InjectedPointer(PointerDeviceType.Touch)]
 	public async Task TestSimple()
-		=> RunTest("Simple", TouchAndMoveOut);
+		=> await RunTest("Simple", TouchAndMoveOut);
 
 	[Test]
 	[AutoRetry]
 	[InjectedPointer(PointerDeviceType.Touch)]
 	public async Task TestVisibility()
-		=> RunTest("Visibility");
+		=> await RunTest("Visibility");
 
 	[Test]
 	[AutoRetry]
 	[InjectedPointer(PointerDeviceType.Touch)]
 	public async Task TestNestedVisibility()
-		=> RunTest("NestedVisibility");
+		=> await RunTest("NestedVisibility");
 
 	[Test]
 	[AutoRetry]
 	[Ignore("Inconsistent behavior between manual and unit test")]
 	[InjectedPointer(PointerDeviceType.Touch)]
 	public async Task TestIsEnabled()
-		=> RunTest("IsEnabled");
+		=> await RunTest("IsEnabled");
 
 	[Test]
 	[AutoRetry]
 	[Ignore("Inconsistent behavior between manual and unit test")]
 	[ActivePlatforms(Platform.Browser)] // The IsEnabled property is not inherited on other platforms yet.
 	[InjectedPointer(PointerDeviceType.Touch)]
 	public async Task TestNestedIsEnabled()
-		=> RunTest("NestedIsEnabled");
+		=> await RunTest("NestedIsEnabled");
 
 
 	private readonly Action<QueryEx> TouchAndHold = element => /*element.TouchAndHold() not implemented ... we can use tap instead */ element.FastTap();

src/SamplesApp/SamplesApp.UITests/Windows_UI_Xaml_Media_Animation/SetTarget_After_Start.cs

@@ -16,7 +16,7 @@ public partial class SetTarget_After_Start : SampleControlUITestBase
 	{
 		[Test]
 		[AutoRetry]
-		public async Task When_Target_Is_Set_After_Start()
+		public void When_Target_Is_Set_After_Start()
 		{
 			Run("UITests.Shared.Windows_UI_Xaml_Media_Animation.SetTargetProperty");
 			var playBtn = _app.Marked("playButton");