Updates & Modernization

Directory.Build.props

@@ -1,34 +1,33 @@
 <Project>
-	<PropertyGroup>
-		<LangVersion>latest</LangVersion>
+  <PropertyGroup>
+	<LangVersion>latest</LangVersion>
 
-		<Nullable>enable</Nullable>
-		<WarningsAsErrors>$(WarningsAsErrors);nullable;</WarningsAsErrors>
+	<Nullable>enable</Nullable>
+	<WarningsAsErrors>$(WarningsAsErrors);nullable;</WarningsAsErrors>
 
-		<ImplicitUsings>enable</ImplicitUsings>
+	<ImplicitUsings>enable</ImplicitUsings>
 
-		<CheckEolTargetFramework>false</CheckEolTargetFramework>
+	<CheckEolTargetFramework>false</CheckEolTargetFramework>
 
-		<AnalysisLevel>latest-all</AnalysisLevel>
-		<EnforceCodeStyleInBuild>true</EnforceCodeStyleInBuild>
+	<AnalysisLevel>latest-all</AnalysisLevel>
+	<EnforceCodeStyleInBuild>true</EnforceCodeStyleInBuild>
 
-		<PolySharpIncludeRuntimeSupportedAttributes>true</PolySharpIncludeRuntimeSupportedAttributes>
+	<GenerateDocumentationFile>true</GenerateDocumentationFile>
+  </PropertyGroup>
 
-		<GenerateDocumentationFile>true</GenerateDocumentationFile>
-	</PropertyGroup>
+  <ItemGroup>
+	<PackageReference Include="Meziantou.Analyzer" PrivateAssets="All" />
+	<PackageReference Include="Microsoft.CodeAnalysis.PerformanceSensitiveAnalyzers" PrivateAssets="All" />
+	<PackageReference Include="PolySharp" PrivateAssets="All" />
+  </ItemGroup>
 
-	<ItemGroup>
-		<PackageReference Include="Microsoft.CodeAnalysis.PerformanceSensitiveAnalyzers" PrivateAssets="All" />
-		<PackageReference Include="PolySharp" PrivateAssets="All" />
-	</ItemGroup>
+  <PropertyGroup Condition="'$(GITHUB_ACTIONS)' == 'true'">
+	<!-- Don't block development work; but block CI if dev work isn't complete. -->
+	<TreatWarningsAsErrors>true</TreatWarningsAsErrors>
 
-	<PropertyGroup Condition="'$(GITHUB_ACTIONS)' == 'true'">
-		<!-- Don't block development work; but block CI if dev work isn't complete. -->
-		<TreatWarningsAsErrors>true</TreatWarningsAsErrors>
-
-		<ContinuousIntegrationBuild>true</ContinuousIntegrationBuild>
-		<EmbedUntrackedSources>true</EmbedUntrackedSources>
-		<CollectCoverage>true</CollectCoverage>
-		<CoverletOutputFormat>opencover</CoverletOutputFormat>
-	</PropertyGroup>
+	<ContinuousIntegrationBuild>true</ContinuousIntegrationBuild>
+	<EmbedUntrackedSources>true</EmbedUntrackedSources>
+	<CollectCoverage>true</CollectCoverage>
+	<CoverletOutputFormat>opencover</CoverletOutputFormat>
+  </PropertyGroup>
 </Project>

Directory.Packages.props

@@ -9,6 +9,7 @@
 		<PackageVersion Include="coverlet.msbuild" Version="6.0.0" />
 		<PackageVersion Include="DocFx.App" Version="2.76.0" />
 		<PackageVersion Include="GitHubActionsTestLogger" Version="2.3.3" />
+	<PackageVersion Include="Meziantou.Analyzer" Version="2.0.146" />
 		<PackageVersion Include="Microsoft.CodeAnalysis.Analyzers" Version="3.3.4" />
 		<PackageVersion Include="Microsoft.CodeAnalysis.CSharp" Version="4.9.2" />
 		<PackageVersion Include="Microsoft.CodeAnalysis.PerformanceSensitiveAnalyzers" Version="3.3.1" />

Generators/SuperLinq.Async.Generator/Generator.cs

@@ -10,7 +10,7 @@ namespace SuperLinq.Async.Generator;
 /// Uses source generation tools to automate the building of some operators
 /// </summary>
 [Generator]
-public class Generator : IIncrementalGenerator
+public sealed class Generator : IIncrementalGenerator
 {
 	/// <inheritdoc />
 	public void Initialize(IncrementalGeneratorInitializationContext context)

Generators/SuperLinq.Generator/EquiZip.sbntxt

@@ -155,7 +155,7 @@ public static partial class SuperEnumerable
 			{{~ end ~}}
 	) => EquiZip({{~ for $j in 1..$i ~}}{{ $ordinals[$j] }}, {{ end }}global::System.ValueTuple.Create);
 
-	private class EquiZipIterator<{{ for $j in 1..$i }}T{{ $j }}, {{ end }}TResult> : ListIterator<TResult>
+	private sealed class EquiZipIterator<{{ for $j in 1..$i }}T{{ $j }}, {{ end }}TResult> : ListIterator<TResult>
 	{
 		{{~ for $j in 1..$i ~}}
 		private readonly global::System.Collections.Generic.IList<T{{ $j }}> _list{{ $j }};

Generators/SuperLinq.Generator/Generator.cs

@@ -9,7 +9,7 @@ namespace SuperLinq.Generator;
 /// Uses source generation tools to automate the building of some operators
 /// </summary>
 [Generator]
-public class Generator : IIncrementalGenerator
+public sealed class Generator : IIncrementalGenerator
 {
 	/// <inheritdoc />
 	public void Initialize(IncrementalGeneratorInitializationContext context)

Generators/SuperLinq.Generator/ToDelimitedString.cs

@@ -1,4 +1,4 @@
-using System.Reflection;
+using System.Reflection;
 using System.Text;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.Text;
@@ -10,16 +10,16 @@ internal static class ToDelimitedString
 {
 	public static SourceText Generate()
 	{
-		var types =
-			from method in typeof(StringBuilder).GetMethods(BindingFlags.Public | BindingFlags.Instance)
-			where string.Equals("Append", method.Name, StringComparison.Ordinal)
-			select method.GetParameters() into parameters
-			where parameters.Length == 1
-			select parameters[0].ParameterType into type
-			where !type.IsGenericType // e.g. ReadOnlySpan<>
-			   && (type.IsValueType || type == typeof(string))
-			orderby type.Name
-			select $"global::{type.FullName}";
+		var types = typeof(StringBuilder).GetMethods(BindingFlags.Public | BindingFlags.Instance)
+			.Where(m => m.Name is "Append")
+			.Select(m => m.GetParameters())
+			.Where(p => p.Length == 1)
+			.Select(p => p[0].ParameterType)
+			.Where(t =>
+				!t.IsGenericType // e.g. ReadOnlySpan<>
+			   && (t.IsValueType || t == typeof(string)))
+			.OrderBy(t => t.Name, StringComparer.Ordinal)
+			.Select(t => $"global::{t.FullName}");
 
 		var template = Template.Parse(ThisAssembly.Resources.ToDelimitedString.Text);
 		var output = template.Render(new { Types = types.ToList(), });

Source/SuperLinq.Async/Amb.cs

@@ -109,7 +109,7 @@ static async IAsyncEnumerable<TSource> Core(
 					tasks.Add(firstMove.AsTask());
 				}
 
-				if (e == null)
+				if (e is null)
 				{
 					// who finishes first?
 					var t = await Task.WhenAny(tasks).ConfigureAwait(false);
@@ -158,7 +158,7 @@ ex is OperationCanceledException
 				{ }
 				// if we're in the normal path, then e != null; in this case, we need to report any exceptions that we
 				// encounter.
-				catch (Exception ex) when (e != null)
+				catch (Exception ex) when (e is not null)
 				{
 					edi = ExceptionDispatchInfo.Capture(ex);
 				}

Source/SuperLinq.Async/FillBackward.cs

@@ -1,4 +1,4 @@
-namespace SuperLinq.Async;
+namespace SuperLinq.Async;
 
 public static partial class AsyncSuperEnumerable
 {
@@ -21,7 +21,7 @@ public static partial class AsyncSuperEnumerable
 
 	public static IAsyncEnumerable<T> FillBackward<T>(this IAsyncEnumerable<T> source)
 	{
-		return source.FillBackward(e => new ValueTask<bool>(e == null));
+		return source.FillBackward(e => new ValueTask<bool>(e is null));
 	}
 
 	/// <summary>
@@ -223,13 +223,13 @@ private static async IAsyncEnumerable<T> FillBackwardImpl<T>(IAsyncEnumerable<T>
 			}
 			else
 			{
-				if (blanks != null)
+				if (blanks is not null)
 				{
 					foreach (var blank in blanks)
 					{
-						yield return fillSelector != null
-								   ? await fillSelector(blank, item).ConfigureAwait(false)
-								   : item;
+						yield return fillSelector is not null
+							? await fillSelector(blank, item).ConfigureAwait(false)
+							: item;
 					}
 
 					blanks.Clear();

Source/SuperLinq.Async/FillForward.cs

@@ -1,4 +1,4 @@
-namespace SuperLinq.Async;
+namespace SuperLinq.Async;
 
 public static partial class AsyncSuperEnumerable
 {
@@ -21,7 +21,7 @@ public static partial class AsyncSuperEnumerable
 
 	public static IAsyncEnumerable<T> FillForward<T>(this IAsyncEnumerable<T> source)
 	{
-		return source.FillForward(e => new ValueTask<bool>(e == null));
+		return source.FillForward(e => new ValueTask<bool>(e is null));
 	}
 
 	/// <summary>
@@ -218,11 +218,12 @@ private static async IAsyncEnumerable<T> FillForwardImpl<T>(IAsyncEnumerable<T>
 		{
 			if (await predicate(item).ConfigureAwait(false))
 			{
-				yield return seed is (true, { } someSeed)
-						   ? fillSelector != null
-							 ? await fillSelector(item, someSeed).ConfigureAwait(false)
-							 : someSeed
-						   : item;
+				yield return (seed, fillSelector) switch
+				{
+					((true, var s), { } f) => await f(item, s!).ConfigureAwait(false),
+					((true, var s), _) => s!,
+					_ => item,
+				};
 			}
 			else
 			{

Source/SuperLinq.Async/Join.HashJoin.cs

@@ -646,7 +646,7 @@ private static async IAsyncEnumerable<TResult> JoinHash<TLeft, TRight, TKey, TRe
 
 			if (!rLookup.Contains(lKey))
 			{
-				if (leftResultSelector != null)
+				if (leftResultSelector is not null)
 					yield return leftResultSelector(l);
 				continue;
 			}
@@ -656,7 +656,7 @@ private static async IAsyncEnumerable<TResult> JoinHash<TLeft, TRight, TKey, TRe
 				yield return bothResultSelector(l, r);
 		}
 
-		if (rightResultSelector != null)
+		if (rightResultSelector is not null)
 		{
 			foreach (var g in rLookup)
 			{

Source/SuperLinq.Async/Join.LoopJoin.cs

@@ -325,7 +325,7 @@ private static async IAsyncEnumerable<TResult> LoopJoin<TLeft, TRight, TKey, TRe
 				}
 			}
 
-			if (leftResultSelector != null
+			if (leftResultSelector is not null
 				&& !flag)
 			{
 				yield return leftResultSelector(l);

Source/SuperLinq.Async/Join.MergeJoin.cs

@@ -664,7 +664,7 @@ private static async IAsyncEnumerable<TResult> JoinMerge<TLeft, TRight, TKey, TR
 
 			if (comparison < 0)
 			{
-				if (leftResultSelector != null)
+				if (leftResultSelector is not null)
 				{
 					foreach (var e in l)
 						yield return leftResultSelector(e);
@@ -674,7 +674,7 @@ private static async IAsyncEnumerable<TResult> JoinMerge<TLeft, TRight, TKey, TR
 			}
 			else if (comparison > 0)
 			{
-				if (rightResultSelector != null)
+				if (rightResultSelector is not null)
 				{
 					foreach (var e in r)
 						yield return rightResultSelector(e);
@@ -695,7 +695,7 @@ private static async IAsyncEnumerable<TResult> JoinMerge<TLeft, TRight, TKey, TR
 			}
 		}
 
-		if (gotLeft && leftResultSelector != null)
+		if (gotLeft && leftResultSelector is not null)
 		{
 			do
 			{
@@ -705,7 +705,7 @@ private static async IAsyncEnumerable<TResult> JoinMerge<TLeft, TRight, TKey, TR
 			yield break;
 		}
 
-		if (gotRight && rightResultSelector != null)
+		if (gotRight && rightResultSelector is not null)
 		{
 			do
 			{

Source/SuperLinq.Async/Memoize.cs

@@ -1,4 +1,4 @@
-using System.Runtime.ExceptionServices;
+using System.Runtime.ExceptionServices;
 
 namespace SuperLinq.Async;
 
@@ -64,7 +64,7 @@ public async ValueTask Reset(CancellationToken cancellationToken = default)
 
 				_buffer = [];
 				_initialized = false;
-				if (_enumerator != null)
+				if (_enumerator is not null)
 					await _enumerator.DisposeAsync().ConfigureAwait(false);
 				_enumerator = null;
 				_exceptionIndex = null;
@@ -152,7 +152,7 @@ private async IAsyncEnumerator<T> GetEnumeratorImpl(CancellationToken cancellati
 							_exception.Throw();
 						}
 
-						if (_enumerator == null)
+						if (_enumerator is null)
 							break;
 
 						var moved = false;
@@ -203,7 +203,7 @@ public async ValueTask DisposeAsync()
 			{
 				_disposed = true;
 				_buffer.Clear();
-				if (_enumerator != null)
+				if (_enumerator is not null)
 					await _enumerator.DisposeAsync().ConfigureAwait(false);
 				_enumerator = null;
 				_source = null;

Source/SuperLinq.Async/Publish.cs

@@ -58,7 +58,7 @@ public async ValueTask Reset(CancellationToken cancellationToken = default)
 
 				_buffers = null;
 
-				if (_enumerator != null)
+				if (_enumerator is not null)
 					await _enumerator.DisposeAsync();
 				_enumerator = null;
 				_exception = null;
@@ -149,7 +149,7 @@ private async IAsyncEnumerator<T> GetEnumeratorImpl(Queue<T> buffer, int version
 						{
 							_exception?.Throw();
 
-							if (_enumerator == null)
+							if (_enumerator is null)
 								break;
 
 							var moved = false;
@@ -216,7 +216,7 @@ public async ValueTask DisposeAsync()
 
 				_buffers = null;
 
-				if (_enumerator != null)
+				if (_enumerator is not null)
 					await _enumerator.DisposeAsync().ConfigureAwait(false);
 				_enumerator = null;
 				_source = null;

Source/SuperLinq.Async/Share.cs

@@ -51,7 +51,7 @@ public async ValueTask Reset(CancellationToken cancellationToken = default)
 				_initialized = false;
 				_version++;
 
-				if (_enumerator != null)
+				if (_enumerator is not null)
 					await _enumerator.DisposeAsync();
 				_enumerator = null;
 				_exception = null;
@@ -126,7 +126,7 @@ private async IAsyncEnumerator<T> GetEnumeratorImpl(CancellationToken cancellati
 
 					_exception?.Throw();
 
-					if (_enumerator == null)
+					if (_enumerator is null)
 						break;
 
 					var moved = false;
@@ -169,7 +169,7 @@ public async ValueTask DisposeAsync()
 			try
 			{
 				_disposed = true;
-				if (_enumerator != null)
+				if (_enumerator is not null)
 					await _enumerator.DisposeAsync().ConfigureAwait(false);
 				_enumerator = null;
 				_source = null;

Source/SuperLinq.Async/Split.cs

@@ -1,4 +1,4 @@
-namespace SuperLinq.Async;
+namespace SuperLinq.Async;
 
 public static partial class AsyncSuperEnumerable
 {
@@ -80,7 +80,7 @@ public static IAsyncEnumerable<TResult> Split<TSource, TResult>(
 		TSource separator, int count,
 		Func<IReadOnlyList<TSource>, TResult> resultSelector)
 	{
-		return Split(source, separator, null, count, resultSelector);
+		return Split(source, separator, comparer: null, count, resultSelector);
 	}
 
 	/// <summary>