Fixes #627.

global-doc-comments.xml

@@ -79,7 +79,7 @@ result ^= expression;
 		<b>
 			<i>
 				This is a large structure, which means it may cost more time to copy instance than normal structures.
-				I strongly recommend you append <see langword="scoped ref readonly"/> to modify the type, as parameter or local variable modifiers,
+				I strongly recommend you append <see langword="ref readonly"/> to modify the type, as parameter or local variable modifiers,
 				to tell runtime that it should be copied by its reference instead of internal value.
 			</i>
 		</b>

src/RootLevelSourceGeneration/Extensions/GeneratorExecutionContextExtensions.cs

@@ -15,9 +15,7 @@ internal static class GeneratorExecutionContextExtensions
 	/// <param name="sourceCode">The source code.</param>
 	/// <seealso cref="GeneratorExecutionContext.AddSource(string, string)"/>
 	[MethodImpl(MethodImplOptions.AggressiveInlining)]
-	internal static void AddSource(
-		this scoped ref GeneratorExecutionContext @this, string fileName,
-		string? sourceGeneratorName, string sourceCode)
+	internal static void AddSource(this ref GeneratorExecutionContext @this, string fileName, string? sourceGeneratorName, string sourceCode)
 		=> @this.AddSource(
 			$"{fileName}{(sourceGeneratorName is null ? string.Empty : $".g.{sourceGeneratorName}")}.cs",
 			SourceText.From(sourceCode, Encoding.UTF8)

src/RootLevelSourceGeneration/Extensions/INamedTypeSymbolExtensions.cs

@@ -59,7 +59,7 @@ public static IEnumerable<ISymbol> GetAllMembers(this INamedTypeSymbol @this)
 	internal static string ToFileName(this INamedTypeSymbol @this)
 	{
 		var result = @this.ToDisplayString(ExtendedSymbolDisplayFormat.FullyQualifiedFormatWithConstraints)[8..];
-		scoped var buffer = (stackalloc char[result.Length]);
+		var buffer = (stackalloc char[result.Length]);
 		buffer.Clear();
 		var pointer = 0;
 		for (var i = 0; i < result.Length; i++)

src/Sudoku.Analytics/Analytics/Analyzer.cs

@@ -91,7 +91,7 @@ where searcher.RunningArea.HasFlag(StepSearcherRunningArea.Searching)
 
 	/// <inheritdoc/>
 	/// <exception cref="InvalidOperationException">Throws when the puzzle has already been solved.</exception>
-	public AnalyzerResult Analyze(scoped ref readonly Grid puzzle, IProgress<AnalyzerProgress>? progress = null, CancellationToken cancellationToken = default)
+	public AnalyzerResult Analyze(ref readonly Grid puzzle, IProgress<AnalyzerProgress>? progress = null, CancellationToken cancellationToken = default)
 	{
 		if (puzzle.IsSolved)
 		{
@@ -146,11 +146,11 @@ NotImplementedException or NotSupportedException
 
 
 		AnalyzerResult analyzeInternal(
-			scoped ref readonly Grid puzzle,
-			scoped ref readonly Grid solution,
+			ref readonly Grid puzzle,
+			ref readonly Grid solution,
 			AnalyzerResult resultBase,
 			SymmetricType symmetricType,
-			scoped ReadOnlySpan<Digit?> mappingDigits,
+			ReadOnlySpan<Digit?> mappingDigits,
 			Mask selfPairedDigitsMask,
 			IProgress<AnalyzerProgress>? progress,
 			CancellationToken cancellationToken
@@ -167,7 +167,7 @@ CancellationToken cancellationToken
 #endif
 				? []
 				: default(List<Step>);
-			scoped var context = new AnalysisContext(in playground, in puzzle)
+			var context = new AnalysisContext(in playground, in puzzle)
 			{
 				Accumulator = accumulator,
 				IsSukaku = puzzle.PuzzleType == SudokuType.Sukaku,
@@ -485,7 +485,7 @@ CancellationToken cancellationToken
 			goto FindNextStep;
 
 
-			static bool verifyConclusionValidity(scoped ref readonly Grid solution, Step step)
+			static bool verifyConclusionValidity(ref readonly Grid solution, Step step)
 			{
 				if (solution.IsUndefined)
 				{
@@ -508,8 +508,8 @@ static bool verifyConclusionValidity(scoped ref readonly Grid solution, Step ste
 			static bool onCollectingSteps(
 				List<Step> steps,
 				Step step,
-				scoped ref readonly AnalysisContext context,
-				scoped ref Grid playground,
+				ref readonly AnalysisContext context,
+				ref Grid playground,
 				long timestampOriginal,
 				List<Grid> steppingGrids,
 				AnalyzerResult resultBase,
@@ -520,7 +520,7 @@ static bool onCollectingSteps(
 				// Optimization: If the grid is inferred as a GSP pattern, we can directly add extra eliminations at symmetric positions.
 				if (context is { GspPatternInferred: { } symmetricType } && step is not GurthSymmetricalPlacementStep)
 				{
-					scoped var mappingRelations = context.MappingRelations;
+					var mappingRelations = context.MappingRelations;
 					var originalConclusions = step.Conclusions;
 					var newConclusions = new List<Conclusion>();
 					foreach (var conclusion in originalConclusions)

src/Sudoku.Analytics/Analytics/AnalyzerResult.Searching.cs

@@ -20,7 +20,7 @@ public partial record AnalyzerResult
 	/// <exception cref="ArgumentOutOfRangeException">
 	/// Throws when the specified puzzle cannot correspond to a paired <see cref="Step"/> instance.
 	/// </exception>
-	public Step this[scoped ref readonly Grid grid]
+	public Step this[ref readonly Grid grid]
 	{
 		get
 		{
@@ -96,7 +96,7 @@ public Step this[scoped ref readonly Grid grid]
 	/// </returns>
 	/// <seealso cref="IsSolved"/>
 	public ReadOnlySpan<Step> this[int difficultyRating]
-		=> StepsSpan.FindAll((scoped ref readonly Step step) => step.Difficulty == difficultyRating);
+		=> StepsSpan.FindAll((ref readonly Step step) => step.Difficulty == difficultyRating);
 
 	/// <summary>
 	/// Gets a list of <see cref="Step"/>s that matches the specified technique.
@@ -106,7 +106,7 @@ public ReadOnlySpan<Step> this[int difficultyRating]
 	/// <inheritdoc cref="this[int]" path="/returns"/>
 	/// </returns>
 	/// <seealso cref="IsSolved"/>
-	public ReadOnlySpan<Step> this[Technique code] => StepsSpan.FindAll((scoped ref readonly Step step) => step.Code == code);
+	public ReadOnlySpan<Step> this[Technique code] => StepsSpan.FindAll((ref readonly Step step) => step.Code == code);
 
 	/// <summary>
 	/// Gets a list of <see cref="Step"/>s that has the same difficulty level as argument <paramref name="difficultyLevel"/>. 
@@ -117,5 +117,5 @@ public ReadOnlySpan<Step> this[int difficultyRating]
 	/// </returns>
 	/// <seealso cref="IsSolved"/>
 	public ReadOnlySpan<Step> this[DifficultyLevel difficultyLevel]
-		=> StepsSpan.FindAll((scoped ref readonly Step step) => step.DifficultyLevel == difficultyLevel);
+		=> StepsSpan.FindAll((ref readonly Step step) => step.DifficultyLevel == difficultyLevel);
 }

src/Sudoku.Analytics/Analytics/AnalyzerResult.cs

@@ -4,7 +4,7 @@ namespace Sudoku.Analytics;
 /// Provides the result after <see cref="Analyzer"/> solving a puzzle.
 /// </summary>
 /// <param name="Puzzle"><inheritdoc cref="IAnalyzerResult{TSolver, TSolverResult}.Puzzle" path="/summary"/></param>
-public sealed partial record AnalyzerResult(scoped ref readonly Grid Puzzle) :
+public sealed partial record AnalyzerResult(ref readonly Grid Puzzle) :
 	IAnalyzerResult<Analyzer, AnalyzerResult>,
 	ICultureFormattable,
 	IEnumerable<Step>
@@ -346,7 +346,7 @@ public Step? DiamondStep
 				return null;
 			}
 
-			if (StepsSpan.All(static (scoped ref readonly Step step) => step is FullHouseStep or HiddenSingleStep { House: < 9 }))
+			if (StepsSpan.All(static (ref readonly Step step) => step is FullHouseStep or HiddenSingleStep { House: < 9 }))
 			{
 				// No diamond step exist in all steps are hidden singles in block.
 				return null;

src/Sudoku.Analytics/Analytics/CachedFields.cs

@@ -87,7 +87,7 @@ public static class CachedFields
 	/// <param name="g">The grid.</param>
 	/// <param name="s">The solution of <paramref name="g"/>.</param>
 	[MethodImpl(MethodImplOptions.AggressiveInlining)]
-	internal static void Initialize(scoped ref readonly Grid g, scoped ref readonly Grid s)
+	internal static void Initialize(ref readonly Grid g, ref readonly Grid s)
 	{
 		EmptyCells = g.EmptyCells;
 		BivalueCells = g.BivalueCells;

src/Sudoku.Analytics/Analytics/Categorization/TechniqueSet.cs

@@ -572,7 +572,7 @@ void ISet<Technique>.UnionWith(IEnumerable<Technique> other)
 file sealed class Converter : JsonConverter<TechniqueSet>
 {
 	/// <inheritdoc/>
-	public override TechniqueSet Read(scoped ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+	public override TechniqueSet Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
 	{
 		var (result, isInitialized) = (TechniqueSets.None, false);
 		while (reader.Read())

src/Sudoku.Analytics/Analytics/Collector.cs

@@ -55,7 +55,7 @@ where searcher.RunningArea.HasFlag(StepSearcherRunningArea.Collecting)
 	/// </returns>
 	/// <exception cref="InvalidOperationException">Throws when property <see cref="DifficultyLevelMode"/> is not defined.</exception>
 	public ReadOnlySpan<Step> Collect(
-		scoped ref readonly Grid puzzle,
+		ref readonly Grid puzzle,
 		IProgress<AnalyzerProgress>? progress = null,
 		CancellationToken cancellationToken = default
 	)
@@ -87,7 +87,7 @@ public ReadOnlySpan<Step> Collect(
 		ReadOnlySpan<Step> searchInternal(
 			bool isSukaku,
 			IProgress<AnalyzerProgress>? progress,
-			scoped ref readonly Grid puzzle,
+			ref readonly Grid puzzle,
 			CancellationToken cancellationToken
 		)
 		{
@@ -100,7 +100,7 @@ CancellationToken cancellationToken
 			Initialize(in playground, playground.SolutionGrid);
 
 			var accumulator = new List<Step>();
-			scoped var context = new AnalysisContext(in playground, in puzzle)
+			var context = new AnalysisContext(in playground, in puzzle)
 			{
 				Accumulator = accumulator,
 				OnlyFindOne = false,

src/Sudoku.Analytics/Analytics/PuzzleInvalidException.cs

@@ -11,7 +11,7 @@ namespace Sudoku.Analytics;
 /// <see cref="StepSearcherType"/> to learn more information.
 /// </remarks>
 /// <seealso cref="StepSearcherType"/>
-public sealed partial class PuzzleInvalidException(scoped ref readonly Grid grid, [PrimaryConstructorParameter] Type stepSearcherType) :
+public sealed partial class PuzzleInvalidException(ref readonly Grid grid, [PrimaryConstructorParameter] Type stepSearcherType) :
 	RuntimeAnalyticsException(in grid)
 {
 	/// <inheritdoc/>

src/Sudoku.Analytics/Analytics/StepMarshal.cs

@@ -45,7 +45,7 @@ public static IEnumerable<TStep> RemoveDuplicateItems<TStep>(List<TStep> accumul
 	/// <exception cref="InvalidOperationException">
 	/// Throws when the length of arguments <paramref name="interimGrids"/> and <paramref name="interimSteps"/> aren't same.
 	/// </exception>
-	public static ReadOnlySpan<(Grid CurrentGrid, Step CurrentStep)> Combine(scoped ReadOnlySpan<Grid> interimGrids, scoped ReadOnlySpan<Step> interimSteps)
+	public static ReadOnlySpan<(Grid CurrentGrid, Step CurrentStep)> Combine(ReadOnlySpan<Grid> interimGrids, ReadOnlySpan<Step> interimSteps)
 	{
 		if (interimGrids.Length != interimSteps.Length)
 		{

src/Sudoku.Analytics/Analytics/StepSearcher.cs

@@ -111,7 +111,7 @@ internal int SplitPriority
 	/// </returns>
 	/// <seealso cref="Step"/>
 	/// <seealso cref="AnalysisContext"/>
-	protected internal abstract Step? Collect(scoped ref AnalysisContext context);
+	protected internal abstract Step? Collect(ref AnalysisContext context);
 
 	/// <inheritdoc/>
 	StepSearcherMetadataInfo IMetadataObject<StepSearcherMetadataInfo>.GetMetadata() => Metadata;

src/Sudoku.Analytics/Analytics/StepSearcherModules/AdvancedDynamicChainingModule.cs

@@ -11,8 +11,8 @@ public static void OnAdvanced(
 		NodeList pendingOn,
 		NodeList pendingOff,
 		NodeSet toOff,
-		scoped ref readonly Grid grid,
-		scoped ref readonly Grid original
+		ref readonly Grid grid,
+		ref readonly Grid original
 	)
 	{
 		if (pendingOn.Count == 0 && pendingOff.Count == 0 && stepSearcher.DynamicNestingLevel > 0)
@@ -40,8 +40,8 @@ scoped ref readonly Grid original
 	[SuppressMessage("CodeQuality", "IDE0051:Remove unused private members", Justification = "<Pending>")]
 	private static NodeList GetAdvancedPotentials(
 		AdvancedMultipleChainingStepSearcher stepSearcher,
-		scoped ref readonly Grid grid,
-		scoped ref readonly Grid original,
+		ref readonly Grid grid,
+		ref readonly Grid original,
 		NodeSet offPotentials
 	)
 	{

src/Sudoku.Analytics/Analytics/StepSearcherModules/AlmostLockedSetsModule.cs

@@ -10,7 +10,7 @@ internal static class AlmostLockedSetsModule
 	/// </summary>
 	/// <param name="grid">The grid to be used.</param>
 	/// <returns>A list of ALSes.</returns>
-	public static ReadOnlySpan<AlmostLockedSet> CollectAlmostLockedSets(scoped ref readonly Grid grid)
+	public static ReadOnlySpan<AlmostLockedSet> CollectAlmostLockedSets(ref readonly Grid grid)
 	{
 		// Get all bi-value-cell ALSes.
 		var result = new List<AlmostLockedSet>();

src/Sudoku.Analytics/Analytics/StepSearcherModules/ChainingModule.cs

@@ -18,7 +18,7 @@ internal class ChainingModule
 	/// <param name="p">The potential that is assumed to be "on"</param>
 	/// <param name="isY">Indicates whether the same-cell strong links are enabled.</param>
 	/// <returns>The set of potentials that must be "off".</returns>
-	public static NodeSet GetOnToOff(scoped ref readonly Grid grid, ChainNode p, bool isY)
+	public static NodeSet GetOnToOff(ref readonly Grid grid, ChainNode p, bool isY)
 	{
 		var result = new NodeSet();
 		var cell = p.Cell;
@@ -67,9 +67,9 @@ public static NodeSet GetOnToOff(scoped ref readonly Grid grid, ChainNode p, boo
 	/// <param name="allowDynamic">Indicates whether the dynamic chaining rules are enabled.</param>
 	/// <returns>The set of potentials that must be "off".</returns>
 	public static NodeSet GetOffToOn(
-		scoped ref readonly Grid grid,
+		ref readonly Grid grid,
 		ChainNode p,
-		scoped in Grid? source,
+		in Grid? source,
 		NodeSet offPotentials,
 		bool isX,
 		bool isY,
@@ -99,7 +99,7 @@ bool allowDynamic
 		if (isX)
 		{
 			// Second rule: if there is only two positions for this potential, the other one gets on.
-			scoped ref readonly var candMaps = ref allowDynamic ? ref grid.CandidatesMap[digit] : ref CandidatesMap[digit];
+			ref readonly var candMaps = ref allowDynamic ? ref grid.CandidatesMap[digit] : ref CandidatesMap[digit];
 			foreach (var houseType in HouseTypes)
 			{
 				var houseIndex = cell.ToHouseIndex(houseType);
@@ -119,7 +119,7 @@ bool allowDynamic
 		return result;
 
 
-		static void addHiddenParentsOfCell(scoped ref ChainNode p, scoped ref readonly Grid current, scoped ref readonly Grid original, NodeSet offPotentials)
+		static void addHiddenParentsOfCell(ref ChainNode p, ref readonly Grid current, ref readonly Grid original, NodeSet offPotentials)
 		{
 			var cell = p.Cell;
 			for (byte digit = 0; digit < 9; digit++)
@@ -138,9 +138,9 @@ static void addHiddenParentsOfCell(scoped ref ChainNode p, scoped ref readonly G
 		}
 
 		static void addHiddenParentsOfHouse(
-			scoped ref ChainNode p,
-			scoped ref readonly Grid current,
-			scoped ref readonly Grid original,
+			ref ChainNode p,
+			ref readonly Grid current,
+			ref readonly Grid original,
 			HouseType currentHouseType,
 			NodeSet offPotentials
 		)
@@ -161,7 +161,7 @@ NodeSet offPotentials
 			}
 
 
-			static Mask g(scoped ref readonly Grid grid, House houseIndex, Digit digit)
+			static Mask g(ref readonly Grid grid, House houseIndex, Digit digit)
 			{
 				var result = (Mask)0;
 				for (var i = 0; i < 9; i++)
@@ -191,7 +191,7 @@ static Mask g(scoped ref readonly Grid grid, House houseIndex, Digit digit)
 	public static (ChainNode On, ChainNode Off)? DoChaining<T>(T stepSearcher, Grid grid, NodeSet toOn, NodeSet toOff, bool allowNishio, bool allowDynamic)
 		where T : StepSearcher
 	{
-		scoped ref readonly var originalGrid = ref grid;
+		ref readonly var originalGrid = ref grid;
 		var (pendingOn, pendingOff) = (new NodeList(toOn), new NodeList(toOff));
 		while (pendingOn.Count > 0 || pendingOff.Count > 0)
 		{
@@ -262,8 +262,8 @@ public static void OnAdvanced<T>(
 		NodeList pendingOn,
 		NodeList pendingOff,
 		NodeSet toOff,
-		scoped ref readonly Grid grid,
-		scoped ref readonly Grid original
+		ref readonly Grid grid,
+		ref readonly Grid original
 	) where T : StepSearcher
 	{
 		return;

src/Sudoku.Analytics/Analytics/StepSearcherModules/FishModule.cs

@@ -24,7 +24,7 @@ internal static class FishModule
 	/// <inheritdoc cref="FishStep.IsSashimi" path="/remarks"/>
 	/// </para>
 	/// </returns>
-	public static bool? IsSashimi(House[] baseSets, scoped ref readonly CellMap fins, Digit digit)
+	public static bool? IsSashimi(House[] baseSets, ref readonly CellMap fins, Digit digit)
 	{
 		if (!fins)
 		{
@@ -84,10 +84,10 @@ static FishShapeKind k(HouseMask mask)
 	/// <param name="accumulator">The accumulator.</param>
 	/// <param name="grid">The grid.</param>
 	/// <returns>All Siamese steps of type <see cref="FishStep"/>.</returns>
-	public static ReadOnlySpan<FishStep> GetSiamese(List<FishStep> accumulator, scoped ref readonly Grid grid)
+	public static ReadOnlySpan<FishStep> GetSiamese(List<FishStep> accumulator, ref readonly Grid grid)
 	{
 		var result = new List<FishStep>();
-		scoped var stepsSpan = accumulator.AsReadOnlySpan();
+		var stepsSpan = accumulator.AsReadOnlySpan();
 		for (var index1 = 0; index1 < accumulator.Count - 1; index1++)
 		{
 			var fish1 = stepsSpan[index1];
@@ -104,7 +104,7 @@ public static ReadOnlySpan<FishStep> GetSiamese(List<FishStep> accumulator, scop
 		return result.AsReadOnlySpan();
 
 
-		static bool check(scoped ref readonly Grid puzzle, FishStep fish1, FishStep fish2, [NotNullWhen(true)] out FishStep? siameseStep)
+		static bool check(ref readonly Grid puzzle, FishStep fish1, FishStep fish2, [NotNullWhen(true)] out FishStep? siameseStep)
 		{
 			if (fish1.BaseSetsMask != fish2.BaseSetsMask || fish1.Digit != fish2.Digit)
 			{

src/Sudoku.Analytics/Analytics/StepSearcherModules/IntersectionModule.cs

@@ -14,10 +14,10 @@ internal static class IntersectionModule
 	/// <param name="cells">The cells.</param>
 	/// <returns>A list of <see cref="CellViewNode"/> instances.</returns>
 	public static ReadOnlySpan<CellViewNode> GetCrosshatchBaseCells(
-		scoped ref readonly Grid grid,
+		ref readonly Grid grid,
 		Digit digit,
 		House house,
-		scoped ref readonly CellMap cells
+		ref readonly CellMap cells
 	)
 	{
 		var info = Crosshatching.TryCreate(in grid, digit, house, in cells);
@@ -52,11 +52,11 @@ scoped ref readonly CellMap cells
 	/// <returns>A <see cref="bool"/> result.</returns>
 	[MethodImpl(MethodImplOptions.AggressiveInlining)]
 	internal static bool IsLockedCandidates(
-		scoped ref readonly Grid grid,
-		scoped ref readonly CellMap a,
-		scoped ref readonly CellMap b,
-		scoped ref readonly CellMap c,
-		scoped ref readonly CellMap emptyCells,
+		ref readonly Grid grid,
+		ref readonly CellMap a,
+		ref readonly CellMap b,
+		ref readonly CellMap c,
+		ref readonly CellMap emptyCells,
 		out Mask digitsMask
 	)
 		=> (digitsMask = 0, emptyCells & c, (grid[in a], grid[in b], grid[in c])) is (_, not [], var (maskA, maskB, maskC))