Add support for ScopedRefAttribute

ICSharpCode.Decompiler.Tests/TestCases/Pretty/RefFields.cs

@@ -2,18 +2,61 @@ using System;
 
 namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 {
+	internal class LifetimeTests
+	{
+		private static int staticField;
+
+		public Span<int> CreateWithoutCapture(scoped ref int value)
+		{
+			// Okay: value is not captured
+			return new Span<int>(ref staticField);
+		}
+
+		public Span<int> CreateAndCapture(ref int value)
+		{
+			// Okay: value Rule 3 specifies that the safe-to-escape be limited to the ref-safe-to-escape
+			// of the ref argument. That is the *calling method* for value hence this is not allowed.
+			return new Span<int>(ref value);
+		}
+
+		public Span<int> ScopedRefSpan(scoped ref Span<int> span)
+		{
+			return span;
+		}
+
+		public Span<int> ScopedSpan(scoped Span<int> span)
+		{
+			return default(Span<int>);
+		}
+
+		public void OutSpan(out Span<int> span)
+		{
+			span = default(Span<int>);
+		}
+
+		public void Calls()
+		{
+			int value = 0;
+			Span<int> span = CreateWithoutCapture(ref value);
+			//span = CreateAndCapture(ref value); -- would need scoped local, not yet implemented
+			span = ScopedRefSpan(ref span);
+			span = ScopedSpan(span);
+			OutSpan(out span);
+		}
+	}
+
 	internal ref struct RefFields
 	{
-		private ref int Field0;
-		private ref readonly int Field1;
-		private readonly ref int Field2;
-		private readonly ref readonly int Field3;
+		public ref int Field0;
+		public ref readonly int Field1;
+		public readonly ref int Field2;
+		public readonly ref readonly int Field3;
 
 		public int PropertyAccessingRefFieldByValue {
-			get { 
+			get {
 				return Field0;
 			}
-			set { 
+			set {
 				Field0 = value;
 			}
 		}
@@ -32,5 +75,13 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 			Console.WriteLine("No inlining");
 			field.ToString();
 		}
+
+		public RefFields(ref int v)
+		{
+			Field0 = ref v;
+			Field1 = ref v;
+			Field2 = ref v;
+			Field3 = ref v;
+		}
 	}
-}
+}

ICSharpCode.Decompiler/CSharp/OutputVisitor/CSharpOutputVisitor.cs

@@ -2589,11 +2589,6 @@ namespace ICSharpCode.Decompiler.CSharp.OutputVisitor
 					Space();
 					break;
 			}
-			if (parameterDeclaration.IsValueScoped)
-			{
-				WriteKeyword(ParameterDeclaration.ValueScopedRole);
-				Space();
-			}
 			parameterDeclaration.Type.AcceptVisitor(this);
 			if (!parameterDeclaration.Type.IsNull && !string.IsNullOrEmpty(parameterDeclaration.Name))
 			{

ICSharpCode.Decompiler/CSharp/Syntax/TypeMembers/ParameterDeclaration.cs

@@ -26,6 +26,8 @@
 
 #nullable enable
 
+using System;
+
 namespace ICSharpCode.Decompiler.CSharp.Syntax
 {
 	public enum ParameterModifier
@@ -46,6 +48,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 		public static readonly TokenRole RefModifierRole = new TokenRole("ref");
 		public static readonly TokenRole OutModifierRole = new TokenRole("out");
 		public static readonly TokenRole InModifierRole = new TokenRole("in");
+		[Obsolete("C# 11 preview: \"ref scoped\" no longer supported")]
 		public static readonly TokenRole ValueScopedRole = new TokenRole("scoped");
 		public static readonly TokenRole ParamsModifierRole = new TokenRole("params");
 
@@ -102,7 +105,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 		}
 
 		bool hasThisModifier;
-		bool isRefScoped, isValueScoped;
+		bool isRefScoped;
 
 		public CSharpTokenNode ThisKeyword {
 			get {
@@ -130,12 +133,10 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 			}
 		}
 
+		[Obsolete("C# 11 preview: \"ref scoped\" no longer supported")]
 		public bool IsValueScoped {
-			get { return isValueScoped; }
-			set {
-				ThrowIfFrozen();
-				isValueScoped = value;
-			}
+			get { return false; }
+			set { }
 		}
 
 		ParameterModifier parameterModifier;

ICSharpCode.Decompiler/CSharp/Syntax/TypeSystemAstBuilder.cs

@@ -1655,7 +1655,6 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 				decl.ParameterModifier = ParameterModifier.Params;
 			}
 			decl.IsRefScoped = parameter.Lifetime.RefScoped;
-			decl.IsValueScoped = parameter.Lifetime.ValueScoped;
 			if (ShowAttributes)
 			{
 				decl.Attributes.AddRange(ConvertAttributes(parameter.GetAttributes()));

ICSharpCode.Decompiler/CSharp/Transforms/EscapeInvalidIdentifiers.cs

@@ -167,6 +167,7 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 			"System.Runtime.CompilerServices.NullableContextAttribute",
 			"System.Runtime.CompilerServices.NativeIntegerAttribute",
 			"System.Runtime.CompilerServices.RefSafetyRulesAttribute",
+			"System.Runtime.CompilerServices.ScopedRefAttribute",
 			"Microsoft.CodeAnalysis.EmbeddedAttribute",
 		};
 

ICSharpCode.Decompiler/DecompilerSettings.cs

@@ -360,8 +360,7 @@ namespace ICSharpCode.Decompiler
 		bool lifetimeAnnotations = true;
 
 		/// <summary>
-		/// Use C# 9 <c>delegate* unmanaged</c> types.
-		/// If this option is disabled, function pointers will instead be decompiled with type `IntPtr`.
+		/// Use C# 11 <c>scoped</c> modifier.
 		/// </summary>
 		[Category("C# 11.0 / VS 2022.4")]
 		[Description("DecompilerSettings.LifetimeAnnotations")]

ICSharpCode.Decompiler/TypeSystem/DecompilerTypeSystem.cs

@@ -120,7 +120,7 @@ namespace ICSharpCode.Decompiler.TypeSystem
 		/// </summary>
 		FunctionPointers = 0x2000,
 		/// <summary>
-		/// Allow C# 11 scoped annotation. If this option is not enabled, LifetimeAnnotationAttribute
+		/// Allow C# 11 scoped annotation. If this option is not enabled, ScopedRefAttribute
 		/// will be reported as custom attribute.
 		/// </summary>
 		LifetimeAnnotations = 0x4000,

ICSharpCode.Decompiler/TypeSystem/IParameter.cs

@@ -18,6 +18,7 @@
 
 #nullable enable
 
+using System;
 using System.Collections.Generic;
 using System.Runtime.CompilerServices;
 
@@ -36,7 +37,12 @@ namespace ICSharpCode.Decompiler.TypeSystem
 
 	public struct LifetimeAnnotation
 	{
+		/// <summary>
+		/// C# 11 scoped annotation: "scoped ref" (ScopedRefAttribute)
+		/// </summary>
 		public bool RefScoped;
+
+		[Obsolete("C# 11 preview: \"ref scoped\" no longer supported")]
 		public bool ValueScoped;
 	}
 

ICSharpCode.Decompiler/TypeSystem/Implementation/AttributeListBuilder.cs

@@ -252,7 +252,7 @@ namespace ICSharpCode.Decompiler.TypeSystem.Implementation
 						case "NullableContextAttribute":
 							return (options & TypeSystemOptions.NullabilityAnnotations) != 0
 								&& (target == SymbolKind.TypeDefinition || IsMethodLike(target));
-						case "LifetimeAnnotationAttribute":
+						case "ScopedRefAttribute":
 							return (options & TypeSystemOptions.LifetimeAnnotations) != 0
 								&& (target == SymbolKind.Parameter);
 						default:

ICSharpCode.Decompiler/TypeSystem/Implementation/KnownAttributes.cs

@@ -94,7 +94,7 @@ namespace ICSharpCode.Decompiler.TypeSystem
 		CallerMemberName,
 		CallerFilePath,
 		CallerLineNumber,
-		LifetimeAnnotation,
+		ScopedRef,
 
 		// Type parameter attributes:
 		IsUnmanaged,
@@ -172,7 +172,7 @@ namespace ICSharpCode.Decompiler.TypeSystem
 			new TopLevelTypeName("System.Runtime.CompilerServices", nameof(CallerMemberNameAttribute)),
 			new TopLevelTypeName("System.Runtime.CompilerServices", nameof(CallerFilePathAttribute)),
 			new TopLevelTypeName("System.Runtime.CompilerServices", nameof(CallerLineNumberAttribute)),
-			new TopLevelTypeName("System.Runtime.CompilerServices", "LifetimeAnnotationAttribute"),
+			new TopLevelTypeName("System.Runtime.CompilerServices", "ScopedRefAttribute"),
 			// Type parameter attributes:
 			new TopLevelTypeName("System.Runtime.CompilerServices", "IsUnmanagedAttribute"),
 			// Marshalling attributes:

ICSharpCode.Decompiler/TypeSystem/Implementation/MetadataParameter.cs

@@ -124,25 +124,10 @@ namespace ICSharpCode.Decompiler.TypeSystem.Implementation
 
 				var metadata = module.metadata;
 				var parameterDef = metadata.GetParameter(handle);
-				foreach (var h in parameterDef.GetCustomAttributes())
+				if (parameterDef.GetCustomAttributes().HasKnownAttribute(metadata, KnownAttribute.ScopedRef))
 				{
-					var custom = metadata.GetCustomAttribute(h);
-					if (!custom.IsKnownAttribute(metadata, KnownAttribute.LifetimeAnnotation))
-						continue;
-
-					var value = custom.DecodeValue(module.TypeProvider);
-					if (value.FixedArguments.Length != 2)
-						continue;
-					if (value.FixedArguments[0].Value is bool refScoped
-						&& value.FixedArguments[1].Value is bool valueScoped)
-					{
-						return new LifetimeAnnotation {
-							RefScoped = refScoped,
-							ValueScoped = valueScoped
-						};
-					}
+					return new LifetimeAnnotation { RefScoped = true };
 				}
-
 				return default;
 			}
 		}