Support params keyword on non-array collections

ICSharpCode.Decompiler.Tests/Helpers/Tester.cs

@@ -459,6 +459,7 @@ namespace System.Runtime.CompilerServices
 					preprocessorSymbols.Add("CS100");
 					preprocessorSymbols.Add("CS110");
 					preprocessorSymbols.Add("CS120");
+					preprocessorSymbols.Add("CS130");
 				}
 			}
 			else if ((flags & CompilerOptions.UseMcsMask) != 0)
@@ -705,7 +706,7 @@ namespace System.Runtime.CompilerServices
 					CompilerOptions.UseRoslyn1_3_2 => CSharp.LanguageVersion.CSharp6,
 					CompilerOptions.UseRoslyn2_10_0 => CSharp.LanguageVersion.CSharp7_3,
 					CompilerOptions.UseRoslyn3_11_0 => CSharp.LanguageVersion.CSharp9_0,
-					_ => cscOptions.HasFlag(CompilerOptions.Preview) ? CSharp.LanguageVersion.Latest : CSharp.LanguageVersion.CSharp12_0,
+					_ => cscOptions.HasFlag(CompilerOptions.Preview) ? CSharp.LanguageVersion.Latest : CSharp.LanguageVersion.CSharp13_0,
 				};
 				DecompilerSettings settings = new(langVersion) {
 					// Never use file-scoped namespaces

ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj

@@ -8,6 +8,7 @@
 
   <PropertyGroup>
     <TargetFramework>net10.0-windows</TargetFramework>
+    <LangVersion>13</LangVersion>
     <RuntimeIdentifier Condition="$(IsWindowsX64) == true">win-x64</RuntimeIdentifier>
     <RuntimeIdentifier Condition="$(IsWindowsARM64) == true">win-arm64</RuntimeIdentifier>
 
@@ -17,7 +18,7 @@
     <AllowUnsafeBlocks>True</AllowUnsafeBlocks>
 
     <NoWarn>1701;1702;1705,67,169,1058,728,1720,649,168,251,660,661,675;1998;162;8632;626;8618;8714;8602;8981</NoWarn>
-    <DefineConstants>ROSLYN;ROSLYN2;ROSLYN3;ROSLYN4;NET60;CS60;CS70;CS71;CS72;CS73;CS80;CS90;CS100;CS110;CS120</DefineConstants>
+    <DefineConstants>ROSLYN;ROSLYN2;ROSLYN3;ROSLYN4;NET60;CS60;CS70;CS71;CS72;CS73;CS80;CS90;CS100;CS110;CS120;CS130</DefineConstants>
 
     <GenerateAssemblyVersionAttribute>False</GenerateAssemblyVersionAttribute>
     <GenerateAssemblyFileVersionAttribute>False</GenerateAssemblyFileVersionAttribute>
@@ -146,6 +147,7 @@
     <Compile Include="TestCases\Pretty\Issue3442.cs" />
     <Compile Include="TestCases\Pretty\Issue3483.cs" />
     <Compile Include="TestCases\Pretty\PointerArithmetic.cs" />
+    <Compile Include="TestCases\Pretty\ParamsCollections.cs" />
     <None Include="TestCases\VBPretty\VBAutomaticEvents.vb" />
     <Compile Include="TestCases\VBPretty\VBAutomaticEvents.cs" />
     <Compile Include="TestCases\VBPretty\VBNonGenericForEach.cs" />

ICSharpCode.Decompiler.Tests/PrettyTestRunner.cs

@@ -605,6 +605,12 @@ namespace ICSharpCode.Decompiler.Tests
 			await RunForLibrary(cscOptions: cscOptions);
 		}
 
+		[Test]
+		public async Task ParamsCollections([ValueSource(nameof(roslyn4OrNewerOptions))] CompilerOptions cscOptions)
+		{
+			await RunForLibrary(cscOptions: cscOptions);
+		}
+
 		[Test]
 		public async Task Issue1080([ValueSource(nameof(roslynOnlyOptions))] CompilerOptions cscOptions)
 		{

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

@@ -0,0 +1,21 @@
+using System;
+using System.Collections.Generic;
+
+namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
+{
+	public static class ParamsCollections
+	{
+		public static void ParamsEnumerable(params IEnumerable<int> values)
+		{
+		}
+		public static void ParamsList(params List<int> values)
+		{
+		}
+		public static void ParamsReadOnlySpan(params ReadOnlySpan<int> values)
+		{
+		}
+		public static void ParamsSpan(params Span<int> values)
+		{
+		}
+	}
+}

ICSharpCode.Decompiler/CSharp/CSharpLanguageVersion.cs

@@ -35,7 +35,8 @@ namespace ICSharpCode.Decompiler.CSharp
 		CSharp10_0 = 1000,
 		CSharp11_0 = 1100,
 		CSharp12_0 = 1200,
-		Preview = 1100,
+		CSharp13_0 = 1300,
+		Preview = 1300,
 		Latest = 0x7FFFFFFF
 	}
 }

ICSharpCode.Decompiler/CSharp/Transforms/EscapeInvalidIdentifiers.cs

@@ -166,6 +166,7 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 			"System.Runtime.CompilerServices.NullableAttribute",
 			"System.Runtime.CompilerServices.NullableContextAttribute",
 			"System.Runtime.CompilerServices.NativeIntegerAttribute",
+			"System.Runtime.CompilerServices.ParamCollectionAttribute",
 			"System.Runtime.CompilerServices.RefSafetyRulesAttribute",
 			"System.Runtime.CompilerServices.ScopedRefAttribute",
 			"System.Runtime.CompilerServices.RequiresLocationAttribute",

ICSharpCode.Decompiler/DecompilerSettings.cs

@@ -166,10 +166,16 @@ namespace ICSharpCode.Decompiler
 				usePrimaryConstructorSyntaxForNonRecordTypes = false;
 				inlineArrays = false;
 			}
+			if (languageVersion < CSharp.LanguageVersion.CSharp13_0)
+			{
+				paramsCollections = false;
+			}
 		}
 
 		public CSharp.LanguageVersion GetMinimumRequiredVersion()
 		{
+			if (paramsCollections)
+				return CSharp.LanguageVersion.CSharp13_0;
 			if (refReadOnlyParameters || usePrimaryConstructorSyntaxForNonRecordTypes || inlineArrays)
 				return CSharp.LanguageVersion.CSharp12_0;
 			if (scopedRef || requiredMembers || numericIntPtr || utf8StringLiterals || unsignedRightShift || checkedOperators)
@@ -849,6 +855,24 @@ namespace ICSharpCode.Decompiler
 			}
 		}
 
+		bool paramsCollections = true;
+
+		/// <summary>
+		/// Support params collections.
+		/// </summary>
+		[Category("C# 13.0 / VS 2022.12")]
+		[Description("DecompilerSettings.DecompileParamsCollections")]
+		public bool ParamsCollections {
+			get { return paramsCollections; }
+			set {
+				if (paramsCollections != value)
+				{
+					paramsCollections = value;
+					OnPropertyChanged();
+				}
+			}
+		}
+
 		bool lockStatement = true;
 
 		/// <summary>

ICSharpCode.Decompiler/TypeSystem/DecompilerTypeSystem.cs

@@ -138,12 +138,19 @@ namespace ICSharpCode.Decompiler.TypeSystem
 		/// </summary>
 		RefReadOnlyParameters = 0x10000,
 		/// <summary>
+		/// If this option is active, [ParamCollectionAttribute] on parameters is removed
+		/// and parameters are marked as params.
+		/// Otherwise, the attribute is preserved but the parameters are not marked
+		/// as if it was a normal parameter without any attributes.
+		/// </summary>
+		ParamsCollections = 0x20000,
+		/// <summary>
 		/// Default settings: typical options for the decompiler, with all C# languages features enabled.
 		/// </summary>
 		Default = Dynamic | Tuple | ExtensionMethods | DecimalConstants | ReadOnlyStructsAndParameters
 			| RefStructs | UnmanagedConstraints | NullabilityAnnotations | ReadOnlyMethods
 			| NativeIntegers | FunctionPointers | ScopedRef | NativeIntegersWithoutAttribute
-			| RefReadOnlyParameters
+			| RefReadOnlyParameters | ParamsCollections
 	}
 
 	/// <summary>
@@ -185,6 +192,8 @@ namespace ICSharpCode.Decompiler.TypeSystem
 				typeSystemOptions |= TypeSystemOptions.NativeIntegersWithoutAttribute;
 			if (settings.RefReadOnlyParameters)
 				typeSystemOptions |= TypeSystemOptions.RefReadOnlyParameters;
+			if (settings.ParamsCollections)
+				typeSystemOptions |= TypeSystemOptions.ParamsCollections;
 			return typeSystemOptions;
 		}
 

ICSharpCode.Decompiler/TypeSystem/Implementation/AttributeListBuilder.cs

@@ -258,6 +258,9 @@ namespace ICSharpCode.Decompiler.TypeSystem.Implementation
 						case "RequiresLocationAttribute":
 							return (options & TypeSystemOptions.RefReadOnlyParameters) != 0
 								&& (target == SymbolKind.Parameter);
+						case "ParamCollectionAttribute":
+							return (options & TypeSystemOptions.ParamsCollections) != 0
+								&& (target == SymbolKind.Parameter);
 						default:
 							return false;
 					}

ICSharpCode.Decompiler/TypeSystem/Implementation/KnownAttributes.cs

@@ -87,6 +87,7 @@ namespace ICSharpCode.Decompiler.TypeSystem
 
 		// Parameter attributes:
 		ParamArray,
+		ParamCollection,
 		In,
 		Out,
 		Optional,
@@ -169,6 +170,7 @@ namespace ICSharpCode.Decompiler.TypeSystem
 			new TopLevelTypeName("System.Runtime.CompilerServices", nameof(IndexerNameAttribute)),
 			// Parameter attributes:
 			new TopLevelTypeName("System", nameof(ParamArrayAttribute)),
+			new TopLevelTypeName("System.Runtime.CompilerServices", "ParamCollectionAttribute"),
 			new TopLevelTypeName("System.Runtime.InteropServices", nameof(InAttribute)),
 			new TopLevelTypeName("System.Runtime.InteropServices", nameof(OutAttribute)),
 			new TopLevelTypeName("System.Runtime.InteropServices", nameof(OptionalAttribute)),

ICSharpCode.Decompiler/TypeSystem/Implementation/MetadataParameter.cs

@@ -125,6 +125,12 @@ namespace ICSharpCode.Decompiler.TypeSystem.Implementation
 
 				var metadata = module.metadata;
 				var parameterDef = metadata.GetParameter(handle);
+				if ((module.TypeSystemOptions & TypeSystemOptions.ParamsCollections) != 0
+					&& parameterDef.GetCustomAttributes().HasKnownAttribute(metadata, KnownAttribute.ParamCollection))
+				{
+					// params collections are implicitly scoped
+					return default;
+				}
 				if (parameterDef.GetCustomAttributes().HasKnownAttribute(metadata, KnownAttribute.ScopedRef))
 				{
 					return new LifetimeAnnotation { ScopedRef = true };
@@ -135,12 +141,18 @@ namespace ICSharpCode.Decompiler.TypeSystem.Implementation
 
 		public bool IsParams {
 			get {
-				if (Type.Kind != TypeKind.Array)
-					return false;
 				var metadata = module.metadata;
 				var parameterDef = metadata.GetParameter(handle);
+				if (Type.Kind == TypeKind.Array)
+				{
 					return parameterDef.GetCustomAttributes().HasKnownAttribute(metadata, KnownAttribute.ParamArray);
 				}
+				if (module.TypeSystemOptions.HasFlag(TypeSystemOptions.ParamsCollections))
+				{
+					return parameterDef.GetCustomAttributes().HasKnownAttribute(metadata, KnownAttribute.ParamCollection);
+				}
+				return false;
+			}
 		}
 
 		public string Name {

ILSpy/Languages/CSharpLanguage.cs

@@ -116,6 +116,7 @@ namespace ICSharpCode.ILSpy
 						new LanguageVersion(Decompiler.CSharp.LanguageVersion.CSharp10_0.ToString(), "C# 10.0 / VS 2022"),
 						new LanguageVersion(Decompiler.CSharp.LanguageVersion.CSharp11_0.ToString(), "C# 11.0 / VS 2022.4"),
 						new LanguageVersion(Decompiler.CSharp.LanguageVersion.CSharp12_0.ToString(), "C# 12.0 / VS 2022.8"),
+						new LanguageVersion(Decompiler.CSharp.LanguageVersion.CSharp13_0.ToString(), "C# 13.0 / VS 2022.12"),
 					};
 				}
 				return versions;

ILSpy/Properties/Resources.Designer.cs

@@ -918,6 +918,15 @@ namespace ICSharpCode.ILSpy.Properties {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Decompile params collections.
+        /// </summary>
+        public static string DecompilerSettings_DecompileParamsCollections {
+            get {
+                return ResourceManager.GetString("DecompilerSettings.DecompileParamsCollections", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Decompile use of the &apos;dynamic&apos; type.
         /// </summary>

ILSpy/Properties/Resources.resx

@@ -327,6 +327,9 @@ Are you sure you want to continue?</value>
   <data name="DecompilerSettings.DecompileForEachWithGetEnumeratorExtension" xml:space="preserve">
     <value>Decompile foreach statements with GetEnumerator extension methods</value>
   </data>
+  <data name="DecompilerSettings.DecompileParamsCollections" xml:space="preserve">
+    <value>Decompile params collections</value>
+  </data>
   <data name="DecompilerSettings.DecompileUseOfTheDynamicType" xml:space="preserve">
     <value>Decompile use of the 'dynamic' type</value>
   </data>

ILSpy/Properties/Resources.zh-Hans.resx

@@ -315,6 +315,9 @@
   <data name="DecompilerSettings.DecompileForEachWithGetEnumeratorExtension" xml:space="preserve">
     <value>反编译使用 GetEnumerator 扩展方法的 foreach 语句</value>
   </data>
+  <data name="DecompilerSettings.DecompileParamsCollections" xml:space="preserve">
+    <value />
+  </data>
   <data name="DecompilerSettings.DecompileUseOfTheDynamicType" xml:space="preserve">
     <value>反编译 dynamic 类型</value>
   </data>