Fix #2475: Add support for sealed records and records with interface

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

@@ -15,6 +15,12 @@
 		public string S = "abc";
 	}
 
+	public record Interface(int B) : IRecord;
+
+	public interface IRecord
+	{
+	}
+
 	public record Pair<A, B>
 	{
 		public A First { get; init; }
@@ -26,11 +32,13 @@
 	public record PrimaryCtor(int A, string B);
 	public record PrimaryCtorWithField(int A, string B)
 	{
-		public double C;
+		public double C = 1.0;
+		public string D = A + B;
 	}
 	public record PrimaryCtorWithProperty(int A, string B)
 	{
-		public double C { get; init; }
+		public double C { get; init; } = 1.0;
+		public string D { get; } = A + B;
 	}
 
 	public record Properties
@@ -48,6 +56,10 @@
 		}
 	}
 
+	public sealed record Sealed(string A);
+
+	public sealed record SealedDerived(int B) : Base(B.ToString());
+
 	public class WithExpressionTests
 	{
 		public Fields Test(Fields input)

ICSharpCode.Decompiler/CSharp/RecordDecompiler.cs

@@ -37,6 +37,8 @@ namespace ICSharpCode.Decompiler.CSharp
 		readonly CancellationToken cancellationToken;
 		readonly List<IMember> orderedMembers;
 		readonly bool isInheritedRecord;
+		readonly bool isStruct;
+		readonly bool isSealed;
 		readonly IMethod primaryCtor;
 		readonly IType baseClass;
 		readonly Dictionary<IField, IProperty> backingFieldToAutoProperty = new Dictionary<IField, IProperty>();
@@ -51,7 +53,9 @@ namespace ICSharpCode.Decompiler.CSharp
 			this.settings = settings;
 			this.cancellationToken = cancellationToken;
 			this.baseClass = recordTypeDef.DirectBaseTypes.FirstOrDefault(b => b.Kind == TypeKind.Class);
-			this.isInheritedRecord = !baseClass.IsKnownType(KnownTypeCode.Object);
+			this.isStruct = baseClass.IsKnownType(KnownTypeCode.ValueType);
+			this.isInheritedRecord = !isStruct && !baseClass.IsKnownType(KnownTypeCode.Object);
+			this.isSealed = recordTypeDef.IsSealed;
 			DetectAutomaticProperties();
 			this.orderedMembers = DetectMemberOrder(recordTypeDef, backingFieldToAutoProperty);
 			this.primaryCtor = DetectPrimaryConstructor();
@@ -180,10 +184,11 @@ namespace ICSharpCode.Decompiler.CSharp
 				if (method.Parameters.Count == 0)
 					return false;
 
-				if (body.Instructions.Count != method.Parameters.Count + 2)
+				var addonInst = isStruct ? 1 : 2;
+				if (body.Instructions.Count < method.Parameters.Count + addonInst)
 					return false;
 
-				for (int i = 0; i < body.Instructions.Count - 2; i++)
+				for (int i = 0; i < method.Parameters.Count; i++)
 				{
 					if (!body.Instructions[i].MatchStFld(out var target, out var field, out var valueInst))
 						return false;
@@ -199,9 +204,12 @@ namespace ICSharpCode.Decompiler.CSharp
 					autoPropertyToPrimaryCtorParameter.Add(property, method.Parameters[i]);
 				}
 
-				var baseCtorCall = body.Instructions.SecondToLastOrDefault() as CallInstruction;
-				if (baseCtorCall == null)
-					return false;
+				if (!isStruct)
+				{
+					var baseCtorCall = body.Instructions.SecondToLastOrDefault() as CallInstruction;
+					if (baseCtorCall == null)
+						return false;
+				}
 
 				var returnInst = body.Instructions.LastOrDefault();
 				return returnInst != null && returnInst.MatchReturn(out var retVal) && retVal.MatchNop();
@@ -233,6 +241,8 @@ namespace ICSharpCode.Decompiler.CSharp
 		/// </summary>
 		public IMethod PrimaryConstructor => primaryCtor;
 
+		public bool IsInheritedRecord => isInheritedRecord;
+
 		bool IsRecordType(IType type)
 		{
 			return type.GetDefinition() == recordTypeDef
@@ -309,7 +319,7 @@ namespace ICSharpCode.Decompiler.CSharp
 		{
 			switch (property.Name)
 			{
-				case "EqualityContract":
+				case "EqualityContract" when !isStruct:
 					return IsGeneratedEqualityContract(property);
 				default:
 					return IsPropertyDeclaredByPrimaryConstructor(property);
@@ -333,7 +343,7 @@ namespace ICSharpCode.Decompiler.CSharp
 			Debug.Assert(method.IsConstructor && method.Parameters.Count == 1);
 			if (method.GetAttributes().Any() || method.GetReturnTypeAttributes().Any())
 				return false;
-			if (method.Accessibility != Accessibility.Protected)
+			if (method.Accessibility != Accessibility.Protected && (!isSealed || method.Accessibility != Accessibility.Private))
 				return false;
 			if (orderedMembers == null)
 				return false;
@@ -393,10 +403,10 @@ namespace ICSharpCode.Decompiler.CSharp
 			// protected virtual Type EqualityContract {
 			//    [CompilerGenerated] get => typeof(R);
 			// }
-			Debug.Assert(property.Name == "EqualityContract");
-			if (property.Accessibility != Accessibility.Protected)
+			Debug.Assert(!isStruct && property.Name == "EqualityContract");
+			if (property.Accessibility != Accessibility.Protected && (!isSealed || property.Accessibility != Accessibility.Private))
 				return false;
-			if (!(property.IsVirtual || property.IsOverride))
+			if (!(isSealed || property.IsVirtual || property.IsOverride))
 				return false;
 			if (property.IsSealed)
 				return false;
@@ -428,11 +438,11 @@ namespace ICSharpCode.Decompiler.CSharp
 			Debug.Assert(method.Name == "PrintMembers");
 			if (method.Parameters.Count != 1)
 				return false;
-			if (!method.IsOverridable)
+			if (!isSealed && !method.IsOverridable)
 				return false;
 			if (method.GetAttributes().Any() || method.GetReturnTypeAttributes().Any())
 				return false;
-			if (method.Accessibility != Accessibility.Protected)
+			if (method.Accessibility != Accessibility.Protected && (!isSealed || method.Accessibility != Accessibility.Private))
 				return false;
 			if (orderedMembers == null)
 				return false;
@@ -551,7 +561,7 @@ namespace ICSharpCode.Decompiler.CSharp
 				{
 					return false; // static fields/properties are not printed
 				}
-				if (member.Name == "EqualityContract")
+				if (!isStruct && member.Name == "EqualityContract")
 				{
 					return false; // EqualityContract is never printed
 				}
@@ -617,7 +627,8 @@ namespace ICSharpCode.Decompiler.CSharp
 			// if (callvirt PrintMembers(ldloc this, ldloc stringBuilder)) { trueInst }
 			if (!body.Instructions[3].MatchIfInstruction(out var condition, out var trueInst))
 				return true;
-			if (!(condition is CallVirt { Method: { Name: "PrintMembers" } } printMembersCall))
+			if (!((condition is CallInstruction { Method: { Name: "PrintMembers" } } printMembersCall) &&
+				(condition is CallVirt || (isSealed && condition is Call))))
 				return false;
 			if (printMembersCall.Arguments.Count != 2)
 				return false;
@@ -670,7 +681,7 @@ namespace ICSharpCode.Decompiler.CSharp
 			Debug.Assert(method.Name == "Equals" && method.Parameters.Count == 1);
 			if (method.Parameters.Count != 1)
 				return false;
-			if (!method.IsOverridable)
+			if (!isSealed && !method.IsOverridable)
 				return false;
 			if (method.GetAttributes().Any() || method.GetReturnTypeAttributes().Any())
 				return false;
@@ -698,58 +709,61 @@ namespace ICSharpCode.Decompiler.CSharp
 			var conditions = UnpackLogicAndChain(returnValue);
 			Debug.Assert(conditions.Count >= 1);
 			int pos = 0;
-			if (isInheritedRecord)
-			{
-				// call BaseClass::Equals(ldloc this, ldloc other)
-				if (pos >= conditions.Count)
-					return false;
-				if (!(conditions[pos] is Call { Method: { Name: "Equals" } } call))
-					return false;
-				if (!NormalizeTypeVisitor.TypeErasure.EquivalentTypes(call.Method.DeclaringType, baseClass))
-					return false;
-				if (call.Arguments.Count != 2)
-					return false;
-				if (!call.Arguments[0].MatchLdThis())
-					return false;
-				if (!call.Arguments[1].MatchLdLoc(other))
-					return false;
-				pos++;
-			}
-			else
+			if (!isStruct)
 			{
-				// comp.o(ldloc other != ldnull)
-				if (pos >= conditions.Count)
-					return false;
-				if (!conditions[pos].MatchCompNotEqualsNull(out var arg))
-					return false;
-				if (!arg.MatchLdLoc(other))
-					return false;
-				pos++;
-				// call op_Equality(callvirt get_EqualityContract(ldloc this), callvirt get_EqualityContract(ldloc other))
-				// Special-cased because Roslyn isn't using EqualityComparer<T> here.
-				if (pos >= conditions.Count)
-					return false;
-				if (!(conditions[pos] is Call { Method: { IsOperator: true, Name: "op_Equality" } } opEqualityCall))
-					return false;
-				if (!opEqualityCall.Method.DeclaringType.IsKnownType(KnownTypeCode.Type))
-					return false;
-				if (opEqualityCall.Arguments.Count != 2)
-					return false;
-				if (!MatchGetEqualityContract(opEqualityCall.Arguments[0], out var target1))
-					return false;
-				if (!MatchGetEqualityContract(opEqualityCall.Arguments[1], out var target2))
-					return false;
-				if (!target1.MatchLdThis())
-					return false;
-				if (!target2.MatchLdLoc(other))
-					return false;
-				pos++;
+				if (isInheritedRecord)
+				{
+					// call BaseClass::Equals(ldloc this, ldloc other)
+					if (pos >= conditions.Count)
+						return false;
+					if (!(conditions[pos] is Call { Method: { Name: "Equals" } } call))
+						return false;
+					if (!NormalizeTypeVisitor.TypeErasure.EquivalentTypes(call.Method.DeclaringType, baseClass))
+						return false;
+					if (call.Arguments.Count != 2)
+						return false;
+					if (!call.Arguments[0].MatchLdThis())
+						return false;
+					if (!call.Arguments[1].MatchLdLoc(other))
+						return false;
+					pos++;
+				}
+				else
+				{
+					// comp.o(ldloc other != ldnull)
+					if (pos >= conditions.Count)
+						return false;
+					if (!conditions[pos].MatchCompNotEqualsNull(out var arg))
+						return false;
+					if (!arg.MatchLdLoc(other))
+						return false;
+					pos++;
+					// call op_Equality(callvirt get_EqualityContract(ldloc this), callvirt get_EqualityContract(ldloc other))
+					// Special-cased because Roslyn isn't using EqualityComparer<T> here.
+					if (pos >= conditions.Count)
+						return false;
+					if (!(conditions[pos] is Call { Method: { IsOperator: true, Name: "op_Equality" } } opEqualityCall))
+						return false;
+					if (!opEqualityCall.Method.DeclaringType.IsKnownType(KnownTypeCode.Type))
+						return false;
+					if (opEqualityCall.Arguments.Count != 2)
+						return false;
+					if (!MatchGetEqualityContract(opEqualityCall.Arguments[0], out var target1))
+						return false;
+					if (!MatchGetEqualityContract(opEqualityCall.Arguments[1], out var target2))
+						return false;
+					if (!target1.MatchLdThis())
+						return false;
+					if (!target2.MatchLdLoc(other))
+						return false;
+					pos++;
+				}
 			}
 			foreach (var member in orderedMembers)
 			{
 				if (!MemberConsideredForEquality(member))
 					continue;
-				if (member.Name == "EqualityContract")
+				if (!isStruct && member.Name == "EqualityContract")
 				{
 					continue; // already special-cased
 				}
@@ -771,7 +785,7 @@ namespace ICSharpCode.Decompiler.CSharp
 					return false;
 				if (!member1.Equals(member))
 					return false;
-				if (!target2.MatchLdLoc(other))
+				if (!(isStruct ? target2.MatchLdLoca(other) : target2.MatchLdLoc(other)))
 					return false;
 				if (!member2.Equals(member))
 					return false;
@@ -800,10 +814,12 @@ namespace ICSharpCode.Decompiler.CSharp
 			}
 		}
 
-		private static bool MatchGetEqualityContract(ILInstruction inst, out ILInstruction target)
+		private bool MatchGetEqualityContract(ILInstruction inst, out ILInstruction target)
 		{
 			target = null;
-			if (!(inst is CallVirt { Method: { Name: "get_EqualityContract" } } call))
+			if (!(inst is CallInstruction { Method: { Name: "get_EqualityContract" } } call))
+				return false;
+			if (!(inst is CallVirt || (isSealed && inst is Call)))
 				return false;
 			if (call.Arguments.Count != 1)
 				return false;
@@ -830,7 +846,7 @@ namespace ICSharpCode.Decompiler.CSharp
 				return false;
 			if (member is IProperty property)
 			{
-				if (property.Name == "EqualityContract")
+				if (!isStruct && property.Name == "EqualityContract")
 					return !isInheritedRecord;
 				return autoPropertyToBackingField.ContainsKey(property);
 			}
@@ -985,14 +1001,14 @@ namespace ICSharpCode.Decompiler.CSharp
 		{
 			target = null;
 			member = null;
-			if (inst is CallVirt
+			if (inst is CallInstruction
 				{
 					Method:
 					{
 						AccessorKind: System.Reflection.MethodSemanticsAttributes.Getter,
 						AccessorOwner: IProperty property
 					}
-				} call)
+				} call && (call is CallVirt || (isSealed && call is Call)))
 			{
 				if (call.Arguments.Count != 1)
 					return false;

ICSharpCode.Decompiler/CSharp/Transforms/TransformFieldAndConstructorInitializers.cs

@@ -118,7 +118,8 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 				&& currentCtor.Equals(record.PrimaryConstructor)
 				&& ci.ConstructorInitializerType == ConstructorInitializerType.Base)
 			{
-				if (constructorDeclaration.Parent is TypeDeclaration { BaseTypes: { Count: >= 1 } } typeDecl)
+				if (record.IsInheritedRecord &&
+					constructorDeclaration.Parent is TypeDeclaration { BaseTypes: { Count: >= 1 } } typeDecl)
 				{
 					var baseType = typeDecl.BaseTypes.First();
 					var newBaseType = new InvocationAstType();