Fix #2475: Fix support for records with custom copy ctor

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

@@ -2,6 +2,13 @@
 {
 	public record Base(string A);
 
+	public record CopyCtor(string A)
+	{
+		protected CopyCtor(CopyCtor _)
+		{
+		}
+	}
+
 	public record Derived(int B) : Base(B.ToString());
 
 	public record Empty;

ICSharpCode.Decompiler/CSharp/RecordDecompiler.cs

@@ -170,6 +170,8 @@ namespace ICSharpCode.Decompiler.CSharp
 				var m = method.Specialize(subst);
 				if (IsPrimaryConstructor(m))
 					return method;
+				primaryCtorParameterToAutoProperty.Clear();
+				autoPropertyToPrimaryCtorParameter.Clear();
 			}
 
 			return null;
@@ -254,13 +256,9 @@ namespace ICSharpCode.Decompiler.CSharp
 		/// </summary>
 		public bool MethodIsGenerated(IMethod method)
 		{
-			if (method.IsConstructor)
+			if (IsCopyConstructor(method))
 			{
-				if (method.Parameters.Count == 1
-					&& IsRecordType(method.Parameters[0].Type))
-				{
-					return IsGeneratedCopyConstructor(method);
-				}
+				return IsGeneratedCopyConstructor(method);
 			}
 
 			switch (method.Name)
@@ -333,6 +331,18 @@ namespace ICSharpCode.Decompiler.CSharp
 				&& autoPropertyToPrimaryCtorParameter.ContainsKey((IProperty)property.Specialize(subst));
 		}
 
+		public bool IsCopyConstructor(IMethod method)
+		{
+			if (method == null)
+				return false;
+
+			Debug.Assert(method.DeclaringTypeDefinition == recordTypeDef);
+
+			return method.IsConstructor
+				&& method.Parameters.Count == 1
+				&& IsRecordType(method.Parameters[0].Type);
+		}
+
 		private bool IsGeneratedCopyConstructor(IMethod method)
 		{
 			/* 

ICSharpCode.Decompiler/CSharp/Transforms/TransformFieldAndConstructorInitializers.cs

@@ -177,6 +177,10 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 				if (!context.DecompileRun.RecordDecompilers.TryGetValue(ctorMethodDef.DeclaringTypeDefinition, out var record))
 					record = null;
 
+				//Filter out copy constructor of records
+				if (record != null)
+					instanceCtorsNotChainingWithThis = instanceCtorsNotChainingWithThis.Where(ctor => !record.IsCopyConstructor(ctor.GetSymbol() as IMethod)).ToArray();
+
 				// Recognize field or property initializers:
 				// Translate first statement in all ctors (if all ctors have the same statement) into an initializer.
 				bool allSame;
@@ -202,9 +206,7 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 					if (initializer.Annotation<ILVariableResolveResult>()?.Variable.Kind == IL.VariableKind.Parameter)
 					{
 						// remove record ctor parameter assignments
-						if (IsPropertyDeclaredByPrimaryCtor(fieldOrPropertyOrEvent as IProperty, record))
-							initializer.Remove();
-						else
+						if (!IsPropertyDeclaredByPrimaryCtor(fieldOrPropertyOrEvent as IProperty, record))
 							break;
 					}
 					else