From e67f230f5f318b9a661ad3d42367172d4dd8c081 Mon Sep 17 00:00:00 2001
From: Sven Boemer <sbomer@gmail.com>
Date: Fri, 4 Oct 2024 09:36:10 -0700
Subject: [PATCH] ILLink: Avoid warning for RUC field rooted as part of a root
 assembly (#108498)

Similar to https://github.com/dotnet/runtime/issues/81864, fields
in a RUC class are producing trim analysis warnings in the OOB
trim step (the mentioned issue was specific to library mode, but
it's also a problem for the normal root assembly mode).

This extends the fix from
https://github.com/dotnet/runtime/pull/84620 to avoid producing
warnings for fields that are marked just because an assembly was
rooted. Arguably rooting an assembly _should_ warn about rooted
RUC members, but that's not the case today for RUC methods, so
this makes the behavior consistent for fields.

---------

Co-authored-by: Jackson Schuster <36744439+jtschuster@users.noreply.github.com>
---
 .../src/linker/Linker.Steps/MarkStep.cs       |  1 +
 .../RequiresInRootAllAssembly.cs              | 59 +++++++++++++++++++
 2 files changed, 60 insertions(+)
 create mode 100644 src/tools/illink/test/Mono.Linker.Tests.Cases/RequiresCapability/RequiresInRootAllAssembly.cs

diff --git a/src/tools/illink/src/linker/Linker.Steps/MarkStep.cs b/src/tools/illink/src/linker/Linker.Steps/MarkStep.cs
index 27859afd6df75..d025204b1315d 100644
--- a/src/tools/illink/src/linker/Linker.Steps/MarkStep.cs
+++ b/src/tools/illink/src/linker/Linker.Steps/MarkStep.cs
@@ -1728,6 +1728,7 @@ void ProcessAnalysisAnnotationsForField (FieldDefinition field, DependencyKind d
 			case DependencyKind.AlreadyMarked:
 			case DependencyKind.TypePreserve:
 			case DependencyKind.PreservedMethod:
+			case DependencyKind.MemberOfType:
 				return;
 
 			case DependencyKind.DynamicallyAccessedMemberOnType:
diff --git a/src/tools/illink/test/Mono.Linker.Tests.Cases/RequiresCapability/RequiresInRootAllAssembly.cs b/src/tools/illink/test/Mono.Linker.Tests.Cases/RequiresCapability/RequiresInRootAllAssembly.cs
new file mode 100644
index 0000000000000..b8fa63c186c1c
--- /dev/null
+++ b/src/tools/illink/test/Mono.Linker.Tests.Cases/RequiresCapability/RequiresInRootAllAssembly.cs
@@ -0,0 +1,59 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using System.Diagnostics.CodeAnalysis;
+using Mono.Linker.Tests.Cases.Expectations.Assertions;
+using Mono.Linker.Tests.Cases.Expectations.Metadata;
+
+namespace Mono.Linker.Tests.Cases.RequiresCapability
+{
+	[SetupLinkerArgument ("-a", "test.exe", "all")]
+
+	[SkipKeptItemsValidation]
+	[ExpectedNoWarnings]
+	public class RequiresInRootAllAssembly
+	{
+		public static void Main ()
+		{
+		}
+
+		[RequiresDynamicCode ("--MethodWhichRequires--")]
+		public static void MethodWhichRequires () { }
+
+		[RequiresDynamicCode ("--InstanceMethodWhichRequires--")]
+		public void InstanceMethodWhichRequires () { }
+
+		public sealed class ClassWithDAMAnnotatedMembers
+		{
+			public static void Method ([DynamicallyAccessedMembers (DynamicallyAccessedMemberTypes.PublicMethods)] Type type) { }
+
+			[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods)]
+			public static Type Field;
+		}
+
+		[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods)]
+		public sealed class ClassWithDAMAnnotation
+		{
+			public void Method () { }
+		}
+
+		[RequiresUnreferencedCode ("--ClassWithRequires--")]
+		public sealed class ClassWithRequires
+		{
+			public static int Field;
+
+			internal static int InternalField;
+
+			private static int PrivateField;
+
+			public static void Method () { }
+
+			public void InstanceMethod () { }
+
+			public static int Property { get; set; }
+
+			public static event EventHandler PropertyChanged;
+		}
+	}
+}