Clean up tests and simplify pending reflection-visible set API

- Remove unnecessary #pragma warning disable IL2060 from tests
- Add ExpectedNoWarnings to explicit layout test
- Remove issue references from test comments
- Clarify comment about IL2026 suppression justification
- Expose pending sets as properties, inline clear in ProcessMarkedPending
- Separate doc comments for method and field pending sets

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Assisted-by: Claude:claude-opus-4.6-1m

Author: sbomer

src/tools/illink/src/linker/Linker.Steps/MarkStep.cs

@@ -502,7 +502,7 @@ bool ProcessMarkedPending()
                 ApplyPreserveInfo(type);
             }
 
-            foreach (var method in Annotations.GetPendingReflectionVisibleMethods())
+            foreach (var method in Annotations.PendingReflectionVisibleMethods)
             {
                 marked = true;
                 var origin = new MessageOrigin(method);
@@ -514,14 +514,16 @@ bool ProcessMarkedPending()
                 // be used as a generic argument in constrained calls via MakeGenericMethod.
                 MarkTypeVisibleToReflection(method.DeclaringType, new DependencyInfo(DependencyKind.DeclaringType, method), origin);
             }
+            Annotations.PendingReflectionVisibleMethods.Clear();
 
-            foreach (var field in Annotations.GetPendingReflectionVisibleFields())
+            foreach (var field in Annotations.PendingReflectionVisibleFields)
             {
                 marked = true;
                 var origin = new MessageOrigin(field);
                 MarkFieldVisibleToReflection(field, new DependencyInfo(DependencyKind.XmlDescriptor, field), origin);
                 MarkTypeVisibleToReflection(field.DeclaringType, new DependencyInfo(DependencyKind.DeclaringType, field), origin);
             }
+            Annotations.PendingReflectionVisibleFields.Clear();
 
             return marked;
         }

src/tools/illink/src/linker/Linker/Annotations.cs

@@ -246,25 +246,17 @@ public bool IsRelevantToVariantCasting(TypeDefinition type)
         }
 
         /// <summary>
-        /// Schedules a method for reflection-visible treatment by MarkStep.
-        /// Used by DescriptorMarker to defer to MarkStep which owns MarkMethodVisibleToReflection.
+        /// Schedules a method for reflection-visible marking by MarkStep.
         /// </summary>
         public void MarkPendingReflectionVisibleMethod(MethodDefinition method) => pending_reflection_visible_methods.Add(method);
-        public void MarkPendingReflectionVisibleField(FieldDefinition field) => pending_reflection_visible_fields.Add(field);
 
-        public MethodDefinition[] GetPendingReflectionVisibleMethods()
-        {
-            var result = pending_reflection_visible_methods.ToArray();
-            pending_reflection_visible_methods.Clear();
-            return result;
-        }
+        /// <summary>
+        /// Schedules a field for reflection-visible marking by MarkStep.
+        /// </summary>
+        public void MarkPendingReflectionVisibleField(FieldDefinition field) => pending_reflection_visible_fields.Add(field);
 
-        public FieldDefinition[] GetPendingReflectionVisibleFields()
-        {
-            var result = pending_reflection_visible_fields.ToArray();
-            pending_reflection_visible_fields.Clear();
-            return result;
-        }
+        public HashSet<MethodDefinition> PendingReflectionVisibleMethods => pending_reflection_visible_methods;
+        public HashSet<FieldDefinition> PendingReflectionVisibleFields => pending_reflection_visible_fields;
 
         public bool SetProcessed(IMetadataTokenProvider provider)
         {

src/tools/illink/test/Mono.Linker.Tests.Cases/Inheritance.Interfaces/StaticInterfaceMethods/DescriptorPreservedTypeIsReflectionVisible.cs

@@ -74,11 +74,9 @@ public static void Method () { }
 		[Kept]
 		static void UseViaReflection ()
 		{
-#pragma warning disable IL2060
 			typeof (IStaticAbstract).GetMethod (nameof (IStaticAbstract.Call))
 				.MakeGenericMethod (ExplicitLayoutPreservedViaDescriptor.GetMyType ())
 				.Invoke (null, null);
-#pragma warning restore IL2060
 		}
 
 		[Kept]

src/tools/illink/test/Mono.Linker.Tests.Cases/Inheritance.Interfaces/StaticInterfaceMethods/StaticAbstractMethodsPreservedViaDescriptor.cs

@@ -12,7 +12,6 @@ namespace Mono.Linker.Tests.Cases.Inheritance.Interfaces.StaticInterfaceMethods
 	/// When a type is preserved via an XML descriptor, its static abstract interface
 	/// implementations should be kept if the static abstract methods are used through
 	/// constrained calls elsewhere in the program.
-	/// Regression test for https://github.com/dotnet/runtime/issues/128120
 	/// </summary>
 	[SetupLinkerDescriptorFile ("StaticAbstractMethodsPreservedViaDescriptor.xml")]
 	[ExpectedNoWarnings]
@@ -64,18 +63,14 @@ public static void Method () { }
 			public static Type GetMyType () => MethodBase.GetCurrentMethod ().DeclaringType;
 		}
 
-		// Mirrors the pattern from the original repro (dotnet/runtime#128120):
-		// typeof(IStaticAbstract).GetMethod("Call").MakeGenericMethod(preservedType).Invoke(...)
-		// The descriptor-preserved method GetMyType returns its DeclaringType, which is then
-		// used as a type argument to MakeGenericMethod on a method constrained by IStaticAbstract.
+		// Mirrors the pattern where a descriptor-preserved method's DeclaringType is used
+		// as a type argument to MakeGenericMethod on a method constrained by IStaticAbstract.
 		[Kept]
 		static void UseViaReflection ()
 		{
-#pragma warning disable IL2060
 			typeof (IStaticAbstract).GetMethod (nameof (IStaticAbstract.Call))
 				.MakeGenericMethod (PreservedViaDescriptorOnly.GetMyType ())
 				.Invoke (null, null);
-#pragma warning restore IL2060
 		}
 
 		[Kept]