From ab9e2862d357a1a45b9908f431913255fd7b240a Mon Sep 17 00:00:00 2001
From: vitek-karas <10670590+vitek-karas@users.noreply.github.com>
Date: Mon, 3 Jan 2022 05:27:39 -0800
Subject: [PATCH 1/2] Propagate Interfaces annotation through Type.BaseType

The Interfaces annotation makes sure the type has all interfaces, meaning `GetInterfaces` reflection call will work on it. That means that all interfaces of the base type are also preserved, so the `Interfaces` annotation should be propagated to the base type as well.
---
 .../ReflectionMethodBodyScanner.cs            |  3 ++
 .../DataFlow/TypeBaseTypeDataFlow.cs          |  8 ++++
 .../Reflection/TypeUsedViaReflection.cs       | 38 +++++++++++++++++++
 3 files changed, 49 insertions(+)

diff --git a/src/linker/Linker.Dataflow/ReflectionMethodBodyScanner.cs b/src/linker/Linker.Dataflow/ReflectionMethodBodyScanner.cs
index d90565b6dd4c..476e86bcf6e6 100644
--- a/src/linker/Linker.Dataflow/ReflectionMethodBodyScanner.cs
+++ b/src/linker/Linker.Dataflow/ReflectionMethodBodyScanner.cs
@@ -1294,6 +1294,9 @@ public override bool HandleCall (MethodBody callingMethodBody, MethodReference c
 
 									if (dynamicallyAccessedMemberNode.DynamicallyAccessedMemberTypes.HasFlag (DynamicallyAccessedMemberTypes.PublicProperties))
 										propagatedMemberTypes |= DynamicallyAccessedMemberTypes.PublicProperties;
+
+									if (dynamicallyAccessedMemberNode.DynamicallyAccessedMemberTypes.HasFlag (DynamicallyAccessedMemberTypes.Interfaces))
+										propagatedMemberTypes |= DynamicallyAccessedMemberTypes.Interfaces;
 								}
 
 								methodReturnValue = MergePointValue.MergeValues (methodReturnValue, CreateMethodReturnValue (calledMethod, propagatedMemberTypes));
diff --git a/test/Mono.Linker.Tests.Cases/DataFlow/TypeBaseTypeDataFlow.cs b/test/Mono.Linker.Tests.Cases/DataFlow/TypeBaseTypeDataFlow.cs
index abe5aaadadc1..68d232252d9a 100644
--- a/test/Mono.Linker.Tests.Cases/DataFlow/TypeBaseTypeDataFlow.cs
+++ b/test/Mono.Linker.Tests.Cases/DataFlow/TypeBaseTypeDataFlow.cs
@@ -34,6 +34,8 @@ public static void Main ()
 			TestNonPublicNestedTypesAreNotPropagated (typeof (TestType));
 			TestNonPublicPropertiesAreNotPropagated (typeof (TestType));
 
+			TestInterfacesPropagated (typeof (TestType));
+
 			TestCombinationOfPublicsIsPropagated (typeof (TestType));
 			TestCombinationOfNonPublicsIsNotPropagated (typeof (TestType));
 			TestCombinationOfPublicAndNonPublicsPropagatesPublicOnly (typeof (TestType));
@@ -164,6 +166,12 @@ static void TestNonPublicPropertiesAreNotPropagated ([DynamicallyAccessedMembers
 			derivedType.BaseType.RequiresNonPublicProperties ();
 		}
 
+		[RecognizedReflectionAccessPattern]
+		static void TestInterfacesPropagated ([DynamicallyAccessedMembers (DynamicallyAccessedMemberTypes.Interfaces)] Type derivedType)
+		{
+			derivedType.BaseType.RequiresInterfaces ();
+		}
+
 		[RecognizedReflectionAccessPattern]
 		static void TestCombinationOfPublicsIsPropagated (
 			[DynamicallyAccessedMembers (DynamicallyAccessedMemberTypes.PublicMethods | DynamicallyAccessedMemberTypes.PublicProperties)] Type derivedType)
diff --git a/test/Mono.Linker.Tests.Cases/Reflection/TypeUsedViaReflection.cs b/test/Mono.Linker.Tests.Cases/Reflection/TypeUsedViaReflection.cs
index 1907cd6536a6..8bfe08da3845 100644
--- a/test/Mono.Linker.Tests.Cases/Reflection/TypeUsedViaReflection.cs
+++ b/test/Mono.Linker.Tests.Cases/Reflection/TypeUsedViaReflection.cs
@@ -42,6 +42,8 @@ public static void Main ()
 			TestUnkownIgnoreCase3Params (1);
 			TestUnkownIgnoreCase5Params (1);
 			TestGenericTypeWithAnnotations ();
+
+			BaseTypeInterfaces.Test ();
 		}
 
 		[Kept]
@@ -409,5 +411,41 @@ static void TestGenericTypeWithAnnotations ()
 				" test, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null";
 			Type.GetType (reflectionTypeKeptString);
 		}
+
+		[Kept]
+		class BaseTypeInterfaces
+		{
+			[Kept]
+			interface ITest
+			{
+				[Kept]
+				void Method ();
+			}
+
+			[Kept]
+			[KeptInterface (typeof (ITest))]
+			class BaseType : ITest
+			{
+				[Kept]
+				public void Method () { }
+			}
+
+			[Kept]
+			[KeptBaseType (typeof (BaseType))]
+			[KeptInterface (typeof (ITest))]
+			class DerivedType : BaseType, ITest
+			{
+				[Kept]
+				public void Method () { }
+			}
+
+			[Kept]
+			public static void Test()
+			{
+				ITest t = null;
+				t.Method ();
+				typeof (DerivedType).GetInterfaces ();
+			}
+		}
 	}
 }

From b2c12f0b80b0dc8b191833a909e3e8a1e39519c6 Mon Sep 17 00:00:00 2001
From: vitek-karas <10670590+vitek-karas@users.noreply.github.com>
Date: Mon, 3 Jan 2022 05:33:54 -0800
Subject: [PATCH 2/2] Formatting

---
 .../Mono.Linker.Tests.Cases/Reflection/TypeUsedViaReflection.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/Mono.Linker.Tests.Cases/Reflection/TypeUsedViaReflection.cs b/test/Mono.Linker.Tests.Cases/Reflection/TypeUsedViaReflection.cs
index 8bfe08da3845..0f660e6ede62 100644
--- a/test/Mono.Linker.Tests.Cases/Reflection/TypeUsedViaReflection.cs
+++ b/test/Mono.Linker.Tests.Cases/Reflection/TypeUsedViaReflection.cs
@@ -440,7 +440,7 @@ public void Method () { }
 			}
 
 			[Kept]
-			public static void Test()
+			public static void Test ()
 			{
 				ITest t = null;
 				t.Method ();