Add test case for interfaces without impls for whole hierarchy

src/tools/illink/test/ILLink.RoslynAnalyzer.Tests/generated/ILLink.RoslynAnalyzer.Tests.Generator/ILLink.RoslynAnalyzer.Tests.TestCaseGenerator/Inheritance.Interfaces.DefaultInterfaceMethodsTests.g.cs

@@ -15,6 +15,12 @@ public Task DefaultInterfaceMethodCallIntoClass ()
 			return RunTest (allowMissingWarnings: true);
 		}
 
+		[Fact]
+		public Task DimProvidedByUnreferencedIfaceInHierarchy ()
+		{
+			return RunTest (allowMissingWarnings: true);
+		}
+
 		[Fact]
 		public Task GenericDefaultInterfaceMethods ()
 		{

src/tools/illink/test/Mono.Linker.Tests.Cases/Inheritance.Interfaces/DefaultInterfaceMethods/Dependencies/DimProvidedByUnreferencedIfaceInHierarchy.il

@@ -0,0 +1,87 @@
+
+// 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.
+
+.assembly extern mscorlib { }
+
+.assembly 'library' { }
+
+.class public auto ansi abstract sealed beforefieldinit Program
+    extends [mscorlib]System.Object
+{
+    // Nested Types
+    .class interface nested public auto ansi abstract beforefieldinit IFoo
+    {
+        // Methods
+        .method public hidebysig newslot abstract virtual
+            instance void Method () cil managed
+        {
+        } // end of method IFoo::Method
+
+    } // end of class IFoo
+
+    .class interface nested public auto ansi abstract beforefieldinit IBar
+        implements Program/IFoo
+    {
+        // Methods
+        .method public final hidebysig virtual
+            instance void Program.IFoo.Method () cil managed
+        {
+            .override method instance void Program/IFoo::Method()
+            // Method begins at RVA 0x2068
+            // Code size 2 (0x2)
+            .maxstack 8
+
+            IL_0000: nop
+            IL_0001: ret
+        } // end of method IBar::Program.IFoo.Method
+
+    } // end of class IBar
+
+    .class interface nested public auto ansi abstract beforefieldinit IBaz
+        implements Program/IBar
+    {
+    } // end of class IBaz
+
+    .class nested public auto ansi beforefieldinit MyFoo
+        extends [mscorlib]System.Object
+        implements Program/IBaz
+    {
+        // Methods
+        .method public hidebysig specialname rtspecialname
+            instance void .ctor () cil managed
+        {
+            // Method begins at RVA 0x2076
+            // Code size 8 (0x8)
+            .maxstack 8
+
+            IL_0000: ldarg.0
+            IL_0001: call instance void [mscorlib]System.Object::.ctor()
+            IL_0006: nop
+            IL_0007: ret
+        } // end of method MyFoo::.ctor
+
+    } // end of class MyFoo
+
+
+    // Methods
+    .method public hidebysig static
+        void CallMethod (
+            class Program/IFoo foo
+        ) cil managed
+    {
+        .custom instance void [mscorlib]mscorlib.CompilerServices.NullableContextAttribute::.ctor(uint8) = (
+            01 00 01 00 00
+        )
+        // Method begins at RVA 0x2050
+        // Code size 9 (0x9)
+        .maxstack 8
+
+        IL_0000: nop
+        IL_0001: ldarg.0
+        IL_0002: callvirt instance void Program/IFoo::Method()
+        IL_0007: nop
+        IL_0008: ret
+    } // end of method Program::CallMethod
+
+} // end of class Program

src/tools/illink/test/Mono.Linker.Tests.Cases/Inheritance.Interfaces/DefaultInterfaceMethods/Dependencies/StaticDimProvidedByUnreferencedIfaceInHierarchy.il

@@ -0,0 +1,70 @@
+// 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.
+
+.assembly extern mscorlib { }
+
+.assembly 'library' { }
+
+.class public auto ansi abstract sealed beforefieldinit Program
+    extends [mscorlib]System.Object
+{
+    // Nested Types
+    .class interface nested public auto ansi abstract beforefieldinit IBase
+    {
+        // Methods
+        .method public hidebysig abstract virtual static
+            void Method () cil managed
+        {
+        } // end of method IBase::Method
+
+    } // end of class IBase
+
+    .class interface nested public auto ansi abstract beforefieldinit I2
+        implements Program/IBase
+    {
+        // Methods
+        .method public hidebysig static
+            void Program.IBase.Method () cil managed
+        {
+            .override method void Program/IBase::Method()
+            // Method begins at RVA 0x205f
+            // Code size 2 (0x2)
+            .maxstack 8
+
+            IL_0000: nop
+            IL_0001: ret
+        } // end of method I2::Program.IBase.Method
+
+    } // end of class I2
+
+    .class interface nested public auto ansi abstract beforefieldinit I3
+        implements Program/I2
+    {
+    } // end of class I3
+
+    .class interface nested public auto ansi abstract beforefieldinit I4
+        implements Program/I3
+    {
+    } // end of class I4
+
+
+    // Methods
+    .method public hidebysig static
+        void CallMethod<(Program/IBase) T> () cil managed
+    {
+        .param constraint T, Program/IBase
+            .custom instance void [mscorlib]mscorlib.CompilerServices.NullableAttribute::.ctor(uint8) = (
+                01 00 01 00 00
+            )
+        // Method begins at RVA 0x2050
+        // Code size 14 (0xe)
+        .maxstack 8
+
+        IL_0000: nop
+        IL_0001: constrained. !!T
+        IL_0007: call void Program/IBase::Method()
+        IL_000c: nop
+        IL_000d: ret
+    } // end of method Program::CallMethod
+
+} // end of class Program

src/tools/illink/test/Mono.Linker.Tests.Cases/Inheritance.Interfaces/DefaultInterfaceMethods/DimProvidedByUnreferencedIfaceInHierarchy.cs

@@ -0,0 +1,68 @@
+
+
+using Mono.Linker.Tests.Cases.Expectations.Assertions;
+using Mono.Linker.Tests.Cases.Expectations.Metadata;
+
+namespace Mono.Linker.Tests.Cases.Inheritance.Interfaces.DefaultInterfaceMethods
+{
+	[SetupLinkerArgument ("--skip-unresolved", "true")]
+	[TestCaseRequirements (TestRunCharacteristics.SupportsDefaultInterfaceMethods, "Requires support for default interface methods")]
+	[Define ("IL_ASSEMBLY_AVAILABLE")]
+	[SetupCompileBefore ("library.dll", new[] { "Dependencies/DimProvidedByUnreferencedIfaceInHierarchy.il" })]
+	[SkipILVerify]
+
+#if IL_ASSEMBLY_AVAILABLE
+	[KeptMemberInAssembly ("library.dll", typeof(Program.IFoo), "Method()")]
+	// https://github.com/dotnet/runtime/issues/98536
+	// [KeptTypeInAssembly ("library.dll", typeof(Program.IBar))]
+	// [KeptMemberInAssembly ("library.dll", typeof(Program.IBar), "Program.IFoo.Method()")]
+	// [KeptInterfaceOnTypeInAssembly ("library.dll", typeof (Program.IBar), "library.dll", typeof (Program.IFoo))]
+	// [KeptInterfaceOnTypeInAssembly ("library.dll", typeof (Program.MyFoo), "library.dll", typeof (Program.IBaz))]
+	// [KeptTypeInAssembly ("library.dll", typeof(Program.IBaz))]
+	// [KeptInterfaceOnTypeInAssembly ("library.dll", typeof (Program.IBaz), "library.dll", typeof (Program.IBar))]
+	[KeptMemberInAssembly ("library.dll", typeof(Program), "CallMethod(Program/IFoo)")]
+#endif
+	class DimProvidedByUnreferencedIfaceInHierarchy
+	{
+		static void Main ()
+		{
+#if IL_ASSEMBLY_AVAILABLE
+			Program.IFoo foo = new Program.MyFoo ();
+			Program.CallMethod(foo);
+#endif
+		}
+	}
+}
+
+
+
+// public static class Program
+// {
+// 	[Kept]
+// 	interface IFoo
+// 	{
+// 		void Method();
+// 	}
+
+// 	[Kept]
+// 	interface IBar : IFoo
+// 	{
+// 		[Kept]
+// 		void IFoo.Method() { }
+// 	}
+
+// 	[Kept]
+// 	interface IBaz: IBar /* not IFoo */
+// 	{
+// 	}
+
+// 	[Kept]
+// 	[KeptInterface(typeof(IBaz))]
+// 	class MyFoo : IBaz /* not IBar, not IFoo */
+// 	{ }
+
+// 	static void CallMethod(IFoo foo)
+// 	{
+// 		foo.Method();
+// 	}
+// }

src/tools/illink/test/Mono.Linker.Tests.Cases/Inheritance.Interfaces/DefaultInterfaceMethods/StaticDimProvidedByUnreferencedIfaceInHierarchy.cs

@@ -0,0 +1,70 @@
+
+
+using Mono.Linker.Tests.Cases.Expectations.Assertions;
+using Mono.Linker.Tests.Cases.Expectations.Metadata;
+
+namespace Mono.Linker.Tests.Cases.Inheritance.Interfaces.DefaultInterfaceMethods
+{
+	[SetupLinkerArgument ("--skip-unresolved", "true")]
+	[TestCaseRequirements (TestRunCharacteristics.SupportsDefaultInterfaceMethods, "Requires support for default interface methods")]
+	[Define ("IL_ASSEMBLY_AVAILABLE")]
+	[SetupCompileBefore ("library.dll", new[] { "Dependencies/StaticDimProvidedByUnreferencedIfaceInHierarchy.il" })]
+	[SkipILVerify]
+
+#if IL_ASSEMBLY_AVAILABLE
+	[KeptMemberInAssembly ("library.dll", typeof(Program), "CallMethod<#1>()")]
+	[KeptTypeInAssembly ("library.dll", typeof(Program.IBase))]
+	[KeptMemberInAssembly ("library.dll", typeof(Program.IBase), "Method()")]
+	[KeptTypeInAssembly ("library.dll", typeof(Program.I4))]
+	// https://github.com/dotnet/runtime/issues/98536
+	// [KeptTypeInAssembly ("library.dll", typeof(Program.I2))]
+	// [KeptMemberInAssembly ("library.dll", typeof(Program.I2), "Program.IBase.Method()")]
+	// [KeptInterfaceOnTypeInAssembly ("library.dll", typeof (Program.I2), "library.dll", typeof (Program.IBase))]
+	// [KeptTypeInAssembly ("library.dll", typeof(Program.I3))]
+	// [KeptInterfaceOnTypeInAssembly ("library.dll", typeof (Program.I3), "library.dll", typeof (Program.I2))]
+	// [KeptInterfaceOnTypeInAssembly ("library.dll", typeof (Program.I4), "library.dll", typeof (Program.I3))]
+#endif
+	class StaticDimProvidedByUnreferencedIfaceInHierarchy
+	{
+		static void Main ()
+		{
+#if IL_ASSEMBLY_AVAILABLE
+			Program.CallMethod<Program.I4>();
+#endif
+		}
+	}
+}
+
+
+
+// public static class Program
+// {
+//	[Kept]
+//	interface IBase
+//	{
+//		[Kept]
+// 		static abstract void Method();
+// 	}
+
+//	[Kept]
+//	[KeptInterface(typeof(IBase)]
+//	interface I2 : IBase
+//	{
+//		[Kept]
+//		static void IBase.Method() { }
+//	}
+
+//	[Kept]
+// 	[KeptInterface(typeof(I2)]
+// 	interface I3 : I2 { }
+
+//	[Kept]
+//	[KeptInterface(typeof(I3)]
+//	interface I4 : I3 { }
+
+//	[Kept]
+//	static void CallMethod<T>() where T : IBase
+//	{
+//		T.Method();
+//	}
+// }