Fix NativeMarshalling attribute override for COM interfaces

src/libraries/System.Runtime.InteropServices/gen/Microsoft.Interop.SourceGeneration/ComInterfaceMarshallingInfoProvider.cs

@@ -25,6 +25,12 @@ public ComInterfaceMarshallingInfoProvider(Compilation compilation)
 
         public MarshallingInfo? ParseAttribute(AttributeData attributeData, ITypeSymbol type, int indirectionDepth, UseSiteAttributeProvider useSiteAttributes, GetMarshallingInfoCallback marshallingInfoCallback)
         {
+            // If the type has a NativeMarshallingAttribute, defer to that parser by returning null
+            if (type.GetAttributes().Any(attr => attr.AttributeClass?.ToDisplayString() == TypeNames.NativeMarshallingAttribute))
+            {
+                return null;
+            }
+
             return CreateComInterfaceMarshallingInfo(_compilation, type);
         }
 

src/libraries/System.Runtime.InteropServices/tests/ComInterfaceGenerator.Unit.Tests/CodeSnippets.cs

@@ -751,5 +751,21 @@ public Bidirectional(IComInterfaceAttributeProvider attributeProvider)
 
             public IComInterfaceAttributeProvider AttributeProvider { get; }
         }
+
+        public string ComInterfaceWithNativeMarshalling => $$"""
+            using System;
+            using System.Runtime.CompilerServices;
+            using System.Runtime.InteropServices;
+            using System.Runtime.InteropServices.Marshalling;
+
+            [assembly:DisableRuntimeMarshalling]
+
+            {{GeneratedComInterface()}}
+            [NativeMarshalling(typeof(UniqueComInterfaceMarshaller<IFoo>))]
+            partial interface IFoo
+            {
+                void DoWorkTogether(IFoo foo);
+            }
+            """;
     }
 }

src/libraries/System.Runtime.InteropServices/tests/ComInterfaceGenerator.Unit.Tests/Compiles.cs

@@ -349,6 +349,7 @@ public static IEnumerable<object[]> ComInterfaceSnippetsToCompile()
             yield return new object[] { ID(), codeSnippets.ForwarderWithPreserveSigAndRefKind("ref readonly") };
             yield return new object[] { ID(), codeSnippets.ForwarderWithPreserveSigAndRefKind("in") };
             yield return new object[] { ID(), codeSnippets.ForwarderWithPreserveSigAndRefKind("out") };
+            yield return new object[] { ID(), codeSnippets.ComInterfaceWithNativeMarshalling };
         }
 
         public static IEnumerable<object[]> ManagedToUnmanagedComInterfaceSnippetsToCompile()

src/libraries/System.Runtime.InteropServices/tests/LibraryImportGenerator.UnitTests/CodeSnippets.cs

@@ -1526,5 +1526,25 @@ public void Free() { }
                 }
             }
             """;
+
+        public static string ComInterfaceWithNativeMarshallingInLibraryImport => """
+            using System.Runtime.InteropServices;
+            using System.Runtime.InteropServices.Marshalling;
+
+            [GeneratedComInterface]
+            [Guid("0E7204B5-4B61-4E06-B872-82BA652F2ECA")]
+            [NativeMarshalling(typeof(UniqueComInterfaceMarshaller<IFoo>))]
+            partial interface IFoo
+            {
+                void DoWork();
+            }
+
+            static partial class PInvokes
+            {
+                [LibraryImport("lib")]
+                [return: MarshalAs(UnmanagedType.I1)]
+                public static partial bool TryGetFoo(out IFoo foo);
+            }
+            """;
     }
 }

src/libraries/System.Runtime.InteropServices/tests/LibraryImportGenerator.UnitTests/Compiles.cs

@@ -255,6 +255,7 @@ public static IEnumerable<object[]> CodeSnippetsToCompile()
 
             // Type-level interop generator trigger attributes
             yield return new[] { ID(), CodeSnippets.GeneratedComInterface };
+            yield return new[] { ID(), CodeSnippets.ComInterfaceWithNativeMarshallingInLibraryImport };
 
             // Parameter modifiers
             yield return new[] { ID(), CodeSnippets.SingleParameterWithModifier("int", "scoped ref") };