ComInterfaceGenerator emits method attributed with [UnmanagedCallersOnly] and in out or ref parameters. #82581
Description
ComInterfaceGenerator generates code that produces error CS8977: Cannot use 'ref', 'in', or 'out' in the signature of a method attributed with 'UnmanagedCallersOnly'.
User Code:
[assembly:DisableRuntimeMarshalling]
[global::System.Runtime.InteropServices.Marshalling.GeneratedComInterfaceAttribute]
partial interface INativeAPI : IUnmanagedInterfaceType
{
void Method(out S value);
}
// Try using the generated native interface
sealed class NativeAPI : IUnmanagedVirtualMethodTableProvider, INativeAPI.Native
{
public VirtualMethodTableInfo GetVirtualMethodTableInfoForKey(System.Type type) => throw null;
}
partial interface INativeAPI
{
static unsafe void* IUnmanagedInterfaceType.VirtualMethodTableManagedImplementation => null;
}
[NativeMarshalling(typeof(Marshaller))]
public struct S
{
#pragma warning disable CS0649 // Field is never assigned to, and will always have its default value
public bool b;
#pragma warning restore CS0649
}
[CustomMarshaller(typeof(S), MarshalMode.ManagedToUnmanagedOut, typeof(Marshaller))]
[CustomMarshaller(typeof(S), MarshalMode.UnmanagedToManagedIn, typeof(Marshaller))]
public static class Marshaller
{
public struct Native { }
public static S ConvertToManaged(Native n) => default;
}NativeToManagedStubs.g.cs
// <auto-generated/>
unsafe partial interface INativeAPI
{
internal unsafe partial interface Native
{
// error CS8977: Cannot use 'ref', 'in', or 'out' in the signature of a method attributed with 'UnmanagedCallersOnly'.
[System.Runtime.InteropServices.UnmanagedCallersOnlyAttribute]
internal static void ABI_Method(void* __this_native, out global::S value)
{
global::INativeAPI @this = default;
try
{
// Unmarshal - Convert native data to managed data.
@this = (global::INativeAPI)System.Runtime.InteropServices.Marshalling.UnmanagedObjectUnwrapper.GetObjectForUnmanagedWrapper<System.Runtime.InteropServices.Marshalling.ComWrappersUnwrapper>(__this_native);
@this.Method(out value);
}
catch (System.Exception __exception)
{
System.Runtime.InteropServices.Marshalling.SwallowExceptionMarshaller.ConvertToUnmanaged(__exception);
}
}
}
}