INetFwAuthorizedApplications fails to return _NewEnum and type returned appears incorrect

[fgimian]

Actual behavior

Calling the _NewEnum method on an instance of INetFwAuthorizedApplications fails with the following exception:

Unhandled exception. System.Runtime.InteropServices.InvalidOleVariantTypeException: Specified OLE variant is invalid.
   at System.StubHelpers.ObjectMarshaler.ConvertToManaged(IntPtr pSrcVariant)
   at Windows.Win32.NetworkManagement.WindowsFirewall.INetFwAuthorizedApplications.get__NewEnum()
   at Fires.Program.Main() in C:\Users\Fots\source\Firewallcs\Program.cs:line 12

The source generated also suggests it returns an object when I think it should either be IUnknown (which can be cast to IEnumVARIANT) or IEnumVARIANT directly.

This all works perfectly in windows-rs (see below for equivalent code).

Expected behavior

I expect to be able to retrieve the _NewEnum so I can iterate through the collection.

Repro steps

1. NativeMethods.txt content:

INetFwMgr
NetFwMgr
IEnumVARIANT
NetFwAuthorizedApplication

2. NativeMethods.json content (if present):

N/A

3. Any of your own code that should be shared?

using Windows.Win32.NetworkManagement.WindowsFirewall;
using Windows.Win32.System.Ole;

namespace Firewallcs;

internal class Program
{
    static void Main()
    {
        var fwMgr = (INetFwMgr)new NetFwMgr();
        var authorizedApplications = fwMgr.LocalPolicy.CurrentProfile.AuthorizedApplications;
        var applicationsEnum = authorizedApplications._NewEnum;
    }
}

Here's the equivalent in Rust...

Cargo.toml

[package]
name = "firewall"
version = "0.1.0"
edition = "2021"

[dependencies]
windows-result = "0.2.0"

[dependencies.windows]
version = "0.58.0"
features = [
    "Win32_System_Com",
    "Win32_System_Ole",
    "Win32_NetworkManagement_WindowsFirewall",
]

main.rs

use std::iter;

use windows::{
    core::{Interface as _, VARIANT},
    Win32::{
        NetworkManagement::WindowsFirewall::{INetFwAuthorizedApplication, INetFwMgr, NetFwMgr},
        System::{
            Com::{CoCreateInstance, CoInitialize, IDispatch, CLSCTX_INPROC_SERVER},
            Ole::IEnumVARIANT,
        },
    },
};
use windows_result::Result;

fn main() -> Result<()> {
    unsafe {
        CoInitialize(None).ok()?;

        let firewall_manager: INetFwMgr = CoCreateInstance(&NetFwMgr, None, CLSCTX_INPROC_SERVER)?;
        let current_profile = firewall_manager.LocalPolicy()?.CurrentProfile()?;
        let authorized_applications = current_profile.AuthorizedApplications()?;

        let applications_enum = authorized_applications._NewEnum()?;
        let applications_enum = applications_enum.cast::<IEnumVARIANT>()?;
        applications_enum.Reset()?;

        let mut variants = iter::repeat(VARIANT::default())
            .take(authorized_applications.Count()? as usize)
            .collect::<Vec<VARIANT>>();
        let mut count = 0;
        applications_enum.Next(&mut variants, &mut count).ok()?;

        for variant in variants {
            let dispatch = IDispatch::try_from(&variant)?;
            let app = dispatch.cast::<INetFwAuthorizedApplication>()?;
            println!(
                "- Name: {}, Enabled: {}, RemoteAddresses: {}",
                app.Name()?,
                app.Enabled()?.as_bool(),
                app.RemoteAddresses()?
            );
            println!(
                "  Scope: {:?}, ProcessImageFileName: {}, IpVersion: {:?}",
                app.Scope()?,
                app.ProcessImageFileName()?,
                app.IpVersion()?
            );
        }
    }

    Ok(())
}

Context

• CsWin32 version: [e.g. 0.4.422-beta]: 0.3.106
• Win32Metadata version (if explicitly set by project): N/A
• Target Framework: [e.g. netstandard2.0]: net8.0-windows
• LangVersion (if explicitly set by project): [e.g. 9]: N/A

Thanks a lot in advance!
Fotis