interface macro should implement IntoParam

[MolotovCherry]

Some methods have signatures like

windows::Windows::Win32::System::Wmi::IUnsecuredApartment
pub unsafe fn CreateObjectStub<'a, Param0>(&self, pobject: Param0) -> ::windows::core::Result<::windows::core::IUnknown>
where
    Param0: ::windows::core::IntoParam<'a, ::windows::core::IUnknown>,

Where the current custom interfaces defined using #[interface] cannot be sent as a parameter to this since they don't seem to implement IntoParam. It would be convenient if they implemented this so they can be easily passed to functions that require it.

Workaround isn't super difficult, something like this works
pUnsecApp.CreateObjectStub::<IUnknown>(event_sink.into())

[kennykerr]

Yes that's missing. Thanks for the reminder. @rylev is still working on that macro.

[kennykerr]

Correction, this seems to work. Here's a complete repro:

[dependencies.windows]
version = "0.34"
features = [
    "implement",
    "interface",
    "Win32_System_WinRT",
]

use windows::{core::*, Win32::System::WinRT::*};

#[interface("bdbec94c-ae60-49e3-894f-009b1ce9af71")]
pub unsafe trait ISample: IUnknown {
    unsafe fn method(&self);
}

#[implement(ISample)]
struct Sample();

impl ISample_Impl for Sample {
    unsafe fn method(&self) {}
}

fn main() {
    let sample: ISample = Sample().into();
    unsafe {
        let _ = RoGetAgileReference(AGILEREFERENCE_DEFAULT, &IUnknown::IID, sample);
    }
}

[MolotovCherry]

Just saw this on Ryan's PR. My title was incorrect, I should have said #[implement()], not interface (but this point is invalid anyways, as that's not the right way to do it). That looks good 👍🏻