Rust Analyzer can't recognize the IUnknown

[Ciantic]

It's very hard to develop on 0.3 since Rust Analyzer can't recognize the IUnknown.

In VSCode settings.json I have this:

{
    "rust-analyzer.procMacro.enable": true
}

And if I write this:

use com::{interfaces, interfaces::iunknown::IUnknown};

fn main() {
    println!("Hello, world!"); 
}

It gives unresolved import:

Yet it builds just fine with cargo build.

I think RLS support is a must, developing without IDE support is pretty difficult, maybe I have misconfigured my setup somehow.

Also from the get-go, I think I don't like the macro approach in 0.3, because I suspect it will break Go to definition etc. IDE features that used to work with trait approach.

[Ciantic]

I've also raised this in Rust Analyzer forums: https://users.rust-lang.org/t/proc-macros-does-not-work-with-com-crate/53731

I can't understand how one can program without intellisense 🙂 I need to get this working.

[MarijnS95]

@Ciantic Afaik this has been working fine in the past, but even going back to rust-analyzer 2020-10-05 shows the same issue. Oddly enough jump-to-symbol works in the webview2 example.

Note that IUnknown is a plain struct here that's not wrapped/generated by proc-macro...

[Ciantic]

Edit I see you managed to repro this with all the way to 2020-10-05? Well something is broken in analyzer in that case.

My repro is here:

https://github.com/Ciantic/rust-analyzer-com-rs-failure/blob/master/src/main.rs

It appears after VSCode has started, it takes like a minute for me to appear.

[rylev]

This was also raised here on Zulip. You'll need to enable both "Load out dirs from check" and "Enable proc macro support".

[Ciantic]

@rylev It didn't work, I added it earlier: https://github.com/Ciantic/rust-analyzer-com-rs-failure/blob/master/.vscode/settings.json

Can you fork my repo and fix the example? I can't figure it out.

[Ciantic]

Uh, looks like my Zulip thing has gone forward more, Jonas Schievink opened an PR rust-lang/rust-analyzer#7171

And commented that

Ah, the problem is that the interfaces! macro collides with the interfaces module, apparently, so I'm assuming the macro expansion fails early on, but works from the IDE later

So maybe it will be fixed in rust-analyzer itself?

[MarijnS95]

Edit I see you managed to repro this with all the way to 2020-10-05? Well something is broken in analyzer in that case.

@Ciantic Yup. Could have been (way) longer since I last actively developed on a crate with com-rs though.

Rebuilt RA at rust-lang/rust-analyzer@861a547 (includes that PR), doesn't solve it (don't think it was intended to, but I have not read into the PR/Zulip yet).