Unknown types in web-sys dependency

[eminence]

(I suspect this is a duplicate, but i'm not sure what the root cause is).

I'm trying to use the web-sys crate, which is highly generated.

I've enabled both loadOutDirsFromCheck and procMacro.enable:

.vscode/settings.jon

{
    "rust-analyzer.cargo.loadOutDirsFromCheck": true,
    "rust-analyzer.procMacro.enable": true,
    "editor.tokenColorCustomizationsExperimental": {
        "unresolvedReference": "#FF0000"
    }
}

Cargo.toml

[package]
name = "foo"
version = "0.1.0"
authors = ["Andrew Chin <achin@eminence32.net>"]
edition = "2018"

[dependencies.web-sys]
version = "0.3"
features = ["Document", "Window"]

Code:

use web_sys::{Document, Window};

pub fn foo() {
    let win: Window = web_sys::window().unwrap();
    let doc: Document = win.document().unwrap();
}

Using RA nightly (fe99a29)

Thanks!

[flodiebold]

Are you using the weekly build? All these definitions are in extern "C" blocks, which we ignored until a few days ago. Apart from that, proc macro support is of course still very experimental and web_sys makes very heavy use of proc macros.

[eminence]

I am using the nightly build (fe99a29). (Sorry, that was an important detail I should not have omitted)

[edwin0cheng]

For example, Here is how web-sys implement Window type. It seem like there is something we are still not yet implemented in RA :

1. proc-macro for custom-attribues (#[wasm_bindgen]), we only support custom-derive now.
2. Extern Type : extern "C" { pub type Window; }

[matklad]

extern "C should be handled by #4111. Though, not sure about extern "C" { pub type Window; }. Opaque types are unstable?

[flodiebold]

It probably gets turned into something different by the macro?

[edwin0cheng]

rust-lang/rust#44295

And we didn't expand it because no custom attr proc-macro support yet. But I doubt if extern types are supported in RA, it might be infered properly ?

[danbrodsky]

Not to hijack but I'm having similar issues with both go-to-definition and completion for the web-sys crate. doing web_sys::ge[completion here] correctly shows completions for web-sys functions but doing something like let canvas = <some web-sys object>; canvas.ge[completion here] does not. I'm using emacs with lsp and have the following set:

        lsp-rust-analyzer-cargo-load-out-dirs-from-check t
        lsp-rust-analyzer-proc-macro-enable t

[crlf0710]

Extern opaque types are supported by chalk now. Hopefully this will help with this issue.

[eminence]

Cool, that helps a bit!

Using the latest commit (60c8941), the Document and Window types are now resolved, though RA still doesn't know about the methods on them:

Edit: Actually, the upgraded chalk isn't in RA head yet, so the above improvements came from elsewhere... Sorry for the noise!

[crlf0710]

I gave adding support for extern opaque types a try in #5993 .

[crlf0710]

That PR has landed. But that didn't help web-sys much. If web-sys was using genuine extern opaque type syntax as input to macros (e.g. impl blocks etc) the issue would have been solved. It seems we need to improve proc macro support next. I'll look into what i can do to help.