Support Goto Definition into `include!`

[cynecx]

settings.json (vscode):

{
    "rust-analyzer.cargoFeatures.loadOutDirsFromCheck": true,
}

rust-analyzer: 1c2d4135db867efe335a0654d86429bea7bb9caf (current master)

How to reproduce:

1. Add lapin = { version = "0.34" } to your deps.
2. Use this code snippet:

use lapin::{
    message::Delivery,
    options::{BasicAckOptions, BasicConsumeOptions, BasicRejectOptions},
    types::FieldTable,
    Connection, ConnectionProperties,
};

BasicAckOptions, BasicConsumeOptions and BasicRejectOptions come from proc-macro. "Go to definition" doesn't work on them. It works but redirects you a wrong source-site.

[edwin0cheng]

Goto definition do not work in include! macro yet. Do completion show them correctly ?

[cynecx]

Oh, I see. Yes, completions do work. Is there an already opened issue for that? (So I might close this one.)

[edwin0cheng]

@cynecx This is the first issue for that :)

[cynecx]

@edwin0cheng ~~I am currently on master. And it seems that it's broken (In terms of it doesn't even find/resolve items). I am not quite sure when it broke though. I haven't realized since today when I came across this again.~~

Nevermind, it seems that the option changed from rust-analyzer.cargoFeatures.loadOutDirsFromCheck to rust-analyzer.cargo.loadOutDirsFromCheck.

[fahrradflucht]

Maybe we update the title? I was about to open an issue for include! macros not being followed for goto definition.

[mvtec-bergdolll]

What is missing for this to be supported?

[matklad]

@mvtec-bergdolll I think it's not so much "anything missing", but rather "we need to redesign one of our core abstractions to support this at all". See https://github.com/rust-lang/rust-analyzer/issues/9403.

[g0hl1n]

This would make life a lot easier when working with tonic in vscode. Any ETA for a fix or any workarounds anybody is aware of?

[sebpuetz]

[...] any workarounds anybody is aware of?

It's a bit hacky and brittle but you can set the output path for the generated Rust files

    tonic_build::configure()
        .out_dir("src/") // put the generated files under src/, could be a nested directory like src/proto, too.
        .compile(&["./protobuf.proto"], &["./"])

and include the generated file like a regular module:

// lib.rs
mod protobuf;

If your CI runs cargo fmt / rustfmt, you'll probably want ot run rustfmt on the generated files since tonic_build / prost don't format the code.

[bjorn3]

If you put that in build.rs you need to be aware that cargo prevents publishing crates if it detects that building them changes their source code.

[sebpuetz]

Publishing should work by adding a feature gate to the code gen (and running rustfmt), e.g. lapin has a code gen feature: https://github.com/amqp-rs/lapin/blob/main/build.rs#L1-L7

with code gen turned off by default: https://github.com/amqp-rs/lapin/blob/main/Cargo.toml#L18

(I have no experience with publishing the workaround through cargo, so this is speculation on my end)

[jonas-schievink]

@rustbot claim