unresolved import for proc-macro generated identifier

[ndmitchell]

In our project we have a bunch of types generated from proc-macros. Recently (probably since #6016) all such imports are flagged as unresolved import. That seems to be an expected consequence. Is there any way to disable such errors, as it makes it vastly harder to see real errors from Rust Analyzer.

[bjorn3]

"rust-analyzer.diagnostics.disabled": ["unresolved-import"] should work I think.

[bjorn3]

Also you can enable proc-macro support using

{
    "rust-analyzer.cargo.loadOutDirsFromCheck": true,
    "rust-analyzer.procMacro.enable": true,
}

[andrewwhitehead]

This just started showing up for me when importing types from the typenum crate. Strangely, if I change it to an unused import (use typenum::U16 when only U32 is referenced), that error seems to take priority over the unresolved type error.

[ecton]

I just started having this show up with use serde_derive::{Serialize, Deserialize}; -- given Serde's popularity, I suspect many others will run into this one, and the main reason for my comment is to try to help make it findable.

@bjorn3's suggestion of enabling procMacro support worked for me to alleviate the issue.

[jonas-schievink]

Is there any way to disable such errors, as it makes it vastly harder to see real errors from Rust Analyzer.

In the settings, add unresolved-import to the list of disabled diagnostics

[Veetaha]

I confirm that proc-macro-derives stopped working for me recently, not sure when exactly, but there should be some definite regression. All the necessary configurations are in place (loadOutDirsFromCheck and procMacro.enable):

[lnicola]

@Veetaha are you using nightly?

[Veetaha]

Yes, I always do

[lnicola]

#5651

Oh, it looks like I need to rebase it.

[suchapalaver]

"rust-analyzer.diagnostics.disabled": ["unresolved-import"] should work I think.

Could somebody tell a noob like me where this should go? I've just been working on a beginner project working with JSON files and my structs all have this proc macro unresolved import message.

[lnicola]

@suchapalaver which editor are you using? In Code, you can put it in settings.json (there's a command to open it).

And can you maybe share your code (or a reduced version) and compiler version?

[suchapalaver]

@lnicola, I'm using Emacs.

≥ rustc --version 11:28 rustc 1.54.0 (a178d0322 2021-07-26)

Here's some code:

use serde::{Deserialize, Serialize};
use std::{fs::{self, File}, io::{self, BufReader, Result}, path::Path};

#[derive(Serialize, Deserialize, Debug)]
pub struct Groceries {
    sections: Vec<Section>,
}
impl Groceries {
    fn write_to_file<P: AsRef<Path>>(groceries: Groceries, path: P) -> Result<()> {
        let json: String = serde_json::to_string(&groceries).unwrap();
	fs::write(path, &json).expect("Unable to write file");
	Ok(())
    }
    fn read_file<P: AsRef<Path>>(path: P) -> Result<Groceries> {
        // Open the file in read-only mode with buffer.
        let reader = BufReader::new(File::open(path).expect("file issue"));
        let groceries: Groceries = serde_json::from_reader(reader).expect("reader issue");
        Ok(groceries)
    }
}

The messages say proc macro 'Deserialize'/'Serialize' not expanded [unresolved-proc-macro].
Thanks for getting back to me!