no_std Can't find crate for 'test'

[rubberduck203]

I have a no_std crate that is returning this single error message.
The code builds fine.

{
	"resource": "/Users/rubberduck/src/stm32f3-discovery/src/lib.rs",
	"owner": "rust",
	"code": "E0463",
	"severity": 8,
	"message": "can't find crate for `test`\n\ncan't find crate",
	"source": "rustc",
	"startLineNumber": 1,
	"startColumn": 1,
	"endLineNumber": 1,
	"endColumn": 1,
	"relatedInformation": [
		{
			"startLineNumber": 1,
			"startColumn": 1,
			"endLineNumber": 1,
			"endColumn": 1,
			"message": "can't find crate",
			"resource": "/Users/rubberduck/src/stm32f3-discovery/src/lib.rs"
		}
	]
}

This is the contents of the lib.rs file that is causing the error message.

#![no_std]

pub use stm32f3xx_hal::*;
pub mod leds;

I found these possibly related issues (but I'm doubtful they're actually related).

• Still getting 'can't find crate` error #579
• [regression] can't find crate when crate is referred to via relative path (in a workspace) rls#1409

[imjasonmiller]

Did you manage to solve this? I'm experiencing the same :-) I do notice I'm also using the stm32f3xx_hal crate for what it's worth, although I'm using rust-analyzer with neovim.

[rubberduck203]

No luck so far @imjasonmiller, but I haven’t dug into it.

[imjasonmiller]

@rubberduck203 I solved it in my case — see the linked issue. Hopefully it is of use to you. :-)

[rubberduck203]

Confirmed works. Thanks @imjasonmiller.
Adding the following to .vscode/settings.json fixed it.

{
    "rust.target": "thumbv7em-none-eabihf",
    "rust.all_targets": false
}

[trown]

And for anyone using rust-analyzer + vscode, the .vscode/settings.json is:

{
    "rust-analyzer.cargo.target": "thumbv7em-none-eabihf",
    "rust-analyzer.checkOnSave.allTargets": false
}

Thanks @imjasonmiller

[JohnDowson]

This solution fixes "can't find crate for 'core'" but not "for 'test'".

[andy-preston]

{
    "rust.target": "thumbv7em-none-eabihf",
    "rust.all_targets": false
}

Sadly, this is not working for me. I'm using RLS not rust-analyzer. I'm still getting "can't find crate for test" on my main lib.rs file.

[duskmoon314]

{
    "rust.target": "thumbv7em-none-eabihf",
    "rust.all_targets": false
}

Sadly, this is not working for me. I'm using RLS not rust-analyzer. I'm still getting "can't find crate for test" on my main lib.rs file.

Me too. I'm getting this on my main.rs.

[YoshieraHuang]

{
    "rust.target": "thumbv7em-none-eabihf",
    "rust.all_targets": false
}

Sadly, this is not working for me. I'm using RLS not rust-analyzer. I'm still getting "can't find crate for test" on my main lib.rs file.

Me too. I wonder that it may need another equivelant settings to this in rust-analyzer:

{
    "rust-analyzer.checkOnSave.extraArgs": [
        "--bins"
    ],
}

[asukiaaa]

I cannot resolve error can't find crate for test`` on rust plugin on VSCode.

However I could resolve it with using rust-analyzer plugin on VSCode.
Ref rust-lang/rust-analyzer#3801

I think that configuration for rust-analyzer via the rust-plugin.
Is there any option to resolve the error on the rust-plugin plugin?
(For each actions, I reload the window of VSCode.)

[lnicola]

@asukiaaa if rust-analyzer works, do you have any reason to avoid it?

[asukiaaa]

I can use rust-analyzer plugin with disabling rust-plugin (this plugin) but what the meaning of presence for rust-plugin?

[lnicola]

rust-analyzer will sooner or later replace RLS (and the Rust extension), see also #927.

[asukiaaa]

I see, thank you for the information.

[rishadbaniya]

For people using rust analyzer with coc and neovim, look for coc-settings.json in google for rust analyzer and fill those attributes

[shenshouer]

Confirmed works. Thanks @imjasonmiller. Adding the following to .vscode/settings.json fixed it.

{
    "rust.target": "thumbv7em-none-eabihf",
    "rust.all_targets": false
}

not worked for me ~

[pluveto]

Not working

{
    "rust.target": "riscv64gc-unknown-none-elf",
    "rust.all_targets": false,
}

[cjm571]

Ran into this same issue and was able to fix it by adding the following to my Cargo.toml:

[[bin]]
name = "app"
test = false
bench = false

[BRA1L0R]

Solution for rust-analyzer

Add these lines in .vscode/settings.json:

{
    "rust-analyzer.cargo.target": "thumbv7em-none-eabihf",
    "rust-analyzer.checkOnSave.allTargets": false,
}