How to activate unstable feature restricted_std in rust-analyzer?

[lattice0]

rust-analyzer version:
0.3.1791-standalone

rustc version: rustc 1.77.0-nightly (fb5ed726f 2023-12-28)

relevant settings: (eg. client settings, or environment variables like CARGO, RUSTC, RUSTUP_HOME or CARGO_HOME)

I'm trying to compile for esp32c6 (riscv32imac-unknown-none-elf). Actually, cargo build runs, but when I save the file rust-analyzer checks it and complains:

error[E0658]: use of unstable library feature 'restricted_std'
   --> /home/lz/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/test/src/formatters/json.rs:225:55
    |
225 |     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> ::std::fmt::Result {
    |                                                       ^^^^^^^^^^^^^^^^^^
    |
    = help: add `#![feature(restricted_std)]` to the crate attributes to enable

As you see, it's complaining about a feature in the std lib, which is strange. I added #![feature(restricted_std)] to main.rs but the error is in the standard library where I cannot add this feature.

I also tried

{
    "rust-analyzer.cargo.cfgs": {
        "build-std": ["core", "std", "alloc", "panic_abort"],
        "restricted_std": true
    },
    "rust-analyzer.check.allTargets": false,
    "rust-analyzer.cargo.target": "riscv32imac-unknown-none-elf"
}

and other variations without success. Also tried

[unstable]
features = ["restricted_std"]

in rust-analyzer.toml.

Also

~/project1$ rustup toolchain install riscv32imac-unknown-none-elf
error: invalid toolchain name: 'riscv32imac-unknown-none-elf'

[Veykril]

In what editor is this? It looks like rust-analyzer is trying to compile the standard library for you here which might be an issue with how the editor reports the workspaces.

[lattice0]

It's vscode. Any idea on how I can switch this?

…

-------- Mensagem Original -------- Em 3 de jan. de 2024, 07:00, Lukas Wirth escreveu:

In what editor is this? It looks like rust-analyzer is trying to compile the standard library for you here which might be an issue with how the editor reports the workspaces. — Reply to this email directly, [view it on GitHub](#16232 (comment)), or [unsubscribe](https://github.com/notifications/unsubscribe-auth/ABSTHAKWGGULC2OHYVTO3YTYMUT4ZAVCNFSM6AAAAABBKZA6JCVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTQNZVGEYTAMRUGU). You are receiving this because you authored the thread.Message ID: ***@***.***>

[lnicola]

rustup toolchain install riscv32imac-unknown-none-elf

rustup +nightly target add riscv32imac-unknown-none-elf

[lnicola]

riscv32imac-unknown-none-elf is a no-std target, does "build-std": ["core", "std", "alloc", "panic_abort"] even work there?

[mohe2015]

You could try the equivalent cargo build including the correct target and using -Zbuild-std to check whether this is a rust analyzer issue.

[mohe2015]

Maybe this is rust-lang/wg-cargo-std-aware#87 so you forgot #![no_std] ?

[lattice0]

@mohe2015 it builds and runs with ˋcargo buildˋ and no ˋ#![no_std]ˋ so I guess no? I actually want to use the std lib. But yeah I added ˋ#![feature(restricted_std)]
#![no_main]ˋ so I could do ˋcargo buildˋ or ˋcargo runˋ etc. How can it work on the command line and not rust-analyzer?

Also @lnicola your suggestion:

rustup +nightly target add riscv32imac-unknown-none-elf
info: component 'rust-std' for target 'riscv32imac-unknown-none-elf' is up to date

[mohe2015]

Is the rust analyzer config to enable build std correct? I'm not sure whether it accepts the build std at that location because I couldn't find any docs and can't test right now

[mohe2015]

Maybe https://users.rust-lang.org/t/rust-analyzer-stops-working-with-build-std-solved/64333 helps

[lattice0]

Ok, if I understood correctly, I'm trying to build, in rust-analyzer, with std, but I actually can only build with restricted_std, for my target. Is this correct? So rust-analyzer does not know what is my target and therefore tries to use std.

[mohe2015]

Ok, if I understood correctly, I'm trying to build, in rust-analyzer, with std, but I actually can only build with restricted_std, for my target. Is this correct? So rust-analyzer does not know what is my target and therefore tries to use std.

Your target does not support std so I personally would add #![no_std] and disable all std features of dependencies. rust-lang/wg-cargo-std-aware#87 is the issue that wants to improve the error message.
See https://github.com/mohe2015/rust-analyzer-issue-16232/tree/main especially the .cargo/config.toml, .vscode/settings.json and src/main.rs.

[lattice0]

But it supports restricted_std because it works with cargo build, just not in rust-analyzer. Am I right?

…

-------- Mensagem Original -------- Em 19 de jan. de 2024, 10:21, Moritz Hedtke escreveu:

> Ok, if I understood correctly, I'm trying to build, in rust-analyzer, with std, but I actually can only build with restricted_std, for my target. Is this correct? So rust-analyzer does not know what is my target and therefore tries to use std. Your target does not support std so I personally would add #![no_std] and disable all std features of dependencies. [rust-lang/wg-cargo-std-aware#87](rust-lang/wg-cargo-std-aware#87) is the issue that wants to improve the error message. See https://github.com/mohe2015/rust-analyzer-issue-16232/tree/main especially the .cargo/config.toml, .vscode/settings.json and src/main.rs. — Reply to this email directly, [view it on GitHub](#16232 (comment)), or [unsubscribe](https://github.com/notifications/unsubscribe-auth/ABSTHAKHEQFEFRV7VYSFPLTYPJXNFAVCNFSM6AAAAABBKZA6JCVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTSMBQGQYTOMZSGE). You are receiving this because you authored the thread.Message ID: ***@***.***>

[mohe2015]

Yeah with cargo it works just not in rust-analyzer. I think I found the issue. I think rust-analyzer sets the build-std "test" because the commit mohe2015/rust-analyzer-issue-16232@143d64a makes it work for cargo but not rust-analyzer and before it's broken for both.

[lattice0]

@mohe2015 are you going to merge this?

[mohe2015]

@mohe2015 are you going to merge this?

It's not a commit in rust-analyzer but only in my test project (https://github.com/mohe2015/rust-analyzer-issue-16232/commits/restricted-std). It's also just an assumption what may happen. Somebody would need to find out whether that's actually the case and where in rust analyzer this is set for the project and fix it there. I currently don't have the time to do that.

[lattice0]

@mohe2015 yes. Unfortunately I'm on vscode.dev so it's a bit hard to compile my own. Any ideas on how to mitigate this with configurations?

[jakzale]

I am having a similar issue, while also targeting a variant of riscv32, which doesn't have std available.

I noticed that setting rust-analyzer.check.allTargets to false in .vscode/settings.json gives me diagnostic for my code, whereas setting it to true, doesn't give me any diagnostics.

I know that running cargo check --workspace --all-targets will fail on my codebase with

• similar errors to error reported by the OP, and
• those errors are not related to my codebase or my dependencies, because
• those errors happen in .rustup/toolchain/<toolchain>/lib/rustlib/src/rust/library/test/src/lib.rs.

which seems to cause rust-analyzer to fail silently, as there is no diagnostic message produced on saving source files.

Regarding the errors that are reported, as of current prerelease of rust-analyzer (rust-analyzer 1.79.0-nightly (0ad927c0 2024-03-21)), they occur once, when the server is reloaded, and the are prefixed with

2024-03-25T15:16:50.782873Z ERROR rust_analyzer::main_loop: FetchBuildDataError:
error[E0658]: use of unstable library feature 'restricted_std'
  |
  = help: add `#![feature(restricted_std)]` to the crate attributes to enable
  = note: this compiler was built on 2024-03-09; consider upgrading it if it is out of date

It looks like the reported error is related to a different step within rust-analyzer, that is happening before cargo check.

I suspect that there might be two separate bugs here

• rust-analyzer using incorrect configuration immediately after server is reloaded, and
• rust-analyzer failing silently when default cargo check fails due to compilation errors unrelated to the project.

[Veykril]

Yes for htese projects you should set .check/build.allTargets to false as otherwise our cargo invocations try to build test targets which require the standard library. We are doing a bad job at telling the user about that as is evident here.

Note that for the FetchBuildDataError we surface that in the status icon (which is not necessarily supported by all clients).

[jakzale]

Yes for htese projects you should set .check/build.allTargets to false as otherwise our cargo invocations try to build test targets which require the standard library. We are doing a bad job at telling the user about that as is evident here.

I don't think you expose .build.allTargets configuration key in VSCode. Neither the Manual mentions it.

Note that for the FetchBuildDataError we surface that in the status icon (which is not necessarily supported by all clients).

Yeah, noticed that in VSCode.

[Veykril]

Ah right, #16924 hasn't been merged yet. So we'll expose that soon

[jakzale]

I confirm that #16924 solves the issue for me. Just need to put

{
  "rust-analyzer.cargo.allTargets": false,
}

in .vscode/settings.json.