extraEnv in rust-anaylzer to define rustflags

[tomocrafter]

Check for existing issues

• Completed

Describe the feature

In vscode version rust-analyzer, you can specify env in rust-analyzer.cargo.extraEnv to define rustflags to be used while analyzing workspace.

How can I specify rustflags in zed?

https://rust-analyzer.github.io/manual.html

If applicable, add mockups / screenshots to help present your vision of the feature

No response

[SomeoneToIgnore]

Zed uses something similar but with a more convoluted syntax due to historic reasons unfortunately.
https://zed.dev/docs/languages/rust has some examples, and similar section could be created for cargo.

[notpeter]

@SomeoneToIgnore Is there any way to define rustflags for rust-analyzer.server.extraEnv or rust-analyzer.cargo.extraEnv currently?

[SomeoneToIgnore]

No clue.

[djmaze]

This prevents working on wasm projects which use the web_sys_unstable_apis flag, because the analyzer bails out on the use of those unstable features / classes.

[djmaze]

Okay, I could make it work by setting the correct RUSTFLAGS as an env variable in the terminal and then starting zed from there.

(To be more precise, I was using a shell.nix which sets up the environment. I added a setting for RUSTFLAGS there.)

[aurexav]

I simply adhere to the format and import the VSCode configuration. It appears to function correctly.

"lsp": {
	"rust-analyzer": {
		"initialization_options": {
			"cargo": {
				"buildScripts": {
					"enable": false
				}
			},
			"check": {
				"command": "clippy",
				"features": "all"
			},
			"checkOnSave": false,
			"completion": {
				"autoimport": {
					"enable": false
				}
			},
			"diagnostics": {
				"enable": false
			},
			"lens": {
				"debug": {
					"enable": false
				}
			},
			"notifications": {
				"cargoTomlNotFound": false
			},
			"rustfmt": {
				"extraArgs": ["+nightly"]
			}
		}
	}
},

[Noah-Kennedy]

I'm running into this while trying to work on tokio in Zed. I need to work on stuff with --cfg tokio_unstable, and am having trouble getting rust-analyzer to be passed that environment variable.

Is it possible to do this, or will I need to avoid zed for now when developing on tokio?

[osiewicz]

@Noah-Kennedy we seem to use tokio_unstable ourselves with config.toml

zed/.cargo/config.toml

Line 3 in fef567b

rustflags = ["-C", "symbol-mangling-version=v0", "--cfg", "tokio_unstable"]

; I haven't heard any complaints from my peers, so maybe you could give that a go?

[Noah-Kennedy]

@Noah-Kennedy we seem to use tokio_unstable ourselves with config.toml

zed/.cargo/config.toml

Line 3 in fef567b
rustflags = ["-C", "symbol-mangling-version=v0", "--cfg", "tokio_unstable"]
; I haven't heard any complaints from my peers, so maybe you could give that a go?

It doesn't work for me, not sure why.

I still get rust-analyzer: code is inactive due to #[cfg] directives: tokio_unstable is disabled

[Noah-Kennedy]

I have gotten this on three different computers while using .cargo/config.toml to specify the relevant RUSTFLAGS invocations.