Native diagnostics do not respect workspace check setting

[my4ng]

rust-analyzer version: rust-analyzer version: 0.3.2379-standalone (8365cf8 2025-04-13)
rustc version: rustc 1.86.0 (05f9846f8 2025-03-31)

editor or extension: VSCode 0.3.2379

relevant settings: .vscode/settings.json:

{
    "rust-analyzer.cargo.features": ["foo"],
    "rust-analyzer.check.workspace": false,
    "rust-analyzer.cargo.extraArgs": ["-p", "foobar"],
}

repository link (if public, optional): https://github.com/my4ng/foobar

In this minimal example, the workspace contains foobar and bart packages, where bart depends on foobar with feature bar. The rust-analyzer setting aims to only check foobar with feature foo (disabled workspace). However, the native diagnostics give the error:

bar is here! rust-analyzer(macro-error)

[{
	"resource": "/home/my4ng/Programming/foobar/src/main.rs",
	"owner": "rust-analyzer",
	"code": {
		"value": "macro-error",
		"target": {
			"$mid": 1,
			"path": "/manual.html",
			"scheme": "https",
			"authority": "rust-analyzer.github.io",
			"fragment": "macro-error"
		}
	},
	"severity": 8,
	"message": "bar is here!",
	"source": "rust-analyzer",
	"startLineNumber": 6,
	"startColumn": 1,
	"endLineNumber": 6,
	"endColumn": 14
}]

Indeed "rust-analyzer.diagnostics.enable": false will disable the diagnostics error. It is also distinct from a rustc error if, for example, the workspace setting is true.

[ChayimFriedman2]

Native diagnostics do not, and will not, respect rust-analyzer.check.workspace, if only for the simple fact that they only work for open files, so this setting has no meaning for them. They trigger here because the feature is active, as feature unification in a workspace takes place.

Maybe you can mess with the cfgs directly (not sure if it'll work) by setting "rust-analyzer.cargo.cfgs": ["!feature=bar"].

[my4ng]

Native diagnostics do not, and will not, respect rust-analyzer.check.workspace, if only for the simple fact that they only work for open files, so this setting has no meaning for them. They trigger here because the feature is active, as feature unification in a workspace takes place.

Thanks for the clarification, that makes sense. In my use case, the workspace has several packages that depend on the main library on mutually exclusive features. Is it possible to configure the feature unification on a per-package basis?

[ChayimFriedman2]

No. This is fundamentally impossible. rust-analyzer operates with one set of cfgs.

You can open multiple workspaces.

[ChayimFriedman2]

An alternative, assuming you control the macro, is to mark the compile_error! invocation as #[cfg(not(rust_analyzer))].