Rust-analyzer stops working with build-std - Solved

[sfbea]

Hi, hope this is the correct place for this:

I'm trying to a work on a project that requires a custom platform; thus build-std is required. Once I put

[unstable]
build-std-features = ["compiler-builtins-mem"]
build-std = ["core", "compiler_builtins", "alloc"]

into .cargo/config.toml and reload VS Code, rust-analyzer fails during/after 'Indexing' and the VS Code button for rust-analyzer in the status bar goes faded-yellow with a small warning symbol, and the mouse-over dialogue says

undefined
Click to reload.

Static analysis would not work while rust-analyzer was in this state (type annotations would be displayed though in some instances).

I was able to reproduce this bug consistently by creating a new folder, cargo init-ing it, add the config file, and launch VS Code in the project dir.

I am using Windows 10, with rust nightly (for the build-std support). I haven't found anything online though and I presume a bug like this would be noticed quickly thus I presume their may be something else awry, if any more information is needed, ask away.

[chrisd]

Just to be clear, does everything else work? E.g. running cargo check?

In any case, you can probably get more detailed error information by going to View -> Output and selecting "Rust Analyzer Language Server" from the drop down list.

[sfbea]

Hi, thanks for the quick response!

cargo check turned up nothing unexpected, however, viewing the output of RALS did indicate the problem:

[ERROR rust_analyzer::reload] failed to switch build data: rust-analyzer failed to run build scripts:
error: -Zbuild-std requires --target

I added this to my config file and it worked:

[build]
target = "x86_64-unknown-uefi.json"

Thank you very much, I was unaware I could access output from VS Code extensions.
Have a good day further.

Edit: should I mark this as the solution?

[chrisd]

@sfbea

Edit: should I mark this as the solution?

Definitely!