In a previous post I shared how I set up the nix home-manager on linux. Now I had the problem that I wanted to make the rust-analyzer work properly in VSCode. Yes, for some reason, just adding the packages to home.nix packages like
{ lib, pkgs, ... }:
{
...
nix = {
package = pkgs.nix;
settings.experimental-features = [ "nix-command" "flakes" ];
};
home = {
packages = with pkgs; [
cargo
rustc
rustfmt
];
};
}
as one may think reading the NixOS rust wiki page does not actually work. I mean, not that they have a home-manager flakes example, but that was my best guess based on what I’ve read there. So using this guess, you can successfully run home-manager switch ... and develop rust code, but then VSCode’s rust extension with rust-analyzer gives you a lovely
error[E0463]: can't find crate for `core`
|
= note: the `aarch64-apple-darwin` target may not be installed
= help: consider downloading the target with `rustup target add aarch64-apple-darwin`
error[E0463]: can't find crate for `compiler_builtins`
error[E0463]: can't find crate for `core`
Which is not super helpful besides indicating it cannot find something it should. As a matter of fact it fails to find any rust standard / core source code, quite annoying to develop without hints based on that.
Well how to fix it?
It turns out you need to explicitly tell nix to set RUST_SRC_PATH, update your config and then restart VSCode. An abbreviated version of what I have found working is the following home.nix file
{ lib, pkgs, ... }:
{
nix = {
package = pkgs.nix;
settings.experimental-features = [ "nix-command" "flakes" ];
};
home = {
packages = with pkgs; [
# rust: https://discourse.nixos.org/t/rust-src-not-found-and-other-misadventures-of-developing-rust-on-nixos/11570/8
pkgs.latest.rustChannels.stable.rust
pkgs.latest.rustChannels.stable.rust-src
];
sessionVariables= {
RUST_SRC_PATH="${pkgs.latest.rustChannels.stable.rust-src}/lib/rustlib/src/rust/library/"; # <---- important
};
# snip
};
# snip
}
The above probably also works with rust-bin or alternatives as well, I just stopped iterating.
Hope this helps!
Datamuncher 