Problems with RLS

[TuurDutoit]

My project is building fine with cargo xbuild as per the instructions. The Rust extension for VSCode - which uses the Rust Language Server - is having a hard time compiling it however, but I managed to fix that so I wanted to document how I did that, in case it can help anyone else.

The initial issue, about the panic_impl being defined twice, was fixed with these instructions I found. With that fixed, another issue popped up about the core crate not being found. This is because the RLS is not using xbuild. However, a workaround is possible because xbuild places the compilation output in the target directory, where a normal Cargo build can find it. I added this comment to the issue above detailing how to go about it.

[phil-opp]

Thank you for sharing your solution! Another way that should also work is to set the RUSTFLAGS environment variable when launching the editor, e.g. RUSTFLAGS="--sysroot /home/…/target/sysroot" code . for VSCode. Then everything should work as normal. (See https://twitter.com/phil_opp/status/1143839524214190080.)

[phil-opp]

I hope that rust-lang/rfcs#2663 makes progess soon, so that the whole cargo-xbuild/xargo wrapper is no longer needed. This should make RLS and rust-analyzer work out of the box, too.