rust-analyzer can't find Rust source on nightly-2020-07-29

[ivan]

I see

rust-analyzer failed to load workspace: Failed to find sysroot for Cargo.toml file [...]/Cargo.toml. Is rust-src installed?: can't load standard library from sysroot /home/at/.rustup/toolchains/nightly-2020-07-29-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src (discovered via `rustc --print sysroot`) try running `rustup component add rust-src` or set `RUST_SRC_PATH`

with the rust-src component installed on nightly-2020-07-29.

rust-analyzer expects let src_path = sysroot_path.join("lib/rustlib/src/rust/src"); but nightly-2020-07-29 seems to have changed the paths:

/home/at/.rustup/toolchains/nightly-2020-07-28-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/:
total 118,784
-rw-r----- 1 at at 115,526 2020-07-29 21:25 Cargo.lock
drwxr-x--- 1 at at     260 2020-07-29 21:25 src/

/home/at/.rustup/toolchains/nightly-2020-07-29-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/:
total 118,784
-rw-r----- 1 at at 115,526 2020-07-29 21:17 Cargo.lock
drwxr-x--- 1 at at     328 2020-07-29 21:17 library/

# ls -l /home/at/.rustup/toolchains/nightly-2020-07-28-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src
total 0
drwxr-x--- 1 at at  32 2020-07-29 21:25 build_helper/
drwxr-x--- 1 at at 340 2020-07-29 21:25 liballoc/
drwxr-x--- 1 at at 638 2020-07-29 21:25 libcore/
drwxr-x--- 1 at at  32 2020-07-29 21:25 libpanic_abort/
drwxr-x--- 1 at at 128 2020-07-29 21:25 libpanic_unwind/
drwxr-x--- 1 at at  96 2020-07-29 21:25 libproc_macro/
drwxr-x--- 1 at at  48 2020-07-29 21:25 libprofiler_builtins/
drwxr-x--- 1 at at 534 2020-07-29 21:25 libstd/
drwxr-x--- 1 at at  60 2020-07-29 21:25 libterm/
drwxr-x--- 1 at at 250 2020-07-29 21:25 libtest/
drwxr-x--- 1 at at  72 2020-07-29 21:25 libunwind/
drwxr-x--- 1 at at 234 2020-07-29 21:25 stdarch/
drwxr-x--- 1 at at 144 2020-07-29 21:25 tools/
# ls -l /home/at/.rustup/toolchains/nightly-2020-07-29-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library
total 0
drwxr-x--- 1 at at  50 2020-07-29 21:17 alloc/
drwxr-x--- 1 at at  50 2020-07-29 21:17 core/
drwxr-x--- 1 at at  26 2020-07-29 21:17 panic_abort/
drwxr-x--- 1 at at  26 2020-07-29 21:17 panic_unwind/
drwxr-x--- 1 at at  36 2020-07-29 21:17 proc_macro/
drwxr-x--- 1 at at  42 2020-07-29 21:17 profiler_builtins/
drwxr-x--- 1 at at  36 2020-07-29 21:17 rtstartup/
drwxr-x--- 1 at at  32 2020-07-29 21:17 rustc-std-workspace-alloc/
drwxr-x--- 1 at at  50 2020-07-29 21:17 rustc-std-workspace-core/
drwxr-x--- 1 at at  50 2020-07-29 21:17 rustc-std-workspace-std/
drwxr-x--- 1 at at  66 2020-07-29 21:17 std/
drwxr-x--- 1 at at 234 2020-07-29 21:17 stdarch/
drwxr-x--- 1 at at  26 2020-07-29 21:17 term/
drwxr-x--- 1 at at  26 2020-07-29 21:17 test/
drwxr-x--- 1 at at  42 2020-07-29 21:17 unwind/

[jonas-schievink]

I was wondering why it stopped resolving std paths... Fallout from rust-lang/rust#73265

[jonas-schievink]

Hmm, this still seems to be broken when editing on rustc

[lnicola]

Do you think that's related to this issue or to the fix in #5586? I'm not sure how it finds the rust-lang/rust stdlib.

[jonas-schievink]

Not sure either, I haven't looked into this yet. There's no error message from rust-analyzer though.

[jonas-schievink]

Ah, looks like this was a local problem. I had RUST_SRC_PATH set to src in my Rust checkout.