I was investigating a high memory usage on sccache rust compilation part and I came accross a failure in the build log

At first I assumed it was just a byproduct of configure step, but it looks like -Z ls changes in rust-lang/rust@ff00763#diff-03c3ed2f6e27e58df63382e00323eea6fd1ce3a4f9546941b2b717fead25e520

One might need to update to -Z ls=root.