[INFO] updating cached repository kentfredric/powerctl
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/kentfredric/powerctl
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/kentfredric/powerctl" "work/ex/beta-1.38-1/sources/1.37.0/gh/kentfredric/powerctl"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/kentfredric/powerctl'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/kentfredric/powerctl" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/kentfredric/powerctl"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/kentfredric/powerctl'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 631c2cbe244ee5937cf38c93e2dd70051860636b
[INFO] sha for GitHub repo kentfredric/powerctl: 631c2cbe244ee5937cf38c93e2dd70051860636b
[INFO] validating manifest of kentfredric/powerctl on toolchain 1.37.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of kentfredric/powerctl on toolchain beta-2019-08-13
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing kentfredric/powerctl
[INFO] finished frobbing kentfredric/powerctl
[INFO] frobbed toml for kentfredric/powerctl written to work/ex/beta-1.38-1/sources/1.37.0/gh/kentfredric/powerctl/Cargo.toml
[INFO] started frobbing kentfredric/powerctl
[INFO] finished frobbing kentfredric/powerctl
[INFO] frobbed toml for kentfredric/powerctl written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/kentfredric/powerctl/Cargo.toml
[INFO] crate kentfredric/powerctl already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr] error: failed to run `rustc` to learn about target-specific information
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustc - --crate-name ___ --print=file-names -C relocation-model=pic -W absolute-paths-not-starting-with-crate -W anonymous-parameters -W bare-trait-objects -W deprecated-in-future -W elided-lifetimes-in-paths -W ellipsis-inclusive-range-patterns -W explicit-outlives-requirements -W future-incompatible -W keyword-idents -W macro-use-extern-crate -W missing-debug-implementations -W nonstandard-style -W private-doc-tests -W question-mark-macro-sep -W rust-2018-compatibility -W rust-2018-idioms -W rustdoc -W single-use-lifetimes -W trivial-numeric-casts -W unreachable-pub -W unsafe-code -A unstable-features -W unused -W unused-extern-crates -W unused-import-braces -W unused-labels -W unused-lifetimes -W unused-qualifications -W unused-results -W variant-size-differences -W warnings -Z strip-debuginfo-if-disabled=yes -Z mir-opt-level=1 --target x86_64-unknown-linux-gnu --crate-type bin --crate-type rlib --crate-type dylib --crate-type cdylib --crate-type staticlib --crate-type proc-macro` (exit code: 1)
[INFO] [stderr] --- stderr
[INFO] [stderr] error: the option `Z` is only accepted on the nightly compiler
[INFO] [stderr] 
[INFO] [stderr] 
[ERROR] this task or one of its parent failed!
[ERROR] command `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"` failed