[INFO] updating cached repository PurpleMyst/purple
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/PurpleMyst/purple
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/PurpleMyst/purple" "work/ex/beta-1.38-1/sources/1.37.0/gh/PurpleMyst/purple"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/PurpleMyst/purple'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/PurpleMyst/purple" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/PurpleMyst/purple"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/PurpleMyst/purple'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 49ee01126bde7cb9542c0a03bed802214c27c459
[INFO] sha for GitHub repo PurpleMyst/purple: 49ee01126bde7cb9542c0a03bed802214c27c459
[INFO] validating manifest of PurpleMyst/purple 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 PurpleMyst/purple 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 PurpleMyst/purple
[INFO] finished frobbing PurpleMyst/purple
[INFO] frobbed toml for PurpleMyst/purple written to work/ex/beta-1.38-1/sources/1.37.0/gh/PurpleMyst/purple/Cargo.toml
[INFO] started frobbing PurpleMyst/purple
[INFO] finished frobbing PurpleMyst/purple
[INFO] frobbed toml for PurpleMyst/purple written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/PurpleMyst/purple/Cargo.toml
[INFO] crate PurpleMyst/purple 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]     Updating git repository `https://github.com/TheDan64/inkwell`
[INFO] [stderr] error: failed to load source for a dependency on `inkwell`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   Unable to update https://github.com/TheDan64/inkwell?branch=llvm7-0#54d7a90c
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   revspec '54d7a90c264776f593515c81f08a490a04efe8a6' not found; class=Reference (4); code=NotFound (-3)
[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