[INFO] updating cached repository marvelm/rivets
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/marvelm/rivets
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/marvelm/rivets" "work/ex/beta-1.38-1/sources/1.37.0/gh/marvelm/rivets"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/marvelm/rivets'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/marvelm/rivets" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/marvelm/rivets"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/marvelm/rivets'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 9ee5a9736589719b05a35a1c25044a366ae72d53
[INFO] sha for GitHub repo marvelm/rivets: 9ee5a9736589719b05a35a1c25044a366ae72d53
[INFO] validating manifest of marvelm/rivets 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 marvelm/rivets 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 marvelm/rivets
[INFO] finished frobbing marvelm/rivets
[INFO] frobbed toml for marvelm/rivets written to work/ex/beta-1.38-1/sources/1.37.0/gh/marvelm/rivets/Cargo.toml
[INFO] started frobbing marvelm/rivets
[INFO] finished frobbing marvelm/rivets
[INFO] frobbed toml for marvelm/rivets written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/marvelm/rivets/Cargo.toml
[INFO] crate marvelm/rivets 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: the lock file /mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/marvelm/rivets/Cargo.lock needs to be updated but --locked was passed to prevent this
[INFO] the lockfile is outdated, regenerating it
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] [stderr]     Updating git repository `https://github.com/marvelm/html5ever.git`
[INFO] [stderr]     Updating git repository `https://github.com/servo/rust-selectors.git`
[INFO] [stderr]     Updating git repository `https://github.com/reem/rust-mac`
[INFO] [stderr]     Updating git repository `https://github.com/servo/string-cache`
[INFO] [stderr] error: no matching package named `string_cache_plugin` found
[INFO] [stderr] location searched: https://github.com/servo/string-cache
[INFO] [stderr] required by package `html5ever v0.0.0 (https://github.com/marvelm/html5ever.git#2b9fd560)`
[INFO] [stderr]     ... which is depended on by `rivets v0.1.0 (/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/marvelm/rivets)`
[ERROR] this task or one of its parent failed!
[ERROR] command `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"` failed