[INFO] updating cached repository timmc/cavern
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/timmc/cavern
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/timmc/cavern" "work/ex/pr-57609/sources/master#03acbd71c977cd63ce5f39ba9b6fe9ffd578785a/gh/timmc/cavern"`
[INFO] [stderr] Cloning into 'work/ex/pr-57609/sources/master#03acbd71c977cd63ce5f39ba9b6fe9ffd578785a/gh/timmc/cavern'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/timmc/cavern" "work/ex/pr-57609/sources/try#26f8d250bb3c8a85e812cf663c730ef9e0df9315/gh/timmc/cavern"`
[INFO] [stderr] Cloning into 'work/ex/pr-57609/sources/try#26f8d250bb3c8a85e812cf663c730ef9e0df9315/gh/timmc/cavern'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 66d7d176b1e4ed72d443f0d2a0e7e600edd1b038
[INFO] sha for GitHub repo timmc/cavern: 66d7d176b1e4ed72d443f0d2a0e7e600edd1b038
[INFO] validating manifest of timmc/cavern on toolchain master#03acbd71c977cd63ce5f39ba9b6fe9ffd578785a
[ERROR] this task or one of its parent failed!
[ERROR] overridden task result to build-fail:broken
[ERROR] caused by: missing Cargo.toml for timmc/cavern
[ERROR]