[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-57967/sources/master#c1c3c4e95b69dfeaca5c5db6c622d7f90ad30a54/gh/timmc/cavern"`
[INFO] [stderr] Cloning into 'work/ex/pr-57967/sources/master#c1c3c4e95b69dfeaca5c5db6c622d7f90ad30a54/gh/timmc/cavern'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/timmc/cavern" "work/ex/pr-57967/sources/try#7fea0229842e79db1159ea58ad9a653b288efee9/gh/timmc/cavern"`
[INFO] [stderr] Cloning into 'work/ex/pr-57967/sources/try#7fea0229842e79db1159ea58ad9a653b288efee9/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#c1c3c4e95b69dfeaca5c5db6c622d7f90ad30a54
[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]