[INFO] updating cached repository https://github.com/rust-lang-nursery/chalk
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune"`
[INFO] [stderr] From https://github.com/rust-lang-nursery/chalk
[INFO] [stderr]  + d13982b9...1503a9ea gh-pages   -> gh-pages  (forced update)
[INFO] [stderr]    122dc191..ef456464  master     -> master
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] ef4564648d3efb056c4cb1588a2d9cf87548694e
[ERROR] this task or one of its parent failed!
[ERROR] command `"/workspace/cargo-home/bin/cargo" "+beta-2019-10-27" "fetch" "--locked" "--manifest-path" "Cargo.toml"` failed
[ERROR] note: run with `RUST_BACKTRACE=1` to display a backtrace.