[INFO] updating cached repository nebulet/nebulet
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/nebulet/nebulet
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/nebulet/nebulet" "work/ex/beta-1.38-1/sources/1.37.0/gh/nebulet/nebulet"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/nebulet/nebulet'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/nebulet/nebulet" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/nebulet/nebulet"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/nebulet/nebulet'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] c0f3c993a87e72a95f85b453df25dc2b12aeedcf
[INFO] sha for GitHub repo nebulet/nebulet: c0f3c993a87e72a95f85b453df25dc2b12aeedcf
[INFO] validating manifest of nebulet/nebulet 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 nebulet/nebulet 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 nebulet/nebulet
[INFO] removed workspace from nebulet/nebulet
[INFO] removed path dependency nebulet-derive from nebulet/nebulet
[INFO] finished frobbing nebulet/nebulet
[INFO] frobbed toml for nebulet/nebulet written to work/ex/beta-1.38-1/sources/1.37.0/gh/nebulet/nebulet/Cargo.toml
[INFO] started frobbing nebulet/nebulet
[INFO] removed workspace from nebulet/nebulet
[INFO] removed path dependency nebulet-derive from nebulet/nebulet
[INFO] finished frobbing nebulet/nebulet
[INFO] frobbed toml for nebulet/nebulet written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/nebulet/nebulet/Cargo.toml
[INFO] crate nebulet/nebulet 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 crates.io index
[INFO] [stderr] error: failed to load source for a dependency on `bootloader`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   Unable to update https://github.com/lachlansneff/bootloader?branch=bootinfo#3657b123
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   failed to parse manifest at `/mnt/big/crater/work/local/cargo-home/git/checkouts/bootloader-1daa235e75294923/3657b12/Cargo.toml`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   the cargo feature `publish-lockfile` requires a nightly version of Cargo, but this is the `stable` channel
[INFO] [stderr] See https://doc.rust-lang.org/book/appendix-07-nightly-rust.html for more information about Rust release channels.
[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