[INFO] updating cached repository rust-lang-nursery/rustup.rs
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/rust-lang-nursery/rustup.rs
[INFO] [stderr]  * branch              HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/rust-lang-nursery/rustup.rs" "work/ex/beta-1.38-1/sources/1.37.0/gh/rust-lang-nursery/rustup.rs"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/rust-lang-nursery/rustup.rs'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/rust-lang-nursery/rustup.rs" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/rust-lang-nursery/rustup.rs"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/rust-lang-nursery/rustup.rs'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 1d14725d6056f459a7c28b46e0ea2e07822fc6a4
[INFO] sha for GitHub repo rust-lang-nursery/rustup.rs: 1d14725d6056f459a7c28b46e0ea2e07822fc6a4
[INFO] validating manifest of rust-lang-nursery/rustup.rs 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 rust-lang-nursery/rustup.rs 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 rust-lang-nursery/rustup.rs
[INFO] removed workspace from rust-lang-nursery/rustup.rs
[INFO] removed path dependency download from rust-lang-nursery/rustup.rs
[INFO] finished frobbing rust-lang-nursery/rustup.rs
[INFO] frobbed toml for rust-lang-nursery/rustup.rs written to work/ex/beta-1.38-1/sources/1.37.0/gh/rust-lang-nursery/rustup.rs/Cargo.toml
[INFO] started frobbing rust-lang-nursery/rustup.rs
[INFO] removed workspace from rust-lang-nursery/rustup.rs
[INFO] removed path dependency download from rust-lang-nursery/rustup.rs
[INFO] finished frobbing rust-lang-nursery/rustup.rs
[INFO] frobbed toml for rust-lang-nursery/rustup.rs written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/rust-lang-nursery/rustup.rs/Cargo.toml
[INFO] crate rust-lang-nursery/rustup.rs 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 select a version for `download`.
[INFO] [stderr]     ... required by package `rustup v1.18.3 (/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/rust-lang-nursery/rustup.rs)`
[INFO] [stderr] versions that meet the requirements `*` are: 0.0.0
[INFO] [stderr] 
[INFO] [stderr] the package `rustup` depends on `download`, with features: `reqwest-backend, curl-backend` but `download` does not have these features.
[INFO] [stderr] 
[INFO] [stderr] 
[INFO] [stderr] failed to select a version for `download` which could resolve this conflict
[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