[INFO] updating cached repository raiker/persistent-rope
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/raiker/persistent-rope
[INFO] [stderr] * branch HEAD -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/raiker/persistent-rope" "work/ex/beta-1.38-1/sources/1.37.0/gh/raiker/persistent-rope"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/raiker/persistent-rope'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/raiker/persistent-rope" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/raiker/persistent-rope"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/raiker/persistent-rope'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 7f638488c32998e1683a0a3ba8de4846c9a5dee7
[INFO] sha for GitHub repo raiker/persistent-rope: 7f638488c32998e1683a0a3ba8de4846c9a5dee7
[INFO] validating manifest of raiker/persistent-rope 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 raiker/persistent-rope 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 raiker/persistent-rope
[INFO] finished frobbing raiker/persistent-rope
[INFO] frobbed toml for raiker/persistent-rope written to work/ex/beta-1.38-1/sources/1.37.0/gh/raiker/persistent-rope/Cargo.toml
[INFO] started frobbing raiker/persistent-rope
[INFO] finished frobbing raiker/persistent-rope
[INFO] frobbed toml for raiker/persistent-rope written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/raiker/persistent-rope/Cargo.toml
[INFO] crate raiker/persistent-rope 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] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing raiker/persistent-rope against beta-2019-08-13 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-1/beta-2019-08-13:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/raiker/persistent-rope:/opt/crater/workdir:ro,Z" "-v" "/mnt/big/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+beta-2019-08-13" "build" "--frozen"`
[INFO] [stdout] ea142022c01a9e74e18a80020c7afedbcacee62f89c6681f523971d172ce6630
[INFO] running `"docker" "start" "-a" "ea142022c01a9e74e18a80020c7afedbcacee62f89c6681f523971d172ce6630"`
[INFO] [stderr] Compiling persistent-rope v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: unused variable: `parent`
[INFO] [stderr] --> src/main.rs:141:69
[INFO] [stderr] |
[INFO] [stderr] 141 | fn rec_insert(key: K, val: V, current: &Rc