[INFO] updating cached repository grenewode/i3switcher
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/grenewode/i3switcher
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/grenewode/i3switcher" "work/ex/beta-1.38-1/sources/1.37.0/gh/grenewode/i3switcher"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/grenewode/i3switcher'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/grenewode/i3switcher" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/grenewode/i3switcher"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/grenewode/i3switcher'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] e64777544167799a69f09d4dca873ad0cc819da7
[INFO] sha for GitHub repo grenewode/i3switcher: e64777544167799a69f09d4dca873ad0cc819da7
[INFO] validating manifest of grenewode/i3switcher 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 grenewode/i3switcher 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 grenewode/i3switcher
[INFO] finished frobbing grenewode/i3switcher
[INFO] frobbed toml for grenewode/i3switcher written to work/ex/beta-1.38-1/sources/1.37.0/gh/grenewode/i3switcher/Cargo.toml
[INFO] started frobbing grenewode/i3switcher
[INFO] finished frobbing grenewode/i3switcher
[INFO] frobbed toml for grenewode/i3switcher written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/grenewode/i3switcher/Cargo.toml
[INFO] crate grenewode/i3switcher 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] [stderr]     Blocking waiting for file lock on package cache
[INFO] testing grenewode/i3switcher against 1.37.0 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-5/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/grenewode/i3switcher:/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" "+1.37.0" "build" "--frozen"`
[INFO] [stdout] ba35b6050e66a70a9622f202fd83b1f0edbd3af765d7688978502b5a7b04ac6d
[INFO] running `"docker" "start" "-a" "ba35b6050e66a70a9622f202fd83b1f0edbd3af765d7688978502b5a7b04ac6d"`
[INFO] [stderr]    Compiling i3ipc v0.8.2
[INFO] [stderr]    Compiling i3switcher v0.3.1 (/opt/crater/workdir)
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:17:17
[INFO] [stderr]    |
[INFO] [stderr] 17 |             let mut iter = workspaces.iter().rev().skip(workspaces.len() - current_idx);
[INFO] [stderr]    |                 ----^^^^
[INFO] [stderr]    |                 |
[INFO] [stderr]    |                 help: remove this `mut`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_mut)] on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 4.95s
[INFO] running `"docker" "inspect" "ba35b6050e66a70a9622f202fd83b1f0edbd3af765d7688978502b5a7b04ac6d"`
[INFO] running `"docker" "rm" "-f" "ba35b6050e66a70a9622f202fd83b1f0edbd3af765d7688978502b5a7b04ac6d"`
[INFO] [stdout] ba35b6050e66a70a9622f202fd83b1f0edbd3af765d7688978502b5a7b04ac6d
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-5/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/grenewode/i3switcher:/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" "+1.37.0" "test" "--frozen" "--no-run"`
[INFO] [stdout] 1a732bfd33b3c3ceac890f26272852c1705f106229d42e70a2c6801a6402c0da
[INFO] running `"docker" "start" "-a" "1a732bfd33b3c3ceac890f26272852c1705f106229d42e70a2c6801a6402c0da"`
[INFO] [stderr]    Compiling i3switcher v0.3.1 (/opt/crater/workdir)
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:17:17
[INFO] [stderr]    |
[INFO] [stderr] 17 |             let mut iter = workspaces.iter().rev().skip(workspaces.len() - current_idx);
[INFO] [stderr]    |                 ----^^^^
[INFO] [stderr]    |                 |
[INFO] [stderr]    |                 help: remove this `mut`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_mut)] on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.00s
[INFO] running `"docker" "inspect" "1a732bfd33b3c3ceac890f26272852c1705f106229d42e70a2c6801a6402c0da"`
[INFO] running `"docker" "rm" "-f" "1a732bfd33b3c3ceac890f26272852c1705f106229d42e70a2c6801a6402c0da"`
[INFO] [stdout] 1a732bfd33b3c3ceac890f26272852c1705f106229d42e70a2c6801a6402c0da
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-5/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/grenewode/i3switcher:/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" "+1.37.0" "test" "--frozen"`
[INFO] [stdout] 4da52ebacc35db9b13156e3ceac5674884d967e4edf30e5d9afc19366f9c14d2
[INFO] running `"docker" "start" "-a" "4da52ebacc35db9b13156e3ceac5674884d967e4edf30e5d9afc19366f9c14d2"`
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.04s
[INFO] [stderr]      Running /opt/crater/target/debug/deps/i3switcher-3f2ee3af584985e9
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] running `"docker" "inspect" "4da52ebacc35db9b13156e3ceac5674884d967e4edf30e5d9afc19366f9c14d2"`
[INFO] running `"docker" "rm" "-f" "4da52ebacc35db9b13156e3ceac5674884d967e4edf30e5d9afc19366f9c14d2"`
[INFO] [stdout] 4da52ebacc35db9b13156e3ceac5674884d967e4edf30e5d9afc19366f9c14d2