[INFO] updating cached repository christiansakai/linked_list_rust
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/christiansakai/linked_list_rust
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/christiansakai/linked_list_rust" "work/ex/beta-1.38-1/sources/1.37.0/gh/christiansakai/linked_list_rust"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/christiansakai/linked_list_rust'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/christiansakai/linked_list_rust" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/christiansakai/linked_list_rust"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/christiansakai/linked_list_rust'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] b59f6d038c7a3a9c7cfb4a83a0103de5a7b175ce
[INFO] sha for GitHub repo christiansakai/linked_list_rust: b59f6d038c7a3a9c7cfb4a83a0103de5a7b175ce
[INFO] validating manifest of christiansakai/linked_list_rust 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 christiansakai/linked_list_rust 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 christiansakai/linked_list_rust
[INFO] finished frobbing christiansakai/linked_list_rust
[INFO] frobbed toml for christiansakai/linked_list_rust written to work/ex/beta-1.38-1/sources/1.37.0/gh/christiansakai/linked_list_rust/Cargo.toml
[INFO] started frobbing christiansakai/linked_list_rust
[INFO] finished frobbing christiansakai/linked_list_rust
[INFO] frobbed toml for christiansakai/linked_list_rust written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/christiansakai/linked_list_rust/Cargo.toml
[INFO] crate christiansakai/linked_list_rust 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 christiansakai/linked_list_rust 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-4/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/christiansakai/linked_list_rust:/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] 674d58816157c7d49c6851b6f436e7e89f20a1cf98d8672c7c0eed386f7528a0
[INFO] running `"docker" "start" "-a" "674d58816157c7d49c6851b6f436e7e89f20a1cf98d8672c7c0eed386f7528a0"`
[INFO] [stderr]    Compiling linked_list_rust v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: unused import: `super::*`
[INFO] [stderr]   --> src/first.rs:75:9
[INFO] [stderr]    |
[INFO] [stderr] 75 |     use super::*;
[INFO] [stderr]    |         ^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `elem`
[INFO] [stderr]   --> src/fourth.rs:51:33
[INFO] [stderr]    |
[INFO] [stderr] 51 |     pub fn pop_front(&mut self, elem: T) -> Option<T> {
[INFO] [stderr]    |                                 ^^^^ help: consider prefixing with an underscore: `_elem`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.81s
[INFO] running `"docker" "inspect" "674d58816157c7d49c6851b6f436e7e89f20a1cf98d8672c7c0eed386f7528a0"`
[INFO] running `"docker" "rm" "-f" "674d58816157c7d49c6851b6f436e7e89f20a1cf98d8672c7c0eed386f7528a0"`
[INFO] [stdout] 674d58816157c7d49c6851b6f436e7e89f20a1cf98d8672c7c0eed386f7528a0
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-4/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/christiansakai/linked_list_rust:/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" "test" "--frozen" "--no-run"`
[INFO] [stdout] e89dd2a66cfc4d8e3b5fe01e928e71b86809158b67c60d79411c04c17df5a1a7
[INFO] running `"docker" "start" "-a" "e89dd2a66cfc4d8e3b5fe01e928e71b86809158b67c60d79411c04c17df5a1a7"`
[INFO] [stderr]    Compiling linked_list_rust v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: unused variable: `elem`
[INFO] [stderr]   --> src/fourth.rs:51:33
[INFO] [stderr]    |
[INFO] [stderr] 51 |     pub fn pop_front(&mut self, elem: T) -> Option<T> {
[INFO] [stderr]    |                                 ^^^^ help: consider prefixing with an underscore: `_elem`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.32s
[INFO] running `"docker" "inspect" "e89dd2a66cfc4d8e3b5fe01e928e71b86809158b67c60d79411c04c17df5a1a7"`
[INFO] running `"docker" "rm" "-f" "e89dd2a66cfc4d8e3b5fe01e928e71b86809158b67c60d79411c04c17df5a1a7"`
[INFO] [stdout] e89dd2a66cfc4d8e3b5fe01e928e71b86809158b67c60d79411c04c17df5a1a7
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-4/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/christiansakai/linked_list_rust:/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" "test" "--frozen"`
[INFO] [stdout] 1a61eac3e79e3842a58f306fb374074f57e1ba3d8cd427867431f6d160ebb1ab
[INFO] running `"docker" "start" "-a" "1a61eac3e79e3842a58f306fb374074f57e1ba3d8cd427867431f6d160ebb1ab"`
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.01s
[INFO] [stderr]      Running /opt/crater/target/debug/deps/linked_list_rust-2f61f299c7683da2
[INFO] [stderr]      Running /opt/crater/target/debug/deps/linked_list_rust-ab1aaa5ca0f0c28b
[INFO] [stderr]    Doc-tests linked_list_rust
[INFO] [stdout] 
[INFO] [stdout] running 3 tests
[INFO] [stdout] test third::test::iter ... ok
[INFO] [stdout] test third::test::basics ... ok
[INFO] [stdout] test first::test::basics ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[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] [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" "1a61eac3e79e3842a58f306fb374074f57e1ba3d8cd427867431f6d160ebb1ab"`
[INFO] running `"docker" "rm" "-f" "1a61eac3e79e3842a58f306fb374074f57e1ba3d8cd427867431f6d160ebb1ab"`
[INFO] [stdout] 1a61eac3e79e3842a58f306fb374074f57e1ba3d8cd427867431f6d160ebb1ab