[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 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/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" "+1.37.0" "build" "--frozen"`
[INFO] [stdout] d70bb70e1d995a1082659fbecba2c822d2f024969fed4e8e8bb321d008793197
[INFO] running `"docker" "start" "-a" "d70bb70e1d995a1082659fbecba2c822d2f024969fed4e8e8bb321d008793197"`
[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 0.80s
[INFO] running `"docker" "inspect" "d70bb70e1d995a1082659fbecba2c822d2f024969fed4e8e8bb321d008793197"`
[INFO] running `"docker" "rm" "-f" "d70bb70e1d995a1082659fbecba2c822d2f024969fed4e8e8bb321d008793197"`
[INFO] [stdout] d70bb70e1d995a1082659fbecba2c822d2f024969fed4e8e8bb321d008793197
[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/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" "+1.37.0" "test" "--frozen" "--no-run"`
[INFO] [stdout] 595714197ad0e56a6013fddcfef09474d4d31c5e9e0e74b83fd35d7aa9fe4d47
[INFO] running `"docker" "start" "-a" "595714197ad0e56a6013fddcfef09474d4d31c5e9e0e74b83fd35d7aa9fe4d47"`
[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 1.64s
[INFO] running `"docker" "inspect" "595714197ad0e56a6013fddcfef09474d4d31c5e9e0e74b83fd35d7aa9fe4d47"`
[INFO] running `"docker" "rm" "-f" "595714197ad0e56a6013fddcfef09474d4d31c5e9e0e74b83fd35d7aa9fe4d47"`
[INFO] [stdout] 595714197ad0e56a6013fddcfef09474d4d31c5e9e0e74b83fd35d7aa9fe4d47
[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/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" "+1.37.0" "test" "--frozen"`
[INFO] [stdout] 8f3402a9cad7b4566e9202e0b3b139a20e5f7b977f67131dfe7419b43108c99f
[INFO] running `"docker" "start" "-a" "8f3402a9cad7b4566e9202e0b3b139a20e5f7b977f67131dfe7419b43108c99f"`
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.02s
[INFO] [stderr]      Running /opt/crater/target/debug/deps/linked_list_rust-debc7ac134298f90
[INFO] [stdout] 
[INFO] [stdout] running 3 tests
[INFO] [stdout] test first::test::basics ... ok
[INFO] [stdout] test third::test::basics ... ok
[INFO] [stdout] test third::test::iter ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr]      Running /opt/crater/target/debug/deps/linked_list_rust-12b449236609f432
[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] [stderr]    Doc-tests linked_list_rust
[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" "8f3402a9cad7b4566e9202e0b3b139a20e5f7b977f67131dfe7419b43108c99f"`
[INFO] running `"docker" "rm" "-f" "8f3402a9cad7b4566e9202e0b3b139a20e5f7b977f67131dfe7419b43108c99f"`
[INFO] [stdout] 8f3402a9cad7b4566e9202e0b3b139a20e5f7b977f67131dfe7419b43108c99f