[INFO] updating cached repository leviathan88/safe_linked_lists_rust
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/leviathan88/safe_linked_lists_rust
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/leviathan88/safe_linked_lists_rust" "work/ex/beta-1.37-6/sources/1.36.0/gh/leviathan88/safe_linked_lists_rust"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.37-6/sources/1.36.0/gh/leviathan88/safe_linked_lists_rust'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/leviathan88/safe_linked_lists_rust" "work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/leviathan88/safe_linked_lists_rust"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/leviathan88/safe_linked_lists_rust'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] e4ba717536e07f5a946d94325cd53edd6273138b
[INFO] sha for GitHub repo leviathan88/safe_linked_lists_rust: e4ba717536e07f5a946d94325cd53edd6273138b
[INFO] validating manifest of leviathan88/safe_linked_lists_rust on toolchain 1.36.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of leviathan88/safe_linked_lists_rust on toolchain beta-2019-07-23
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing leviathan88/safe_linked_lists_rust
[INFO] finished frobbing leviathan88/safe_linked_lists_rust
[INFO] frobbed toml for leviathan88/safe_linked_lists_rust written to work/ex/beta-1.37-6/sources/1.36.0/gh/leviathan88/safe_linked_lists_rust/Cargo.toml
[INFO] started frobbing leviathan88/safe_linked_lists_rust
[INFO] finished frobbing leviathan88/safe_linked_lists_rust
[INFO] frobbed toml for leviathan88/safe_linked_lists_rust written to work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/leviathan88/safe_linked_lists_rust/Cargo.toml
[INFO] crate leviathan88/safe_linked_lists_rust already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] testing leviathan88/safe_linked_lists_rust against beta-2019-07-23 for beta-1.37-6
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.37-6/worker-4/beta-2019-07-23:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/leviathan88/safe_linked_lists_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-2019-07-23" "build" "--frozen"`
[INFO] [stdout] e4f3c34a6429a2a472ae39890663e687676d0b0e5104cf22873f5d9a279cb2c8
[INFO] running `"docker" "start" "-a" "e4f3c34a6429a2a472ae39890663e687676d0b0e5104cf22873f5d9a279cb2c8"`
[INFO] [stderr]    Compiling linky_lists v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: unused import: `std::cell::RefCell`
[INFO] [stderr]  --> src/lists/mod.rs:2:5
[INFO] [stderr]   |
[INFO] [stderr] 2 | use std::cell::RefCell;
[INFO] [stderr]   |     ^^^^^^^^^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(unused_imports)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `super::*`
[INFO] [stderr]   --> src/lists/node.rs:70:9
[INFO] [stderr]    |
[INFO] [stderr] 70 |     use super::*;
[INFO] [stderr]    |         ^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `super::*`
[INFO] [stderr]    --> src/lists/mod.rs:141:9
[INFO] [stderr]     |
[INFO] [stderr] 141 |     use super::*;
[INFO] [stderr]     |         ^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `new_empty`
[INFO] [stderr]   --> src/lists/mod.rs:18:5
[INFO] [stderr]    |
[INFO] [stderr] 18 |     pub fn new_empty() -> Self {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.63s
[INFO] running `"docker" "inspect" "e4f3c34a6429a2a472ae39890663e687676d0b0e5104cf22873f5d9a279cb2c8"`
[INFO] running `"docker" "rm" "-f" "e4f3c34a6429a2a472ae39890663e687676d0b0e5104cf22873f5d9a279cb2c8"`
[INFO] [stdout] e4f3c34a6429a2a472ae39890663e687676d0b0e5104cf22873f5d9a279cb2c8
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.37-6/worker-4/beta-2019-07-23:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/leviathan88/safe_linked_lists_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-2019-07-23" "test" "--frozen" "--no-run"`
[INFO] [stdout] 14b1c4dc053a9a8c3d603d77fb7336bd166f088b32a4479054c03eac6b442965
[INFO] running `"docker" "start" "-a" "14b1c4dc053a9a8c3d603d77fb7336bd166f088b32a4479054c03eac6b442965"`
[INFO] [stderr]    Compiling linky_lists v0.1.0 (/opt/crater/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.06s
[INFO] running `"docker" "inspect" "14b1c4dc053a9a8c3d603d77fb7336bd166f088b32a4479054c03eac6b442965"`
[INFO] running `"docker" "rm" "-f" "14b1c4dc053a9a8c3d603d77fb7336bd166f088b32a4479054c03eac6b442965"`
[INFO] [stdout] 14b1c4dc053a9a8c3d603d77fb7336bd166f088b32a4479054c03eac6b442965
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.37-6/worker-4/beta-2019-07-23:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/beta-2019-07-23/gh/leviathan88/safe_linked_lists_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-2019-07-23" "test" "--frozen"`
[INFO] [stdout] d1a9de6ff82b9fa537a28da805469452c05236219789918d3d229d9f87483d2a
[INFO] running `"docker" "start" "-a" "d1a9de6ff82b9fa537a28da805469452c05236219789918d3d229d9f87483d2a"`
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.02s
[INFO] [stderr]      Running /opt/crater/target/debug/deps/linky_lists-91260671239dd86a
[INFO] [stdout] 
[INFO] [stdout] running 7 tests
[INFO] [stdout] test lists::tests::test_new_empty_list ... ok
[INFO] [stdout] test lists::tests::test_new_list ... ok
[INFO] [stdout] test lists::node::tests::test_new_node ... ok
[INFO] [stdout] test lists::tests::test_linked_list_append_start ... ok
[INFO] [stdout] test lists::tests::test_linked_list_append_end ... ok
[INFO] [stdout] test lists::tests::test_pop_end ... ok
[INFO] [stdout] test lists::tests::test_pop_head ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 7 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] running `"docker" "inspect" "d1a9de6ff82b9fa537a28da805469452c05236219789918d3d229d9f87483d2a"`
[INFO] running `"docker" "rm" "-f" "d1a9de6ff82b9fa537a28da805469452c05236219789918d3d229d9f87483d2a"`
[INFO] [stdout] d1a9de6ff82b9fa537a28da805469452c05236219789918d3d229d9f87483d2a