[INFO] updating cached repository https://github.com/HunDunDM/leetcode-rust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune", kill_on_drop: false }`
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 414d7a1b71e19a9ca48ae76b8abe01c28d15afdc
[INFO] testing HunDunDM/leetcode-rust against beta-2020-07-24 for beta-1.46-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FHunDunDM%2Fleetcode-rust" "/workspace/builds/worker-8/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-8/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/HunDunDM/leetcode-rust on toolchain beta-2020-07-24
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-07-24" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] removed /workspace/builds/worker-8/source/.cargo/config
[INFO] started tweaking git repo https://github.com/HunDunDM/leetcode-rust
[INFO] finished tweaking git repo https://github.com/HunDunDM/leetcode-rust
[INFO] tweaked toml for git repo https://github.com/HunDunDM/leetcode-rust written to /workspace/builds/worker-8/source/Cargo.toml
[INFO] crate git repo https://github.com/HunDunDM/leetcode-rust already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-07-24" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=0" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-07-24" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 1f51667a34bebf9bf67bf0af17d00455bd6cbdf0c5258d30a1a4518321d178fd
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "1f51667a34bebf9bf67bf0af17d00455bd6cbdf0c5258d30a1a4518321d178fd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "1f51667a34bebf9bf67bf0af17d00455bd6cbdf0c5258d30a1a4518321d178fd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1f51667a34bebf9bf67bf0af17d00455bd6cbdf0c5258d30a1a4518321d178fd", kill_on_drop: false }`
[INFO] [stdout] 1f51667a34bebf9bf67bf0af17d00455bd6cbdf0c5258d30a1a4518321d178fd
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=0" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-07-24" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 26de1e8ad3232a682ee521204f0640f678a6a3d87078ae1ad6f95c297cb3a99d
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "26de1e8ad3232a682ee521204f0640f678a6a3d87078ae1ad6f95c297cb3a99d", kill_on_drop: false }`
[INFO] [stderr]    Compiling leetcode-rust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(inner_deref)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `to_list`
[INFO] [stdout]   --> src/p0002_add_two_numbers.rs:15:43
[INFO] [stdout]    |
[INFO] [stdout] 15 | use super::utils::linked_list::{ListNode, to_list};
[INFO] [stdout]    |                                           ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::borrow::BorrowMut`
[INFO] [stdout]   --> src/p0002_add_two_numbers.rs:16:5
[INFO] [stdout]    |
[INFO] [stdout] 16 | use std::borrow::BorrowMut;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `leetcode-rust`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "26de1e8ad3232a682ee521204f0640f678a6a3d87078ae1ad6f95c297cb3a99d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "26de1e8ad3232a682ee521204f0640f678a6a3d87078ae1ad6f95c297cb3a99d", kill_on_drop: false }`
[INFO] [stdout] 26de1e8ad3232a682ee521204f0640f678a6a3d87078ae1ad6f95c297cb3a99d