[INFO] cloning repository https://github.com/acseed/rust_practice
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/acseed/rust_practice" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Facseed%2Frust_practice", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Facseed%2Frust_practice'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 3bd4f3a46fb6ed293440bb0ed57f563938e61a7e
[INFO] checking acseed/rust_practice against master#fe348cd1a8e0fa445b772393147ed865904dcd4d for pr-139587-2
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Facseed%2Frust_practice" "/workspace/builds/worker-0-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/acseed/rust_practice on toolchain fe348cd1a8e0fa445b772393147ed865904dcd4d
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+fe348cd1a8e0fa445b772393147ed865904dcd4d" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/acseed/rust_practice
[INFO] finished tweaking git repo https://github.com/acseed/rust_practice
[INFO] tweaked toml for git repo https://github.com/acseed/rust_practice written to /workspace/builds/worker-0-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/acseed/rust_practice already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+fe348cd1a8e0fa445b772393147ed865904dcd4d" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/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" "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" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:b0b074c097205a61b89e8ad263052f976b2b332c4dc5f02aef1fe52501660d6e" "/opt/rustwide/cargo-home/bin/cargo" "+fe348cd1a8e0fa445b772393147ed865904dcd4d" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] dd780dae27e2e67a914b6bafca2dc8240ef1ffc4a7dceb70cdb3268137a51be9
[INFO] running `Command { std: "docker" "start" "-a" "dd780dae27e2e67a914b6bafca2dc8240ef1ffc4a7dceb70cdb3268137a51be9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "dd780dae27e2e67a914b6bafca2dc8240ef1ffc4a7dceb70cdb3268137a51be9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "dd780dae27e2e67a914b6bafca2dc8240ef1ffc4a7dceb70cdb3268137a51be9", kill_on_drop: false }`
[INFO] [stdout] dd780dae27e2e67a914b6bafca2dc8240ef1ffc4a7dceb70cdb3268137a51be9
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/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" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:b0b074c097205a61b89e8ad263052f976b2b332c4dc5f02aef1fe52501660d6e" "/opt/rustwide/cargo-home/bin/cargo" "+fe348cd1a8e0fa445b772393147ed865904dcd4d" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 072c289ae3364752f3a3b33bac99f14cd92704c90156fa5d68cb545fdc700bf4
[INFO] running `Command { std: "docker" "start" "-a" "072c289ae3364752f3a3b33bac99f14cd92704c90156fa5d68cb545fdc700bf4", kill_on_drop: false }`
[INFO] [stderr]     Checking rust_practice v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: methods `size`, `get`, `maximum`, and `minimum` are never used
[INFO] [stdout]    --> src/ds/rbtree.rs:132:12
[INFO] [stdout]     |
[INFO] [stdout] 114 | impl<K, V> RBTree<K, V> where K: Ord + Clone + Display + ToString, V: Clone + Display + ToString {
[INFO] [stdout]     | ------------------------------------------------------------------------------------------------ methods in this implementation
[INFO] [stdout] ...
[INFO] [stdout] 132 |     pub fn size(&self) -> usize {
[INFO] [stdout]     |            ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 138 |     pub fn get(&self, key: &K) -> Option<&V> {
[INFO] [stdout]     |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 151 |     pub fn maximum(&self) -> Option<(&K,&V)> {
[INFO] [stdout]     |            ^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 156 |     pub fn minimum(&self) -> Option<(&K,&V)> {
[INFO] [stdout]     |            ^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.17s
[INFO] running `Command { std: "docker" "inspect" "072c289ae3364752f3a3b33bac99f14cd92704c90156fa5d68cb545fdc700bf4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "072c289ae3364752f3a3b33bac99f14cd92704c90156fa5d68cb545fdc700bf4", kill_on_drop: false }`
[INFO] [stdout] 072c289ae3364752f3a3b33bac99f14cd92704c90156fa5d68cb545fdc700bf4