[INFO] cloning repository https://github.com/isidroevc/hands_on_data_structures_rust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/isidroevc/hands_on_data_structures_rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fisidroevc%2Fhands_on_data_structures_rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fisidroevc%2Fhands_on_data_structures_rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 82fdd2a4083385ad532ae27fe46d3bcd8940809d
[INFO] checking isidroevc/hands_on_data_structures_rust against try#afeffcd090fe6cee35c99f8b5539d74aa443fe34 for pr-140956
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fisidroevc%2Fhands_on_data_structures_rust" "/workspace/builds/worker-4-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/isidroevc/hands_on_data_structures_rust
[INFO] finished tweaking git repo https://github.com/isidroevc/hands_on_data_structures_rust
[INFO] tweaked toml for git repo https://github.com/isidroevc/hands_on_data_structures_rust written to /workspace/builds/worker-4-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/isidroevc/hands_on_data_structures_rust on toolchain afeffcd090fe6cee35c99f8b5539d74aa443fe34
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+afeffcd090fe6cee35c99f8b5539d74aa443fe34" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/isidroevc/hands_on_data_structures_rust 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" "+afeffcd090fe6cee35c99f8b5539d74aa443fe34" "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-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/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@sha256:90999bfc7ae267e83380e433d8e61a7c072ca6729e92edbae886d3423b3a6f4c" "/opt/rustwide/cargo-home/bin/cargo" "+afeffcd090fe6cee35c99f8b5539d74aa443fe34" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 63d00407a9b55418732584d9347619da0cdf1a8837c94b26f012f702fb249755
[INFO] running `Command { std: "docker" "start" "-a" "63d00407a9b55418732584d9347619da0cdf1a8837c94b26f012f702fb249755", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "63d00407a9b55418732584d9347619da0cdf1a8837c94b26f012f702fb249755", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "63d00407a9b55418732584d9347619da0cdf1a8837c94b26f012f702fb249755", kill_on_drop: false }`
[INFO] [stdout] 63d00407a9b55418732584d9347619da0cdf1a8837c94b26f012f702fb249755
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/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@sha256:90999bfc7ae267e83380e433d8e61a7c072ca6729e92edbae886d3423b3a6f4c" "/opt/rustwide/cargo-home/bin/cargo" "+afeffcd090fe6cee35c99f8b5539d74aa443fe34" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] ea4933126422baa0a58040bf454f312ba2254eec87c4af3d50d515d6fa4ac84e
[INFO] running `Command { std: "docker" "start" "-a" "ea4933126422baa0a58040bf454f312ba2254eec87c4af3d50d515d6fa4ac84e", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.153
[INFO] [stderr]     Checking ppv-lite86 v0.2.17
[INFO] [stderr]     Checking getrandom v0.2.12
[INFO] [stderr]     Checking rand_core v0.6.4
[INFO] [stderr]     Checking rand_chacha v0.3.1
[INFO] [stderr]     Checking rand v0.8.5
[INFO] [stderr]     Checking data_structures_book v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `Ref`
[INFO] [stdout]  --> src/trees/red_black_tree.rs:3:17
[INFO] [stdout]   |
[INFO] [stdout] 3 | use std::cell::{Ref, RefCell};
[INFO] [stdout]   |                 ^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `seq`
[INFO] [stdout]  --> src/trees/red_black_tree.rs:7:12
[INFO] [stdout]   |
[INFO] [stdout] 7 | use rand::{seq, Rng};
[INFO] [stdout]   |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Ref`
[INFO] [stdout]  --> src/trees/red_black_tree.rs:3:17
[INFO] [stdout]   |
[INFO] [stdout] 3 | use std::cell::{Ref, RefCell};
[INFO] [stdout]   |                 ^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `seq`
[INFO] [stdout]  --> src/trees/red_black_tree.rs:7:12
[INFO] [stdout]   |
[INFO] [stdout] 7 | use rand::{seq, Rng};
[INFO] [stdout]   |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `i`
[INFO] [stdout]    --> src/trees/red_black_tree.rs:428:9
[INFO] [stdout]     |
[INFO] [stdout] 428 |     for i in 0..n {
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_i`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `i`
[INFO] [stdout]    --> src/trees/red_black_tree.rs:428:9
[INFO] [stdout]     |
[INFO] [stdout] 428 |     for i in 0..n {
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_i`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `::data_structures_book::trees`
[INFO] [stdout]  --> src/main.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use ::data_structures_book::trees;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `::data_structures_book::trees`
[INFO] [stdout]  --> src/main.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use ::data_structures_book::trees;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 1.75s
[INFO] running `Command { std: "docker" "inspect" "ea4933126422baa0a58040bf454f312ba2254eec87c4af3d50d515d6fa4ac84e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ea4933126422baa0a58040bf454f312ba2254eec87c4af3d50d515d6fa4ac84e", kill_on_drop: false }`
[INFO] [stdout] ea4933126422baa0a58040bf454f312ba2254eec87c4af3d50d515d6fa4ac84e