[INFO] cloning repository https://github.com/howeih/Day-14-Huffman-codes
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/howeih/Day-14-Huffman-codes" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhoweih%2FDay-14-Huffman-codes", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhoweih%2FDay-14-Huffman-codes'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 65a14d8fffeb7cd8a8ef5c8b78f23847140c1d84
[INFO] building howeih/Day-14-Huffman-codes against master#461e8078010433ff7de2db2aaae8a3cfb0847215 for pr-94962
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhoweih%2FDay-14-Huffman-codes" "/workspace/builds/worker-39/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-39/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/howeih/Day-14-Huffman-codes on toolchain 461e8078010433ff7de2db2aaae8a3cfb0847215
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+461e8078010433ff7de2db2aaae8a3cfb0847215" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/howeih/Day-14-Huffman-codes
[INFO] finished tweaking git repo https://github.com/howeih/Day-14-Huffman-codes
[INFO] tweaked toml for git repo https://github.com/howeih/Day-14-Huffman-codes written to /workspace/builds/worker-39/source/Cargo.toml
[INFO] crate git repo https://github.com/howeih/Day-14-Huffman-codes already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+461e8078010433ff7de2db2aaae8a3cfb0847215" "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-39/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-39/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:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+461e8078010433ff7de2db2aaae8a3cfb0847215" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 897b92c008bc6a214730b5659cdfed2e3476cb4dd5b4cea4a5ad60d53495218e
[INFO] running `Command { std: "docker" "start" "-a" "897b92c008bc6a214730b5659cdfed2e3476cb4dd5b4cea4a5ad60d53495218e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "897b92c008bc6a214730b5659cdfed2e3476cb4dd5b4cea4a5ad60d53495218e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "897b92c008bc6a214730b5659cdfed2e3476cb4dd5b4cea4a5ad60d53495218e", kill_on_drop: false }`
[INFO] [stdout] 897b92c008bc6a214730b5659cdfed2e3476cb4dd5b4cea4a5ad60d53495218e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-39/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-39/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" "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:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+461e8078010433ff7de2db2aaae8a3cfb0847215" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 94778a36a09684f6853ac2a949097c6bae96ef2d3c9fedd48376733cb9063319
[INFO] running `Command { std: "docker" "start" "-a" "94778a36a09684f6853ac2a949097c6bae96ef2d3c9fedd48376733cb9063319", kill_on_drop: false }`
[INFO] [stderr]    Compiling huffman_codes v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: field is never read: `node_id`
[INFO] [stdout]   --> src/main.rs:16:5
[INFO] [stdout]    |
[INFO] [stdout] 16 |     node_id: i32,
[INFO] [stdout]    |     ^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] note: `Node` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]   --> src/main.rs:14:10
[INFO] [stdout]    |
[INFO] [stdout] 14 | #[derive(Debug)]
[INFO] [stdout]    |          ^^^^^
[INFO] [stdout]    = note: this warning originates in the derive macro `Debug` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.87s
[INFO] running `Command { std: "docker" "inspect" "94778a36a09684f6853ac2a949097c6bae96ef2d3c9fedd48376733cb9063319", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "94778a36a09684f6853ac2a949097c6bae96ef2d3c9fedd48376733cb9063319", kill_on_drop: false }`
[INFO] [stdout] 94778a36a09684f6853ac2a949097c6bae96ef2d3c9fedd48376733cb9063319
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-39/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-39/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" "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:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+461e8078010433ff7de2db2aaae8a3cfb0847215" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 99b74f3f1733295799201a17342a64cbda53a47a1bd5f08f92c930c5fe9cbbb4
[INFO] running `Command { std: "docker" "start" "-a" "99b74f3f1733295799201a17342a64cbda53a47a1bd5f08f92c930c5fe9cbbb4", kill_on_drop: false }`
[INFO] [stderr]    Compiling huffman_codes v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: field is never read: `node_id`
[INFO] [stdout]   --> src/main.rs:16:5
[INFO] [stdout]    |
[INFO] [stdout] 16 |     node_id: i32,
[INFO] [stdout]    |     ^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] note: `Node` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]   --> src/main.rs:14:10
[INFO] [stdout]    |
[INFO] [stdout] 14 | #[derive(Debug)]
[INFO] [stdout]    |          ^^^^^
[INFO] [stdout]    = note: this warning originates in the derive macro `Debug` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.63s
[INFO] [stderr]   Executable unittests src/main.rs (/opt/rustwide/target/debug/deps/huffman_codes-c5be69cf48675fe2)
[INFO] running `Command { std: "docker" "inspect" "99b74f3f1733295799201a17342a64cbda53a47a1bd5f08f92c930c5fe9cbbb4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "99b74f3f1733295799201a17342a64cbda53a47a1bd5f08f92c930c5fe9cbbb4", kill_on_drop: false }`
[INFO] [stdout] 99b74f3f1733295799201a17342a64cbda53a47a1bd5f08f92c930c5fe9cbbb4