[INFO] cloning repository https://github.com/ShardulVanage/Rust-Question
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/ShardulVanage/Rust-Question" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FShardulVanage%2FRust-Question", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FShardulVanage%2FRust-Question'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 9d7ebd56a69f142c82655e7bbb03b0e5986f9732
[INFO] checking ShardulVanage/Rust-Question against master#b286722878e18db29a7fbe672be7c4d3b02e8e4d for pr-127655
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FShardulVanage%2FRust-Question" "/workspace/builds/worker-2-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/ShardulVanage/Rust-Question on toolchain b286722878e18db29a7fbe672be7c4d3b02e8e4d
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+b286722878e18db29a7fbe672be7c4d3b02e8e4d" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/ShardulVanage/Rust-Question
[INFO] finished tweaking git repo https://github.com/ShardulVanage/Rust-Question
[INFO] tweaked toml for git repo https://github.com/ShardulVanage/Rust-Question written to /workspace/builds/worker-2-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/ShardulVanage/Rust-Question 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" "+b286722878e18db29a7fbe672be7c4d3b02e8e4d" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[ERROR] error running command: no output for 300 seconds
[ERROR] this task or one of its parent failed!
[ERROR] no output for 300 seconds
[ERROR] note: run with `RUST_BACKTRACE=1` to display a backtrace.
[INFO] checking ShardulVanage/Rust-Question against try#6a5749073f2ebf59d7740d30e50a932a85756ee7 for pr-127655
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FShardulVanage%2FRust-Question" "/workspace/builds/worker-2-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/ShardulVanage/Rust-Question on toolchain 6a5749073f2ebf59d7740d30e50a932a85756ee7
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+6a5749073f2ebf59d7740d30e50a932a85756ee7" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/ShardulVanage/Rust-Question
[INFO] finished tweaking git repo https://github.com/ShardulVanage/Rust-Question
[INFO] tweaked toml for git repo https://github.com/ShardulVanage/Rust-Question written to /workspace/builds/worker-2-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/ShardulVanage/Rust-Question 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" "+6a5749073f2ebf59d7740d30e50a932a85756ee7" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-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:dff56e7819e73ed36160586b3445e93eb0be776c16704aeeded9c3fb668b2384" "/opt/rustwide/cargo-home/bin/cargo" "+6a5749073f2ebf59d7740d30e50a932a85756ee7" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] a0d54e3c5f2dbca2c16cab050bb1a8bb204188d60f58c0d3ef8b5463d76a1cfb
[INFO] running `Command { std: "docker" "start" "-a" "a0d54e3c5f2dbca2c16cab050bb1a8bb204188d60f58c0d3ef8b5463d76a1cfb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "a0d54e3c5f2dbca2c16cab050bb1a8bb204188d60f58c0d3ef8b5463d76a1cfb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a0d54e3c5f2dbca2c16cab050bb1a8bb204188d60f58c0d3ef8b5463d76a1cfb", kill_on_drop: false }`
[INFO] [stdout] a0d54e3c5f2dbca2c16cab050bb1a8bb204188d60f58c0d3ef8b5463d76a1cfb
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-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:dff56e7819e73ed36160586b3445e93eb0be776c16704aeeded9c3fb668b2384" "/opt/rustwide/cargo-home/bin/cargo" "+6a5749073f2ebf59d7740d30e50a932a85756ee7" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 1481b42d68c5f65e97f1762d3d7fed55e937782139f996c1a8e60b36a5a0fe72
[INFO] running `Command { std: "docker" "start" "-a" "1481b42d68c5f65e97f1762d3d7fed55e937782139f996c1a8e60b36a5a0fe72", kill_on_drop: false }`
[INFO] [stderr]     Checking rust_assignment v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:37:9
[INFO] [stdout]    |
[INFO] [stdout] 37 |     let mut nums_kth = vec![4, 1, 3, 2, 5];
[INFO] [stdout]    |         ----^^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `max_depth` is never used
[INFO] [stdout]   --> src/max_depth.rs:16:8
[INFO] [stdout]    |
[INFO] [stdout] 16 | pub fn max_depth(root: Option<Box<TreeNode>>) -> i32 {
[INFO] [stdout]    |        ^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:37:9
[INFO] [stdout]    |
[INFO] [stdout] 37 |     let mut nums_kth = vec![4, 1, 3, 2, 5];
[INFO] [stdout]    |         ----^^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `max_depth` is never used
[INFO] [stdout]   --> src/max_depth.rs:16:8
[INFO] [stdout]    |
[INFO] [stdout] 16 | pub fn max_depth(root: Option<Box<TreeNode>>) -> i32 {
[INFO] [stdout]    |        ^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.09s
[INFO] running `Command { std: "docker" "inspect" "1481b42d68c5f65e97f1762d3d7fed55e937782139f996c1a8e60b36a5a0fe72", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1481b42d68c5f65e97f1762d3d7fed55e937782139f996c1a8e60b36a5a0fe72", kill_on_drop: false }`
[INFO] [stdout] 1481b42d68c5f65e97f1762d3d7fed55e937782139f996c1a8e60b36a5a0fe72