[INFO] cloning repository https://github.com/googlercolin/Rust_program_optimization
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/googlercolin/Rust_program_optimization" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fgooglercolin%2FRust_program_optimization", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fgooglercolin%2FRust_program_optimization'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 67d4c75b8df987640dd599ff883d8904fb071fd3
[INFO] checking googlercolin/Rust_program_optimization against master#bca37a20bd376ce3fd138e7cdee7fe704e0f8814 for pr-139493-3
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fgooglercolin%2FRust_program_optimization" "/workspace/builds/worker-6-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc1/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/googlercolin/Rust_program_optimization
[INFO] finished tweaking git repo https://github.com/googlercolin/Rust_program_optimization
[INFO] tweaked toml for git repo https://github.com/googlercolin/Rust_program_optimization written to /workspace/builds/worker-6-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/googlercolin/Rust_program_optimization on toolchain bca37a20bd376ce3fd138e7cdee7fe704e0f8814
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+bca37a20bd376ce3fd138e7cdee7fe704e0f8814" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/googlercolin/Rust_program_optimization 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" "+bca37a20bd376ce3fd138e7cdee7fe704e0f8814" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded sha2 v0.9.1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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:aa71247004a7fa38d13ec170f48f06cdedf5bc50b2a8645e56ed7e992e6fa513" "/opt/rustwide/cargo-home/bin/cargo" "+bca37a20bd376ce3fd138e7cdee7fe704e0f8814" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 140c4e0693179b6de85c84cd9baaed01e861a51e072c88de55211a048044f99b
[INFO] running `Command { std: "docker" "start" "-a" "140c4e0693179b6de85c84cd9baaed01e861a51e072c88de55211a048044f99b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "140c4e0693179b6de85c84cd9baaed01e861a51e072c88de55211a048044f99b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "140c4e0693179b6de85c84cd9baaed01e861a51e072c88de55211a048044f99b", kill_on_drop: false }`
[INFO] [stdout] 140c4e0693179b6de85c84cd9baaed01e861a51e072c88de55211a048044f99b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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:aa71247004a7fa38d13ec170f48f06cdedf5bc50b2a8645e56ed7e992e6fa513" "/opt/rustwide/cargo-home/bin/cargo" "+bca37a20bd376ce3fd138e7cdee7fe704e0f8814" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] a9e1093fd62f7a38df5fa8dc487b6fadb73f28fac962188415118ee780f7b8b6
[INFO] running `Command { std: "docker" "start" "-a" "a9e1093fd62f7a38df5fa8dc487b6fadb73f28fac962188415118ee780f7b8b6", kill_on_drop: false }`
[INFO] [stderr]    Compiling typenum v1.12.0
[INFO] [stderr]    Compiling memoffset v0.5.5
[INFO] [stderr]     Checking cpuid-bool v0.1.2
[INFO] [stderr]    Compiling generic-array v0.14.4
[INFO] [stderr]     Checking hex v0.4.2
[INFO] [stderr]     Checking crossbeam-queue v0.2.3
[INFO] [stderr]     Checking crossbeam-channel v0.4.3
[INFO] [stderr]     Checking crossbeam-epoch v0.8.2
[INFO] [stderr]     Checking crossbeam-deque v0.7.3
[INFO] [stderr]     Checking crossbeam v0.7.3
[INFO] [stderr]     Checking block-buffer v0.9.0
[INFO] [stderr]     Checking digest v0.9.0
[INFO] [stderr]     Checking sha2 v0.9.1
[INFO] [stderr]     Checking lab4 v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: field `num_pkgs` is never read
[INFO] [stdout]   --> src/idea.rs:17:5
[INFO] [stdout]    |
[INFO] [stdout] 13 | pub struct IdeaGenerator {
[INFO] [stdout]    |            ------------- field in this struct
[INFO] [stdout] ...
[INFO] [stdout] 17 |     num_pkgs: usize,
[INFO] [stdout]    |     ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `id` is never read
[INFO] [stdout]  --> src/student.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 5 | pub struct Student {
[INFO] [stdout]   |            ------- field in this struct
[INFO] [stdout] 6 |     id: usize,
[INFO] [stdout]   |     ^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `num_pkgs` is never read
[INFO] [stdout]   --> src/idea.rs:17:5
[INFO] [stdout]    |
[INFO] [stdout] 13 | pub struct IdeaGenerator {
[INFO] [stdout]    |            ------------- field in this struct
[INFO] [stdout] ...
[INFO] [stdout] 17 |     num_pkgs: usize,
[INFO] [stdout]    |     ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `id` is never read
[INFO] [stdout]  --> src/student.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 5 | pub struct Student {
[INFO] [stdout]   |            ------- field in this struct
[INFO] [stdout] 6 |     id: usize,
[INFO] [stdout]   |     ^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/main.rs:153:9
[INFO] [stdout]     |
[INFO] [stdout] 153 |         idea_send.send(Event::OutOfIdeas);
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 153 |         let _ = idea_send.send(Event::OutOfIdeas);
[INFO] [stdout]     |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/main.rs:153:9
[INFO] [stdout]     |
[INFO] [stdout] 153 |         idea_send.send(Event::OutOfIdeas);
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 153 |         let _ = idea_send.send(Event::OutOfIdeas);
[INFO] [stdout]     |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 3.28s
[INFO] running `Command { std: "docker" "inspect" "a9e1093fd62f7a38df5fa8dc487b6fadb73f28fac962188415118ee780f7b8b6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a9e1093fd62f7a38df5fa8dc487b6fadb73f28fac962188415118ee780f7b8b6", kill_on_drop: false }`
[INFO] [stdout] a9e1093fd62f7a38df5fa8dc487b6fadb73f28fac962188415118ee780f7b8b6