[INFO] cloning repository https://github.com/yuizho/rust_system_programming_introduction
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/yuizho/rust_system_programming_introduction" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fyuizho%2Frust_system_programming_introduction", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fyuizho%2Frust_system_programming_introduction'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] bee2ddc890ff2e036f18e3af0ee0b63c5b554012
[INFO] checking yuizho/rust_system_programming_introduction against try#39e1293fce4b650061e85dda88aa428f726a8444 for pr-88041
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fyuizho%2Frust_system_programming_introduction" "/workspace/builds/worker-62/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-62/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/yuizho/rust_system_programming_introduction on toolchain 39e1293fce4b650061e85dda88aa428f726a8444
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+39e1293fce4b650061e85dda88aa428f726a8444" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/yuizho/rust_system_programming_introduction
[INFO] finished tweaking git repo https://github.com/yuizho/rust_system_programming_introduction
[INFO] tweaked toml for git repo https://github.com/yuizho/rust_system_programming_introduction written to /workspace/builds/worker-62/source/Cargo.toml
[INFO] crate git repo https://github.com/yuizho/rust_system_programming_introduction already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+39e1293fce4b650061e85dda88aa428f726a8444" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-62/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-62/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+39e1293fce4b650061e85dda88aa428f726a8444" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] e7a7d061ba69a79efd95a01a2f7ae6950cc3dc5b22458e9df5603b01c0c83846
[INFO] running `Command { std: "docker" "start" "-a" "e7a7d061ba69a79efd95a01a2f7ae6950cc3dc5b22458e9df5603b01c0c83846", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e7a7d061ba69a79efd95a01a2f7ae6950cc3dc5b22458e9df5603b01c0c83846", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e7a7d061ba69a79efd95a01a2f7ae6950cc3dc5b22458e9df5603b01c0c83846", kill_on_drop: false }`
[INFO] [stdout] e7a7d061ba69a79efd95a01a2f7ae6950cc3dc5b22458e9df5603b01c0c83846
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-62/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-62/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+39e1293fce4b650061e85dda88aa428f726a8444" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] e4532e34df91b69395734642c0e4b8a57b1bfc8ba4385a156fdbf75d2339fc24
[INFO] running `Command { std: "docker" "start" "-a" "e4532e34df91b69395734642c0e4b8a57b1bfc8ba4385a156fdbf75d2339fc24", kill_on_drop: false }`
[INFO] [stderr]     Checking rust_system_programming_introduction v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/reader/file.rs:15:9
[INFO] [stdout]    |
[INFO] [stdout] 15 |     let mut reader = BufReader::with_capacity(4, f);
[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: unused `Result` that must be used
[INFO] [stdout]  --> src/reader/file.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 |     f.read_to_string(&mut buffer);
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/writer/network.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 |     stream.write(b"GET / HTTP/1.0\r\nHost: ascii.jp\r\n\r\n");
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/writer/network.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 |     stream.read_to_string(&mut buff);
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/writer/network.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 |     stream.write(b"GET / HTTP/1.0\r\nHost: ascii.jp\r\n\r\n");
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/writer/network.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 |     stream.read_to_string(&mut buff);
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[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] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/reader/file.rs:15:9
[INFO] [stdout]    |
[INFO] [stdout] 15 |     let mut reader = BufReader::with_capacity(4, f);
[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: unused `Result` that must be used
[INFO] [stdout]  --> src/reader/file.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 |     f.read_to_string(&mut buffer);
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.17s
[INFO] running `Command { std: "docker" "inspect" "e4532e34df91b69395734642c0e4b8a57b1bfc8ba4385a156fdbf75d2339fc24", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e4532e34df91b69395734642c0e4b8a57b1bfc8ba4385a156fdbf75d2339fc24", kill_on_drop: false }`
[INFO] [stdout] e4532e34df91b69395734642c0e4b8a57b1bfc8ba4385a156fdbf75d2339fc24