[INFO] updating cached 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" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune", kill_on_drop: false }`
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] bee2ddc890ff2e036f18e3af0ee0b63c5b554012
[INFO] checking yuizho/rust_system_programming_introduction against master#1557fb031b272b4c5bfcc7de5df7eddc7b36a584 for pr-73166
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fyuizho%2Frust_system_programming_introduction" "/workspace/builds/worker-1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/yuizho/rust_system_programming_introduction on toolchain 1557fb031b272b4c5bfcc7de5df7eddc7b36a584
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1557fb031b272b4c5bfcc7de5df7eddc7b36a584" "read-manifest" "--manifest-path" "Cargo.toml", 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-1/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" "+1557fb031b272b4c5bfcc7de5df7eddc7b36a584" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+1557fb031b272b4c5bfcc7de5df7eddc7b36a584" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 72c18b31186cfd9bc44c35f93670d0e3005ad7c25d55ec72f7a738868c0fead9
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "72c18b31186cfd9bc44c35f93670d0e3005ad7c25d55ec72f7a738868c0fead9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "72c18b31186cfd9bc44c35f93670d0e3005ad7c25d55ec72f7a738868c0fead9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "72c18b31186cfd9bc44c35f93670d0e3005ad7c25d55ec72f7a738868c0fead9", kill_on_drop: false }`
[INFO] [stdout] 72c18b31186cfd9bc44c35f93670d0e3005ad7c25d55ec72f7a738868c0fead9
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+1557fb031b272b4c5bfcc7de5df7eddc7b36a584" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 9d6d8bee0d0c6e393690fce36a07572d6f2737712f8c9b01fbfd15b8433dae72
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "9d6d8bee0d0c6e393690fce36a07572d6f2737712f8c9b01fbfd15b8433dae72", kill_on_drop: false }`
[INFO] [stderr]     Checking rust_system_programming_introduction v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused `std::result::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 `std::result::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: 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 `std::result::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 `std::result::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 `std::result::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 `std::result::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 1.22s
[INFO] running `Command { std: "docker" "inspect" "9d6d8bee0d0c6e393690fce36a07572d6f2737712f8c9b01fbfd15b8433dae72", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9d6d8bee0d0c6e393690fce36a07572d6f2737712f8c9b01fbfd15b8433dae72", kill_on_drop: false }`
[INFO] [stdout] 9d6d8bee0d0c6e393690fce36a07572d6f2737712f8c9b01fbfd15b8433dae72