[INFO] cloning repository https://github.com/fahrenkrug/rust_learn_book_errors
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/fahrenkrug/rust_learn_book_errors" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffahrenkrug%2Frust_learn_book_errors", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffahrenkrug%2Frust_learn_book_errors'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] aa959a404d3e1af5bf3df0465fa974898c211764
[INFO] checking fahrenkrug/rust_learn_book_errors against master#90442458ac46b1d5eed752c316da25450f67285b for pr-81477
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffahrenkrug%2Frust_learn_book_errors" "/workspace/builds/worker-14/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-14/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/fahrenkrug/rust_learn_book_errors on toolchain 90442458ac46b1d5eed752c316da25450f67285b
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+90442458ac46b1d5eed752c316da25450f67285b" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/fahrenkrug/rust_learn_book_errors
[INFO] finished tweaking git repo https://github.com/fahrenkrug/rust_learn_book_errors
[INFO] tweaked toml for git repo https://github.com/fahrenkrug/rust_learn_book_errors written to /workspace/builds/worker-14/source/Cargo.toml
[INFO] crate git repo https://github.com/fahrenkrug/rust_learn_book_errors already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+90442458ac46b1d5eed752c316da25450f67285b" "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-14/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/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" "+90442458ac46b1d5eed752c316da25450f67285b" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 02ef93e978527021f1934f822ea0f110ab0187cfdd49edc25699ae3e14c610d8
[INFO] running `Command { std: "docker" "start" "-a" "02ef93e978527021f1934f822ea0f110ab0187cfdd49edc25699ae3e14c610d8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "02ef93e978527021f1934f822ea0f110ab0187cfdd49edc25699ae3e14c610d8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "02ef93e978527021f1934f822ea0f110ab0187cfdd49edc25699ae3e14c610d8", kill_on_drop: false }`
[INFO] [stdout] 02ef93e978527021f1934f822ea0f110ab0187cfdd49edc25699ae3e14c610d8
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/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" "+90442458ac46b1d5eed752c316da25450f67285b" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 51ea5025c1a07fe2c335bbe915d4018d42b0aa8f52abb28e03dc3776926fec29
[INFO] running `Command { std: "docker" "start" "-a" "51ea5025c1a07fe2c335bbe915d4018d42b0aa8f52abb28e03dc3776926fec29", kill_on_drop: false }`
[INFO] [stderr]     Checking errors v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/main.rs:65:9
[INFO] [stdout]    |
[INFO] [stdout] 65 |     let f = File::open("hello.txt")?;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `read_username_from_file`
[INFO] [stdout]   --> src/main.rs:69:4
[INFO] [stdout]    |
[INFO] [stdout] 69 | fn read_username_from_file() -> Result<String, io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/main.rs:65:9
[INFO] [stdout]    |
[INFO] [stdout] 65 |     let f = File::open("hello.txt")?;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `read_username_from_file`
[INFO] [stdout]   --> src/main.rs:69:4
[INFO] [stdout]    |
[INFO] [stdout] 69 | fn read_username_from_file() -> Result<String, io::Error> {
[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 [unoptimized + debuginfo] target(s) in 0.17s
[INFO] running `Command { std: "docker" "inspect" "51ea5025c1a07fe2c335bbe915d4018d42b0aa8f52abb28e03dc3776926fec29", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "51ea5025c1a07fe2c335bbe915d4018d42b0aa8f52abb28e03dc3776926fec29", kill_on_drop: false }`
[INFO] [stdout] 51ea5025c1a07fe2c335bbe915d4018d42b0aa8f52abb28e03dc3776926fec29