[INFO] cloning repository https://github.com/kpaxian/rust-lessons
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/kpaxian/rust-lessons" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkpaxian%2Frust-lessons", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkpaxian%2Frust-lessons'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 17c58f1d96fd41059f522e9534f27530b31651cd
[INFO] checking kpaxian/rust-lessons against try#d83b14207998f47b18a34e930157ac0d7c18b16e for pr-149137
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkpaxian%2Frust-lessons" "/workspace/builds/worker-5-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-5-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/kpaxian/rust-lessons
[INFO] finished tweaking git repo https://github.com/kpaxian/rust-lessons
[INFO] tweaked toml for git repo https://github.com/kpaxian/rust-lessons written to /workspace/builds/worker-5-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/kpaxian/rust-lessons on toolchain d83b14207998f47b18a34e930157ac0d7c18b16e
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+d83b14207998f47b18a34e930157ac0d7c18b16e" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/kpaxian/rust-lessons 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" "+d83b14207998f47b18a34e930157ac0d7c18b16e" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-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@sha256:94a0c148923f5b2b52a63ef0eeb1882ad339ab61bce784c8077cbe41c61feb6c" "/opt/rustwide/cargo-home/bin/cargo" "+d83b14207998f47b18a34e930157ac0d7c18b16e" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] bf92585398c1b11bdb49bb0f2a0be27a0b057db9792f4da768f9d417a174b294
[INFO] running `Command { std: "docker" "start" "-a" "bf92585398c1b11bdb49bb0f2a0be27a0b057db9792f4da768f9d417a174b294", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "bf92585398c1b11bdb49bb0f2a0be27a0b057db9792f4da768f9d417a174b294", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "bf92585398c1b11bdb49bb0f2a0be27a0b057db9792f4da768f9d417a174b294", kill_on_drop: false }`
[INFO] [stdout] bf92585398c1b11bdb49bb0f2a0be27a0b057db9792f4da768f9d417a174b294
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-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@sha256:94a0c148923f5b2b52a63ef0eeb1882ad339ab61bce784c8077cbe41c61feb6c" "/opt/rustwide/cargo-home/bin/cargo" "+d83b14207998f47b18a34e930157ac0d7c18b16e" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] dab066dba61cbf87dcfe9e331fa68bfe8cd51fe39a1dd44a7e4b9c026dd9274e
[INFO] running `Command { std: "docker" "start" "-a" "dab066dba61cbf87dcfe9e331fa68bfe8cd51fe39a1dd44a7e4b9c026dd9274e", kill_on_drop: false }`
[INFO] [stderr]     Checking rust-lessons v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `greeting_file`
[INFO] [stdout]   --> src/lesson/errs/mod.rs:34:9
[INFO] [stdout]    |
[INFO] [stdout] 34 |     let greeting_file = match greeting_file_result {
[INFO] [stdout]    |         ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_greeting_file`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `greeting_file`
[INFO] [stdout]   --> src/lesson/errs/mod.rs:34:9
[INFO] [stdout]    |
[INFO] [stdout] 34 |     let greeting_file = match greeting_file_result {
[INFO] [stdout]    |         ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_greeting_file`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `init` is never used
[INFO] [stdout]  --> src/lesson/hmaps/mod.rs:4:8
[INFO] [stdout]   |
[INFO] [stdout] 4 | pub fn init() {
[INFO] [stdout]   |        ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `init` is never used
[INFO] [stdout]  --> src/lesson/errs/mod.rs:4:8
[INFO] [stdout]   |
[INFO] [stdout] 4 | pub fn init() {
[INFO] [stdout]   |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `init` is never used
[INFO] [stdout]  --> src/lesson/hmaps/mod.rs:4:8
[INFO] [stdout]   |
[INFO] [stdout] 4 | pub fn init() {
[INFO] [stdout]   |        ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `read_username_from_file` is never used
[INFO] [stdout]   --> src/lesson/errs/mod.rs:13:4
[INFO] [stdout]    |
[INFO] [stdout] 13 | fn read_username_from_file() -> Result<String, std::io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `init` is never used
[INFO] [stdout]  --> src/lesson/errs/mod.rs:4:8
[INFO] [stdout]   |
[INFO] [stdout] 4 | pub fn init() {
[INFO] [stdout]   |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `file_open_handler` is never used
[INFO] [stdout]   --> src/lesson/errs/mod.rs:32:4
[INFO] [stdout]    |
[INFO] [stdout] 32 | fn file_open_handler() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo` is never used
[INFO] [stdout]   --> src/lesson/errs/mod.rs:49:4
[INFO] [stdout]    |
[INFO] [stdout] 49 | fn foo() {
[INFO] [stdout]    |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `read_username_from_file` is never used
[INFO] [stdout]   --> src/lesson/errs/mod.rs:13:4
[INFO] [stdout]    |
[INFO] [stdout] 13 | fn read_username_from_file() -> Result<String, std::io::Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `file_open_handler` is never used
[INFO] [stdout]   --> src/lesson/errs/mod.rs:32:4
[INFO] [stdout]    |
[INFO] [stdout] 32 | fn file_open_handler() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo` is never used
[INFO] [stdout]   --> src/lesson/errs/mod.rs:49:4
[INFO] [stdout]    |
[INFO] [stdout] 49 | fn foo() {
[INFO] [stdout]    |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/lesson/errs/mod.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 |     read_username_from_file();
[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] 5 |     let _ = read_username_from_file();
[INFO] [stdout]   |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/lesson/errs/mod.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 |     read_username_from_file();
[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] 5 |     let _ = read_username_from_file();
[INFO] [stdout]   |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.09s
[INFO] running `Command { std: "docker" "inspect" "dab066dba61cbf87dcfe9e331fa68bfe8cd51fe39a1dd44a7e4b9c026dd9274e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "dab066dba61cbf87dcfe9e331fa68bfe8cd51fe39a1dd44a7e4b9c026dd9274e", kill_on_drop: false }`
[INFO] [stdout] dab066dba61cbf87dcfe9e331fa68bfe8cd51fe39a1dd44a7e4b9c026dd9274e