[INFO] cloning repository https://github.com/nifey/tutor
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/nifey/tutor" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnifey%2Ftutor", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnifey%2Ftutor'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] c79140d29ead31abd85aefc621a8dcad731b7d3b
[INFO] checking nifey/tutor against master#33fdb797f59421c7bbecaa4588ed5d7a31a9494a for pr-87190-3
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnifey%2Ftutor" "/workspace/builds/worker-20/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-20/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/nifey/tutor on toolchain 33fdb797f59421c7bbecaa4588ed5d7a31a9494a
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+33fdb797f59421c7bbecaa4588ed5d7a31a9494a" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/nifey/tutor
[INFO] finished tweaking git repo https://github.com/nifey/tutor
[INFO] tweaked toml for git repo https://github.com/nifey/tutor written to /workspace/builds/worker-20/source/Cargo.toml
[INFO] crate git repo https://github.com/nifey/tutor already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+33fdb797f59421c7bbecaa4588ed5d7a31a9494a" "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-20/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-20/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" "+33fdb797f59421c7bbecaa4588ed5d7a31a9494a" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 58e08d0177fb51492a5c100e765202d9102d6ecf6a5a3be4bfe89008279ad4a3
[INFO] running `Command { std: "docker" "start" "-a" "58e08d0177fb51492a5c100e765202d9102d6ecf6a5a3be4bfe89008279ad4a3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "58e08d0177fb51492a5c100e765202d9102d6ecf6a5a3be4bfe89008279ad4a3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "58e08d0177fb51492a5c100e765202d9102d6ecf6a5a3be4bfe89008279ad4a3", kill_on_drop: false }`
[INFO] [stdout] 58e08d0177fb51492a5c100e765202d9102d6ecf6a5a3be4bfe89008279ad4a3
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-20/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-20/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" "+33fdb797f59421c7bbecaa4588ed5d7a31a9494a" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] e9e1fa1bd44ef6042d17df45c6f2c43ef5a850d25d1148eb82b1599d4edd2a04
[INFO] running `Command { std: "docker" "start" "-a" "e9e1fa1bd44ef6042d17df45c6f2c43ef5a850d25d1148eb82b1599d4edd2a04", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling proc-macro2 v1.0.19
[INFO] [stderr]    Compiling unicode-xid v0.2.1
[INFO] [stderr]    Compiling syn v1.0.35
[INFO] [stderr]    Compiling serde_derive v1.0.114
[INFO] [stderr]    Compiling libc v0.2.72
[INFO] [stderr]    Compiling serde v1.0.114
[INFO] [stderr]    Compiling bitflags v1.2.1
[INFO] [stderr]    Compiling quote v1.0.7
[INFO] [stderr]     Checking atty v0.2.14
[INFO] [stderr]     Checking clap v2.33.1
[INFO] [stderr]     Checking toml v0.5.6
[INFO] [stderr]     Checking tutor v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `section_str`
[INFO] [stdout]   --> src/main.rs:99:13
[INFO] [stdout]    |
[INFO] [stdout] 99 |         let section_str = cmd_matches.value_of("section").unwrap_or("");
[INFO] [stdout]    |             ^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_section_str`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `cmd_matches`
[INFO] [stdout]    --> src/main.rs:102:17
[INFO] [stdout]     |
[INFO] [stdout] 102 |     if let Some(cmd_matches) = matches.subcommand_matches("instruction") {
[INFO] [stdout]     |                 ^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_cmd_matches`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `lesson_index`
[INFO] [stdout]    --> src/main.rs:132:13
[INFO] [stdout]     |
[INFO] [stdout] 132 |         let lesson_index = cmd_matches.value_of("lesson_index").unwrap_or("");
[INFO] [stdout]     |             ^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_lesson_index`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `lesson_index`
[INFO] [stdout]    --> src/main.rs:141:13
[INFO] [stdout]     |
[INFO] [stdout] 141 |         let lesson_index = cmd_matches.value_of("lesson_index").unwrap_or("");
[INFO] [stdout]     |             ^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_lesson_index`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `next`
[INFO] [stdout]    --> src/main.rs:150:13
[INFO] [stdout]     |
[INFO] [stdout] 150 |         let next = cmd_matches.value_of("section").is_some();
[INFO] [stdout]     |             ^^^^ help: if this is intentional, prefix it with an underscore: `_next`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `get_string`
[INFO] [stdout]  --> src/index.rs:6:12
[INFO] [stdout]   |
[INFO] [stdout] 6 |     pub fn get_string(&self) -> String {
[INFO] [stdout]   |            ^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `new`
[INFO] [stdout]   --> src/index.rs:29:8
[INFO] [stdout]    |
[INFO] [stdout] 29 | pub fn new(section: u32, lesson: u32) -> Index {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `get_title`
[INFO] [stdout]   --> src/info.rs:14:12
[INFO] [stdout]    |
[INFO] [stdout] 14 |     pub fn get_title(&self) -> String {
[INFO] [stdout]    |            ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `get_title`
[INFO] [stdout]   --> src/info.rs:30:12
[INFO] [stdout]    |
[INFO] [stdout] 30 |     pub fn get_title(&self) -> String {
[INFO] [stdout]    |            ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `get_lesson_title`
[INFO] [stdout]   --> src/info.rs:34:12
[INFO] [stdout]    |
[INFO] [stdout] 34 |     pub fn get_lesson_title(&self, lesson_index: u32) -> Result<String, String> {
[INFO] [stdout]    |            ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `get_tutorial_version`
[INFO] [stdout]   --> src/stat.rs:16:12
[INFO] [stdout]    |
[INFO] [stdout] 16 |     pub fn get_tutorial_version(&self) -> String {
[INFO] [stdout]    |            ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `get_hints_used`
[INFO] [stdout]   --> src/stat.rs:24:12
[INFO] [stdout]    |
[INFO] [stdout] 24 |     pub fn get_hints_used(&self, lesson: String) -> Result<u32, String> {
[INFO] [stdout]    |            ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `section_str`
[INFO] [stdout]   --> src/main.rs:99:13
[INFO] [stdout]    |
[INFO] [stdout] 99 |         let section_str = cmd_matches.value_of("section").unwrap_or("");
[INFO] [stdout]    |             ^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_section_str`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `cmd_matches`
[INFO] [stdout]    --> src/main.rs:102:17
[INFO] [stdout]     |
[INFO] [stdout] 102 |     if let Some(cmd_matches) = matches.subcommand_matches("instruction") {
[INFO] [stdout]     |                 ^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_cmd_matches`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `lesson_index`
[INFO] [stdout]    --> src/main.rs:132:13
[INFO] [stdout]     |
[INFO] [stdout] 132 |         let lesson_index = cmd_matches.value_of("lesson_index").unwrap_or("");
[INFO] [stdout]     |             ^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_lesson_index`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `lesson_index`
[INFO] [stdout]    --> src/main.rs:141:13
[INFO] [stdout]     |
[INFO] [stdout] 141 |         let lesson_index = cmd_matches.value_of("lesson_index").unwrap_or("");
[INFO] [stdout]     |             ^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_lesson_index`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `next`
[INFO] [stdout]    --> src/main.rs:150:13
[INFO] [stdout]     |
[INFO] [stdout] 150 |         let next = cmd_matches.value_of("section").is_some();
[INFO] [stdout]     |             ^^^^ help: if this is intentional, prefix it with an underscore: `_next`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/stat.rs:68:5
[INFO] [stdout]    |
[INFO] [stdout] 68 |     stat_file.write_all(toml::to_string_pretty(&stat).unwrap().as_bytes());
[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: 13 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `get_string`
[INFO] [stdout]  --> src/index.rs:6:12
[INFO] [stdout]   |
[INFO] [stdout] 6 |     pub fn get_string(&self) -> String {
[INFO] [stdout]   |            ^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `new`
[INFO] [stdout]   --> src/index.rs:29:8
[INFO] [stdout]    |
[INFO] [stdout] 29 | pub fn new(section: u32, lesson: u32) -> Index {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `get_title`
[INFO] [stdout]   --> src/info.rs:14:12
[INFO] [stdout]    |
[INFO] [stdout] 14 |     pub fn get_title(&self) -> String {
[INFO] [stdout]    |            ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `get_title`
[INFO] [stdout]   --> src/info.rs:30:12
[INFO] [stdout]    |
[INFO] [stdout] 30 |     pub fn get_title(&self) -> String {
[INFO] [stdout]    |            ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `get_lesson_title`
[INFO] [stdout]   --> src/info.rs:34:12
[INFO] [stdout]    |
[INFO] [stdout] 34 |     pub fn get_lesson_title(&self, lesson_index: u32) -> Result<String, String> {
[INFO] [stdout]    |            ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `get_tutorial_version`
[INFO] [stdout]   --> src/stat.rs:16:12
[INFO] [stdout]    |
[INFO] [stdout] 16 |     pub fn get_tutorial_version(&self) -> String {
[INFO] [stdout]    |            ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `get_hints_used`
[INFO] [stdout]   --> src/stat.rs:24:12
[INFO] [stdout]    |
[INFO] [stdout] 24 |     pub fn get_hints_used(&self, lesson: String) -> Result<u32, String> {
[INFO] [stdout]    |            ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/stat.rs:68:5
[INFO] [stdout]    |
[INFO] [stdout] 68 |     stat_file.write_all(toml::to_string_pretty(&stat).unwrap().as_bytes());
[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: 13 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 48.54s
[INFO] running `Command { std: "docker" "inspect" "e9e1fa1bd44ef6042d17df45c6f2c43ef5a850d25d1148eb82b1599d4edd2a04", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e9e1fa1bd44ef6042d17df45c6f2c43ef5a850d25d1148eb82b1599d4edd2a04", kill_on_drop: false }`
[INFO] [stdout] e9e1fa1bd44ef6042d17df45c6f2c43ef5a850d25d1148eb82b1599d4edd2a04