[INFO] cloning repository https://github.com/rayz/learn-rust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/rayz/learn-rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Frayz%2Flearn-rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Frayz%2Flearn-rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 4f1d55c55d8e66fca1a2013200cf12eb99a48d55
[INFO] checking rayz/learn-rust against master#4fa76a4a7742bb9c1febe33019f5a9e7e4839a65 for pr-83744
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Frayz%2Flearn-rust" "/workspace/builds/worker-10/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-10/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/rayz/learn-rust on toolchain 4fa76a4a7742bb9c1febe33019f5a9e7e4839a65
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+4fa76a4a7742bb9c1febe33019f5a9e7e4839a65" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/rayz/learn-rust
[INFO] finished tweaking git repo https://github.com/rayz/learn-rust
[INFO] tweaked toml for git repo https://github.com/rayz/learn-rust written to /workspace/builds/worker-10/source/Cargo.toml
[INFO] crate git repo https://github.com/rayz/learn-rust already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+4fa76a4a7742bb9c1febe33019f5a9e7e4839a65" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+4fa76a4a7742bb9c1febe33019f5a9e7e4839a65" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] cd1451ce3f9844d63785c49d3ef707bdae0de75cf6c4d8f0b232152ded204209
[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" "cd1451ce3f9844d63785c49d3ef707bdae0de75cf6c4d8f0b232152ded204209", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "cd1451ce3f9844d63785c49d3ef707bdae0de75cf6c4d8f0b232152ded204209", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "cd1451ce3f9844d63785c49d3ef707bdae0de75cf6c4d8f0b232152ded204209", kill_on_drop: false }`
[INFO] [stdout] cd1451ce3f9844d63785c49d3ef707bdae0de75cf6c4d8f0b232152ded204209
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+4fa76a4a7742bb9c1febe33019f5a9e7e4839a65" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 4651b3ee8cc0287400b50730ba65cca5ec5b63ec55777d50a938b070d95641d1
[INFO] running `Command { std: "docker" "start" "-a" "4651b3ee8cc0287400b50730ba65cca5ec5b63ec55777d50a938b070d95641d1", kill_on_drop: false }`
[INFO] [stderr]     Checking learn-rust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/bin/vec.rs:18:13
[INFO] [stdout]    |
[INFO] [stdout] 18 |         let y = i;
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::io`
[INFO] [stdout]  --> src/bin/err_from_main.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::io;
[INFO] [stdout]   |     ^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `test_iter_mut`
[INFO] [stdout]  --> src/bin/vec.rs:7:4
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn test_iter_mut() {
[INFO] [stdout]   |    ^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `test_fold`
[INFO] [stdout]   --> src/bin/vec.rs:15:4
[INFO] [stdout]    |
[INFO] [stdout] 15 | fn test_fold() {
[INFO] [stdout]    |    ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `file`
[INFO] [stdout]  --> src/bin/err_from_main.rs:5:13
[INFO] [stdout]   |
[INFO] [stdout] 5 |     let mut file = File::open("foo.txt")?;
[INFO] [stdout]   |             ^^^^ help: if this is intentional, prefix it with an underscore: `_file`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]  --> src/bin/err_from_main.rs:5:9
[INFO] [stdout]   |
[INFO] [stdout] 5 |     let mut file = File::open("foo.txt")?;
[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: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `e`
[INFO] [stdout]  --> src/bin/errs.rs:8:13
[INFO] [stdout]   |
[INFO] [stdout] 8 |         Err(e) => println!("Error reading username from file!"),
[INFO] [stdout]   |             ^ help: if this is intentional, prefix it with an underscore: `_e`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `e`
[INFO] [stdout]  --> src/bin/errs.rs:8:13
[INFO] [stdout]   |
[INFO] [stdout] 8 |         Err(e) => println!("Error reading username from file!"),
[INFO] [stdout]   |             ^ help: if this is intentional, prefix it with an underscore: `_e`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/bin/vec.rs:18:13
[INFO] [stdout]    |
[INFO] [stdout] 18 |         let y = i;
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `test_iter_mut`
[INFO] [stdout]  --> src/bin/vec.rs:7:4
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn test_iter_mut() {
[INFO] [stdout]   |    ^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `test_fold`
[INFO] [stdout]   --> src/bin/vec.rs:15:4
[INFO] [stdout]    |
[INFO] [stdout] 15 | fn test_fold() {
[INFO] [stdout]    |    ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::io`
[INFO] [stdout]  --> src/bin/err_from_main.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::io;
[INFO] [stdout]   |     ^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `file`
[INFO] [stdout]  --> src/bin/err_from_main.rs:5:13
[INFO] [stdout]   |
[INFO] [stdout] 5 |     let mut file = File::open("foo.txt")?;
[INFO] [stdout]   |             ^^^^ help: if this is intentional, prefix it with an underscore: `_file`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]  --> src/bin/err_from_main.rs:5:9
[INFO] [stdout]   |
[INFO] [stdout] 5 |     let mut file = File::open("foo.txt")?;
[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: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 2.38s
[INFO] running `Command { std: "docker" "inspect" "4651b3ee8cc0287400b50730ba65cca5ec5b63ec55777d50a938b070d95641d1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4651b3ee8cc0287400b50730ba65cca5ec5b63ec55777d50a938b070d95641d1", kill_on_drop: false }`
[INFO] [stdout] 4651b3ee8cc0287400b50730ba65cca5ec5b63ec55777d50a938b070d95641d1