[INFO] updating cached repository https://github.com/Ermain-12/Introduction-to-Rust
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/big/crater/work/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune"`
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 19db755187092c11f3f3ea13092682fc7bc92786
[INFO] testing Ermain-12/Introduction-to-Rust against beta-2019-09-28 for beta-1.39-1
[INFO] running `"git" "clone" "work/cache/git-repos/https%3A%2F%2Fgithub.com%2FErmain-12%2FIntroduction-to-Rust" "work/builds/worker-4/source"`
[INFO] [stderr] Cloning into 'work/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/Ermain-12/Introduction-to-Rust on toolchain beta-2019-09-28
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+beta-2019-09-28" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/Ermain-12/Introduction-to-Rust
[INFO] finished tweaking git repo https://github.com/Ermain-12/Introduction-to-Rust
[INFO] tweaked toml for git repo https://github.com/Ermain-12/Introduction-to-Rust written to work/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/Ermain-12/Introduction-to-Rust already has a lockfile, it will not be regenerated
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+beta-2019-09-28" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/big/crater/work/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/big/crater/work/builds/worker-4/source:/opt/rustwide/workdir:ro,Z" "-v" "/big/crater/work/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/big/crater/work/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-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" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2019-09-28" "build" "--frozen"`
[INFO] [stdout] 1dd2502fa2c5a351af268f6d1ac9366db6b18a330f9b643287ad4b4a304ab746
[INFO] running `"docker" "start" "-a" "1dd2502fa2c5a351af268f6d1ac9366db6b18a330f9b643287ad4b4a304ab746"`
[INFO] [stderr]    Compiling hello_world v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:27:8
[INFO] [stderr]    |
[INFO] [stderr] 27 |    let mut twenty_one = my_vec.pop();
[INFO] [stderr]    |        ----^^^^^^^^^^
[INFO] [stderr]    |        |
[INFO] [stderr]    |        help: remove this `mut`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 3.06s
[INFO] running `"docker" "inspect" "1dd2502fa2c5a351af268f6d1ac9366db6b18a330f9b643287ad4b4a304ab746"`
[INFO] running `"docker" "rm" "-f" "1dd2502fa2c5a351af268f6d1ac9366db6b18a330f9b643287ad4b4a304ab746"`
[INFO] [stdout] 1dd2502fa2c5a351af268f6d1ac9366db6b18a330f9b643287ad4b4a304ab746
[INFO] running `"docker" "create" "-v" "/big/crater/work/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/big/crater/work/builds/worker-4/source:/opt/rustwide/workdir:ro,Z" "-v" "/big/crater/work/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/big/crater/work/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-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" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2019-09-28" "test" "--frozen" "--no-run"`
[INFO] [stdout] 59f479514d7b26c0c1b715134caaa91a768000bd15cc882d900d85ad0d0ea2d9
[INFO] running `"docker" "start" "-a" "59f479514d7b26c0c1b715134caaa91a768000bd15cc882d900d85ad0d0ea2d9"`
[INFO] [stderr]    Compiling hello_world v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:27:8
[INFO] [stderr]    |
[INFO] [stderr] 27 |    let mut twenty_one = my_vec.pop();
[INFO] [stderr]    |        ----^^^^^^^^^^
[INFO] [stderr]    |        |
[INFO] [stderr]    |        help: remove this `mut`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.58s
[INFO] running `"docker" "inspect" "59f479514d7b26c0c1b715134caaa91a768000bd15cc882d900d85ad0d0ea2d9"`
[INFO] running `"docker" "rm" "-f" "59f479514d7b26c0c1b715134caaa91a768000bd15cc882d900d85ad0d0ea2d9"`
[INFO] [stdout] 59f479514d7b26c0c1b715134caaa91a768000bd15cc882d900d85ad0d0ea2d9
[INFO] running `"docker" "create" "-v" "/big/crater/work/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/big/crater/work/builds/worker-4/source:/opt/rustwide/workdir:ro,Z" "-v" "/big/crater/work/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/big/crater/work/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-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" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2019-09-28" "test" "--frozen"`
[INFO] [stdout] e236d275d0f3692653d2a7c13fb4ed65365b5bb47e9912ce06bd6499b2ccf34d
[INFO] running `"docker" "start" "-a" "e236d275d0f3692653d2a7c13fb4ed65365b5bb47e9912ce06bd6499b2ccf34d"`
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.02s
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/hello_world-90240d63d3ed70ea
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] running `"docker" "inspect" "e236d275d0f3692653d2a7c13fb4ed65365b5bb47e9912ce06bd6499b2ccf34d"`
[INFO] running `"docker" "rm" "-f" "e236d275d0f3692653d2a7c13fb4ed65365b5bb47e9912ce06bd6499b2ccf34d"`
[INFO] [stdout] e236d275d0f3692653d2a7c13fb4ed65365b5bb47e9912ce06bd6499b2ccf34d