[INFO] updating cached repository Cancain/rust_arena
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/Cancain/rust_arena
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/Cancain/rust_arena" "work/ex/beta-1.38-1/sources/1.37.0/gh/Cancain/rust_arena"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/Cancain/rust_arena'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/Cancain/rust_arena" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Cancain/rust_arena"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Cancain/rust_arena'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 139f1603368b07ced0078101143c2aafa2854a6a
[INFO] sha for GitHub repo Cancain/rust_arena: 139f1603368b07ced0078101143c2aafa2854a6a
[INFO] validating manifest of Cancain/rust_arena on toolchain 1.37.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of Cancain/rust_arena on toolchain beta-2019-08-13
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing Cancain/rust_arena
[INFO] finished frobbing Cancain/rust_arena
[INFO] frobbed toml for Cancain/rust_arena written to work/ex/beta-1.38-1/sources/1.37.0/gh/Cancain/rust_arena/Cargo.toml
[INFO] started frobbing Cancain/rust_arena
[INFO] finished frobbing Cancain/rust_arena
[INFO] frobbed toml for Cancain/rust_arena written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Cancain/rust_arena/Cargo.toml
[INFO] crate Cancain/rust_arena already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing Cancain/rust_arena against beta-2019-08-13 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-6/beta-2019-08-13:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Cancain/rust_arena:/opt/crater/workdir:ro,Z" "-v" "/mnt/big/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+beta-2019-08-13" "build" "--frozen"`
[INFO] [stdout] cb0ccef480ec927d4e27b92be27cf36ad81775b509afb1903ce12eff70611e22
[INFO] running `"docker" "start" "-a" "cb0ccef480ec927d4e27b92be27cf36ad81775b509afb1903ce12eff70611e22"`
[INFO] [stderr]    Compiling getrandom v0.1.6
[INFO] [stderr]    Compiling rand_core v0.5.0
[INFO] [stderr]    Compiling rand_chacha v0.2.0
[INFO] [stderr]    Compiling rand v0.7.0
[INFO] [stderr]    Compiling rust_arena v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: value assigned to `game_on` is never read
[INFO] [stderr]   --> src/characters.rs:34:29
[INFO] [stderr]    |
[INFO] [stderr] 34 |             "e" | "exit" => game_on = false,
[INFO] [stderr]    |                             ^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stderr]    = help: maybe it is overwritten before being read?
[INFO] [stderr] 
[INFO] [stderr] warning: variable `game_on` is assigned to, but never used
[INFO] [stderr]   --> src/characters.rs:20:35
[INFO] [stderr]    |
[INFO] [stderr] 20 | pub fn start_new_player_character(game_on: bool) -> Character {
[INFO] [stderr]    |                                   ^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr]    = note: consider using `_game_on` instead
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:18:9
[INFO] [stderr]    |
[INFO] [stderr] 18 |     let mut game_on = true;
[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] error[E0384]: cannot assign to immutable argument `game_on`
[INFO] [stderr]   --> src/characters.rs:34:29
[INFO] [stderr]    |
[INFO] [stderr] 20 | pub fn start_new_player_character(game_on: bool) -> Character {
[INFO] [stderr]    |                                   ------- help: make this binding mutable: `mut game_on`
[INFO] [stderr] ...
[INFO] [stderr] 34 |             "e" | "exit" => game_on = false,
[INFO] [stderr]    |                             ^^^^^^^^^^^^^^^ cannot assign to immutable argument
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0384`.
[INFO] [stderr] error: Could not compile `rust_arena`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "cb0ccef480ec927d4e27b92be27cf36ad81775b509afb1903ce12eff70611e22"`
[INFO] running `"docker" "rm" "-f" "cb0ccef480ec927d4e27b92be27cf36ad81775b509afb1903ce12eff70611e22"`
[INFO] [stdout] cb0ccef480ec927d4e27b92be27cf36ad81775b509afb1903ce12eff70611e22