[INFO] cloning repository https://github.com/brecert/a2048
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/brecert/a2048" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fbrecert%2Fa2048", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fbrecert%2Fa2048'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 510cc8b060e5f8b7875f3f34ca1cb3aea328c494
[INFO] testing brecert/a2048 against 1.55.0 for beta-1.56-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fbrecert%2Fa2048" "/workspace/builds/worker-3/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/brecert/a2048 on toolchain 1.55.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/brecert/a2048
[INFO] finished tweaking git repo https://github.com/brecert/a2048
[INFO] tweaked toml for git repo https://github.com/brecert/a2048 written to /workspace/builds/worker-3/source/Cargo.toml
[INFO] crate git repo https://github.com/brecert/a2048 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] f20d91731bace43106668ac418cf02bf1917337be8bbed7917bacce50f9d2eba
[INFO] running `Command { std: "docker" "start" "-a" "f20d91731bace43106668ac418cf02bf1917337be8bbed7917bacce50f9d2eba", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "f20d91731bace43106668ac418cf02bf1917337be8bbed7917bacce50f9d2eba", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f20d91731bace43106668ac418cf02bf1917337be8bbed7917bacce50f9d2eba", kill_on_drop: false }`
[INFO] [stdout] f20d91731bace43106668ac418cf02bf1917337be8bbed7917bacce50f9d2eba
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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=warn" "-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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] c67cddd33fa121897ff72caa762265fec63fac802d62a5c513de801bc8107423
[INFO] running `Command { std: "docker" "start" "-a" "c67cddd33fa121897ff72caa762265fec63fac802d62a5c513de801bc8107423", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.101
[INFO] [stderr]    Compiling proc-macro2 v1.0.29
[INFO] [stderr]    Compiling unicode-xid v0.2.2
[INFO] [stderr]    Compiling syn v1.0.75
[INFO] [stderr]    Compiling unicode-segmentation v1.8.0
[INFO] [stderr]    Compiling argh_shared v0.1.5
[INFO] [stderr]    Compiling numtoa v0.1.0
[INFO] [stderr]    Compiling no-std-compat v0.4.1
[INFO] [stderr]    Compiling paste v1.0.5
[INFO] [stderr]    Compiling grid v0.5.1-alpha.0 (https://github.com/brecert/grid#4b840059)
[INFO] [stderr]    Compiling heck v0.3.3
[INFO] [stderr]    Compiling quote v1.0.9
[INFO] [stderr]    Compiling getrandom v0.2.3
[INFO] [stderr]    Compiling termion v1.5.6
[INFO] [stderr]    Compiling rand_core v0.6.3
[INFO] [stderr]    Compiling rand_chacha v0.3.1
[INFO] [stderr]    Compiling rand v0.8.4
[INFO] [stderr]    Compiling argh_derive v0.1.5
[INFO] [stderr]    Compiling argh v0.1.5
[INFO] [stderr]    Compiling a2048 v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(const_generics)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `a2048` due to 2 previous errors
[INFO] running `Command { std: "docker" "inspect" "c67cddd33fa121897ff72caa762265fec63fac802d62a5c513de801bc8107423", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c67cddd33fa121897ff72caa762265fec63fac802d62a5c513de801bc8107423", kill_on_drop: false }`
[INFO] [stdout] c67cddd33fa121897ff72caa762265fec63fac802d62a5c513de801bc8107423