[INFO] fetching crate brack 0.2.0...
[INFO] testing brack-0.2.0 against 1.55.0 for beta-1.56-1
[INFO] extracting crate brack 0.2.0 into /workspace/builds/worker-32/source
[INFO] validating manifest of crates.io crate brack 0.2.0 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 crates.io crate brack 0.2.0
[INFO] finished tweaking crates.io crate brack 0.2.0
[INFO] tweaked toml for crates.io crate brack 0.2.0 written to /workspace/builds/worker-32/source/Cargo.toml
[INFO] crate crates.io crate brack 0.2.0 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-32/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-32/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] 02dbc870d6f074f4107da748fe6041bf34f583a91dfd0f964d523ec10cc74894
[INFO] running `Command { std: "docker" "start" "-a" "02dbc870d6f074f4107da748fe6041bf34f583a91dfd0f964d523ec10cc74894", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "02dbc870d6f074f4107da748fe6041bf34f583a91dfd0f964d523ec10cc74894", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "02dbc870d6f074f4107da748fe6041bf34f583a91dfd0f964d523ec10cc74894", kill_on_drop: false }`
[INFO] [stdout] 02dbc870d6f074f4107da748fe6041bf34f583a91dfd0f964d523ec10cc74894
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-32/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-32/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] 09fa03c4654ea743e2f535892544e4e67240e73c86b51428bb82741f1d72431b
[INFO] running `Command { std: "docker" "start" "-a" "09fa03c4654ea743e2f535892544e4e67240e73c86b51428bb82741f1d72431b", kill_on_drop: false }`
[INFO] [stderr]    Compiling anyhow v1.0.41
[INFO] [stderr]    Compiling glob v0.3.0
[INFO] [stderr]    Compiling brack v0.2.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/main.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(assert_matches)]
[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 `brack` due to 2 previous errors
[INFO] running `Command { std: "docker" "inspect" "09fa03c4654ea743e2f535892544e4e67240e73c86b51428bb82741f1d72431b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "09fa03c4654ea743e2f535892544e4e67240e73c86b51428bb82741f1d72431b", kill_on_drop: false }`
[INFO] [stdout] 09fa03c4654ea743e2f535892544e4e67240e73c86b51428bb82741f1d72431b