[INFO] fetching crate xpq 0.2.1...
[INFO] testing xpq-0.2.1 against 1.49.0 for beta-1.50-1
[INFO] extracting crate xpq 0.2.1 into /workspace/builds/worker-5/source
[INFO] validating manifest of crates.io crate xpq 0.2.1 on toolchain 1.49.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate xpq 0.2.1
[INFO] finished tweaking crates.io crate xpq 0.2.1
[INFO] tweaked toml for crates.io crate xpq 0.2.1 written to /workspace/builds/worker-5/source/Cargo.toml
[INFO] crate crates.io crate xpq 0.2.1 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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" "rustops/crates-build-env@sha256:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 1b3fb8b187008b6071cf5b35d54161b7cb3780c96f8ca5ca4a4190d2c014c37d
[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" "1b3fb8b187008b6071cf5b35d54161b7cb3780c96f8ca5ca4a4190d2c014c37d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "1b3fb8b187008b6071cf5b35d54161b7cb3780c96f8ca5ca4a4190d2c014c37d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1b3fb8b187008b6071cf5b35d54161b7cb3780c96f8ca5ca4a4190d2c014c37d", kill_on_drop: false }`
[INFO] [stdout] 1b3fb8b187008b6071cf5b35d54161b7cb3780c96f8ca5ca4a4190d2c014c37d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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" "rustops/crates-build-env@sha256:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 572ca602d8fd456e63f6c653dde9a84a2231be04ed7ba83b43e89fbdff8fd094
[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" "572ca602d8fd456e63f6c653dde9a84a2231be04ed7ba83b43e89fbdff8fd094", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.80
[INFO] [stderr]    Compiling serde v1.0.117
[INFO] [stderr]    Compiling syn v1.0.48
[INFO] [stderr]    Compiling serde_derive v1.0.117
[INFO] [stderr]    Compiling alloc-no-stdlib v2.0.1
[INFO] [stderr]    Compiling serde_json v1.0.59
[INFO] [stderr]    Compiling integer-encoding v1.1.5
[INFO] [stderr]    Compiling snap v1.0.1
[INFO] [stderr]    Compiling parquet v1.0.1
[INFO] [stderr]    Compiling hex v0.4.2
[INFO] [stderr]    Compiling num-bigint v0.3.0
[INFO] [stderr]    Compiling num-rational v0.3.1
[INFO] [stderr]    Compiling itertools v0.9.0
[INFO] [stderr]    Compiling flatbuffers v0.6.1
[INFO] [stderr]    Compiling tabwriter v1.2.1
[INFO] [stderr]    Compiling alloc-stdlib v0.2.1
[INFO] [stderr]    Compiling regex-automata v0.1.9
[INFO] [stderr]    Compiling aho-corasick v0.7.14
[INFO] [stderr]    Compiling csv-core v0.1.10
[INFO] [stderr]    Compiling brotli-decompressor v2.3.1
[INFO] [stderr]    Compiling ordered-float v1.1.0
[INFO] [stderr]    Compiling num-complex v0.3.1
[INFO] [stderr]    Compiling streaming-stats v0.2.3
[INFO] [stderr]    Compiling num-iter v0.1.42
[INFO] [stderr]    Compiling jobserver v0.1.21
[INFO] [stderr]    Compiling getrandom v0.1.15
[INFO] [stderr]    Compiling num_cpus v1.13.0
[INFO] [stderr]    Compiling time v0.1.44
[INFO] [stderr]    Compiling atty v0.2.14
[INFO] [stderr]    Compiling flate2 v1.0.18
[INFO] [stderr]    Compiling clap v2.33.3
[INFO] [stderr]    Compiling regex v1.4.2
[INFO] [stderr]    Compiling threadpool v1.8.1
[INFO] [stderr]    Compiling rand_core v0.5.1
[INFO] [stderr]    Compiling cc v1.0.61
[INFO] [stderr]    Compiling chrono v0.4.19
[INFO] [stderr]    Compiling brotli v3.3.0
[INFO] [stderr]    Compiling thrift v0.13.0
[INFO] [stderr]    Compiling rand_chacha v0.2.2
[INFO] [stderr]    Compiling parquet-format v2.6.1
[INFO] [stderr]    Compiling rand v0.7.3
[INFO] [stderr]    Compiling num v0.3.0
[INFO] [stderr]    Compiling zstd-sys v1.4.17+zstd.1.4.5
[INFO] [stderr]    Compiling lz4-sys v1.9.2
[INFO] [stderr]    Compiling bstr v0.2.14
[INFO] [stderr]    Compiling csv v1.1.3
[INFO] [stderr]    Compiling lz4 v1.23.2
[INFO] [stderr]    Compiling arrow v1.0.1
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/arrow-1.0.1/src/lib.rs:24:1
[INFO] [stdout]    |
[INFO] [stdout] 24 | #![feature(specialization)]
[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 `arrow`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "572ca602d8fd456e63f6c653dde9a84a2231be04ed7ba83b43e89fbdff8fd094", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "572ca602d8fd456e63f6c653dde9a84a2231be04ed7ba83b43e89fbdff8fd094", kill_on_drop: false }`
[INFO] [stdout] 572ca602d8fd456e63f6c653dde9a84a2231be04ed7ba83b43e89fbdff8fd094