[INFO] fetching crate library_of_babel 0.1.2...
[INFO] testing library_of_babel-0.1.2 against 1.49.0 for beta-1.50-1
[INFO] extracting crate library_of_babel 0.1.2 into /workspace/builds/worker-7/source
[INFO] validating manifest of crates.io crate library_of_babel 0.1.2 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 library_of_babel 0.1.2
[INFO] finished tweaking crates.io crate library_of_babel 0.1.2
[INFO] tweaked toml for crates.io crate library_of_babel 0.1.2 written to /workspace/builds/worker-7/source/Cargo.toml
[INFO] crate crates.io crate library_of_babel 0.1.2 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] [stderr] warning: only one of `license` or `license-file` is necessary
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 0c5f35407b8c3b8bde6f5ec0b719854a857917c19df2b1cdddefd89e859b23b8
[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" "0c5f35407b8c3b8bde6f5ec0b719854a857917c19df2b1cdddefd89e859b23b8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "0c5f35407b8c3b8bde6f5ec0b719854a857917c19df2b1cdddefd89e859b23b8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0c5f35407b8c3b8bde6f5ec0b719854a857917c19df2b1cdddefd89e859b23b8", kill_on_drop: false }`
[INFO] [stdout] 0c5f35407b8c3b8bde6f5ec0b719854a857917c19df2b1cdddefd89e859b23b8
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] ce22feed5d2ae0750476269676f765585327e00d8520848df87208ab7b4823e5
[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" "ce22feed5d2ae0750476269676f765585327e00d8520848df87208ab7b4823e5", kill_on_drop: false }`
[INFO] [stderr] warning: only one of `license` or `license-file` is necessary
[INFO] [stderr]    Compiling cfg-if v0.1.10
[INFO] [stderr]    Compiling ppv-lite86 v0.2.10
[INFO] [stderr]    Compiling unicode-width v0.1.8
[INFO] [stderr]    Compiling vec_map v0.8.2
[INFO] [stderr]    Compiling ansi_term v0.11.0
[INFO] [stderr]    Compiling strsim v0.8.0
[INFO] [stderr]    Compiling lazy_static v1.4.0
[INFO] [stderr]    Compiling libc v0.2.81
[INFO] [stderr]    Compiling num-traits v0.2.14
[INFO] [stderr]    Compiling bitflags v1.2.1
[INFO] [stderr]    Compiling textwrap v0.11.0
[INFO] [stderr]    Compiling getrandom v0.2.0
[INFO] [stderr]    Compiling atty v0.2.14
[INFO] [stderr]    Compiling clap v2.33.3
[INFO] [stderr]    Compiling rand_core v0.6.0
[INFO] [stderr]    Compiling num-integer v0.1.44
[INFO] [stderr]    Compiling num-complex v0.3.1
[INFO] [stderr]    Compiling rand_chacha v0.3.0
[INFO] [stderr]    Compiling num-bigint v0.3.1
[INFO] [stderr]    Compiling num-iter v0.1.42
[INFO] [stderr]    Compiling rand v0.8.0
[INFO] [stderr]    Compiling num-rational v0.3.2
[INFO] [stderr]    Compiling num v0.3.1
[INFO] [stderr]    Compiling library_of_babel v0.1.2 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:3:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![feature(str_split_as_str)]
[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 `library_of_babel`
[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" "ce22feed5d2ae0750476269676f765585327e00d8520848df87208ab7b4823e5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ce22feed5d2ae0750476269676f765585327e00d8520848df87208ab7b4823e5", kill_on_drop: false }`
[INFO] [stdout] ce22feed5d2ae0750476269676f765585327e00d8520848df87208ab7b4823e5