[INFO] fetching crate yolk 0.6.0...
[INFO] testing yolk-0.6.0 against 1.49.0 for beta-1.50-1
[INFO] extracting crate yolk 0.6.0 into /workspace/builds/worker-5/source
[INFO] validating manifest of crates.io crate yolk 0.6.0 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 yolk 0.6.0
[INFO] finished tweaking crates.io crate yolk 0.6.0
[INFO] tweaked toml for crates.io crate yolk 0.6.0 written to /workspace/builds/worker-5/source/Cargo.toml
[INFO] crate crates.io crate yolk 0.6.0 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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] b38bdb3756796deca368467aeadb5699bf1bf830d64c30453af6146b5c66635a
[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" "b38bdb3756796deca368467aeadb5699bf1bf830d64c30453af6146b5c66635a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "b38bdb3756796deca368467aeadb5699bf1bf830d64c30453af6146b5c66635a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b38bdb3756796deca368467aeadb5699bf1bf830d64c30453af6146b5c66635a", kill_on_drop: false }`
[INFO] [stdout] b38bdb3756796deca368467aeadb5699bf1bf830d64c30453af6146b5c66635a
[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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] f4fa48f83191428bc9d2bf01e42100a8ec4383702ea14892beeca2b6ff5151ff
[INFO] running `Command { std: "docker" "start" "-a" "f4fa48f83191428bc9d2bf01e42100a8ec4383702ea14892beeca2b6ff5151ff", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.2
[INFO] [stderr]    Compiling syn v1.0.5
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling unicode-xid v0.1.0
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling serde v1.0.99
[INFO] [stderr]    Compiling libc v0.2.62
[INFO] [stderr]    Compiling memchr v2.2.1
[INFO] [stderr]    Compiling autocfg v0.1.6
[INFO] [stderr]    Compiling cc v1.0.41
[INFO] [stderr]    Compiling ryu v1.0.0
[INFO] [stderr]    Compiling regex-syntax v0.6.11
[INFO] [stderr]    Compiling ucd-trie v0.1.2
[INFO] [stderr]    Compiling itoa v0.4.4
[INFO] [stderr]    Compiling bitflags v1.1.0
[INFO] [stderr]    Compiling failure_derive v0.1.5
[INFO] [stderr]    Compiling rustc-demangle v0.1.16
[INFO] [stderr]    Compiling unicode-width v0.1.6
[INFO] [stderr]    Compiling cfg-if v0.1.9
[INFO] [stderr]    Compiling vec_map v0.8.1
[INFO] [stderr]    Compiling strsim v0.8.0
[INFO] [stderr]    Compiling ansi_term v0.11.0
[INFO] [stderr]    Compiling thread_local v0.3.6
[INFO] [stderr]    Compiling pest v2.1.1
[INFO] [stderr]    Compiling num-traits v0.2.8
[INFO] [stderr]    Compiling textwrap v0.11.0
[INFO] [stderr]    Compiling backtrace-sys v0.1.31
[INFO] [stderr]    Compiling aho-corasick v0.7.6
[INFO] [stderr]    Compiling quote v0.6.13
[INFO] [stderr]    Compiling quote v1.0.2
[INFO] [stderr]    Compiling pest_meta v2.1.1
[INFO] [stderr]    Compiling atty v0.2.13
[INFO] [stderr]    Compiling clap v2.33.0
[INFO] [stderr]    Compiling backtrace v0.3.35
[INFO] [stderr]    Compiling regex v1.2.1
[INFO] [stderr]    Compiling synstructure v0.10.2
[INFO] [stderr]    Compiling pest_generator v2.1.0
[INFO] [stderr]    Compiling pest_derive v2.1.0
[INFO] [stderr]    Compiling failure v0.1.5
[INFO] [stderr]    Compiling serde_derive v1.0.99
[INFO] [stderr]    Compiling serde_json v1.0.40
[INFO] [stderr]    Compiling yolol_number v0.7.0
[INFO] [stderr]    Compiling yolol_number v0.6.2
[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/yolol_number-0.6.2/src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(trait_alias)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[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/yolol_number-0.7.0/src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(trait_alias)]
[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 `yolol_number`
[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] [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: build failed
[INFO] running `Command { std: "docker" "inspect" "f4fa48f83191428bc9d2bf01e42100a8ec4383702ea14892beeca2b6ff5151ff", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f4fa48f83191428bc9d2bf01e42100a8ec4383702ea14892beeca2b6ff5151ff", kill_on_drop: false }`
[INFO] [stdout] f4fa48f83191428bc9d2bf01e42100a8ec4383702ea14892beeca2b6ff5151ff