[INFO] fetching crate kg-js 0.1.1...
[INFO] testing kg-js-0.1.1 against 1.49.0 for beta-1.50-1
[INFO] extracting crate kg-js 0.1.1 into /workspace/builds/worker-5/source
[INFO] validating manifest of crates.io crate kg-js 0.1.1 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 kg-js 0.1.1
[INFO] finished tweaking crates.io crate kg-js 0.1.1
[INFO] tweaked toml for crates.io crate kg-js 0.1.1 written to /workspace/builds/worker-5/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "fetch" "--locked" "--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-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] a30cf6fe759d5431d16836f693dc72674c95f08b1b0e63204bd3314afa1e5fc2
[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" "a30cf6fe759d5431d16836f693dc72674c95f08b1b0e63204bd3314afa1e5fc2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "a30cf6fe759d5431d16836f693dc72674c95f08b1b0e63204bd3314afa1e5fc2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a30cf6fe759d5431d16836f693dc72674c95f08b1b0e63204bd3314afa1e5fc2", kill_on_drop: false }`
[INFO] [stdout] a30cf6fe759d5431d16836f693dc72674c95f08b1b0e63204bd3314afa1e5fc2
[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] [stdout] 910e3ed9b38e5cfb3461d19ed86881c9baf6f7743d9d7635089b6c6661d2ec4d
[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" "910e3ed9b38e5cfb3461d19ed86881c9baf6f7743d9d7635089b6c6661d2ec4d", kill_on_drop: false }`
[INFO] [stderr]    Compiling rlibc v1.0.0
[INFO] [stderr]    Compiling lock_api v0.2.0
[INFO] [stderr]    Compiling parking_lot_core v0.5.0
[INFO] [stderr]    Compiling parking_lot v0.8.0
[INFO] [stderr]    Compiling kg-utils v0.2.4
[INFO] [stderr]    Compiling serde_yaml v0.8.14
[INFO] [stderr]    Compiling kg-utils v0.3.1
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling nom v5.1.2
[INFO] [stderr]    Compiling synstructure v0.5.2
[INFO] [stderr]    Compiling kg-js v0.1.1 (/opt/rustwide/workdir)
[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/kg-utils-0.2.4/src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(allocator_api, alloc_layout_extra, test)]
[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/lock_api-0.2.0/src/lib.rs:89:34
[INFO] [stdout]    |
[INFO] [stdout] 89 | #![cfg_attr(feature = "nightly", feature(const_fn))]
[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 `lock_api`
[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[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/kg-utils-0.3.1/src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(allocator_api, alloc_layout_extra, test)]
[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] [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" "910e3ed9b38e5cfb3461d19ed86881c9baf6f7743d9d7635089b6c6661d2ec4d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "910e3ed9b38e5cfb3461d19ed86881c9baf6f7743d9d7635089b6c6661d2ec4d", kill_on_drop: false }`
[INFO] [stdout] 910e3ed9b38e5cfb3461d19ed86881c9baf6f7743d9d7635089b6c6661d2ec4d