[INFO] fetching crate zekin_data_structure 1.0.0...
[INFO] testing zekin_data_structure-1.0.0 against 1.49.0 for beta-1.50-1
[INFO] extracting crate zekin_data_structure 1.0.0 into /workspace/builds/worker-9/source
[INFO] validating manifest of crates.io crate zekin_data_structure 1.0.0 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 zekin_data_structure 1.0.0
[INFO] finished tweaking crates.io crate zekin_data_structure 1.0.0
[INFO] tweaked toml for crates.io crate zekin_data_structure 1.0.0 written to /workspace/builds/worker-9/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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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] 73720490994ce691510a13c5fe39e4f66635392c998ced69154b78c24082da9e
[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" "73720490994ce691510a13c5fe39e4f66635392c998ced69154b78c24082da9e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "73720490994ce691510a13c5fe39e4f66635392c998ced69154b78c24082da9e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "73720490994ce691510a13c5fe39e4f66635392c998ced69154b78c24082da9e", kill_on_drop: false }`
[INFO] [stdout] 73720490994ce691510a13c5fe39e4f66635392c998ced69154b78c24082da9e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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] 2e6fdfa01206684e95acc229fe1333f2ea38d976df9b15061b9adbfb8fea8cbe
[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" "2e6fdfa01206684e95acc229fe1333f2ea38d976df9b15061b9adbfb8fea8cbe", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.24
[INFO] [stderr]    Compiling unicode-xid v0.2.1
[INFO] [stderr]    Compiling syn v1.0.57
[INFO] [stderr]    Compiling log v0.4.11
[INFO] [stderr]    Compiling wasm-bindgen-shared v0.2.69
[INFO] [stderr]    Compiling serde_derive v1.0.118
[INFO] [stderr]    Compiling cfg-if v0.1.10
[INFO] [stderr]    Compiling lazy_static v1.4.0
[INFO] [stderr]    Compiling serde v1.0.118
[INFO] [stderr]    Compiling bumpalo v3.4.0
[INFO] [stderr]    Compiling ryu v1.0.5
[INFO] [stderr]    Compiling version_check v0.9.2
[INFO] [stderr]    Compiling serde_json v1.0.61
[INFO] [stderr]    Compiling itoa v0.4.7
[INFO] [stderr]    Compiling wasm-bindgen v0.2.69
[INFO] [stderr]    Compiling cfg-if v1.0.0
[INFO] [stderr]    Compiling autocfg v1.0.1
[INFO] [stderr]    Compiling either v1.6.1
[INFO] [stderr]    Compiling scoped-tls v1.0.0
[INFO] [stderr]    Compiling itertools v0.9.0
[INFO] [stderr]    Compiling proc-macro-error-attr v1.0.4
[INFO] [stderr]    Compiling proc-macro-error v1.0.4
[INFO] [stderr]    Compiling num-traits v0.2.14
[INFO] [stderr]    Compiling quote v1.0.8
[INFO] [stderr]    Compiling wasm-bindgen-test-macro v0.3.19
[INFO] [stderr]    Compiling float-cmp v0.8.0
[INFO] [stderr]    Compiling wasm-bindgen-backend v0.2.69
[INFO] [stderr]    Compiling wasm-bindgen-macro-support v0.2.69
[INFO] [stderr]    Compiling getset v0.1.1
[INFO] [stderr]    Compiling wasm-bindgen-macro v0.2.69
[INFO] [stderr]    Compiling js-sys v0.3.46
[INFO] [stderr]    Compiling console_error_panic_hook v0.1.6
[INFO] [stderr]    Compiling wasm-bindgen-futures v0.4.19
[INFO] [stderr]    Compiling wasm-bindgen-test v0.3.19
[INFO] [stderr]    Compiling zekin_data_structure v1.0.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:7:1
[INFO] [stdout]   |
[INFO] [stdout] 7 | #![feature(get_mut_unchecked)]
[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 `zekin_data_structure`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "2e6fdfa01206684e95acc229fe1333f2ea38d976df9b15061b9adbfb8fea8cbe", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2e6fdfa01206684e95acc229fe1333f2ea38d976df9b15061b9adbfb8fea8cbe", kill_on_drop: false }`
[INFO] [stdout] 2e6fdfa01206684e95acc229fe1333f2ea38d976df9b15061b9adbfb8fea8cbe