[INFO] fetching crate oncemutex 0.1.1...
[INFO] checking oncemutex-0.1.1 against beta for pr-78714
[INFO] extracting crate oncemutex 0.1.1 into /workspace/builds/worker-8/source
[INFO] validating manifest of crates.io crate oncemutex 0.1.1 on toolchain beta
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate oncemutex 0.1.1
[INFO] finished tweaking crates.io crate oncemutex 0.1.1
[INFO] tweaked toml for crates.io crate oncemutex 0.1.1 written to /workspace/builds/worker-8/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+beta" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 8495aba4d8fc0a749554e43bfa8c34d8507695df1977a5c5572a8b361b57bb7c
[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" "8495aba4d8fc0a749554e43bfa8c34d8507695df1977a5c5572a8b361b57bb7c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8495aba4d8fc0a749554e43bfa8c34d8507695df1977a5c5572a8b361b57bb7c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8495aba4d8fc0a749554e43bfa8c34d8507695df1977a5c5572a8b361b57bb7c", kill_on_drop: false }`
[INFO] [stdout] 8495aba4d8fc0a749554e43bfa8c34d8507695df1977a5c5572a8b361b57bb7c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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=forbid" "-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@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+beta" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 62efa4aac45fff1ae10437eca5459c0e7ee5c30907abc365b5c59f695529f89e
[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" "62efa4aac45fff1ae10437eca5459c0e7ee5c30907abc365b5c59f695529f89e", kill_on_drop: false }`
[INFO] [stderr]     Checking oncemutex v0.1.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:2:19
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![cfg_attr(test, feature(test))]
[INFO] [stdout]   |                   ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: unnecessary `unsafe` block
[INFO] [stdout]   --> src/lib.rs:86:9
[INFO] [stdout]    |
[INFO] [stdout] 86 |         unsafe { self.data.into_inner() }
[INFO] [stdout]    |         ^^^^^^ unnecessary `unsafe` block
[INFO] [stdout]    |
[INFO] [stdout] note: the lint level is defined here
[INFO] [stdout]   --> src/lib.rs:1:23
[INFO] [stdout]    |
[INFO] [stdout] 1  | #![deny(missing_docs, warnings)]
[INFO] [stdout]    |                       ^^^^^^^^
[INFO] [stdout]    = note: `#[deny(unused_unsafe)]` implied by `#[deny(warnings)]`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `oncemutex`
[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" "62efa4aac45fff1ae10437eca5459c0e7ee5c30907abc365b5c59f695529f89e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "62efa4aac45fff1ae10437eca5459c0e7ee5c30907abc365b5c59f695529f89e", kill_on_drop: false }`
[INFO] [stdout] 62efa4aac45fff1ae10437eca5459c0e7ee5c30907abc365b5c59f695529f89e