[INFO] crate magic-ring-buffer 0.1.0 is already in cache
[INFO] testing magic-ring-buffer-0.1.0 against beta-2020-07-24 for beta-1.46-1
[INFO] extracting crate magic-ring-buffer 0.1.0 into /workspace/builds/worker-1/source
[INFO] validating manifest of crates.io crate magic-ring-buffer 0.1.0 on toolchain beta-2020-07-24
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-07-24" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate magic-ring-buffer 0.1.0
[INFO] finished tweaking crates.io crate magic-ring-buffer 0.1.0
[INFO] tweaked toml for crates.io crate magic-ring-buffer 0.1.0 written to /workspace/builds/worker-1/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-07-24" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-07-24" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-07-24" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] cf3bf4f080486348430b562f93559d3b9f4b30dea37f09e6f1118ae2f5f83b51
[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" "cf3bf4f080486348430b562f93559d3b9f4b30dea37f09e6f1118ae2f5f83b51", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "cf3bf4f080486348430b562f93559d3b9f4b30dea37f09e6f1118ae2f5f83b51", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "cf3bf4f080486348430b562f93559d3b9f4b30dea37f09e6f1118ae2f5f83b51", kill_on_drop: false }`
[INFO] [stdout] cf3bf4f080486348430b562f93559d3b9f4b30dea37f09e6f1118ae2f5f83b51
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-07-24" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 02f6042fa82b79f957ba52b240313e53f4f738da58015e53d9347cdcddcc07f1
[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" "02f6042fa82b79f957ba52b240313e53f4f738da58015e53d9347cdcddcc07f1", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling unicode-xid v0.1.0
[INFO] [stderr]    Compiling libc v0.2.74
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling memchr v2.3.3
[INFO] [stderr]    Compiling arrayvec v0.4.12
[INFO] [stderr]    Compiling bitflags v1.2.1
[INFO] [stderr]    Compiling unicode-segmentation v1.6.0
[INFO] [stderr]    Compiling nodrop v0.1.14
[INFO] [stderr]    Compiling cfg-if v0.1.10
[INFO] [stderr]    Compiling strum v0.13.0
[INFO] [stderr]    Compiling likely v0.1.0
[INFO] [stderr]    Compiling heck v0.3.1
[INFO] [stderr]    Compiling quote v0.6.13
[INFO] [stderr]    Compiling errno v0.2.6
[INFO] [stderr]    Compiling strum_macros v0.13.0
[INFO] [stderr]    Compiling file-descriptors v0.8.7
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/file-descriptors-0.8.7/src/lib.rs:10:1
[INFO] [stdout]    |
[INFO] [stdout] 10 | #![feature(core_intrinsics)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/file-descriptors-0.8.7/src/lib.rs:11:1
[INFO] [stdout]    |
[INFO] [stdout] 11 | #![feature(read_initializer)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/file-descriptors-0.8.7/src/lib.rs:12:1
[INFO] [stdout]    |
[INFO] [stdout] 12 | #![feature(try_from)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 3 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `file-descriptors`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "02f6042fa82b79f957ba52b240313e53f4f738da58015e53d9347cdcddcc07f1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "02f6042fa82b79f957ba52b240313e53f4f738da58015e53d9347cdcddcc07f1", kill_on_drop: false }`
[INFO] [stdout] 02f6042fa82b79f957ba52b240313e53f4f738da58015e53d9347cdcddcc07f1