[INFO] cloning repository https://github.com/mgdm/rrt
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/mgdm/rrt" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmgdm%2Frrt", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmgdm%2Frrt'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 85a6af7711c77651bad4e398a48bb36f8a87e6aa
[INFO] checking mgdm/rrt against beta for pr-78714
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmgdm%2Frrt" "/workspace/builds/worker-6/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/mgdm/rrt 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 git repo https://github.com/mgdm/rrt
[INFO] finished tweaking git repo https://github.com/mgdm/rrt
[INFO] tweaked toml for git repo https://github.com/mgdm/rrt written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] crate git repo https://github.com/mgdm/rrt already has a lockfile, it will not be regenerated
[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-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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] e3da67d9693358aee4e79d50953ffc71fbeed48d001847ff913aa8e66c69e4fd
[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" "e3da67d9693358aee4e79d50953ffc71fbeed48d001847ff913aa8e66c69e4fd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e3da67d9693358aee4e79d50953ffc71fbeed48d001847ff913aa8e66c69e4fd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e3da67d9693358aee4e79d50953ffc71fbeed48d001847ff913aa8e66c69e4fd", kill_on_drop: false }`
[INFO] [stdout] e3da67d9693358aee4e79d50953ffc71fbeed48d001847ff913aa8e66c69e4fd
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 13497493cb8707bc9c4f79d5ce677bb7e0152c9333f43dcc0a1ef95fe97b4b0e
[INFO] running `Command { std: "docker" "start" "-a" "13497493cb8707bc9c4f79d5ce677bb7e0152c9333f43dcc0a1ef95fe97b4b0e", kill_on_drop: false }`
[INFO] [stderr]     Checking libc v0.2.18
[INFO] [stderr]     Checking num-traits v0.1.36
[INFO] [stderr]     Checking rustc-serialize v0.3.22
[INFO] [stderr]    Compiling quote v0.3.10
[INFO] [stderr]     Checking serde v0.8.21
[INFO] [stderr]     Checking dtoa v0.2.2
[INFO] [stderr]     Checking itoa v0.1.1
[INFO] [stderr]     Checking lazy_static v0.2.2
[INFO] [stderr]    Compiling syn v0.10.5
[INFO] [stderr]     Checking memchr v0.1.11
[INFO] [stderr]     Checking rand v0.3.15
[INFO] [stderr]     Checking thread-id v2.0.0
[INFO] [stderr]     Checking thread_local v0.2.7
[INFO] [stderr]     Checking aho-corasick v0.5.3
[INFO] [stderr]     Checking num-integer v0.1.32
[INFO] [stderr]     Checking regex v0.1.80
[INFO] [stderr]     Checking num-iter v0.1.32
[INFO] [stderr]    Compiling serde_codegen_internals v0.11.3
[INFO] [stderr]    Compiling serde_codegen v0.8.21
[INFO] [stderr]     Checking num-bigint v0.1.35
[INFO] [stderr]     Checking num-complex v0.1.35
[INFO] [stderr]     Checking docopt v0.6.86
[INFO] [stderr]     Checking serde_json v0.8.4
[INFO] [stderr]     Checking num-rational v0.1.35
[INFO] [stderr]     Checking num v0.1.36
[INFO] [stderr]    Compiling serde_derive v0.8.21
[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/serde_derive-0.8.21/src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(proc_macro, proc_macro_lib)]
[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 `serde_derive`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "13497493cb8707bc9c4f79d5ce677bb7e0152c9333f43dcc0a1ef95fe97b4b0e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "13497493cb8707bc9c4f79d5ce677bb7e0152c9333f43dcc0a1ef95fe97b4b0e", kill_on_drop: false }`
[INFO] [stdout] 13497493cb8707bc9c4f79d5ce677bb7e0152c9333f43dcc0a1ef95fe97b4b0e