[INFO] cloning repository https://github.com/zhongzc/minitrace-fbs
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/zhongzc/minitrace-fbs" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fzhongzc%2Fminitrace-fbs", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fzhongzc%2Fminitrace-fbs'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 5c1d846e77ccd1cd5a5fb971c32909233f0d86dc
[INFO] documenting zhongzc/minitrace-fbs against beta-2020-08-29 for beta-1.47-rustdoc-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fzhongzc%2Fminitrace-fbs" "/workspace/builds/worker-0/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/zhongzc/minitrace-fbs on toolchain beta-2020-08-29
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-08-29" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/zhongzc/minitrace-fbs
[INFO] finished tweaking git repo https://github.com/zhongzc/minitrace-fbs
[INFO] tweaked toml for git repo https://github.com/zhongzc/minitrace-fbs written to /workspace/builds/worker-0/source/Cargo.toml
[INFO] crate git repo https://github.com/zhongzc/minitrace-fbs already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-08-29" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded flatbuffers v0.6.1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-08-29" "metadata" "--no-deps" "--format-version=1", 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] a37092fbaac8aea4af784c750a4a8b8f3d917df60c36cc37ee8c3bd7287a4cc4
[INFO] running `Command { std: "docker" "start" "-a" "a37092fbaac8aea4af784c750a4a8b8f3d917df60c36cc37ee8c3bd7287a4cc4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "a37092fbaac8aea4af784c750a4a8b8f3d917df60c36cc37ee8c3bd7287a4cc4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a37092fbaac8aea4af784c750a4a8b8f3d917df60c36cc37ee8c3bd7287a4cc4", kill_on_drop: false }`
[INFO] [stdout] a37092fbaac8aea4af784c750a4a8b8f3d917df60c36cc37ee8c3bd7287a4cc4
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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" "RUSTDOCFLAGS=--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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-08-29" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] a658bb52122fc1a5581f1a5a6997d2fbe439dec4980f3a4dd338f85ab2ec5740
[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" "a658bb52122fc1a5581f1a5a6997d2fbe439dec4980f3a4dd338f85ab2ec5740", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.19
[INFO] [stderr]    Compiling autocfg v1.0.0
[INFO] [stderr]    Compiling syn v1.0.35
[INFO] [stderr]    Compiling maybe-uninit v2.0.0
[INFO] [stderr]    Compiling pin-project-internal v0.4.22
[INFO] [stderr]    Compiling proc-macro-nested v0.1.6
[INFO] [stderr]    Compiling proc-macro-hack v0.5.16
[INFO] [stderr]     Checking once_cell v1.4.0
[INFO] [stderr]     Checking futures-core v0.3.5
[INFO] [stderr]     Checking futures-sink v0.3.5
[INFO] [stderr]     Checking futures-io v0.3.5
[INFO] [stderr]     Checking pin-utils v0.1.0
[INFO] [stderr]    Compiling libc v0.2.73
[INFO] [stderr]     Checking scopeguard v1.1.0
[INFO] [stderr]     Checking futures v0.1.29
[INFO] [stderr]     Checking smallvec v1.4.1
[INFO] [stderr]     Checking futures-channel v0.3.5
[INFO] [stderr]     Checking futures-task v0.3.5
[INFO] [stderr]     Checking flatbuffers v0.6.1
[INFO] [stderr]    Compiling crossbeam-utils v0.7.2
[INFO] [stderr]    Compiling memoffset v0.5.5
[INFO] [stderr]    Compiling crossbeam-epoch v0.8.2
[INFO] [stderr]    Compiling quote v1.0.7
[INFO] [stderr]     Checking minstant v0.0.0 (https://github.com/zhongzc/minstant.git#48a631c1)
[INFO] [stderr]     Checking crossbeam-queue v0.2.3
[INFO] [stderr]     Checking crossbeam-channel v0.4.3
[INFO] [stderr]     Checking crossbeam-deque v0.7.3
[INFO] [stderr]     Checking crossbeam v0.7.3
[INFO] [stderr]    Compiling syn-mid v0.5.0
[INFO] [stderr]    Compiling futures-macro v0.3.5
[INFO] [stderr]    Compiling proc-macro-error-attr v1.0.3
[INFO] [stderr]    Compiling proc-macro-error v1.0.3
[INFO] [stderr]    Compiling minitrace-attribute v0.1.0 (https://github.com/pingcap-incubator/minitrace-rust.git#6f6750f3)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> /opt/rustwide/cargo-home/git/checkouts/minitrace-rust-4a91d55623f07cfc/6f6750f/crates/attribute/src/lib.rs:3:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![feature(proc_macro_diagnostic)]
[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 `minitrace-attribute`.
[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] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "a658bb52122fc1a5581f1a5a6997d2fbe439dec4980f3a4dd338f85ab2ec5740", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a658bb52122fc1a5581f1a5a6997d2fbe439dec4980f3a4dd338f85ab2ec5740", kill_on_drop: false }`
[INFO] [stdout] a658bb52122fc1a5581f1a5a6997d2fbe439dec4980f3a4dd338f85ab2ec5740