[INFO] fetching crate flv-metadata 1.0.0...
[INFO] testing flv-metadata-1.0.0 against 1.49.0 for beta-1.50-1
[INFO] extracting crate flv-metadata 1.0.0 into /workspace/builds/worker-9/source
[INFO] validating manifest of crates.io crate flv-metadata 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 flv-metadata 1.0.0
[INFO] finished tweaking crates.io crate flv-metadata 1.0.0
[INFO] tweaked toml for crates.io crate flv-metadata 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] 88cafc876f76e5cb159a9b018ed99b111f5dd005ae7501fa18511644c0c6eae4
[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" "88cafc876f76e5cb159a9b018ed99b111f5dd005ae7501fa18511644c0c6eae4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "88cafc876f76e5cb159a9b018ed99b111f5dd005ae7501fa18511644c0c6eae4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "88cafc876f76e5cb159a9b018ed99b111f5dd005ae7501fa18511644c0c6eae4", kill_on_drop: false }`
[INFO] [stdout] 88cafc876f76e5cb159a9b018ed99b111f5dd005ae7501fa18511644c0c6eae4
[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] 181afdd82307ea0cf468638bf089bf9084bb1b5b022f3493e06ba7d0e5c11879
[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" "181afdd82307ea0cf468638bf089bf9084bb1b5b022f3493e06ba7d0e5c11879", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.81
[INFO] [stderr]    Compiling syn v1.0.57
[INFO] [stderr]    Compiling log v0.4.11
[INFO] [stderr]    Compiling memchr v2.3.4
[INFO] [stderr]    Compiling futures-core v0.3.8
[INFO] [stderr]    Compiling itoa v0.4.7
[INFO] [stderr]    Compiling regex-syntax v0.6.21
[INFO] [stderr]    Compiling futures-io v0.3.8
[INFO] [stderr]    Compiling proc-macro-hack v0.5.19
[INFO] [stderr]    Compiling once_cell v1.5.2
[INFO] [stderr]    Compiling pin-project-lite v0.2.0
[INFO] [stderr]    Compiling gimli v0.23.0
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling cache-padded v1.1.1
[INFO] [stderr]    Compiling adler v0.2.3
[INFO] [stderr]    Compiling fastrand v1.4.0
[INFO] [stderr]    Compiling waker-fn v1.1.0
[INFO] [stderr]    Compiling unicode-xid v0.1.0
[INFO] [stderr]    Compiling object v0.22.0
[INFO] [stderr]    Compiling parking v2.0.0
[INFO] [stderr]    Compiling rustc-demangle v0.1.18
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling bytes v0.5.6
[INFO] [stderr]    Compiling futures-sink v0.3.8
[INFO] [stderr]    Compiling event-listener v2.5.1
[INFO] [stderr]    Compiling vec-arena v1.0.0
[INFO] [stderr]    Compiling percent-encoding v1.0.1
[INFO] [stderr]    Compiling proc-macro-nested v0.1.6
[INFO] [stderr]    Compiling pin-utils v0.1.0
[INFO] [stderr]    Compiling num-derive v0.2.5
[INFO] [stderr]    Compiling async-task v4.0.3
[INFO] [stderr]    Compiling termcolor v1.1.2
[INFO] [stderr]    Compiling pin-project-internal v0.4.27
[INFO] [stderr]    Compiling atomic-waker v1.0.0
[INFO] [stderr]    Compiling nix v0.17.0
[INFO] [stderr]    Compiling crc32c v0.4.0
[INFO] [stderr]    Compiling pin-project-lite v0.1.11
[INFO] [stderr]    Compiling ansi_term v0.12.1
[INFO] [stderr]    Compiling smallvec v1.6.0
[INFO] [stderr]    Compiling void v1.0.2
[INFO] [stderr]    Compiling futures-timer v2.0.2
[INFO] [stderr]    Compiling num-traits v0.2.14
[INFO] [stderr]    Compiling miniz_oxide v0.4.3
[INFO] [stderr]    Compiling num-integer v0.1.44
[INFO] [stderr]    Compiling tracing-core v0.1.17
[INFO] [stderr]    Compiling sharded-slab v0.1.0
[INFO] [stderr]    Compiling error-chain v0.12.4
[INFO] [stderr]    Compiling concurrent-queue v1.2.2
[INFO] [stderr]    Compiling futures-task v0.3.8
[INFO] [stderr]    Compiling futures-channel v0.3.8
[INFO] [stderr]    Compiling async-mutex v1.4.0
[INFO] [stderr]    Compiling tokio v0.2.24
[INFO] [stderr]    Compiling async-channel v1.5.1
[INFO] [stderr]    Compiling crossbeam-utils v0.8.1
[INFO] [stderr]    Compiling aho-corasick v0.7.15
[INFO] [stderr]    Compiling futures-lite v1.11.3
[INFO] [stderr]    Compiling content_inspector v0.2.4
[INFO] [stderr]    Compiling tracing-log v0.1.1
[INFO] [stderr]    Compiling kv-log-macro v1.0.7
[INFO] [stderr]    Compiling flv-types v0.1.0
[INFO] [stderr]    Compiling quote v0.6.13
[INFO] [stderr]    Compiling regex-automata v0.1.9
[INFO] [stderr]    Compiling tokio-util v0.3.1
[INFO] [stderr]    Compiling addr2line v0.14.1
[INFO] [stderr]    Compiling paste-impl v0.1.18
[INFO] [stderr]    Compiling regex v1.4.2
[INFO] [stderr]    Compiling time v0.1.44
[INFO] [stderr]    Compiling polling v2.0.2
[INFO] [stderr]    Compiling atty v0.2.14
[INFO] [stderr]    Compiling nb-connect v1.0.2
[INFO] [stderr]    Compiling signal-hook-registry v1.3.0
[INFO] [stderr]    Compiling iovec v0.1.4
[INFO] [stderr]    Compiling num_cpus v1.13.0
[INFO] [stderr]    Compiling memmap v0.7.0
[INFO] [stderr]    Compiling async-executor v1.4.0
[INFO] [stderr]    Compiling blocking v1.0.2
[INFO] [stderr]    Compiling backtrace v0.3.55
[INFO] [stderr]    Compiling async-io v1.3.1
[INFO] [stderr]    Compiling bytes v0.4.12
[INFO] [stderr]    Compiling chrono v0.4.19
[INFO] [stderr]    Compiling signal-hook v0.1.17
[INFO] [stderr]    Compiling matchers v0.0.1
[INFO] [stderr]    Compiling paste v0.1.18
[INFO] [stderr]    Compiling env_logger v0.6.2
[INFO] [stderr]    Compiling env_logger v0.7.1
[INFO] [stderr]    Compiling async-process v1.0.1
[INFO] [stderr]    Compiling async-global-executor v1.4.3
[INFO] [stderr]    Compiling http v0.1.21
[INFO] [stderr]    Compiling async-std v1.8.0
[INFO] [stderr]    Compiling flv-util v0.1.1
[INFO] [stderr]    Compiling flv-util v0.2.1
[INFO] [stderr]    Compiling kf-protocol-derive v0.1.1
[INFO] [stderr]    Compiling serde_derive v1.0.118
[INFO] [stderr]    Compiling pin-project-internal v1.0.2
[INFO] [stderr]    Compiling futures-macro v0.3.8
[INFO] [stderr]    Compiling tracing-attributes v0.1.11
[INFO] [stderr]    Compiling async-trait v0.1.42
[INFO] [stderr]    Compiling pin-project v1.0.2
[INFO] [stderr]    Compiling futures-util v0.3.8
[INFO] [stderr]    Compiling tracing v0.1.22
[INFO] [stderr]    Compiling pin-project v0.4.27
[INFO] [stderr]    Compiling serde v1.0.118
[INFO] [stderr]    Compiling futures-executor v0.3.8
[INFO] [stderr]    Compiling futures v0.3.8
[INFO] [stderr]    Compiling serde_json v1.0.61
[INFO] [stderr]    Compiling serde_qs v0.4.6
[INFO] [stderr]    Compiling tracing-serde v0.1.2
[INFO] [stderr]    Compiling kf-protocol-core v0.1.2
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/kf-protocol-core-0.1.2/src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(specialization)]
[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 `kf-protocol-core`
[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" "181afdd82307ea0cf468638bf089bf9084bb1b5b022f3493e06ba7d0e5c11879", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "181afdd82307ea0cf468638bf089bf9084bb1b5b022f3493e06ba7d0e5c11879", kill_on_drop: false }`
[INFO] [stdout] 181afdd82307ea0cf468638bf089bf9084bb1b5b022f3493e06ba7d0e5c11879