[INFO] fetching crate libp3p 0.0.0...
[INFO] testing libp3p-0.0.0 against 1.49.0 for beta-1.50-1
[INFO] extracting crate libp3p 0.0.0 into /workspace/builds/worker-0/source
[INFO] validating manifest of crates.io crate libp3p 0.0.0 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 libp3p 0.0.0
[INFO] finished tweaking crates.io crate libp3p 0.0.0
[INFO] tweaked toml for crates.io crate libp3p 0.0.0 written to /workspace/builds/worker-0/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] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 798ffb2532109ae1df72037bf03afebee3d8ceacf87cc89c3d45165cd922b120
[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" "798ffb2532109ae1df72037bf03afebee3d8ceacf87cc89c3d45165cd922b120", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "798ffb2532109ae1df72037bf03afebee3d8ceacf87cc89c3d45165cd922b120", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "798ffb2532109ae1df72037bf03afebee3d8ceacf87cc89c3d45165cd922b120", kill_on_drop: false }`
[INFO] [stdout] 798ffb2532109ae1df72037bf03afebee3d8ceacf87cc89c3d45165cd922b120
[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" "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] 39638407efab132ccdb6fa6ee8abfcb716439cbfc7a4a0d330bd43b11dc749f1
[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" "39638407efab132ccdb6fa6ee8abfcb716439cbfc7a4a0d330bd43b11dc749f1", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling packed_simd v0.3.3
[INFO] [stderr]    Compiling crunchy v0.2.2
[INFO] [stderr]    Compiling rustc-hex v2.1.0
[INFO] [stderr]    Compiling subtle v2.4.0
[INFO] [stderr]    Compiling num-bigint-dig v0.4.0
[INFO] [stderr]    Compiling num-iter v0.1.42
[INFO] [stderr]    Compiling futures-timer v1.0.3
[INFO] [stderr]    Compiling async-macros v1.0.0
[INFO] [stderr]    Compiling thread-id v3.3.0
[INFO] [stderr]    Compiling async-task v1.3.1
[INFO] [stderr]    Compiling petgraph v0.5.1
[INFO] [stderr]    Compiling digest v0.8.1
[INFO] [stderr]    Compiling mio v0.6.23
[INFO] [stderr]    Compiling thiserror-impl v1.0.23
[INFO] [stderr]    Compiling serde v1.0.118
[INFO] [stderr]    Compiling zeroize_derive v1.0.1
[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/subtle-2.4.0/src/lib.rs:12:34
[INFO] [stdout]    |
[INFO] [stdout] 12 | #![cfg_attr(feature = "nightly", feature(external_doc))]
[INFO] [stdout]    |                                  ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling crossbeam v0.7.3
[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 `subtle`
[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" "39638407efab132ccdb6fa6ee8abfcb716439cbfc7a4a0d330bd43b11dc749f1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "39638407efab132ccdb6fa6ee8abfcb716439cbfc7a4a0d330bd43b11dc749f1", kill_on_drop: false }`
[INFO] [stdout] 39638407efab132ccdb6fa6ee8abfcb716439cbfc7a4a0d330bd43b11dc749f1