[INFO] fetching crate intercom-common 0.3.0...
[INFO] testing intercom-common-0.3.0 against 1.49.0 for beta-1.50-1
[INFO] extracting crate intercom-common 0.3.0 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate intercom-common 0.3.0 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 intercom-common 0.3.0
[INFO] finished tweaking crates.io crate intercom-common 0.3.0
[INFO] tweaked toml for crates.io crate intercom-common 0.3.0 written to /workspace/builds/worker-4/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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "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] 071b8d85fc2b039128eb10a1aa53eb3edae153b8ab07ff33e83f36e71a64b32a
[INFO] running `Command { std: "docker" "start" "-a" "071b8d85fc2b039128eb10a1aa53eb3edae153b8ab07ff33e83f36e71a64b32a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "071b8d85fc2b039128eb10a1aa53eb3edae153b8ab07ff33e83f36e71a64b32a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "071b8d85fc2b039128eb10a1aa53eb3edae153b8ab07ff33e83f36e71a64b32a", kill_on_drop: false }`
[INFO] [stdout] 071b8d85fc2b039128eb10a1aa53eb3edae153b8ab07ff33e83f36e71a64b32a
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] b19270a4cc081b22e981fdc1c7235b9d2ce89118844db663fb4b45c4036f74e2
[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" "b19270a4cc081b22e981fdc1c7235b9d2ce89118844db663fb4b45c4036f74e2", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.81
[INFO] [stderr]    Compiling ucd-util v0.1.8
[INFO] [stderr]    Compiling regex v0.2.11
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling utf8-ranges v1.0.4
[INFO] [stderr]    Compiling pest v0.3.3
[INFO] [stderr]    Compiling sha1 v0.3.0
[INFO] [stderr]    Compiling ordermap v0.3.5
[INFO] [stderr]    Compiling thread_local v0.3.6
[INFO] [stderr]    Compiling aho-corasick v0.6.10
[INFO] [stderr]    Compiling log v0.3.9
[INFO] [stderr]    Compiling regex-syntax v0.5.6
[INFO] [stderr]    Compiling backtrace v0.3.55
[INFO] [stderr]    Compiling failure v0.1.8
[INFO] [stderr]    Compiling handlebars v0.29.1
[INFO] [stderr]    Compiling intercom-common v0.3.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(non_exhaustive)]
[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 `intercom-common`
[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" "b19270a4cc081b22e981fdc1c7235b9d2ce89118844db663fb4b45c4036f74e2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b19270a4cc081b22e981fdc1c7235b9d2ce89118844db663fb4b45c4036f74e2", kill_on_drop: false }`
[INFO] [stdout] b19270a4cc081b22e981fdc1c7235b9d2ce89118844db663fb4b45c4036f74e2