[INFO] fetching crate unw 0.1.0...
[INFO] testing unw-0.1.0 against 1.49.0 for beta-1.50-1
[INFO] extracting crate unw 0.1.0 into /workspace/builds/worker-9/source
[INFO] validating manifest of crates.io crate unw 0.1.0 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 unw 0.1.0
[INFO] finished tweaking crates.io crate unw 0.1.0
[INFO] tweaked toml for crates.io crate unw 0.1.0 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] [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] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded void v1.0.2
[INFO] [stderr]   Downloaded unreachable v1.0.0
[INFO] [stderr]   Downloaded utf v0.1.5
[INFO] [stderr]   Downloaded fallible v0.1.3
[INFO] [stderr]   Downloaded null-terminated v0.3.14
[INFO] [stderr]   Downloaded null-terminated v0.2.11
[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] 7f704b59767f717e27907024f9aa383d56ea5d18446ebaadb2a5920b65ae45c0
[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" "7f704b59767f717e27907024f9aa383d56ea5d18446ebaadb2a5920b65ae45c0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "7f704b59767f717e27907024f9aa383d56ea5d18446ebaadb2a5920b65ae45c0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7f704b59767f717e27907024f9aa383d56ea5d18446ebaadb2a5920b65ae45c0", kill_on_drop: false }`
[INFO] [stdout] 7f704b59767f717e27907024f9aa383d56ea5d18446ebaadb2a5920b65ae45c0
[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] e1ca6f46a75ddd3e9e8443b2fc4d74a6e25a35f1637ab88017bd66984363c07e
[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" "e1ca6f46a75ddd3e9e8443b2fc4d74a6e25a35f1637ab88017bd66984363c07e", kill_on_drop: false }`
[INFO] [stderr]    Compiling utf v0.1.5
[INFO] [stderr]    Compiling fallible v0.1.3
[INFO] [stderr]    Compiling null-terminated v0.3.14
[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/null-terminated-0.3.14/src/lib.rs:25:1
[INFO] [stdout]    |
[INFO] [stdout] 25 | #![feature(cfg_doctest)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[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/null-terminated-0.3.14/src/lib.rs:26:1
[INFO] [stdout]    |
[INFO] [stdout] 26 | #![feature(const_fn)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[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/null-terminated-0.3.14/src/lib.rs:27:1
[INFO] [stdout]    |
[INFO] [stdout] 27 | #![feature(const_raw_ptr_deref)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[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/null-terminated-0.3.14/src/lib.rs:28:1
[INFO] [stdout]    |
[INFO] [stdout] 28 | #![feature(extern_types)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 4 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `null-terminated`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "e1ca6f46a75ddd3e9e8443b2fc4d74a6e25a35f1637ab88017bd66984363c07e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e1ca6f46a75ddd3e9e8443b2fc4d74a6e25a35f1637ab88017bd66984363c07e", kill_on_drop: false }`
[INFO] [stdout] e1ca6f46a75ddd3e9e8443b2fc4d74a6e25a35f1637ab88017bd66984363c07e