[INFO] fetching crate unix-signal 0.1.4...
[INFO] testing unix-signal-0.1.4 against 1.55.0 for beta-1.56-1
[INFO] extracting crate unix-signal 0.1.4 into /workspace/builds/worker-1/source
[INFO] validating manifest of crates.io crate unix-signal 0.1.4 on toolchain 1.55.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate unix-signal 0.1.4
[INFO] finished tweaking crates.io crate unix-signal 0.1.4
[INFO] tweaked toml for crates.io crate unix-signal 0.1.4 written to /workspace/builds/worker-1/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 8a9cd247d294dd4a3b17c06a422c18f8dbabaee2e1e30a2b07f3bb569c6bc6e2
[INFO] running `Command { std: "docker" "start" "-a" "8a9cd247d294dd4a3b17c06a422c18f8dbabaee2e1e30a2b07f3bb569c6bc6e2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8a9cd247d294dd4a3b17c06a422c18f8dbabaee2e1e30a2b07f3bb569c6bc6e2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8a9cd247d294dd4a3b17c06a422c18f8dbabaee2e1e30a2b07f3bb569c6bc6e2", kill_on_drop: false }`
[INFO] [stdout] 8a9cd247d294dd4a3b17c06a422c18f8dbabaee2e1e30a2b07f3bb569c6bc6e2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] f9ac02d36ba69d79acc923078ec9274aa6cb3681d36785b63c6c0a99619fc835
[INFO] running `Command { std: "docker" "start" "-a" "f9ac02d36ba69d79acc923078ec9274aa6cb3681d36785b63c6c0a99619fc835", kill_on_drop: false }`
[INFO] [stderr]    Compiling rand_core v0.4.2
[INFO] [stderr]    Compiling ptr v0.2.3
[INFO] [stderr]    Compiling hash-table v0.2.5
[INFO] [stderr]    Compiling containers v0.9.12
[INFO] [stderr]    Compiling i-o v0.4.7
[INFO] [stderr]    Compiling rel v0.2.0
[INFO] [stderr]    Compiling heap v0.1.0
[INFO] [stderr]    Compiling idem v0.4.0
[INFO] [stderr]    Compiling abort v0.1.3
[INFO] [stderr]    Compiling libc-interface v0.1.2
[INFO] [stderr]    Compiling utf v0.1.6
[INFO] [stderr]    Compiling system-call v0.1.3
[INFO] [stderr]    Compiling flags v0.1.5
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]    Compiling unreachable v1.0.0
[INFO] [stderr]    Compiling fallible v0.1.3
[INFO] [stderr]    Compiling unix v0.6.12
[INFO] [stderr]    Compiling idem v0.1.1
[INFO] [stderr]    Compiling rand_core v0.3.1
[INFO] [stderr]    Compiling rand_jitter v0.1.4
[INFO] [stderr]    Compiling rand_pcg 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/system-call-0.1.3/src/lib.rs:15:1
[INFO] [stdout]    |
[INFO] [stdout] 15 | #![feature(llvm_asm)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling null-terminated v0.3.15
[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 `system-call` due to 2 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[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-0.3.15/src/lib.rs:25:1
[INFO] [stdout]    |
[INFO] [stdout] 25 | #![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-0.3.15/src/lib.rs:26:1
[INFO] [stdout]    |
[INFO] [stdout] 26 | #![feature(extern_types)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "f9ac02d36ba69d79acc923078ec9274aa6cb3681d36785b63c6c0a99619fc835", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f9ac02d36ba69d79acc923078ec9274aa6cb3681d36785b63c6c0a99619fc835", kill_on_drop: false }`
[INFO] [stdout] f9ac02d36ba69d79acc923078ec9274aa6cb3681d36785b63c6c0a99619fc835