[INFO] fetching crate kg-io 0.1.1...
[INFO] testing kg-io-0.1.1 against 1.90.0 for beta-1.91-3
[INFO] extracting crate kg-io 0.1.1 into /workspace/builds/worker-5-tc1/source
[INFO] started tweaking crates.io crate kg-io 0.1.1
[INFO] finished tweaking crates.io crate kg-io 0.1.1
[INFO] tweaked toml for crates.io crate kg-io 0.1.1 written to /workspace/builds/worker-5-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate kg-io 0.1.1 on toolchain 1.90.0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.90.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.90.0" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]      Locking 52 packages to latest compatible versions
[INFO] [stderr]       Adding kg-diag v0.1.1 (available: v0.4.0)
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.90.0" "fetch" "--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 kg-display-derive v0.1.1
[INFO] [stderr]   Downloaded kg-display v0.1.2
[INFO] [stderr]   Downloaded assert_approx_eq v1.1.0
[INFO] [stderr]   Downloaded heapsize v0.4.2
[INFO] [stderr]   Downloaded kg-utils v0.2.4
[INFO] [stderr]   Downloaded kg-diag v0.1.1
[INFO] [stderr]   Downloaded synstructure v0.11.0
[INFO] [stderr]   Downloaded nom v5.1.3
[INFO] [stderr]   Downloaded lexical-core v0.7.6
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+1.90.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] bac23803c2368a7e4a10950603925b5038259caab55f647acb5695a003801bb5
[INFO] running `Command { std: "docker" "start" "-a" "bac23803c2368a7e4a10950603925b5038259caab55f647acb5695a003801bb5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "bac23803c2368a7e4a10950603925b5038259caab55f647acb5695a003801bb5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "bac23803c2368a7e4a10950603925b5038259caab55f647acb5695a003801bb5", kill_on_drop: false }`
[INFO] [stdout] bac23803c2368a7e4a10950603925b5038259caab55f647acb5695a003801bb5
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/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" "RUSTDOCFLAGS=--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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+1.90.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 4fd7b95a8add8d769e44536904f743ad1f3ca0fee5e301382ce746e5b50846ff
[INFO] running `Command { std: "docker" "start" "-a" "4fd7b95a8add8d769e44536904f743ad1f3ca0fee5e301382ce746e5b50846ff", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling lexical-core v0.7.6
[INFO] [stderr]    Compiling memchr v2.7.6
[INFO] [stderr]    Compiling unicode-xid v0.1.0
[INFO] [stderr]    Compiling serde_core v1.0.228
[INFO] [stderr]    Compiling ryu v1.0.20
[INFO] [stderr]    Compiling serde v1.0.228
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling arrayvec v0.5.2
[INFO] [stderr]    Compiling bitflags v1.3.2
[INFO] [stderr]    Compiling static_assertions v1.1.0
[INFO] [stderr]    Compiling heapsize v0.4.2
[INFO] [stderr]    Compiling object v0.37.3
[INFO] [stderr]    Compiling nom v5.1.3
[INFO] [stderr]    Compiling libc v0.2.176
[INFO] [stderr]    Compiling adler2 v2.0.1
[INFO] [stderr]    Compiling gimli v0.32.3
[INFO] [stderr]    Compiling miniz_oxide v0.8.9
[INFO] [stderr]    Compiling rustc-demangle v0.1.26
[INFO] [stderr]    Compiling syn v2.0.106
[INFO] [stderr]    Compiling quote v0.6.13
[INFO] [stderr]    Compiling serde_derive v1.0.228
[INFO] [stderr]    Compiling addr2line v0.25.1
[INFO] [stderr]    Compiling kg-utils v0.2.4
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> /opt/rustwide/cargo-home/registry/src/index.crates.io-1949cf8c6b5b557f/kg-utils-0.2.4/src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(allocator_api, alloc_layout_extra, test)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `kg-utils` (lib) due to 1 previous error
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "4fd7b95a8add8d769e44536904f743ad1f3ca0fee5e301382ce746e5b50846ff", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4fd7b95a8add8d769e44536904f743ad1f3ca0fee5e301382ce746e5b50846ff", kill_on_drop: false }`
[INFO] [stdout] 4fd7b95a8add8d769e44536904f743ad1f3ca0fee5e301382ce746e5b50846ff