[INFO] fetching crate kg-symbol 0.2.0...
[INFO] testing kg-symbol-0.2.0 against 1.47.0 for beta-1.48-1
[INFO] extracting crate kg-symbol 0.2.0 into /workspace/builds/worker-12/source
[INFO] validating manifest of crates.io crate kg-symbol 0.2.0 on toolchain 1.47.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.47.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate kg-symbol 0.2.0
[INFO] finished tweaking crates.io crate kg-symbol 0.2.0
[INFO] tweaked toml for crates.io crate kg-symbol 0.2.0 written to /workspace/builds/worker-12/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.47.0" "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" "+1.47.0" "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 instant v0.1.7
[INFO] [stderr]   Downloaded cloudabi v0.1.0
[INFO] [stderr]   Downloaded smallvec v1.4.2
[INFO] [stderr]   Downloaded parking_lot v0.11.0
[INFO] [stderr]   Downloaded lock_api v0.4.1
[INFO] [stderr]   Downloaded parking_lot_core v0.8.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1.47.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] c3fca03fdce3af04ea60dafac2bc5e502cbbe60d2e720e2822c36c90265f73ea
[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" "c3fca03fdce3af04ea60dafac2bc5e502cbbe60d2e720e2822c36c90265f73ea", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "c3fca03fdce3af04ea60dafac2bc5e502cbbe60d2e720e2822c36c90265f73ea", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c3fca03fdce3af04ea60dafac2bc5e502cbbe60d2e720e2822c36c90265f73ea", kill_on_drop: false }`
[INFO] [stdout] c3fca03fdce3af04ea60dafac2bc5e502cbbe60d2e720e2822c36c90265f73ea
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1.47.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 8a604fae724e10c34f2e7080670d62dca1bf42055196d834b9ef1e06df663835
[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" "8a604fae724e10c34f2e7080670d62dca1bf42055196d834b9ef1e06df663835", kill_on_drop: false }`
[INFO] [stderr]    Compiling heapsize v0.4.2
[INFO] [stderr]    Compiling lock_api v0.4.1
[INFO] [stderr]    Compiling parking_lot_core v0.8.0
[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/lock_api-0.4.1/src/lib.rs:91:34
[INFO] [stdout]    |
[INFO] [stdout] 91 | #![cfg_attr(feature = "nightly", feature(const_fn))]
[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 `lock_api`.
[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" "8a604fae724e10c34f2e7080670d62dca1bf42055196d834b9ef1e06df663835", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8a604fae724e10c34f2e7080670d62dca1bf42055196d834b9ef1e06df663835", kill_on_drop: false }`
[INFO] [stdout] 8a604fae724e10c34f2e7080670d62dca1bf42055196d834b9ef1e06df663835
