[INFO] fetching crate slabmalloc 0.7.0...
[INFO] testing slabmalloc-0.7.0 against 1.49.0 for beta-1.50-1
[INFO] extracting crate slabmalloc 0.7.0 into /workspace/builds/worker-11/source
[INFO] validating manifest of crates.io crate slabmalloc 0.7.0 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 slabmalloc 0.7.0
[INFO] finished tweaking crates.io crate slabmalloc 0.7.0
[INFO] tweaked toml for crates.io crate slabmalloc 0.7.0 written to /workspace/builds/worker-11/source/Cargo.toml
[INFO] crate crates.io crate slabmalloc 0.7.0 already has a lockfile, it will not be regenerated
[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-11/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/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] 0b7468e593c51ffde070d0375da19954387ba8f70592e6f139bda9e802555068
[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" "0b7468e593c51ffde070d0375da19954387ba8f70592e6f139bda9e802555068", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "0b7468e593c51ffde070d0375da19954387ba8f70592e6f139bda9e802555068", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0b7468e593c51ffde070d0375da19954387ba8f70592e6f139bda9e802555068", kill_on_drop: false }`
[INFO] [stdout] 0b7468e593c51ffde070d0375da19954387ba8f70592e6f139bda9e802555068
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/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] 4eb0e3aa3d36044737ada7cc40fa362d11244c71a7cb40844f9b88a7ff0f247d
[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" "4eb0e3aa3d36044737ada7cc40fa362d11244c71a7cb40844f9b88a7ff0f247d", kill_on_drop: false }`
[INFO] [stderr]    Compiling slabmalloc v0.7.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:21:35
[INFO] [stdout]    |
[INFO] [stdout] 21 | #![cfg_attr(feature = "unstable", feature(const_fn))]
[INFO] [stdout]    |                                   ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `slabmalloc`
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "4eb0e3aa3d36044737ada7cc40fa362d11244c71a7cb40844f9b88a7ff0f247d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4eb0e3aa3d36044737ada7cc40fa362d11244c71a7cb40844f9b88a7ff0f247d", kill_on_drop: false }`
[INFO] [stdout] 4eb0e3aa3d36044737ada7cc40fa362d11244c71a7cb40844f9b88a7ff0f247d