[INFO] fetching crate concurrent 0.2.2...
[INFO] documenting concurrent-0.2.2 against 1.46.0 for beta-1.47-rustdoc-1
[INFO] extracting crate concurrent 0.2.2 into /workspace/builds/worker-12/source
[INFO] validating manifest of crates.io crate concurrent 0.2.2 on toolchain 1.46.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.46.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate concurrent 0.2.2
[INFO] finished tweaking crates.io crate concurrent 0.2.2
[INFO] tweaked toml for crates.io crate concurrent 0.2.2 written to /workspace/builds/worker-12/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.46.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.46.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-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" "+1.46.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 596775a6c73468c4461d269b8096aa0fbbc33dd1d715881c2902d3bb517d3902
[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" "596775a6c73468c4461d269b8096aa0fbbc33dd1d715881c2902d3bb517d3902", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "596775a6c73468c4461d269b8096aa0fbbc33dd1d715881c2902d3bb517d3902", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "596775a6c73468c4461d269b8096aa0fbbc33dd1d715881c2902d3bb517d3902", kill_on_drop: false }`
[INFO] [stdout] 596775a6c73468c4461d269b8096aa0fbbc33dd1d715881c2902d3bb517d3902
[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" "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" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1.46.0" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 4a9e8bf89bbd4fdfee42dc63ce13738a05476630578765d22a700bdea36048fa
[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" "4a9e8bf89bbd4fdfee42dc63ce13738a05476630578765d22a700bdea36048fa", kill_on_drop: false }`
[INFO] [stderr]     Checking spin v0.4.10
[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/spin-0.4.10/src/lib.rs:6:35
[INFO] [stdout]   |
[INFO] [stdout] 6 | #![cfg_attr(feature = "const_fn", 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 `spin`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "4a9e8bf89bbd4fdfee42dc63ce13738a05476630578765d22a700bdea36048fa", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4a9e8bf89bbd4fdfee42dc63ce13738a05476630578765d22a700bdea36048fa", kill_on_drop: false }`
[INFO] [stdout] 4a9e8bf89bbd4fdfee42dc63ce13738a05476630578765d22a700bdea36048fa