[INFO] fetching crate pumpkindb_mio_server 0.2.0...
[INFO] testing pumpkindb_mio_server-0.2.0 against 1.55.0 for beta-1.56-1
[INFO] extracting crate pumpkindb_mio_server 0.2.0 into /workspace/builds/worker-7/source
[INFO] validating manifest of crates.io crate pumpkindb_mio_server 0.2.0 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 pumpkindb_mio_server 0.2.0
[INFO] finished tweaking crates.io crate pumpkindb_mio_server 0.2.0
[INFO] tweaked toml for crates.io crate pumpkindb_mio_server 0.2.0 written to /workspace/builds/worker-7/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] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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] 1621f5873f76f2df3dc4cfb26f485d437b883783d8cea8a2efd983f7d296c521
[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" "1621f5873f76f2df3dc4cfb26f485d437b883783d8cea8a2efd983f7d296c521", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "1621f5873f76f2df3dc4cfb26f485d437b883783d8cea8a2efd983f7d296c521", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1621f5873f76f2df3dc4cfb26f485d437b883783d8cea8a2efd983f7d296c521", kill_on_drop: false }`
[INFO] [stdout] 1621f5873f76f2df3dc4cfb26f485d437b883783d8cea8a2efd983f7d296c521
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] d951888ad16f9dd78aa3688af226c25d161ad3c030374edade5a4fa324401bbd
[INFO] running `Command { std: "docker" "start" "-a" "d951888ad16f9dd78aa3688af226c25d161ad3c030374edade5a4fa324401bbd", kill_on_drop: false }`
[INFO] [stderr]    Compiling linked-hash-map v0.3.0
[INFO] [stderr]    Compiling hex-slice v0.1.4
[INFO] [stderr]    Compiling log-mdc v0.1.0
[INFO] [stderr]    Compiling toml v0.3.2
[INFO] [stderr]    Compiling toml v0.2.1
[INFO] [stderr]    Compiling memmap v0.5.2
[INFO] [stderr]    Compiling rand v0.3.23
[INFO] [stderr]    Compiling miniz-sys v0.1.12
[INFO] [stderr]    Compiling serde_bytes v0.10.5
[INFO] [stderr]    Compiling liblmdb-sys v0.2.2
[INFO] [stderr]    Compiling tempdir v0.3.7
[INFO] [stderr]    Compiling ordered-float v0.4.0
[INFO] [stderr]    Compiling num-bigint v0.1.44
[INFO] [stderr]    Compiling snowflake v1.3.0
[INFO] [stderr]    Compiling chrono v0.3.0
[INFO] [stderr]    Compiling suppositions v0.1.4
[INFO] [stderr]    Compiling rust-crypto v0.2.36
[INFO] [stderr]    Compiling uuid v0.4.0
[INFO] [stderr]    Compiling yaml-rust v0.3.5
[INFO] [stderr]    Compiling flate2 v0.2.20
[INFO] [stderr]    Compiling lmdb-zero v0.4.4
[INFO] [stderr]    Compiling serde_cbor v0.6.1
[INFO] [stderr]    Compiling serde-value v0.4.1
[INFO] [stderr]    Compiling config v0.3.1
[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/config-0.3.1/src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(drop_types_in_const)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove the attribute
[INFO] [stdout]   |
[INFO] [stdout]   = help: the feature `drop_types_in_const` has been stable since 1.22.0 and no longer requires an attribute to enable
[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/config-0.3.1/src/lib.rs:4:1
[INFO] [stdout]   |
[INFO] [stdout] 4 | #![feature(trace_macros)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling hybrid-clocks v0.3.4
[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: could not compile `config` due to 3 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "d951888ad16f9dd78aa3688af226c25d161ad3c030374edade5a4fa324401bbd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d951888ad16f9dd78aa3688af226c25d161ad3c030374edade5a4fa324401bbd", kill_on_drop: false }`
[INFO] [stdout] d951888ad16f9dd78aa3688af226c25d161ad3c030374edade5a4fa324401bbd