[INFO] fetching crate casper-engine-test-support 0.2.1...
[INFO] testing casper-engine-test-support-0.2.1 against 1.49.0 for beta-1.50-1
[INFO] extracting crate casper-engine-test-support 0.2.1 into /workspace/builds/worker-6/source
[INFO] validating manifest of crates.io crate casper-engine-test-support 0.2.1 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 casper-engine-test-support 0.2.1
[INFO] finished tweaking crates.io crate casper-engine-test-support 0.2.1
[INFO] tweaked toml for crates.io crate casper-engine-test-support 0.2.1 written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[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-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", 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] 7a7be66cbf8b66d5798652a82fe9f3e4eca2f384c3999a175456b3bfffdbca71
[INFO] running `Command { std: "docker" "start" "-a" "7a7be66cbf8b66d5798652a82fe9f3e4eca2f384c3999a175456b3bfffdbca71", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "7a7be66cbf8b66d5798652a82fe9f3e4eca2f384c3999a175456b3bfffdbca71", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7a7be66cbf8b66d5798652a82fe9f3e4eca2f384c3999a175456b3bfffdbca71", kill_on_drop: false }`
[INFO] [stdout] 7a7be66cbf8b66d5798652a82fe9f3e4eca2f384c3999a175456b3bfffdbca71
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 91b220005d90b934a5d276e558812621c9b596bcd729c9edf6e43a03ed4716da
[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" "91b220005d90b934a5d276e558812621c9b596bcd729c9edf6e43a03ed4716da", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.81
[INFO] [stderr]    Compiling proc-macro2 v1.0.24
[INFO] [stderr]    Compiling serde v1.0.118
[INFO] [stderr]    Compiling futures v0.1.30
[INFO] [stderr]    Compiling getrandom v0.1.16
[INFO] [stderr]    Compiling crunchy v0.2.2
[INFO] [stderr]    Compiling serde_json v1.0.61
[INFO] [stderr]    Compiling cc v1.0.66
[INFO] [stderr]    Compiling bit-vec v0.6.3
[INFO] [stderr]    Compiling schemars v0.8.0
[INFO] [stderr]    Compiling rustc-hex v2.1.0
[INFO] [stderr]    Compiling dyn-clone v1.0.4
[INFO] [stderr]    Compiling nix v0.18.0
[INFO] [stderr]    Compiling hex v0.4.2
[INFO] [stderr]    Compiling num-traits v0.2.14
[INFO] [stderr]    Compiling num-integer v0.1.44
[INFO] [stderr]    Compiling num-bigint v0.3.1
[INFO] [stderr]    Compiling indexmap v1.6.1
[INFO] [stderr]    Compiling num-rational v0.3.2
[INFO] [stderr]    Compiling num-bigint v0.2.6
[INFO] [stderr]    Compiling num-iter v0.1.42
[INFO] [stderr]    Compiling num-rational v0.2.4
[INFO] [stderr]    Compiling bit-set v0.5.2
[INFO] [stderr]    Compiling crypto-mac v0.8.0
[INFO] [stderr]    Compiling uint v0.8.5
[INFO] [stderr]    Compiling blake2 v0.9.1
[INFO] [stderr]    Compiling lmdb-sys v0.8.0
[INFO] [stderr]    Compiling quote v1.0.8
[INFO] [stderr]    Compiling tokio-executor v0.1.10
[INFO] [stderr]    Compiling tokio-sync v0.1.8
[INFO] [stderr]    Compiling tokio-timer v0.1.2
[INFO] [stderr]    Compiling syn v1.0.57
[INFO] [stderr]    Compiling tokio-timer v0.2.13
[INFO] [stderr]    Compiling tokio-current-thread v0.1.7
[INFO] [stderr]    Compiling num-complex v0.3.1
[INFO] [stderr]    Compiling iovec v0.1.4
[INFO] [stderr]    Compiling num_cpus v1.13.0
[INFO] [stderr]    Compiling net2 v0.2.37
[INFO] [stderr]    Compiling parking_lot_core v0.6.2
[INFO] [stderr]    Compiling wait-timeout v0.2.0
[INFO] [stderr]    Compiling rand v0.4.6
[INFO] [stderr]    Compiling unix_socket v0.5.0
[INFO] [stderr]    Compiling time v0.1.44
[INFO] [stderr]    Compiling dirs-sys v0.3.5
[INFO] [stderr]    Compiling hostname v0.3.1
[INFO] [stderr]    Compiling atty v0.2.14
[INFO] [stderr]    Compiling wee_alloc v0.4.5
[INFO] [stderr]    Compiling bytes v0.4.12
[INFO] [stderr]    Compiling rand_core v0.5.1
[INFO] [stderr]    Compiling futures-cpupool v0.1.8
[INFO] [stderr]    Compiling parking_lot v0.9.0
[INFO] [stderr]    Compiling dirs v3.0.1
[INFO] [stderr]    Compiling chrono v0.4.19
[INFO] [stderr]    Compiling clap v2.33.3
[INFO] [stderr]    Compiling tempdir v0.3.7
[INFO] [stderr]    Compiling rand_chacha v0.2.2
[INFO] [stderr]    Compiling rand_pcg v0.2.1
[INFO] [stderr]    Compiling rand_xorshift v0.2.0
[INFO] [stderr]    Compiling protobuf v2.8.2
[INFO] [stderr]    Compiling rand v0.7.3
[INFO] [stderr]    Compiling lmdb v0.8.0
[INFO] [stderr]    Compiling wasmi v0.6.2
[INFO] [stderr]    Compiling tempfile v3.1.0
[INFO] [stderr]    Compiling rusty-fork v0.3.0
[INFO] [stderr]    Compiling proptest v0.10.1
[INFO] [stderr]    Compiling ctrlc v3.1.7
[INFO] [stderr]    Compiling synstructure v0.12.4
[INFO] [stderr]    Compiling serde_derive_internals v0.25.0
[INFO] [stderr]    Compiling protobuf-codegen v2.8.2
[INFO] [stderr]    Compiling grpc-compiler v0.6.2
[INFO] [stderr]    Compiling serde_derive v1.0.118
[INFO] [stderr]    Compiling schemars_derive v0.8.0
[INFO] [stderr]    Compiling failure_derive v0.1.8
[INFO] [stderr]    Compiling datasize_derive v0.2.3
[INFO] [stderr]    Compiling num-derive v0.3.3
[INFO] [stderr]    Compiling thiserror-impl v1.0.23
[INFO] [stderr]    Compiling tracing-attributes v0.1.11
[INFO] [stderr]    Compiling failure v0.1.8
[INFO] [stderr]    Compiling datasize v0.2.3
[INFO] [stderr]    Compiling tracing v0.1.22
[INFO] [stderr]    Compiling thiserror v1.0.23
[INFO] [stderr]    Compiling log v0.4.11
[INFO] [stderr]    Compiling bstr v0.2.14
[INFO] [stderr]    Compiling uuid v0.8.1
[INFO] [stderr]    Compiling hex-buffer-serde v0.2.2
[INFO] [stderr]    Compiling bincode v1.3.1
[INFO] [stderr]    Compiling tokio-io v0.1.13
[INFO] [stderr]    Compiling mio v0.6.23
[INFO] [stderr]    Compiling tokio-threadpool v0.1.18
[INFO] [stderr]    Compiling protoc v2.8.2
[INFO] [stderr]    Compiling tls-api v0.1.22
[INFO] [stderr]    Compiling log v0.3.9
[INFO] [stderr]    Compiling pwasm-utils v0.12.0
[INFO] [stderr]    Compiling tls-api-stub v0.1.22
[INFO] [stderr]    Compiling protoc-rust v2.8.2
[INFO] [stderr]    Compiling num v0.3.1
[INFO] [stderr]    Compiling csv v1.1.5
[INFO] [stderr]    Compiling protoc-rust-grpc v0.6.2
[INFO] [stderr]    Compiling tokio-codec v0.1.2
[INFO] [stderr]    Compiling tokio-tls-api v0.1.22
[INFO] [stderr]    Compiling casper-engine-grpc-server v0.2.1
[INFO] [stderr]    Compiling tokio-fs v0.1.7
[INFO] [stderr]    Compiling tokio-reactor v0.1.12
[INFO] [stderr]    Compiling mio-uds v0.6.8
[INFO] [stderr]    Compiling tokio-udp v0.1.6
[INFO] [stderr]    Compiling tokio-uds v0.2.7
[INFO] [stderr]    Compiling tokio-tcp v0.1.4
[INFO] [stderr]    Compiling tokio v0.1.22
[INFO] [stderr]    Compiling tokio-core v0.1.18
[INFO] [stderr]    Compiling casper-types v0.2.1
[INFO] [stderr]    Compiling tokio-uds v0.1.7
[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/casper-types-0.2.1/src/lib.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 11 |     feature(min_specialization, try_reserve)
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling httpbis v0.7.0
[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 `casper-types`
[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" "91b220005d90b934a5d276e558812621c9b596bcd729c9edf6e43a03ed4716da", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "91b220005d90b934a5d276e558812621c9b596bcd729c9edf6e43a03ed4716da", kill_on_drop: false }`
[INFO] [stdout] 91b220005d90b934a5d276e558812621c9b596bcd729c9edf6e43a03ed4716da