[INFO] fetching crate casperlabs-engine-shared 0.7.1...
[INFO] testing casperlabs-engine-shared-0.7.1 against 1.49.0 for beta-1.50-1
[INFO] extracting crate casperlabs-engine-shared 0.7.1 into /workspace/builds/worker-0/source
[INFO] validating manifest of crates.io crate casperlabs-engine-shared 0.7.1 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 casperlabs-engine-shared 0.7.1
[INFO] removed 0 missing tests
[INFO] finished tweaking crates.io crate casperlabs-engine-shared 0.7.1
[INFO] tweaked toml for crates.io crate casperlabs-engine-shared 0.7.1 written to /workspace/builds/worker-0/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] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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] [stdout] 7cc39da202714bd68d868032bb17397d4024632e90f6996f2474c697094bfc35
[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" "7cc39da202714bd68d868032bb17397d4024632e90f6996f2474c697094bfc35", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "7cc39da202714bd68d868032bb17397d4024632e90f6996f2474c697094bfc35", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7cc39da202714bd68d868032bb17397d4024632e90f6996f2474c697094bfc35", kill_on_drop: false }`
[INFO] [stdout] 7cc39da202714bd68d868032bb17397d4024632e90f6996f2474c697094bfc35
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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] 82c4d8e5966390a1d7341ba5d2abdeabe4bd0a4d72e881a29399353a172e994e
[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" "82c4d8e5966390a1d7341ba5d2abdeabe4bd0a4d72e881a29399353a172e994e", kill_on_drop: false }`
[INFO] [stderr]    Compiling byteorder v1.3.4
[INFO] [stderr]    Compiling crunchy v0.2.2
[INFO] [stderr]    Compiling bit-vec v0.6.3
[INFO] [stderr]    Compiling log v0.4.11
[INFO] [stderr]    Compiling rustc-hex v2.1.0
[INFO] [stderr]    Compiling hex_fmt v0.3.0
[INFO] [stderr]    Compiling base16 v0.2.1
[INFO] [stderr]    Compiling parity-wasm v0.41.0
[INFO] [stderr]    Compiling num-iter v0.1.42
[INFO] [stderr]    Compiling num-rational v0.2.4
[INFO] [stderr]    Compiling num-complex v0.2.4
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]    Compiling cmake v0.1.45
[INFO] [stderr]    Compiling wait-timeout v0.2.0
[INFO] [stderr]    Compiling hostname v0.3.1
[INFO] [stderr]    Compiling crypto-mac v0.7.0
[INFO] [stderr]    Compiling chrono v0.4.19
[INFO] [stderr]    Compiling synstructure v0.12.4
[INFO] [stderr]    Compiling num-derive v0.3.3
[INFO] [stderr]    Compiling serde v1.0.118
[INFO] [stderr]    Compiling bit-set v0.5.2
[INFO] [stderr]    Compiling blake2 v0.8.1
[INFO] [stderr]    Compiling rusty-fork v0.2.2
[INFO] [stderr]    Compiling wabt-sys v0.8.0
[INFO] [stderr]    Compiling failure_derive v0.1.8
[INFO] [stderr]    Compiling uint v0.8.5
[INFO] [stderr]    Compiling num v0.2.1
[INFO] [stderr]    Compiling proptest v0.9.6
[INFO] [stderr]    Compiling failure v0.1.8
[INFO] [stderr]    Compiling serde_json v1.0.61
[INFO] [stderr]    Compiling uuid v0.8.1
[INFO] [stderr]    Compiling pwasm-utils v0.12.0
[INFO] [stderr]    Compiling casperlabs-types v0.6.1
[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/casperlabs-types-0.6.1/src/lib.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 11 |     feature(min_specialization, try_reserve)
[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 `casperlabs-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" "82c4d8e5966390a1d7341ba5d2abdeabe4bd0a4d72e881a29399353a172e994e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "82c4d8e5966390a1d7341ba5d2abdeabe4bd0a4d72e881a29399353a172e994e", kill_on_drop: false }`
[INFO] [stdout] 82c4d8e5966390a1d7341ba5d2abdeabe4bd0a4d72e881a29399353a172e994e