[INFO] fetching crate multiproof-rs 0.1.9...
[INFO] testing multiproof-rs-0.1.9 against 1.55.0 for beta-1.56-1
[INFO] extracting crate multiproof-rs 0.1.9 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate multiproof-rs 0.1.9 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 multiproof-rs 0.1.9
[INFO] finished tweaking crates.io crate multiproof-rs 0.1.9
[INFO] tweaked toml for crates.io crate multiproof-rs 0.1.9 written to /workspace/builds/worker-4/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] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded derive_arbitrary v0.4.7
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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] 0bc60ec3113c8775617a35150ca98a2e2bab96ee47aeebe46ec89a34b1ad4d58
[INFO] running `Command { std: "docker" "start" "-a" "0bc60ec3113c8775617a35150ca98a2e2bab96ee47aeebe46ec89a34b1ad4d58", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "0bc60ec3113c8775617a35150ca98a2e2bab96ee47aeebe46ec89a34b1ad4d58", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0bc60ec3113c8775617a35150ca98a2e2bab96ee47aeebe46ec89a34b1ad4d58", kill_on_drop: false }`
[INFO] [stdout] 0bc60ec3113c8775617a35150ca98a2e2bab96ee47aeebe46ec89a34b1ad4d58
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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] [stdout] 9f3aa8e5c5b4e5d491f8e48ef30e591f44b9a692f0a04f8f13108d35b7b54e9b
[INFO] running `Command { std: "docker" "start" "-a" "9f3aa8e5c5b4e5d491f8e48ef30e591f44b9a692f0a04f8f13108d35b7b54e9b", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling byte-tools v0.3.1
[INFO] [stderr]    Compiling byteorder v1.4.3
[INFO] [stderr]    Compiling keccak v0.1.0
[INFO] [stderr]    Compiling half v1.7.1
[INFO] [stderr]    Compiling rustc-hex v2.1.0
[INFO] [stderr]    Compiling opaque-debug v0.2.3
[INFO] [stderr]    Compiling generic-array v0.12.4
[INFO] [stderr]    Compiling serde v1.0.130
[INFO] [stderr]    Compiling block-padding v0.1.5
[INFO] [stderr]    Compiling rlp v0.4.6
[INFO] [stderr]    Compiling block-buffer v0.7.3
[INFO] [stderr]    Compiling digest v0.8.1
[INFO] [stderr]    Compiling sha3 v0.8.2
[INFO] [stderr]    Compiling serde_cbor v0.10.2
[INFO] [stderr]    Compiling serde_json v1.0.67
[INFO] [stderr]    Compiling multiproof-rs v0.1.9 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(box_syntax, box_patterns)]
[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 `multiproof-rs` due to 2 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "9f3aa8e5c5b4e5d491f8e48ef30e591f44b9a692f0a04f8f13108d35b7b54e9b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9f3aa8e5c5b4e5d491f8e48ef30e591f44b9a692f0a04f8f13108d35b7b54e9b", kill_on_drop: false }`
[INFO] [stdout] 9f3aa8e5c5b4e5d491f8e48ef30e591f44b9a692f0a04f8f13108d35b7b54e9b