[INFO] fetching crate casper-erc20 0.2.1...
[INFO] testing casper-erc20-0.2.1 against 1.59.0 for beta-1.60-1
[INFO] extracting crate casper-erc20 0.2.1 into /workspace/builds/worker-20/source
[INFO] validating manifest of crates.io crate casper-erc20 0.2.1 on toolchain 1.59.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.59.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate casper-erc20 0.2.1
[INFO] finished tweaking crates.io crate casper-erc20 0.2.1
[INFO] tweaked toml for crates.io crate casper-erc20 0.2.1 written to /workspace/builds/worker-20/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.59.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.59.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-20/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-20/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@sha256:0cd99ca24d8e8c98e67c542213511d985b8778b5bdcbb160e038429496686047" "/opt/rustwide/cargo-home/bin/cargo" "+1.59.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 3fd8b07e5a059d7a1edeebb63658e6e4aac77a311d6da2fa67b690b0dc4ea0df
[INFO] running `Command { std: "docker" "start" "-a" "3fd8b07e5a059d7a1edeebb63658e6e4aac77a311d6da2fa67b690b0dc4ea0df", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "3fd8b07e5a059d7a1edeebb63658e6e4aac77a311d6da2fa67b690b0dc4ea0df", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3fd8b07e5a059d7a1edeebb63658e6e4aac77a311d6da2fa67b690b0dc4ea0df", kill_on_drop: false }`
[INFO] [stdout] 3fd8b07e5a059d7a1edeebb63658e6e4aac77a311d6da2fa67b690b0dc4ea0df
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-20/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-20/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@sha256:0cd99ca24d8e8c98e67c542213511d985b8778b5bdcbb160e038429496686047" "/opt/rustwide/cargo-home/bin/cargo" "+1.59.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 923b54c1da71c5b51a5725ccc8565c2fffaccb8e5dbb8ac9fdc29d290860d5e2
[INFO] running `Command { std: "docker" "start" "-a" "923b54c1da71c5b51a5725ccc8565c2fffaccb8e5dbb8ac9fdc29d290860d5e2", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling rand_core v0.5.1
[INFO] [stderr]    Compiling subtle v2.4.1
[INFO] [stderr]    Compiling funty v1.1.0
[INFO] [stderr]    Compiling wyz v0.2.0
[INFO] [stderr]    Compiling serde v1.0.136
[INFO] [stderr]    Compiling ppv-lite86 v0.2.16
[INFO] [stderr]    Compiling byteorder v1.4.3
[INFO] [stderr]    Compiling serde_json v1.0.79
[INFO] [stderr]    Compiling hex v0.4.3
[INFO] [stderr]    Compiling rand_core v0.6.3
[INFO] [stderr]    Compiling base64 v0.13.0
[INFO] [stderr]    Compiling once_cell v1.9.0
[INFO] [stderr]    Compiling num-traits v0.2.14
[INFO] [stderr]    Compiling num-integer v0.1.44
[INFO] [stderr]    Compiling num-bigint v0.4.3
[INFO] [stderr]    Compiling num-rational v0.4.0
[INFO] [stderr]    Compiling num-iter v0.1.42
[INFO] [stderr]    Compiling wee_alloc v0.4.5
[INFO] [stderr]    Compiling digest v0.9.0
[INFO] [stderr]    Compiling serde_derive v1.0.136
[INFO] [stderr]    Compiling num-derive v0.3.3
[INFO] [stderr]    Compiling zeroize_derive v1.3.2
[INFO] [stderr]    Compiling sha2 v0.9.9
[INFO] [stderr]    Compiling signature v1.2.2
[INFO] [stderr]    Compiling rand v0.8.5
[INFO] [stderr]    Compiling crypto-mac v0.10.1
[INFO] [stderr]    Compiling crypto-mac v0.8.0
[INFO] [stderr]    Compiling ed25519 v1.2.0
[INFO] [stderr]    Compiling hmac v0.10.1
[INFO] [stderr]    Compiling blake2 v0.9.2
[INFO] [stderr]    Compiling uint v0.9.3
[INFO] [stderr]    Compiling rand_chacha v0.2.2
[INFO] [stderr]    Compiling bitvec v0.18.5
[INFO] [stderr]    Compiling rand v0.7.3
[INFO] [stderr]    Compiling zeroize v1.3.0
[INFO] [stderr]    Compiling num-complex v0.4.0
[INFO] [stderr]    Compiling curve25519-dalek v3.2.1
[INFO] [stderr]    Compiling ed25519-dalek v1.0.1
[INFO] [stderr]    Compiling ff v0.8.0
[INFO] [stderr]    Compiling group v0.8.0
[INFO] [stderr]    Compiling elliptic-curve v0.8.5
[INFO] [stderr]    Compiling ecdsa v0.10.2
[INFO] [stderr]    Compiling k256 v0.7.3
[INFO] [stderr]    Compiling num v0.4.0
[INFO] [stderr]    Compiling serde_bytes v0.11.5
[INFO] [stderr]    Compiling casper-types v1.4.6
[INFO] [stderr]    Compiling casper-contract v1.4.3
[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-contract-1.4.3/src/lib.rs:51:5
[INFO] [stdout]    |
[INFO] [stdout] 51 |     feature(alloc_error_handler, core_intrinsics, lang_items)
[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 `casper-contract` 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" "923b54c1da71c5b51a5725ccc8565c2fffaccb8e5dbb8ac9fdc29d290860d5e2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "923b54c1da71c5b51a5725ccc8565c2fffaccb8e5dbb8ac9fdc29d290860d5e2", kill_on_drop: false }`
[INFO] [stdout] 923b54c1da71c5b51a5725ccc8565c2fffaccb8e5dbb8ac9fdc29d290860d5e2