[INFO] fetching crate iter-opt-filter 0.1.0...
[INFO] testing iter-opt-filter-0.1.0 against 1.54.0 for beta-1.55-1
[INFO] extracting crate iter-opt-filter 0.1.0 into /workspace/builds/worker-16/source
[INFO] validating manifest of crates.io crate iter-opt-filter 0.1.0 on toolchain 1.54.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate iter-opt-filter 0.1.0
[INFO] finished tweaking crates.io crate iter-opt-filter 0.1.0
[INFO] tweaked toml for crates.io crate iter-opt-filter 0.1.0 written to /workspace/builds/worker-16/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-16/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-16/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+1.54.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] ef2bb02eccdf2dc01ef2d0c0132e1ddcc1bd243325eac5237d0afed9ef8c6926
[INFO] running `Command { std: "docker" "start" "-a" "ef2bb02eccdf2dc01ef2d0c0132e1ddcc1bd243325eac5237d0afed9ef8c6926", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "ef2bb02eccdf2dc01ef2d0c0132e1ddcc1bd243325eac5237d0afed9ef8c6926", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ef2bb02eccdf2dc01ef2d0c0132e1ddcc1bd243325eac5237d0afed9ef8c6926", kill_on_drop: false }`
[INFO] [stdout] ef2bb02eccdf2dc01ef2d0c0132e1ddcc1bd243325eac5237d0afed9ef8c6926
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-16/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-16/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+1.54.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] c25a27619ff36f6ba2284daef811ded16abe6b58cb98260e9e9f8e2428f72a57
[INFO] running `Command { std: "docker" "start" "-a" "c25a27619ff36f6ba2284daef811ded16abe6b58cb98260e9e9f8e2428f72a57", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling iter-opt-filter v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.03s
[INFO] running `Command { std: "docker" "inspect" "c25a27619ff36f6ba2284daef811ded16abe6b58cb98260e9e9f8e2428f72a57", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c25a27619ff36f6ba2284daef811ded16abe6b58cb98260e9e9f8e2428f72a57", kill_on_drop: false }`
[INFO] [stdout] c25a27619ff36f6ba2284daef811ded16abe6b58cb98260e9e9f8e2428f72a57
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-16/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-16/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+1.54.0" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 3dbd14cc1fd6b63d291a373acd193e7f1532cce535c89879bc059019c0adcc0a
[INFO] running `Command { std: "docker" "start" "-a" "3dbd14cc1fd6b63d291a373acd193e7f1532cce535c89879bc059019c0adcc0a", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling iter-opt-filter v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:11:19
[INFO] [stdout]    |
[INFO] [stdout] 11 | #![cfg_attr(test, feature(test))]
[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 `iter-opt-filter`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "3dbd14cc1fd6b63d291a373acd193e7f1532cce535c89879bc059019c0adcc0a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3dbd14cc1fd6b63d291a373acd193e7f1532cce535c89879bc059019c0adcc0a", kill_on_drop: false }`
[INFO] [stdout] 3dbd14cc1fd6b63d291a373acd193e7f1532cce535c89879bc059019c0adcc0a
