[INFO] fetching crate fuzzcheck_mutators 0.6.0...
[INFO] checking fuzzcheck_mutators-0.6.0 against 1.95.0 for pr-155915
[INFO] extracting crate fuzzcheck_mutators 0.6.0 into /workspace/builds/worker-6-tc1/source
[INFO] started tweaking crates.io crate fuzzcheck_mutators 0.6.0
[INFO] finished tweaking crates.io crate fuzzcheck_mutators 0.6.0
[INFO] tweaked toml for crates.io crate fuzzcheck_mutators 0.6.0 written to /workspace/builds/worker-6-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate fuzzcheck_mutators 0.6.0 on toolchain 1.95.0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.95.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate crates.io crate fuzzcheck_mutators 0.6.0 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.95.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded proc-macro2 v1.0.24
[INFO] [stderr]   Downloaded instant v0.1.9
[INFO] [stderr]   Downloaded fuzzcheck_traits v0.6.0
[INFO] [stderr]   Downloaded fastrand v1.4.0
[INFO] [stderr]   Downloaded decent-synquote-alternative v0.3.0
[INFO] [stderr]   Downloaded fuzzcheck_mutators_derive v0.6.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+1.95.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 17ae4ee248bc04c3ebea7e3e121bf7b88694ba017f364252b4f895900a6d6093
[INFO] running `Command { std: "docker" "start" "-a" "17ae4ee248bc04c3ebea7e3e121bf7b88694ba017f364252b4f895900a6d6093", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "17ae4ee248bc04c3ebea7e3e121bf7b88694ba017f364252b4f895900a6d6093", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "17ae4ee248bc04c3ebea7e3e121bf7b88694ba017f364252b4f895900a6d6093", kill_on_drop: false }`
[INFO] [stdout] 17ae4ee248bc04c3ebea7e3e121bf7b88694ba017f364252b4f895900a6d6093
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/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=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+1.95.0" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 2a039a8b6bdd9b675235f3d39b587a1845f18ab2a14b597d317407f39b25232d
[INFO] running `Command { std: "docker" "start" "-a" "2a039a8b6bdd9b675235f3d39b587a1845f18ab2a14b597d317407f39b25232d", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.24
[INFO] [stderr]     Checking fuzzcheck_traits v0.6.0
[INFO] [stderr]     Checking fastrand v1.4.0
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> /opt/rustwide/cargo-home/registry/src/index.crates.io-1949cf8c6b5b557f/fuzzcheck_traits-0.6.0/src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(arc_new_cyclic)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `fuzzcheck_traits` (lib) due to 1 previous error
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "2a039a8b6bdd9b675235f3d39b587a1845f18ab2a14b597d317407f39b25232d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2a039a8b6bdd9b675235f3d39b587a1845f18ab2a14b597d317407f39b25232d", kill_on_drop: false }`
[INFO] [stdout] 2a039a8b6bdd9b675235f3d39b587a1845f18ab2a14b597d317407f39b25232d