[INFO] fetching crate metron_core 0.0.1...
[INFO] testing metron_core-0.0.1 against 1.60.0 for beta-1.61-1
[INFO] extracting crate metron_core 0.0.1 into /workspace/builds/worker-15/source
[INFO] validating manifest of crates.io crate metron_core 0.0.1 on toolchain 1.60.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate metron_core 0.0.1
[INFO] finished tweaking crates.io crate metron_core 0.0.1
[INFO] tweaked toml for crates.io crate metron_core 0.0.1 written to /workspace/builds/worker-15/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "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" "+1.60.0" "fetch" "--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-15/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-15/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:b0c94ce3c1162fcb8e57cac5b65ec2f72eabb1eebea4fcc35e269e823f681646" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] fbb4c3778fb102ac8172ad6a71076f29c8b4ad08705ec63fbc7bad68dfd7cfe6
[INFO] running `Command { std: "docker" "start" "-a" "fbb4c3778fb102ac8172ad6a71076f29c8b4ad08705ec63fbc7bad68dfd7cfe6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "fbb4c3778fb102ac8172ad6a71076f29c8b4ad08705ec63fbc7bad68dfd7cfe6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "fbb4c3778fb102ac8172ad6a71076f29c8b4ad08705ec63fbc7bad68dfd7cfe6", kill_on_drop: false }`
[INFO] [stdout] fbb4c3778fb102ac8172ad6a71076f29c8b4ad08705ec63fbc7bad68dfd7cfe6
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-15/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-15/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:b0c94ce3c1162fcb8e57cac5b65ec2f72eabb1eebea4fcc35e269e823f681646" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] bb0ce6924a4f08bd7de621728ae3765fe7c95a1a6000d70f9ab94a9afb51abf7
[INFO] running `Command { std: "docker" "start" "-a" "bb0ce6924a4f08bd7de621728ae3765fe7c95a1a6000d70f9ab94a9afb51abf7", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling metron_core v0.0.1 (/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(associated_type_bounds)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(once_cell)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `metron_core` due to 3 previous errors
[INFO] running `Command { std: "docker" "inspect" "bb0ce6924a4f08bd7de621728ae3765fe7c95a1a6000d70f9ab94a9afb51abf7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "bb0ce6924a4f08bd7de621728ae3765fe7c95a1a6000d70f9ab94a9afb51abf7", kill_on_drop: false }`
[INFO] [stdout] bb0ce6924a4f08bd7de621728ae3765fe7c95a1a6000d70f9ab94a9afb51abf7