[INFO] fetching crate niobium 0.0.0...
[INFO] testing niobium-0.0.0 against 1.60.0 for beta-1.61-1
[INFO] extracting crate niobium 0.0.0 into /workspace/builds/worker-26/source
[INFO] validating manifest of crates.io crate niobium 0.0.0 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 niobium 0.0.0
[INFO] finished tweaking crates.io crate niobium 0.0.0
[INFO] tweaked toml for crates.io crate niobium 0.0.0 written to /workspace/builds/worker-26/source/Cargo.toml
[INFO] crate crates.io crate niobium 0.0.0 already has a lockfile, it will not be regenerated
[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-26/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-26/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] cb1051e02b0edd229cc073f6e4d6a22a248867abff538da03be1c35dd59e8efe
[INFO] running `Command { std: "docker" "start" "-a" "cb1051e02b0edd229cc073f6e4d6a22a248867abff538da03be1c35dd59e8efe", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "cb1051e02b0edd229cc073f6e4d6a22a248867abff538da03be1c35dd59e8efe", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "cb1051e02b0edd229cc073f6e4d6a22a248867abff538da03be1c35dd59e8efe", kill_on_drop: false }`
[INFO] [stdout] cb1051e02b0edd229cc073f6e4d6a22a248867abff538da03be1c35dd59e8efe
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-26/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-26/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] 2d0fff0901d75ce2b0ee977c9ecf94273effab31c6baad3015361af719a06439
[INFO] running `Command { std: "docker" "start" "-a" "2d0fff0901d75ce2b0ee977c9ecf94273effab31c6baad3015361af719a06439", kill_on_drop: false }`
[INFO] [stderr]    Compiling niobium v0.0.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.66s
[INFO] running `Command { std: "docker" "inspect" "2d0fff0901d75ce2b0ee977c9ecf94273effab31c6baad3015361af719a06439", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2d0fff0901d75ce2b0ee977c9ecf94273effab31c6baad3015361af719a06439", kill_on_drop: false }`
[INFO] [stdout] 2d0fff0901d75ce2b0ee977c9ecf94273effab31c6baad3015361af719a06439
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-26/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-26/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" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] a8face28df31c97297fa2ad8f066b01832cc3efa936b68301dc47cbeb5a31ed4
[INFO] running `Command { std: "docker" "start" "-a" "a8face28df31c97297fa2ad8f066b01832cc3efa936b68301dc47cbeb5a31ed4", kill_on_drop: false }`
[INFO] [stderr]    Compiling niobium v0.0.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> examples/hello_magic.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(start)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: language item required, but not found: `eh_personality`
[INFO] [stdout]   |
[INFO] [stdout]   = note: this can occur when a binary crate with `#![no_std]` is compiled for a target where `eh_personality` is defined in the standard library
[INFO] [stdout]   = help: you may be able to compile for a target that doesn't need `eh_personality`, specify a target with `--target` or in `.cargo/config`
[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 `niobium` due to 3 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "a8face28df31c97297fa2ad8f066b01832cc3efa936b68301dc47cbeb5a31ed4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a8face28df31c97297fa2ad8f066b01832cc3efa936b68301dc47cbeb5a31ed4", kill_on_drop: false }`
[INFO] [stdout] a8face28df31c97297fa2ad8f066b01832cc3efa936b68301dc47cbeb5a31ed4