[INFO] cloning repository https://github.com/mwdowns/rust_matt_os
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/mwdowns/rust_matt_os" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmwdowns%2Frust_matt_os", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmwdowns%2Frust_matt_os'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 8be087538b6e755d725d7f790c3696a14d08456a
[INFO] checking mwdowns/rust_matt_os against try#1c5262aa6c045a581fb974488793f09ed51fc498 for pr-78376
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmwdowns%2Frust_matt_os" "/workspace/builds/worker-2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/mwdowns/rust_matt_os on toolchain 1c5262aa6c045a581fb974488793f09ed51fc498
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1c5262aa6c045a581fb974488793f09ed51fc498" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/mwdowns/rust_matt_os
[INFO] finished tweaking git repo https://github.com/mwdowns/rust_matt_os
[INFO] tweaked toml for git repo https://github.com/mwdowns/rust_matt_os written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] crate git repo https://github.com/mwdowns/rust_matt_os already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1c5262aa6c045a581fb974488793f09ed51fc498" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1c5262aa6c045a581fb974488793f09ed51fc498" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] feabbc45b4e8af82c84895825921b7b4a2a651cb559d0a67e9b830c87d8249b2
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "feabbc45b4e8af82c84895825921b7b4a2a651cb559d0a67e9b830c87d8249b2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "feabbc45b4e8af82c84895825921b7b4a2a651cb559d0a67e9b830c87d8249b2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "feabbc45b4e8af82c84895825921b7b4a2a651cb559d0a67e9b830c87d8249b2", kill_on_drop: false }`
[INFO] [stdout] feabbc45b4e8af82c84895825921b7b4a2a651cb559d0a67e9b830c87d8249b2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1c5262aa6c045a581fb974488793f09ed51fc498" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 967a5b632edd06b20adec1fe63dfa19964d81536047e0e17673755f145a1d44d
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "967a5b632edd06b20adec1fe63dfa19964d81536047e0e17673755f145a1d44d", kill_on_drop: false }`
[INFO] [stderr]     Checking matt_os v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0522]: definition of an unknown language item: `panic_fmt`
[INFO] [stdout]  --> src/main.rs:5:1
[INFO] [stdout]   |
[INFO] [stdout] 5 | #[lang = "panic_fmt"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^ definition of unknown language item `panic_fmt`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: `#[panic_handler]` function required, but not found
[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 E0522`.
[INFO] [stdout] 
[INFO] [stdout] error[E0522]: definition of an unknown language item: `panic_fmt`
[INFO] [stdout]  --> src/main.rs:5:1
[INFO] [stdout]   |
[INFO] [stdout] 5 | #[lang = "panic_fmt"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^ definition of unknown language item `panic_fmt`
[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 E0522`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `matt_os`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "967a5b632edd06b20adec1fe63dfa19964d81536047e0e17673755f145a1d44d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "967a5b632edd06b20adec1fe63dfa19964d81536047e0e17673755f145a1d44d", kill_on_drop: false }`
[INFO] [stdout] 967a5b632edd06b20adec1fe63dfa19964d81536047e0e17673755f145a1d44d