[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 master#af3c6e733a40e671550e0f0f5aeecaa13772ba56 for pr-74989
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmwdowns%2Frust_matt_os" "/workspace/builds/worker-7/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/mwdowns/rust_matt_os on toolchain af3c6e733a40e671550e0f0f5aeecaa13772ba56
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+af3c6e733a40e671550e0f0f5aeecaa13772ba56" "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-7/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" "+af3c6e733a40e671550e0f0f5aeecaa13772ba56" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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" "+af3c6e733a40e671550e0f0f5aeecaa13772ba56" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 7b16005bd6caafcb1bdd4b43c98644ce7a23842c29b0a3e105229072f20378cc
[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" "7b16005bd6caafcb1bdd4b43c98644ce7a23842c29b0a3e105229072f20378cc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "7b16005bd6caafcb1bdd4b43c98644ce7a23842c29b0a3e105229072f20378cc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7b16005bd6caafcb1bdd4b43c98644ce7a23842c29b0a3e105229072f20378cc", kill_on_drop: false }`
[INFO] [stdout] 7b16005bd6caafcb1bdd4b43c98644ce7a23842c29b0a3e105229072f20378cc
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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" "+af3c6e733a40e671550e0f0f5aeecaa13772ba56" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 2e63611ea81d6f2cb7bdbc463feb38232a57748bfc1dc6eeaead7c957d833963
[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" "2e63611ea81d6f2cb7bdbc463feb38232a57748bfc1dc6eeaead7c957d833963", 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] [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] [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: build failed
[INFO] running `Command { std: "docker" "inspect" "2e63611ea81d6f2cb7bdbc463feb38232a57748bfc1dc6eeaead7c957d833963", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2e63611ea81d6f2cb7bdbc463feb38232a57748bfc1dc6eeaead7c957d833963", kill_on_drop: false }`
[INFO] [stdout] 2e63611ea81d6f2cb7bdbc463feb38232a57748bfc1dc6eeaead7c957d833963
