[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] testing mwdowns/rust_matt_os against beta-2021-09-08 for beta-1.56-1
[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 beta-2021-09-08
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-09-08" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", 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" "+beta-2021-09-08" "fetch" "--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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-09-08" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 008a2b0e27477704c00f4efa435fa51382fc13a28bedac6e0ff4ba9180c96a84
[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" "008a2b0e27477704c00f4efa435fa51382fc13a28bedac6e0ff4ba9180c96a84", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "008a2b0e27477704c00f4efa435fa51382fc13a28bedac6e0ff4ba9180c96a84", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "008a2b0e27477704c00f4efa435fa51382fc13a28bedac6e0ff4ba9180c96a84", kill_on_drop: false }`
[INFO] [stdout] 008a2b0e27477704c00f4efa435fa51382fc13a28bedac6e0ff4ba9180c96a84
[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=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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-09-08" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] a14e2b1c9a889a47d469b1f669d8553f8a352d61f1d4a5fb13140333934bcd82
[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" "a14e2b1c9a889a47d469b1f669d8553f8a352d61f1d4a5fb13140333934bcd82", kill_on_drop: false }`
[INFO] [stderr]    Compiling matt_os v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/main.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(lang_items)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0152]: found duplicate lang item `panic_fmt`
[INFO] [stdout]  --> src/main.rs:7:1
[INFO] [stdout]   |
[INFO] [stdout] 7 | / pub extern fn rust_begin_panic(_msg: core::fmt::Arguments,
[INFO] [stdout] 8 | |     _file: &'static str, _line: u32, _column: u32) -> !
[INFO] [stdout]   | |_______________________________________________________^
[INFO] [stdout]   |
[INFO] [stdout]   = note: the lang item is first defined in crate `core` (which `matt_os` depends on)
[INFO] [stdout]   = note: first definition in `core` loaded from /opt/rustwide/rustup-home/toolchains/beta-2021-09-08-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcore-8ef7dd43fc671f88.rlib
[INFO] [stdout]   = note: second definition in the local crate (`matt_os`)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: `#[panic_handler]` function required, but not found
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 3 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0152, E0554.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0152`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `matt_os` due to 4 previous errors
[INFO] running `Command { std: "docker" "inspect" "a14e2b1c9a889a47d469b1f669d8553f8a352d61f1d4a5fb13140333934bcd82", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a14e2b1c9a889a47d469b1f669d8553f8a352d61f1d4a5fb13140333934bcd82", kill_on_drop: false }`
[INFO] [stdout] a14e2b1c9a889a47d469b1f669d8553f8a352d61f1d4a5fb13140333934bcd82