[INFO] cloning repository https://github.com/WilliamVenner/gm_async_write
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/WilliamVenner/gm_async_write" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FWilliamVenner%2Fgm_async_write", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FWilliamVenner%2Fgm_async_write'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 4d565e1c0f641b8f18d699e9de19229a75adda2d
[INFO] testing WilliamVenner/gm_async_write 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%2FWilliamVenner%2Fgm_async_write" "/workspace/builds/worker-3/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/WilliamVenner/gm_async_write 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] removed /workspace/builds/worker-3/source/rust-toolchain.toml
[INFO] started tweaking git repo https://github.com/WilliamVenner/gm_async_write
[INFO] finished tweaking git repo https://github.com/WilliamVenner/gm_async_write
[INFO] tweaked toml for git repo https://github.com/WilliamVenner/gm_async_write written to /workspace/builds/worker-3/source/Cargo.toml
[INFO] crate git repo https://github.com/WilliamVenner/gm_async_write 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] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded cstr v0.2.8
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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] f079d0f3cb580b42849435e1c57f94eb412683b1fbba8d8524184c7ce37fdc31
[INFO] running `Command { std: "docker" "start" "-a" "f079d0f3cb580b42849435e1c57f94eb412683b1fbba8d8524184c7ce37fdc31", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "f079d0f3cb580b42849435e1c57f94eb412683b1fbba8d8524184c7ce37fdc31", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f079d0f3cb580b42849435e1c57f94eb412683b1fbba8d8524184c7ce37fdc31", kill_on_drop: false }`
[INFO] [stdout] f079d0f3cb580b42849435e1c57f94eb412683b1fbba8d8524184c7ce37fdc31
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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] 1e698a03ac15cf6f316ece14080dfbb45c34c212a038fe9e8afd17162188f1ec
[INFO] running `Command { std: "docker" "start" "-a" "1e698a03ac15cf6f316ece14080dfbb45c34c212a038fe9e8afd17162188f1ec", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.29
[INFO] [stderr]    Compiling syn v1.0.76
[INFO] [stderr]    Compiling libc v0.2.101
[INFO] [stderr]    Compiling memchr v2.4.1
[INFO] [stderr]    Compiling pin-project-lite v0.2.7
[INFO] [stderr]    Compiling bytes v1.1.0
[INFO] [stderr]    Compiling path-clean v0.1.0
[INFO] [stderr]    Compiling tokio v1.11.0
[INFO] [stderr]    Compiling libloading v0.7.0
[INFO] [stderr]    Compiling quote v1.0.9
[INFO] [stderr]    Compiling num_cpus v1.13.0
[INFO] [stderr]    Compiling cstr v0.2.8
[INFO] [stderr]    Compiling tokio-macros v1.3.0
[INFO] [stderr]    Compiling gm_async_write v0.1.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(c_unwind)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(option_result_unwrap_unchecked)]
[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 `gm_async_write` due to 3 previous errors
[INFO] running `Command { std: "docker" "inspect" "1e698a03ac15cf6f316ece14080dfbb45c34c212a038fe9e8afd17162188f1ec", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1e698a03ac15cf6f316ece14080dfbb45c34c212a038fe9e8afd17162188f1ec", kill_on_drop: false }`
[INFO] [stdout] 1e698a03ac15cf6f316ece14080dfbb45c34c212a038fe9e8afd17162188f1ec