[INFO] cloning repository https://github.com/Rasarex/hangman_hardest_word
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/Rasarex/hangman_hardest_word" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FRasarex%2Fhangman_hardest_word", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FRasarex%2Fhangman_hardest_word'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 1bf971719b7eb6ef29a781915808e5dbb2f811ce
[INFO] testing Rasarex/hangman_hardest_word against 1.49.0 for beta-1.50-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FRasarex%2Fhangman_hardest_word" "/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/Rasarex/hangman_hardest_word on toolchain 1.49.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/Rasarex/hangman_hardest_word
[INFO] finished tweaking git repo https://github.com/Rasarex/hangman_hardest_word
[INFO] tweaked toml for git repo https://github.com/Rasarex/hangman_hardest_word written to /workspace/builds/worker-3/source/Cargo.toml
[INFO] crate git repo https://github.com/Rasarex/hangman_hardest_word already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 0a33118093de8ca102871fccb2cd886ed9316b59f4186619c2a1944b5a49a16d
[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" "0a33118093de8ca102871fccb2cd886ed9316b59f4186619c2a1944b5a49a16d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "0a33118093de8ca102871fccb2cd886ed9316b59f4186619c2a1944b5a49a16d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0a33118093de8ca102871fccb2cd886ed9316b59f4186619c2a1944b5a49a16d", kill_on_drop: false }`
[INFO] [stdout] 0a33118093de8ca102871fccb2cd886ed9316b59f4186619c2a1944b5a49a16d
[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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 2ca600a9e73c6f61782a9c9108ad711973cba1cdbe64c3f1878ec3f58235c948
[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" "2ca600a9e73c6f61782a9c9108ad711973cba1cdbe64c3f1878ec3f58235c948", kill_on_drop: false }`
[INFO] [stderr]    Compiling threadpool v1.8.1
[INFO] [stderr]    Compiling hardest_word v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/main.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(drain_filter)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[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 E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `hardest_word`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "2ca600a9e73c6f61782a9c9108ad711973cba1cdbe64c3f1878ec3f58235c948", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2ca600a9e73c6f61782a9c9108ad711973cba1cdbe64c3f1878ec3f58235c948", kill_on_drop: false }`
[INFO] [stdout] 2ca600a9e73c6f61782a9c9108ad711973cba1cdbe64c3f1878ec3f58235c948