[INFO] cloning repository https://github.com/ruggeri/rust_learning
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/ruggeri/rust_learning" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fruggeri%2Frust_learning"`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fruggeri%2Frust_learning'...
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 6564c9e695a39cf690d74e0eb370d542f146007c
[INFO] testing ruggeri/rust_learning against 1.44.0 for beta-1.45-1
[INFO] running `"git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fruggeri%2Frust_learning" "/workspace/builds/worker-0/source"`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/ruggeri/rust_learning on toolchain 1.44.0
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/ruggeri/rust_learning
[INFO] finished tweaking git repo https://github.com/ruggeri/rust_learning
[INFO] tweaked toml for git repo https://github.com/ruggeri/rust_learning written to /workspace/builds/worker-0/source/Cargo.toml
[INFO] crate git repo https://github.com/ruggeri/rust_learning already has a lockfile, it will not be regenerated
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+1.44.0" "build" "--frozen"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] e742dc62b07b8bf5c3c7cf11fb199093e3815e0d5d346f8f1a7f7cae7cdb21a5
[INFO] running `"docker" "start" "-a" "e742dc62b07b8bf5c3c7cf11fb199093e3815e0d5d346f8f1a7f7cae7cdb21a5"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling rust_learning v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]  --> src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(box_patterns, box_syntax)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: could not compile `rust_learning`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "e742dc62b07b8bf5c3c7cf11fb199093e3815e0d5d346f8f1a7f7cae7cdb21a5"`
[INFO] running `"docker" "rm" "-f" "e742dc62b07b8bf5c3c7cf11fb199093e3815e0d5d346f8f1a7f7cae7cdb21a5"`
[INFO] [stdout] e742dc62b07b8bf5c3c7cf11fb199093e3815e0d5d346f8f1a7f7cae7cdb21a5