[INFO] crate combinatorics 0.0.1 is already in cache
[INFO] testing combinatorics-0.0.1 against beta-2020-06-03 for beta-1.45-1
[INFO] extracting crate combinatorics 0.0.1 into /workspace/builds/worker-3/source
[INFO] validating manifest of crates.io crate combinatorics 0.0.1 on toolchain beta-2020-06-03
[INFO] running `"/workspace/cargo-home/bin/cargo" "+beta-2020-06-03" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking crates.io crate combinatorics 0.0.1
[INFO] finished tweaking crates.io crate combinatorics 0.0.1
[INFO] tweaked toml for crates.io crate combinatorics 0.0.1 written to /workspace/builds/worker-3/source/Cargo.toml
[INFO] running `"/workspace/cargo-home/bin/cargo" "+beta-2020-06-03" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/workspace/cargo-home/bin/cargo" "+beta-2020-06-03" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `"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" "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" "+beta-2020-06-03" "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] 436b23bb312d768d1a2f16cd3ea4a0dc3e7db16711861a6efb2bd21ea56de697
[INFO] running `"docker" "start" "-a" "436b23bb312d768d1a2f16cd3ea4a0dc3e7db16711861a6efb2bd21ea56de697"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling combinatorics v0.0.1 (/opt/rustwide/workdir)
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stderr]  --> src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(libc)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: use of unstable library feature 'rustc_private': this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via `Cargo.toml` instead?
[INFO] [stderr]   --> src/lib.rs:29:1
[INFO] [stderr]    |
[INFO] [stderr] 29 | extern crate libc;
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: see issue #27812 <https://github.com/rust-lang/rust/issues/27812> for more information
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 2 previous errors
[INFO] [stderr] 
[INFO] [stderr] Some errors have detailed explanations: E0554, E0658.
[INFO] [stderr] For more information about an error, try `rustc --explain E0554`.
[INFO] [stderr] error: could not compile `combinatorics`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "436b23bb312d768d1a2f16cd3ea4a0dc3e7db16711861a6efb2bd21ea56de697"`
[INFO] running `"docker" "rm" "-f" "436b23bb312d768d1a2f16cd3ea4a0dc3e7db16711861a6efb2bd21ea56de697"`
[INFO] [stdout] 436b23bb312d768d1a2f16cd3ea4a0dc3e7db16711861a6efb2bd21ea56de697