[INFO] fetching crate high_mem_utils 0.2.7...
[INFO] testing high_mem_utils-0.2.7 against 1.44.0 for beta-1.45-1
[INFO] extracting crate high_mem_utils 0.2.7 into /workspace/builds/worker-2/source
[INFO] validating manifest of crates.io crate high_mem_utils 0.2.7 on toolchain 1.44.0
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking crates.io crate high_mem_utils 0.2.7
[INFO] finished tweaking crates.io crate high_mem_utils 0.2.7
[INFO] tweaked toml for crates.io crate high_mem_utils 0.2.7 written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[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-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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] 7a3a8d87a4797789bc24faa2548e26663581bb701978d2b49fbc93c8b3436b78
[INFO] running `"docker" "start" "-a" "7a3a8d87a4797789bc24faa2548e26663581bb701978d2b49fbc93c8b3436b78"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling fixed_len_str v0.2.9
[INFO] [stderr]    Compiling syn_str v0.1.58
[INFO] [stderr]    Compiling fast_new_type v0.1.7
[INFO] [stderr]    Compiling high_mem_utils v0.2.7 (/opt/rustwide/workdir)
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]  --> src/lib.rs:2:1
[INFO] [stderr]   |
[INFO] [stderr] 2 | #![feature(vec_leak, untagged_unions, const_fn, const_fn_union)]
[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 `high_mem_utils`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "7a3a8d87a4797789bc24faa2548e26663581bb701978d2b49fbc93c8b3436b78"`
[INFO] running `"docker" "rm" "-f" "7a3a8d87a4797789bc24faa2548e26663581bb701978d2b49fbc93c8b3436b78"`
[INFO] [stdout] 7a3a8d87a4797789bc24faa2548e26663581bb701978d2b49fbc93c8b3436b78