[INFO] fetching crate esp32 0.4.0...
[INFO] testing esp32-0.4.0 against 1.44.0 for beta-1.45-1
[INFO] extracting crate esp32 0.4.0 into /workspace/builds/worker-6/source
[INFO] validating manifest of crates.io crate esp32 0.4.0 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 esp32 0.4.0
[INFO] finished tweaking crates.io crate esp32 0.4.0
[INFO] tweaked toml for crates.io crate esp32 0.4.0 written to /workspace/builds/worker-6/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-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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] 53c5dd744c82298555ee34ea942b51d6b379cf7bc15c85dfd9ef8f571b37f727
[INFO] running `"docker" "start" "-a" "53c5dd744c82298555ee34ea942b51d6b379cf7bc15c85dfd9ef8f571b37f727"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling syn v1.0.30
[INFO] [stderr]    Compiling xtensa-lx6-rt v0.1.0
[INFO] [stderr]    Compiling esp32 v0.4.0 (/opt/rustwide/workdir)
[INFO] [stderr]    Compiling r0 v1.0.0
[INFO] [stderr]    Compiling xtensa-lx6-rt-proc-macros v0.1.0
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/xtensa-lx6-rt-0.1.0/src/lib.rs:2:1
[INFO] [stderr]   |
[INFO] [stderr] 2 | #![feature(llvm_asm)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/xtensa-lx6-rt-0.1.0/src/lib.rs:3:1
[INFO] [stderr]   |
[INFO] [stderr] 3 | #![feature(global_asm)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/xtensa-lx6-rt-0.1.0/src/lib.rs:4:1
[INFO] [stderr]   |
[INFO] [stderr] 4 | #![feature(naked_functions)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/xtensa-lx6-rt-0.1.0/src/lib.rs:5:1
[INFO] [stderr]   |
[INFO] [stderr] 5 | #![feature(core_intrinsics)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 4 previous errors
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: could not compile `xtensa-lx6-rt`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "53c5dd744c82298555ee34ea942b51d6b379cf7bc15c85dfd9ef8f571b37f727"`
[INFO] running `"docker" "rm" "-f" "53c5dd744c82298555ee34ea942b51d6b379cf7bc15c85dfd9ef8f571b37f727"`
[INFO] [stdout] 53c5dd744c82298555ee34ea942b51d6b379cf7bc15c85dfd9ef8f571b37f727