[INFO] fetching crate riot-wrappers 0.7.4...
[INFO] testing riot-wrappers-0.7.4 against 1.55.0 for beta-1.56-1
[INFO] extracting crate riot-wrappers 0.7.4 into /workspace/builds/worker-8/source
[INFO] validating manifest of crates.io crate riot-wrappers 0.7.4 on toolchain 1.55.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate riot-wrappers 0.7.4
[INFO] finished tweaking crates.io crate riot-wrappers 0.7.4
[INFO] tweaked toml for crates.io crate riot-wrappers 0.7.4 written to /workspace/builds/worker-8/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] e1b4a283ced3c52405fde0be12cd929cc8c32e142678c86fafe9dc1a77463ca1
[INFO] running `Command { std: "docker" "start" "-a" "e1b4a283ced3c52405fde0be12cd929cc8c32e142678c86fafe9dc1a77463ca1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e1b4a283ced3c52405fde0be12cd929cc8c32e142678c86fafe9dc1a77463ca1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e1b4a283ced3c52405fde0be12cd929cc8c32e142678c86fafe9dc1a77463ca1", kill_on_drop: false }`
[INFO] [stdout] e1b4a283ced3c52405fde0be12cd929cc8c32e142678c86fafe9dc1a77463ca1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] b56e0e2856a36996b32a069d43b602ed66e75c300762b255c3f2a0fe1b4b2882
[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" "b56e0e2856a36996b32a069d43b602ed66e75c300762b255c3f2a0fe1b4b2882", kill_on_drop: false }`
[INFO] [stderr]    Compiling heapless v0.5.6
[INFO] [stderr]    Compiling c2rust-asm-casts v0.2.0
[INFO] [stderr]    Compiling mutex-trait v0.2.0
[INFO] [stderr]    Compiling hex-noalloc v0.3.2-post1
[INFO] [stderr]    Compiling riot-wrappers v0.7.4 (/opt/rustwide/workdir)
[INFO] [stderr]    Compiling hash32 v0.1.1
[INFO] [stderr]    Compiling embedded-graphics v0.6.2
[INFO] [stderr]    Compiling cstr_core v0.2.4
[INFO] [stderr]    Compiling c2rust-bitfields-derive v0.2.1
[INFO] [stderr]    Compiling bindgen v0.53.3
[INFO] [stderr]    Compiling serde_json v1.0.67
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/cstr_core-0.2.4/src/lib.rs:3:34
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![cfg_attr(feature = "nightly", feature(const_raw_ptr_deref))]
[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 `cstr_core` due to 2 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "b56e0e2856a36996b32a069d43b602ed66e75c300762b255c3f2a0fe1b4b2882", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b56e0e2856a36996b32a069d43b602ed66e75c300762b255c3f2a0fe1b4b2882", kill_on_drop: false }`
[INFO] [stdout] b56e0e2856a36996b32a069d43b602ed66e75c300762b255c3f2a0fe1b4b2882