[INFO] fetching crate buddyalloc 0.1.5...
[INFO] testing buddyalloc-0.1.5 against 1.55.0 for beta-1.56-1
[INFO] extracting crate buddyalloc 0.1.5 into /workspace/builds/worker-44/source
[INFO] validating manifest of crates.io crate buddyalloc 0.1.5 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 buddyalloc 0.1.5
[INFO] finished tweaking crates.io crate buddyalloc 0.1.5
[INFO] tweaked toml for crates.io crate buddyalloc 0.1.5 written to /workspace/builds/worker-44/source/Cargo.toml
[INFO] crate crates.io crate buddyalloc 0.1.5 already has a lockfile, it will not be regenerated
[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-44/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-44/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] [stdout] a69f301f911b885fff75418833dc843861ff83cbedbfa76de682cf8ba5d558bc
[INFO] running `Command { std: "docker" "start" "-a" "a69f301f911b885fff75418833dc843861ff83cbedbfa76de682cf8ba5d558bc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "a69f301f911b885fff75418833dc843861ff83cbedbfa76de682cf8ba5d558bc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a69f301f911b885fff75418833dc843861ff83cbedbfa76de682cf8ba5d558bc", kill_on_drop: false }`
[INFO] [stdout] a69f301f911b885fff75418833dc843861ff83cbedbfa76de682cf8ba5d558bc
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-44/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-44/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] 7fedd8e067f82992a130c2284f6ed9d11f516c13bc12561f06e1c23cf60997df
[INFO] running `Command { std: "docker" "start" "-a" "7fedd8e067f82992a130c2284f6ed9d11f516c13bc12561f06e1c23cf60997df", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling buddyalloc v0.1.5 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.71s
[INFO] running `Command { std: "docker" "inspect" "7fedd8e067f82992a130c2284f6ed9d11f516c13bc12561f06e1c23cf60997df", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7fedd8e067f82992a130c2284f6ed9d11f516c13bc12561f06e1c23cf60997df", kill_on_drop: false }`
[INFO] [stdout] 7fedd8e067f82992a130c2284f6ed9d11f516c13bc12561f06e1c23cf60997df
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-44/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-44/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" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 053aae8dcbc7ebe7d683e0acebd343999ff57f7d431babd85b21e56b45f89532
[INFO] running `Command { std: "docker" "start" "-a" "053aae8dcbc7ebe7d683e0acebd343999ff57f7d431babd85b21e56b45f89532", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling buddyalloc v0.1.5 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> examples/allocator.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(allocator_api, const_mut_refs, const_ptr_offset)]
[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 `buddyalloc` 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" "053aae8dcbc7ebe7d683e0acebd343999ff57f7d431babd85b21e56b45f89532", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "053aae8dcbc7ebe7d683e0acebd343999ff57f7d431babd85b21e56b45f89532", kill_on_drop: false }`
[INFO] [stdout] 053aae8dcbc7ebe7d683e0acebd343999ff57f7d431babd85b21e56b45f89532