[INFO] cloning repository https://github.com/mlsteele/bittles
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/mlsteele/bittles" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmlsteele%2Fbittles", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmlsteele%2Fbittles'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 68441273c2e5aaa5e7e19d35c2b8fdeee0ac92af
[INFO] testing mlsteele/bittles against 1.55.0 for beta-1.56-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmlsteele%2Fbittles" "/workspace/builds/worker-4/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/mlsteele/bittles 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 git repo https://github.com/mlsteele/bittles
[INFO] finished tweaking git repo https://github.com/mlsteele/bittles
[INFO] tweaked toml for git repo https://github.com/mlsteele/bittles written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/mlsteele/bittles 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-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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] 55e65fe4c6a128ed9b36e560b1818dffabd93d17628402a79c8f73523d9be775
[INFO] running `Command { std: "docker" "start" "-a" "55e65fe4c6a128ed9b36e560b1818dffabd93d17628402a79c8f73523d9be775", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "55e65fe4c6a128ed9b36e560b1818dffabd93d17628402a79c8f73523d9be775", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "55e65fe4c6a128ed9b36e560b1818dffabd93d17628402a79c8f73523d9be775", kill_on_drop: false }`
[INFO] [stdout] 55e65fe4c6a128ed9b36e560b1818dffabd93d17628402a79c8f73523d9be775
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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] 686b96b1424f68c3ce51dd1a28d6badc3856e4ccabfe95fbe8a7d8c9210e9829
[INFO] running `Command { std: "docker" "start" "-a" "686b96b1424f68c3ce51dd1a28d6badc3856e4ccabfe95fbe8a7d8c9210e9829", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.21
[INFO] [stderr]    Compiling winapi-build v0.1.1
[INFO] [stderr]    Compiling gcc v0.3.45
[INFO] [stderr]    Compiling semver v0.1.20
[INFO] [stderr]    Compiling cfg-if v0.1.0
[INFO] [stderr]    Compiling rayon-core v1.0.0
[INFO] [stderr]    Compiling void v1.0.2
[INFO] [stderr]    Compiling lazy_static v0.2.8
[INFO] [stderr]    Compiling winapi v0.2.8
[INFO] [stderr]    Compiling log v0.3.7
[INFO] [stderr]    Compiling num-traits v0.1.37
[INFO] [stderr]    Compiling backtrace v0.3.0
[INFO] [stderr]    Compiling byteorder v1.0.0
[INFO] [stderr]    Compiling matches v0.1.4
[INFO] [stderr]    Compiling rustc-demangle v0.1.4
[INFO] [stderr]    Compiling unicode-xid v0.0.4
[INFO] [stderr]    Compiling quote v0.3.15
[INFO] [stderr]    Compiling unicode-normalization v0.1.4
[INFO] [stderr]    Compiling slog v2.0.5
[INFO] [stderr]    Compiling lazycell v0.4.0
[INFO] [stderr]    Compiling slab v0.3.0
[INFO] [stderr]    Compiling regex-syntax v0.4.0
[INFO] [stderr]    Compiling futures v0.1.13
[INFO] [stderr]    Compiling rustc-serialize v0.3.23
[INFO] [stderr]    Compiling utf8-ranges v1.0.0
[INFO] [stderr]    Compiling strsim v0.6.0
[INFO] [stderr]    Compiling take_mut v0.1.3
[INFO] [stderr]    Compiling scoped-tls v0.1.0
[INFO] [stderr]    Compiling serde v0.9.15
[INFO] [stderr]    Compiling httparse v1.2.2
[INFO] [stderr]    Compiling either v1.1.0
[INFO] [stderr]    Compiling term v0.4.5
[INFO] [stderr]    Compiling untrusted v0.3.2
[INFO] [stderr]    Compiling unicode-bidi v0.2.5
[INFO] [stderr]    Compiling unreachable v0.1.1
[INFO] [stderr]    Compiling itertools v0.6.0
[INFO] [stderr]    Compiling mime v0.2.3
[INFO] [stderr]    Compiling synom v0.11.3
[INFO] [stderr]    Compiling rustc_version v0.1.7
[INFO] [stderr]    Compiling dbghelp-sys v0.2.0
[INFO] [stderr]    Compiling kernel32-sys v0.2.2
[INFO] [stderr]    Compiling num-integer v0.1.34
[INFO] [stdout] error[E0446]: private type `NeverStruct` in public interface
[INFO] [stdout]     --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/slog-2.0.5/src/lib.rs:1180:5
[INFO] [stdout]      |
[INFO] [stdout] 1180 |     type Err = Never;
[INFO] [stdout]      |     ^^^^^^^^^^^^^^^^^ can't leak private type
[INFO] [stdout] ...
[INFO] [stdout] 2868 | struct NeverStruct(());
[INFO] [stdout]      | ----------------------- `NeverStruct` declared as private
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0446]: private type `NeverStruct` in public interface
[INFO] [stdout]     --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/slog-2.0.5/src/lib.rs:1465:5
[INFO] [stdout]      |
[INFO] [stdout] 1465 |     type Err = Never;
[INFO] [stdout]      |     ^^^^^^^^^^^^^^^^^ can't leak private type
[INFO] [stdout] ...
[INFO] [stdout] 2868 | struct NeverStruct(());
[INFO] [stdout]      | ----------------------- `NeverStruct` declared as private
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0446]: private type `NeverStruct` in public interface
[INFO] [stdout]     --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/slog-2.0.5/src/lib.rs:1630:5
[INFO] [stdout]      |
[INFO] [stdout] 1630 |     type Err = Never;
[INFO] [stdout]      |     ^^^^^^^^^^^^^^^^^ can't leak private type
[INFO] [stdout] ...
[INFO] [stdout] 2868 | struct NeverStruct(());
[INFO] [stdout]      | ----------------------- `NeverStruct` declared as private
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0446]: private type `NeverStruct` in public interface
[INFO] [stdout]     --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/slog-2.0.5/src/lib.rs:1662:5
[INFO] [stdout]      |
[INFO] [stdout] 1662 |     type Err = Never;
[INFO] [stdout]      |     ^^^^^^^^^^^^^^^^^ can't leak private type
[INFO] [stdout] ...
[INFO] [stdout] 2868 | struct NeverStruct(());
[INFO] [stdout]      | ----------------------- `NeverStruct` declared as private
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 4 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0446`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `slog` due to 5 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "686b96b1424f68c3ce51dd1a28d6badc3856e4ccabfe95fbe8a7d8c9210e9829", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "686b96b1424f68c3ce51dd1a28d6badc3856e4ccabfe95fbe8a7d8c9210e9829", kill_on_drop: false }`
[INFO] [stdout] 686b96b1424f68c3ce51dd1a28d6badc3856e4ccabfe95fbe8a7d8c9210e9829