[INFO] cloning repository https://github.com/Michael-F-Bryan/mdbook-epub
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/Michael-F-Bryan/mdbook-epub" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FMichael-F-Bryan%2Fmdbook-epub"`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FMichael-F-Bryan%2Fmdbook-epub'...
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 640a81209b9de4af8da082222f31f62dc9d21af0
[INFO] testing Michael-F-Bryan/mdbook-epub against 1.44.0 for beta-1.45-1
[INFO] running `"git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FMichael-F-Bryan%2Fmdbook-epub" "/workspace/builds/worker-7/source"`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/Michael-F-Bryan/mdbook-epub on toolchain 1.44.0
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/Michael-F-Bryan/mdbook-epub
[INFO] finished tweaking git repo https://github.com/Michael-F-Bryan/mdbook-epub
[INFO] tweaked toml for git repo https://github.com/Michael-F-Bryan/mdbook-epub written to /workspace/builds/worker-7/source/Cargo.toml
[INFO] crate git repo https://github.com/Michael-F-Bryan/mdbook-epub already has a lockfile, it will not be regenerated
[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-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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] 542e5b7eea90758ca8aaf54ace70ba5b3eee1931a6cd02bb3ddc963fd496def2
[INFO] running `"docker" "start" "-a" "542e5b7eea90758ca8aaf54ace70ba5b3eee1931a6cd02bb3ddc963fd496def2"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling libc v0.2.67
[INFO] [stderr]    Compiling rand_core v0.4.2
[INFO] [stderr]    Compiling autocfg v0.1.7
[INFO] [stderr]    Compiling syn v1.0.14
[INFO] [stderr]    Compiling siphasher v0.2.3
[INFO] [stderr]    Compiling log v0.4.8
[INFO] [stderr]    Compiling string_cache_shared v0.3.0
[INFO] [stderr]    Compiling cc v1.0.50
[INFO] [stderr]    Compiling version_check v0.9.1
[INFO] [stderr]    Compiling smallvec v1.2.0
[INFO] [stderr]    Compiling matches v0.1.8
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling unicode-width v0.1.7
[INFO] [stderr]    Compiling precomputed-hash v0.1.1
[INFO] [stderr]    Compiling new_debug_unreachable v1.0.4
[INFO] [stderr]    Compiling rustversion v1.0.2
[INFO] [stderr]    Compiling mac v0.1.1
[INFO] [stderr]    Compiling traitobject v0.1.0
[INFO] [stderr]    Compiling typenum v1.11.2
[INFO] [stderr]    Compiling httparse v1.3.4
[INFO] [stderr]    Compiling utf-8 v0.7.5
[INFO] [stderr]    Compiling rustc-demangle v0.1.16
[INFO] [stderr]    Compiling quick-error v1.2.3
[INFO] [stderr]    Compiling percent-encoding v1.0.1
[INFO] [stderr]    Compiling safemem v0.3.3
[INFO] [stderr]    Compiling maplit v1.0.2
[INFO] [stderr]    Compiling ident_case v1.0.1
[INFO] [stderr]    Compiling unicode-segmentation v1.6.0
[INFO] [stderr]    Compiling byte-tools v0.3.1
[INFO] [stderr]    Compiling typeable v0.1.2
[INFO] [stderr]    Compiling language-tags v0.2.2
[INFO] [stderr]    Compiling crc32fast v1.2.0
[INFO] [stderr]    Compiling failure_derive v0.1.6
[INFO] [stderr]    Compiling lazy_static v0.2.11
[INFO] [stderr]    Compiling serde v0.9.15
[INFO] [stderr]    Compiling adler32 v1.0.4
[INFO] [stderr]    Compiling modifier v0.1.0
[INFO] [stderr]    Compiling ucd-util v0.1.7
[INFO] [stderr]    Compiling termcolor v1.1.0
[INFO] [stderr]    Compiling opaque-debug v0.2.3
[INFO] [stderr]    Compiling pulldown-cmark v0.6.1
[INFO] [stderr]    Compiling fake-simd v0.1.2
[INFO] [stderr]    Compiling regex v0.2.11
[INFO] [stderr]    Compiling sequence_trie v0.3.6
[INFO] [stderr]    Compiling pulldown-cmark v0.7.0
[INFO] [stderr]    Compiling utf8-ranges v1.0.4
[INFO] [stderr]    Compiling either v1.5.3
[INFO] [stderr]    Compiling strum v0.15.0
[INFO] [stderr]    Compiling is-match v0.1.0
[INFO] [stderr]    Compiling podio v0.1.6
[INFO] [stderr]    Compiling mime v0.3.16
[INFO] [stderr]    Compiling open v1.3.4
[INFO] [stderr]    Compiling shlex v0.1.1
[INFO] [stderr]    Compiling pest v0.3.3
[INFO] [stderr]    Compiling thread_local v0.3.6
[INFO] [stderr]    Compiling unicase v1.4.2
[INFO] [stderr]    Compiling unicode-bidi v0.3.4
[INFO] [stderr]    Compiling num-traits v0.2.11
[INFO] [stderr]    Compiling num-integer v0.1.42
[INFO] [stderr]    Compiling textwrap v0.11.0
[INFO] [stderr]    Compiling getopts v0.2.21
[INFO] [stderr]    Compiling futf v0.1.4
[INFO] [stderr]    Compiling unsafe-any v0.4.2
[INFO] [stderr]    Compiling rand_core v0.3.1
[INFO] [stderr]    Compiling rand_jitter v0.1.4
[INFO] [stderr]    Compiling c2-chacha v0.2.3
[INFO] [stderr]    Compiling unicode-normalization v0.1.12
[INFO] [stderr]    Compiling humantime v1.3.0
[INFO] [stderr]    Compiling unreachable v0.1.1
[INFO] [stderr]    Compiling pest v2.1.2
[INFO] [stderr]    Compiling block-padding v0.1.5
[INFO] [stderr]    Compiling miniz_oxide v0.3.6
[INFO] [stderr]    Compiling regex-syntax v0.5.6
[INFO] [stderr]    Compiling unicase v2.6.0
[INFO] [stderr]    Compiling error-chain v0.12.2
[INFO] [stderr]    Compiling rand_chacha v0.1.1
[INFO] [stderr]    Compiling rand_pcg v0.1.2
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]    Compiling gitignore v1.0.6
[INFO] [stderr]    Compiling heck v0.3.1
[INFO] [stderr]    Compiling itertools v0.8.2
[INFO] [stderr]    Compiling rand_hc v0.1.0
[INFO] [stderr]    Compiling rand_isaac v0.1.1
[INFO] [stderr]    Compiling rand_xorshift v0.1.1
[INFO] [stderr]    Compiling typemap v0.3.3
[INFO] [stderr]    Compiling tendril v0.4.1
[INFO] [stderr]    Compiling debug_unreachable v0.1.1
[INFO] [stderr]    Compiling aho-corasick v0.6.10
[INFO] [stderr]    Compiling hashbrown v0.5.0
[INFO] [stderr]    Compiling toml v0.5.6
[INFO] [stderr]    Compiling base64 v0.9.3
[INFO] [stderr]    Compiling plugin v0.2.6
[INFO] [stderr]    Compiling idna v0.1.5
[INFO] [stderr]    Compiling idna v0.2.0
[INFO] [stderr]    Compiling log v0.3.9
[INFO] [stderr]    Compiling backtrace-sys v0.1.32
[INFO] [stderr]    Compiling bzip2-sys v0.1.7
[INFO] [stderr]    Compiling pest_meta v2.1.2
[INFO] [stderr]    Compiling phf_shared v0.7.24
[INFO] [stderr]    Compiling rand_os v0.1.3
[INFO] [stderr]    Compiling time v0.1.42
[INFO] [stderr]    Compiling getrandom v0.1.14
[INFO] [stderr]    Compiling iovec v0.1.4
[INFO] [stderr]    Compiling net2 v0.2.33
[INFO] [stderr]    Compiling atty v0.2.14
[INFO] [stderr]    Compiling num_cpus v1.12.0
[INFO] [stderr]    Compiling inotify-sys v0.1.3
[INFO] [stderr]    Compiling flate2 v1.0.13
[INFO] [stderr]    Compiling filetime v0.2.8
[INFO] [stderr]    Compiling rand v0.4.6
[INFO] [stderr]    Compiling mime v0.2.6
[INFO] [stderr]    Compiling mustache v0.9.0
[INFO] [stderr]    Compiling generic-array v0.12.3
[INFO] [stderr]    Compiling mime_guess v2.0.1
[INFO] [stderr]    Compiling phf v0.7.24
[INFO] [stderr]    Compiling url v1.7.2
[INFO] [stderr]    Compiling bytes v0.4.12
[INFO] [stderr]    Compiling rand_core v0.5.1
[INFO] [stderr]    Compiling url v2.1.1
[INFO] [stderr]    Compiling clap v2.33.0
[INFO] [stderr]    Compiling env_logger v0.6.2
[INFO] [stderr]    Compiling env_logger v0.7.1
[INFO] [stderr]    Compiling mio v0.6.21
[INFO] [stderr]    Compiling inotify v0.7.0
[INFO] [stderr]    Compiling digest v0.8.1
[INFO] [stderr]    Compiling block-buffer v0.7.3
[INFO] [stderr]    Compiling tempdir v0.3.7
[INFO] [stderr]    Compiling rand_chacha v0.2.1
[INFO] [stderr]    Compiling phf_generator v0.7.24
[INFO] [stderr]    Compiling hyper v0.10.16
[INFO] [stderr]    Compiling chrono v0.4.10
[INFO] [stderr]    Compiling backtrace v0.3.44
[INFO] [stderr]    Compiling sha-1 v0.8.2
[INFO] [stderr]    Compiling bzip2 v0.3.3
[INFO] [stderr]    Compiling mio-extras v2.0.6
[INFO] [stderr]    Compiling rand v0.7.3
[INFO] [stderr]    Compiling string_cache_codegen v0.4.4
[INFO] [stderr]    Compiling phf_codegen v0.7.24
[INFO] [stderr]    Compiling zip v0.5.4
[INFO] [stderr]    Compiling notify v4.0.15
[INFO] [stderr]    Compiling mime_guess v1.8.7
[INFO] [stderr]    Compiling string_cache v0.7.5
[INFO] [stderr]    Compiling string_cache v0.5.2
[INFO] [stderr]    Compiling html5ever-atoms v0.3.0
[INFO] [stderr]    Compiling handlebars v0.29.1
[INFO] [stderr]    Compiling tempfile v3.1.0
[INFO] [stderr]    Compiling uuid v0.8.1
[INFO] [stderr]    Compiling ws v0.9.1
[INFO] [stderr]    Compiling darling_core v0.8.6
[INFO] [stderr]    Compiling syn-mid v0.5.0
[INFO] [stderr]    Compiling synstructure v0.12.3
[INFO] [stderr]    Compiling pest_generator v2.1.1
[INFO] [stderr]    Compiling iron v0.6.1
[INFO] [stderr]    Compiling mount v0.4.0
[INFO] [stderr] error: could not compile `syn`.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustc --crate-name syn /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/syn-0.15.44/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts --crate-type lib --emit=dep-info,metadata,link -C debuginfo=2 --cfg 'feature="clone-impls"' --cfg 'feature="default"' --cfg 'feature="derive"' --cfg 'feature="extra-traits"' --cfg 'feature="full"' --cfg 'feature="parsing"' --cfg 'feature="printing"' --cfg 'feature="proc-macro"' --cfg 'feature="quote"' -C metadata=bf687b48a0047046 -C extra-filename=-bf687b48a0047046 --out-dir /opt/rustwide/target/debug/deps -L dependency=/opt/rustwide/target/debug/deps --extern proc_macro2=/opt/rustwide/target/debug/deps/libproc_macro2-5784ddc7a5716111.rmeta --extern quote=/opt/rustwide/target/debug/deps/libquote-31334cd4bfa58489.rmeta --extern unicode_xid=/opt/rustwide/target/debug/deps/libunicode_xid-741f30ee4c0a2029.rmeta --cap-lints allow --cap-lints=warn --cfg syn_can_match_trailing_dollar --cfg syn_can_use_thread_id --cfg syn_can_use_associated_constants --cfg syn_can_call_macro_by_path --cfg syn_disable_nightly_tests` (signal: 9, SIGKILL: kill)
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "542e5b7eea90758ca8aaf54ace70ba5b3eee1931a6cd02bb3ddc963fd496def2"`
[INFO] running `"docker" "rm" "-f" "542e5b7eea90758ca8aaf54ace70ba5b3eee1931a6cd02bb3ddc963fd496def2"`
[INFO] [stdout] 542e5b7eea90758ca8aaf54ace70ba5b3eee1931a6cd02bb3ddc963fd496def2