[INFO] crate mdbook-epub 0.2.0 is already in cache
[INFO] extracting crate mdbook-epub 0.2.0 into work/ex/beta-1.37-6/sources/1.36.0/reg/mdbook-epub/0.2.0
[INFO] extracting crate mdbook-epub 0.2.0 into work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/mdbook-epub/0.2.0
[INFO] validating manifest of mdbook-epub-0.2.0 on toolchain 1.36.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of mdbook-epub-0.2.0 on toolchain beta-2019-07-23
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing mdbook-epub-0.2.0
[INFO] finished frobbing mdbook-epub-0.2.0
[INFO] frobbed toml for mdbook-epub-0.2.0 written to work/ex/beta-1.37-6/sources/1.36.0/reg/mdbook-epub/0.2.0/Cargo.toml
[INFO] started frobbing mdbook-epub-0.2.0
[INFO] finished frobbing mdbook-epub-0.2.0
[INFO] frobbed toml for mdbook-epub-0.2.0 written to work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/mdbook-epub/0.2.0/Cargo.toml
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing mdbook-epub-0.2.0 against 1.36.0 for beta-1.37-6
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.37-6/worker-4/1.36.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/1.36.0/reg/mdbook-epub/0.2.0:/opt/crater/workdir:ro,Z" "-v" "/mnt/big/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+1.36.0" "build" "--frozen"`
[INFO] [stdout] 117b9b48805f74d5ba73960c6a106ae1dee90a44dba0e966fcd8fd7afd1031e4
[INFO] running `"docker" "start" "-a" "117b9b48805f74d5ba73960c6a106ae1dee90a44dba0e966fcd8fd7afd1031e4"`
[INFO] [stderr]    Compiling pulldown-cmark v0.1.2
[INFO] [stderr]    Compiling shell-escape v0.1.4
[INFO] [stderr]    Compiling crossbeam v0.3.2
[INFO] [stderr]    Compiling home v0.3.4
[INFO] [stderr]    Compiling is-match v0.1.0
[INFO] [stderr]    Compiling libgit2-sys v0.6.19
[INFO] [stderr]    Compiling getrandom v0.1.7
[INFO] [stderr]    Compiling filetime v0.2.5
[INFO] [stderr]    Compiling inotify-sys v0.1.3
[INFO] [stderr]    Compiling filetime v0.1.15
[INFO] [stderr]    Compiling fs2 v0.4.3
[INFO] [stderr]    Compiling openssl-sys v0.9.48
[INFO] [stderr]    Compiling libz-sys v1.0.25
[INFO] [stderr]    Compiling jobserver v0.1.16
[INFO] [stderr]    Compiling semver v0.8.0
[INFO] [stderr]    Compiling serde_ignored v0.0.4
[INFO] [stderr]    Compiling miniz_oxide_c_api v0.2.3
[INFO] [stderr]    Compiling structopt-derive v0.1.6
[INFO] [stderr]    Compiling inotify v0.6.1
[INFO] [stderr]    Compiling curl v0.4.22
[INFO] [stderr]    Compiling tar v0.4.25
[INFO] [stderr]    Compiling rand_core v0.5.0
[INFO] [stderr]    Compiling mio-extras v2.0.5
[INFO] [stderr]    Compiling uuid v0.5.1
[INFO] [stderr]    Compiling structopt v0.1.7
[INFO] [stderr]    Compiling error-chain v0.11.0
[INFO] [stderr]    Compiling error-chain v0.12.1
[INFO] [stderr]    Compiling curl-sys v0.4.20
[INFO] [stderr]    Compiling libssh2-sys v0.2.11
[INFO] [stderr]    Compiling openssl v0.10.24
[INFO] [stderr]    Compiling globset v0.2.1
[INFO] [stderr]    Compiling string_cache_codegen v0.4.2
[INFO] [stderr]    Compiling rand_chacha v0.2.1
[INFO] [stderr]    Compiling flate2 v1.0.9
[INFO] [stderr]    Compiling docopt v0.8.3
[INFO] [stderr]    Compiling elasticlunr-rs v2.3.6
[INFO] [stderr]    Compiling notify v4.0.12
[INFO] [stderr]    Compiling ws v0.7.9
[INFO] [stderr]    Compiling toml-query v0.7.0
[INFO] [stderr]    Compiling rand v0.7.0
[INFO] [stderr]    Compiling handlebars v1.1.0
[INFO] [stderr]    Compiling failure v0.1.5
[INFO] [stderr]    Compiling zip v0.2.8
[INFO] [stderr]    Compiling string_cache v0.7.3
[INFO] [stderr]    Compiling markup5ever v0.7.5
[INFO] [stderr]    Compiling ignore v0.2.2
[INFO] [stderr]    Compiling crates-io v0.13.0
[INFO] [stderr]    Compiling crypto-hash v0.3.3
[INFO] [stderr]    Compiling tempfile v3.1.0
[INFO] [stderr]    Compiling epub-builder v0.3.0
[INFO] [stderr]    Compiling iron v0.6.0
[INFO] [stderr] error[E0283]: type annotations required: cannot resolve `std::string::String: std::convert::AsRef<_>`
[INFO] [stderr]    --> /opt/crater/cargo-home/registry/src/github.com-1ecc6299db9ec823/epub-builder-0.3.0/src/epub.rs:207:74
[INFO] [stderr]     |
[INFO] [stderr] 207 |         self.toc.add(TocElement::new("toc.xhtml", self.metadata.toc_name.as_ref()));
[INFO] [stderr]     |                                                                          ^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0283`.
[INFO] [stderr] error: Could not compile `epub-builder`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "117b9b48805f74d5ba73960c6a106ae1dee90a44dba0e966fcd8fd7afd1031e4"`
[INFO] running `"docker" "rm" "-f" "117b9b48805f74d5ba73960c6a106ae1dee90a44dba0e966fcd8fd7afd1031e4"`
[INFO] [stdout] 117b9b48805f74d5ba73960c6a106ae1dee90a44dba0e966fcd8fd7afd1031e4