[INFO] fetching crate mdbook-skill-tree 2.0.0...
[INFO] testing mdbook-skill-tree-2.0.0 against master#5d5ff84130da0d74c6ece368dbe821d8f83fa526 for pr-79296
[INFO] extracting crate mdbook-skill-tree 2.0.0 into /workspace/builds/worker-5/source
[INFO] validating manifest of crates.io crate mdbook-skill-tree 2.0.0 on toolchain 5d5ff84130da0d74c6ece368dbe821d8f83fa526
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+5d5ff84130da0d74c6ece368dbe821d8f83fa526" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate mdbook-skill-tree 2.0.0
[INFO] finished tweaking crates.io crate mdbook-skill-tree 2.0.0
[INFO] tweaked toml for crates.io crate mdbook-skill-tree 2.0.0 written to /workspace/builds/worker-5/source/Cargo.toml
[INFO] crate crates.io crate mdbook-skill-tree 2.0.0 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+5d5ff84130da0d74c6ece368dbe821d8f83fa526" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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" "rustops/crates-build-env@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+5d5ff84130da0d74c6ece368dbe821d8f83fa526" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] aa22be0044c710e7d0e0ec7e70276448b10aace9b316076e2c24fdfb35f4af07
[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" "aa22be0044c710e7d0e0ec7e70276448b10aace9b316076e2c24fdfb35f4af07", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "aa22be0044c710e7d0e0ec7e70276448b10aace9b316076e2c24fdfb35f4af07", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "aa22be0044c710e7d0e0ec7e70276448b10aace9b316076e2c24fdfb35f4af07", kill_on_drop: false }`
[INFO] [stdout] aa22be0044c710e7d0e0ec7e70276448b10aace9b316076e2c24fdfb35f4af07
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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=forbid" "-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" "rustops/crates-build-env@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+5d5ff84130da0d74c6ece368dbe821d8f83fa526" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] d48049b610bb2a8bc804ce0e321594b88cbee6f82241b84744ede530c8312eaf
[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" "d48049b610bb2a8bc804ce0e321594b88cbee6f82241b84744ede530c8312eaf", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.71
[INFO] [stderr]    Compiling syn v1.0.31
[INFO] [stderr]    Compiling version_check v0.9.2
[INFO] [stderr]    Compiling siphasher v0.3.3
[INFO] [stderr]    Compiling ryu v1.0.5
[INFO] [stderr]    Compiling typenum v1.12.0
[INFO] [stderr]    Compiling ucd-trie v0.1.3
[INFO] [stderr]    Compiling gimli v0.21.0
[INFO] [stderr]    Compiling object v0.19.0
[INFO] [stderr]    Compiling failure_derive v0.1.8
[INFO] [stderr]    Compiling vec_map v0.8.2
[INFO] [stderr]    Compiling either v1.5.3
[INFO] [stderr]    Compiling pulldown-cmark v0.7.1
[INFO] [stderr]    Compiling htmlescape v0.3.1
[INFO] [stderr]    Compiling svg v0.5.12
[INFO] [stderr]    Compiling open v1.4.0
[INFO] [stderr]    Compiling proc-macro2 v1.0.18
[INFO] [stderr]    Compiling idna v0.1.5
[INFO] [stderr]    Compiling idna v0.2.0
[INFO] [stderr]    Compiling phf_shared v0.8.0
[INFO] [stderr]    Compiling pest v2.1.3
[INFO] [stderr]    Compiling toml v0.5.6
[INFO] [stderr]    Compiling itertools v0.8.2
[INFO] [stderr]    Compiling combine v3.8.1
[INFO] [stderr]    Compiling phf v0.8.0
[INFO] [stderr]    Compiling string_cache v0.8.0
[INFO] [stderr]    Compiling regex v1.3.9
[INFO] [stderr]    Compiling darling_core v0.8.6
[INFO] [stderr]    Compiling unicase v2.6.0
[INFO] [stderr]    Compiling proc-macro-error-attr v1.0.2
[INFO] [stderr]    Compiling proc-macro-error v1.0.2
[INFO] [stderr]    Compiling error-chain v0.12.2
[INFO] [stderr]    Compiling quote v1.0.7
[INFO] [stderr]    Compiling serde_json v1.0.55
[INFO] [stderr]    Compiling url v1.7.2
[INFO] [stderr]    Compiling url v2.1.1
[INFO] [stderr]    Compiling pest_meta v2.1.3
[INFO] [stderr]    Compiling pulldown-cmark v0.6.1
[INFO] [stderr]    Compiling getrandom v0.1.14
[INFO] [stderr]    Compiling rand_os v0.1.3
[INFO] [stderr]    Compiling time v0.1.43
[INFO] [stderr]    Compiling iovec v0.1.4
[INFO] [stderr]    Compiling atty v0.2.14
[INFO] [stderr]    Compiling num_cpus v1.13.0
[INFO] [stderr]    Compiling net2 v0.2.34
[INFO] [stderr]    Compiling inotify-sys v0.1.3
[INFO] [stderr]    Compiling filetime v0.2.10
[INFO] [stderr]    Compiling rand_core v0.5.1
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]    Compiling generic-array v0.12.3
[INFO] [stderr]    Compiling clap v2.33.1
[INFO] [stderr]    Compiling env_logger v0.6.2
[INFO] [stderr] error: could not compile `darling_core`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustc --crate-name darling_core /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/darling_core-0.8.6/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C debuginfo=2 --cfg 'feature="default"' -C metadata=f2da6c1f0e3f4719 -C extra-filename=-f2da6c1f0e3f4719 --out-dir /opt/rustwide/target/debug/deps -L dependency=/opt/rustwide/target/debug/deps --extern fnv=/opt/rustwide/target/debug/deps/libfnv-eef866999c50c67e.rmeta --extern ident_case=/opt/rustwide/target/debug/deps/libident_case-c360dd6ce4b6268c.rmeta --extern proc_macro2=/opt/rustwide/target/debug/deps/libproc_macro2-ab33b97f38e6e831.rmeta --extern quote=/opt/rustwide/target/debug/deps/libquote-476d26c939207289.rmeta --extern syn=/opt/rustwide/target/debug/deps/libsyn-15f04aac8ae0e620.rmeta --cap-lints allow --cap-lints=forbid` (signal: 9, SIGKILL: kill)
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "d48049b610bb2a8bc804ce0e321594b88cbee6f82241b84744ede530c8312eaf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d48049b610bb2a8bc804ce0e321594b88cbee6f82241b84744ede530c8312eaf", kill_on_drop: false }`
[INFO] [stdout] d48049b610bb2a8bc804ce0e321594b88cbee6f82241b84744ede530c8312eaf