[INFO] fetching crate json-ld 0.2.0-alpha...
[INFO] documenting json-ld-0.2.0-alpha against 1.46.0 for beta-1.47-rustdoc-1
[INFO] extracting crate json-ld 0.2.0-alpha into /workspace/builds/worker-13/source
[INFO] validating manifest of crates.io crate json-ld 0.2.0-alpha on toolchain 1.46.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.46.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate json-ld 0.2.0-alpha
[INFO] removed 0 missing examples
[INFO] finished tweaking crates.io crate json-ld 0.2.0-alpha
[INFO] tweaked toml for crates.io crate json-ld 0.2.0-alpha written to /workspace/builds/worker-13/source/Cargo.toml
[INFO] crate crates.io crate json-ld 0.2.0-alpha already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.46.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", 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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1.46.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 6013a0e1a48acf97d25dde7557f24b3127d098bb39a68e59376d743a4c4d72d5
[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" "6013a0e1a48acf97d25dde7557f24b3127d098bb39a68e59376d743a4c4d72d5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "6013a0e1a48acf97d25dde7557f24b3127d098bb39a68e59376d743a4c4d72d5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6013a0e1a48acf97d25dde7557f24b3127d098bb39a68e59376d743a4c4d72d5", kill_on_drop: false }`
[INFO] [stdout] 6013a0e1a48acf97d25dde7557f24b3127d098bb39a68e59376d743a4c4d72d5
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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" "RUSTDOCFLAGS=--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" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1.46.0" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] d7c457c9ef2927ada19d1deef2321c8292f76e77a100f91c907ecce9da5ccce2
[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" "d7c457c9ef2927ada19d1deef2321c8292f76e77a100f91c907ecce9da5ccce2", kill_on_drop: false }`
[INFO] [stderr]     Checking futures-sink v0.3.4
[INFO] [stderr]     Checking futures-io v0.3.4
[INFO] [stderr]    Compiling log v0.4.8
[INFO] [stderr]     Checking pct-str v1.0.2
[INFO] [stderr]     Checking json v0.12.3
[INFO] [stderr]     Checking mown v0.2.0
[INFO] [stderr]    Compiling proc-macro-hack v0.5.12
[INFO] [stderr]     Checking futures-channel v0.3.4
[INFO] [stderr]     Checking iref v1.1.5
[INFO] [stderr]    Compiling futures-macro v0.3.4
[INFO] [stderr]     Checking futures-util v0.3.4
[INFO] [stderr]     Checking futures-executor v0.3.4
[INFO] [stderr]     Checking futures v0.3.4
[INFO] [stderr]  Documenting json-ld v0.2.0-alpha (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(str_strip)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(arbitrary_self_types)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: Compilation failed, aborting rustdoc
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 3 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: Could not document `json-ld`.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type lib --crate-name json_ld src/lib.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi --document-private-items -L dependency=/opt/rustwide/target/debug/deps --extern futures=/opt/rustwide/target/debug/deps/libfutures-430d479feb060437.rmeta --extern iref=/opt/rustwide/target/debug/deps/libiref-38ab3d763310a6ba.rmeta --extern json=/opt/rustwide/target/debug/deps/libjson-cb765ad72084c52f.rmeta --extern log=/opt/rustwide/target/debug/deps/liblog-85e430c763becc5d.rmeta --extern mown=/opt/rustwide/target/debug/deps/libmown-b164525d02d2273f.rmeta --cap-lints=warn` (exit code: 1)
[INFO] running `Command { std: "docker" "inspect" "d7c457c9ef2927ada19d1deef2321c8292f76e77a100f91c907ecce9da5ccce2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d7c457c9ef2927ada19d1deef2321c8292f76e77a100f91c907ecce9da5ccce2", kill_on_drop: false }`
[INFO] [stdout] d7c457c9ef2927ada19d1deef2321c8292f76e77a100f91c907ecce9da5ccce2