[INFO] fetching crate unsplash-rs 0.1.1...
[INFO] documenting unsplash-rs-0.1.1 against 1.46.0 for beta-1.47-rustdoc-1
[INFO] extracting crate unsplash-rs 0.1.1 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate unsplash-rs 0.1.1 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 unsplash-rs 0.1.1
[INFO] finished tweaking crates.io crate unsplash-rs 0.1.1
[INFO] tweaked toml for crates.io crate unsplash-rs 0.1.1 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.46.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[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] 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" "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] 58ed6950f8a8fc04cda485005f2b0a7e1b1f0cee5b98ad7e733def9ec8cf7ad7
[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" "58ed6950f8a8fc04cda485005f2b0a7e1b1f0cee5b98ad7e733def9ec8cf7ad7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "58ed6950f8a8fc04cda485005f2b0a7e1b1f0cee5b98ad7e733def9ec8cf7ad7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "58ed6950f8a8fc04cda485005f2b0a7e1b1f0cee5b98ad7e733def9ec8cf7ad7", kill_on_drop: false }`
[INFO] [stdout] 58ed6950f8a8fc04cda485005f2b0a7e1b1f0cee5b98ad7e733def9ec8cf7ad7
[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" "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] 21d1f51f1169463ab3c7adcc6f5ebbee6c2a7a6c9da8d8659cd639740bba4618
[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" "21d1f51f1169463ab3c7adcc6f5ebbee6c2a7a6c9da8d8659cd639740bba4618", kill_on_drop: false }`
[INFO] [stderr]     Checking serde_url_params v0.1.1
[INFO] [stderr]     Checking tokio v0.1.22
[INFO] [stderr]     Checking hyper v0.12.35
[INFO] [stderr]  Documenting unsplash-rs v0.1.1 (/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(option_replace)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: Compilation failed, aborting rustdoc
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 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 `unsplash-rs`.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --crate-type lib --crate-name unsplash_rs 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 chrono=/opt/rustwide/target/debug/deps/libchrono-7fd335931d34b3f7.rmeta --extern failure=/opt/rustwide/target/debug/deps/libfailure-d9fcd1e065ee1e23.rmeta --extern futures=/opt/rustwide/target/debug/deps/libfutures-29a973654112bb9d.rmeta --extern hyper=/opt/rustwide/target/debug/deps/libhyper-bf1d9071c99fc4d0.rmeta --extern itertools=/opt/rustwide/target/debug/deps/libitertools-49413a7f189b5ff7.rmeta --extern lazy_static=/opt/rustwide/target/debug/deps/liblazy_static-57a7edc7f441d44c.rmeta --extern log=/opt/rustwide/target/debug/deps/liblog-75d540134d633bf3.rmeta --extern serde=/opt/rustwide/target/debug/deps/libserde-5429dd6d097468fb.rmeta --extern serde_derive=/opt/rustwide/target/debug/deps/libserde_derive-3af9a6345491720f.so --extern serde_json=/opt/rustwide/target/debug/deps/libserde_json-6755a24efcfc79e1.rmeta --extern serde_url_params=/opt/rustwide/target/debug/deps/libserde_url_params-7938a024b9f0868f.rmeta --cap-lints=warn` (exit code: 1)
[INFO] running `Command { std: "docker" "inspect" "21d1f51f1169463ab3c7adcc6f5ebbee6c2a7a6c9da8d8659cd639740bba4618", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "21d1f51f1169463ab3c7adcc6f5ebbee6c2a7a6c9da8d8659cd639740bba4618", kill_on_drop: false }`
[INFO] [stdout] 21d1f51f1169463ab3c7adcc6f5ebbee6c2a7a6c9da8d8659cd639740bba4618