[INFO] fetching crate back-to-the-future 0.1.7...
[INFO] documenting back-to-the-future-0.1.7 against 1.54.0 for beta-1.55-rustdoc-1
[INFO] extracting crate back-to-the-future 0.1.7 into /workspace/builds/worker-7/source
[INFO] validating manifest of crates.io crate back-to-the-future 0.1.7 on toolchain 1.54.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate back-to-the-future 0.1.7
[INFO] finished tweaking crates.io crate back-to-the-future 0.1.7
[INFO] tweaked toml for crates.io crate back-to-the-future 0.1.7 written to /workspace/builds/worker-7/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "fetch" "--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-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" "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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+1.54.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 4bda23c0d7af49768e8d49651b28ab9eebf97ddb027e25471a698cf859b7185d
[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" "4bda23c0d7af49768e8d49651b28ab9eebf97ddb027e25471a698cf859b7185d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4bda23c0d7af49768e8d49651b28ab9eebf97ddb027e25471a698cf859b7185d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4bda23c0d7af49768e8d49651b28ab9eebf97ddb027e25471a698cf859b7185d", kill_on_drop: false }`
[INFO] [stdout] 4bda23c0d7af49768e8d49651b28ab9eebf97ddb027e25471a698cf859b7185d
[INFO] running `Command { std: "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" "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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+1.54.0" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 9637577c884ab977a45baa7640285b6706332ad186160a0e531ba975e6b1f83a
[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" "9637577c884ab977a45baa7640285b6706332ad186160a0e531ba975e6b1f83a", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Documenting back-to-the-future v0.1.7 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0557]: feature has been removed
[INFO] [stdout]   --> src/lib.rs:36:12
[INFO] [stdout]    |
[INFO] [stdout] 36 | #![feature(await_macro)]
[INFO] [stdout]    |            ^^^^^^^^^^^ feature has been removed
[INFO] [stdout]    |
[INFO] [stdout]    = note: subsumed by `.await` syntax
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:34:1
[INFO] [stdout]    |
[INFO] [stdout] 34 | #![feature(arbitrary_self_types)]
[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:35:1
[INFO] [stdout]    |
[INFO] [stdout] 35 | #![feature(async_await)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove the attribute
[INFO] [stdout]    |
[INFO] [stdout]    = help: the feature `async_await` has been stable since 1.39.0 and no longer requires an attribute to enable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:36:1
[INFO] [stdout]    |
[INFO] [stdout] 36 | #![feature(await_macro)]
[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:37:1
[INFO] [stdout]    |
[INFO] [stdout] 37 | #![feature(futures_api)]
[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:38:1
[INFO] [stdout]    |
[INFO] [stdout] 38 | #![feature(never_type)]
[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:39:1
[INFO] [stdout]    |
[INFO] [stdout] 39 | #![feature(trait_alias)]
[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:40:1
[INFO] [stdout]    |
[INFO] [stdout] 40 | #![feature(specialization)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: Compilation failed, aborting rustdoc
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 9 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0554, E0557.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not document `back-to-the-future`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type lib --crate-name back_to_the_future 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-533cf53875604e8f.rmeta --cap-lints=warn --crate-version 0.1.7` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "9637577c884ab977a45baa7640285b6706332ad186160a0e531ba975e6b1f83a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9637577c884ab977a45baa7640285b6706332ad186160a0e531ba975e6b1f83a", kill_on_drop: false }`
[INFO] [stdout] 9637577c884ab977a45baa7640285b6706332ad186160a0e531ba975e6b1f83a
