[INFO] fetching crate messenger 0.1.0...
[INFO] documenting messenger-0.1.0 against 1.61.0 for beta-1.62-rustdoc-1
[INFO] extracting crate messenger 0.1.0 into /workspace/builds/worker-27/source
[INFO] validating manifest of crates.io crate messenger 0.1.0 on toolchain 1.61.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.61.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate messenger 0.1.0
[INFO] finished tweaking crates.io crate messenger 0.1.0
[INFO] tweaked toml for crates.io crate messenger 0.1.0 written to /workspace/builds/worker-27/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.61.0" "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" "+1.61.0" "fetch" "--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-27/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-27/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:d190cb871061d98bc6d0581d85cb2ecb09a0f8a142ba5463de30be9999fc3251" "/opt/rustwide/cargo-home/bin/cargo" "+1.61.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] ef31db8c3507c852b621860c2e4e0ee16fcc1aea76b618efe7239a5d050c1fa7
[INFO] running `Command { std: "docker" "start" "-a" "ef31db8c3507c852b621860c2e4e0ee16fcc1aea76b618efe7239a5d050c1fa7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "ef31db8c3507c852b621860c2e4e0ee16fcc1aea76b618efe7239a5d050c1fa7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ef31db8c3507c852b621860c2e4e0ee16fcc1aea76b618efe7239a5d050c1fa7", kill_on_drop: false }`
[INFO] [stdout] ef31db8c3507c852b621860c2e4e0ee16fcc1aea76b618efe7239a5d050c1fa7
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-27/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-27/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:d190cb871061d98bc6d0581d85cb2ecb09a0f8a142ba5463de30be9999fc3251" "/opt/rustwide/cargo-home/bin/cargo" "+1.61.0" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] b711bf0fc82ef541331b52f70fada9d0afac7f95e8dc49bf87f1e8cd0b7840e8
[INFO] running `Command { std: "docker" "start" "-a" "b711bf0fc82ef541331b52f70fada9d0afac7f95e8dc49bf87f1e8cd0b7840e8", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.39
[INFO] [stderr]    Compiling unicode-ident v1.0.0
[INFO] [stderr]    Compiling syn v1.0.95
[INFO] [stderr]    Compiling serde_derive v1.0.137
[INFO] [stderr]    Compiling serde v1.0.137
[INFO] [stderr]     Checking futures v0.1.31
[INFO] [stderr]    Compiling quote v1.0.18
[INFO] [stderr]  Documenting messenger v0.1.0 (/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(integer_atomics)]
[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(conservative_impl_trait)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove the attribute
[INFO] [stdout]   |
[INFO] [stdout]   = help: the feature `conservative_impl_trait` has been stable since 1.26.0 and no longer requires an attribute to enable
[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 `messenger`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --crate-type lib --crate-name messenger src/lib.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=996e9482a15fe458 -L dependency=/opt/rustwide/target/debug/deps --extern futures=/opt/rustwide/target/debug/deps/libfutures-34937b916995a2ad.rmeta --extern serde=/opt/rustwide/target/debug/deps/libserde-495ec9fdc6b7531e.rmeta --extern serde_derive=/opt/rustwide/target/debug/deps/libserde_derive-83f91e0782093c72.so --cap-lints=warn --crate-version 0.1.0` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "b711bf0fc82ef541331b52f70fada9d0afac7f95e8dc49bf87f1e8cd0b7840e8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b711bf0fc82ef541331b52f70fada9d0afac7f95e8dc49bf87f1e8cd0b7840e8", kill_on_drop: false }`
[INFO] [stdout] b711bf0fc82ef541331b52f70fada9d0afac7f95e8dc49bf87f1e8cd0b7840e8