[INFO] fetching crate antlr-rust 0.1.2...
[INFO] documenting antlr-rust-0.1.2 against 1.46.0 for beta-1.47-rustdoc-1
[INFO] extracting crate antlr-rust 0.1.2 into /workspace/builds/worker-2/source
[INFO] validating manifest of crates.io crate antlr-rust 0.1.2 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 antlr-rust 0.1.2
[INFO] finished tweaking crates.io crate antlr-rust 0.1.2
[INFO] tweaked toml for crates.io crate antlr-rust 0.1.2 written to /workspace/builds/worker-2/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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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] 43ef230421291a34c0c0502718eaf237f6d9f502da8e2bbe36727fe1f6e98119
[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" "43ef230421291a34c0c0502718eaf237f6d9f502da8e2bbe36727fe1f6e98119", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "43ef230421291a34c0c0502718eaf237f6d9f502da8e2bbe36727fe1f6e98119", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "43ef230421291a34c0c0502718eaf237f6d9f502da8e2bbe36727fe1f6e98119", kill_on_drop: false }`
[INFO] [stdout] 43ef230421291a34c0c0502718eaf237f6d9f502da8e2bbe36727fe1f6e98119
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] ce4893d0271699f2c63b8751396da4d935a406bc21491cf3f159ab76b8e89699
[INFO] running `Command { std: "docker" "start" "-a" "ce4893d0271699f2c63b8751396da4d935a406bc21491cf3f159ab76b8e89699", 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] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Checking bit-vec v0.6.2
[INFO] [stderr]     Checking typed-arena v2.0.1
[INFO] [stderr]     Checking once_cell v1.4.1
[INFO] [stderr]     Checking uuid v0.6.5
[INFO] [stderr]     Checking murmur3 v0.4.1
[INFO] [stderr]     Checking backtrace v0.3.50
[INFO] [stderr]     Checking bit-set v0.5.2
[INFO] [stderr]  Documenting antlr-rust v0.1.2 (/opt/rustwide/workdir)
[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(try_blocks)]
[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:4:1
[INFO] [stdout]   |
[INFO] [stdout] 4 | #![feature(raw)]
[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:5:1
[INFO] [stdout]   |
[INFO] [stdout] 5 | #![feature(inner_deref)]
[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:6:1
[INFO] [stdout]   |
[INFO] [stdout] 6 | #![feature(is_sorted)]
[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:7:1
[INFO] [stdout]   |
[INFO] [stdout] 7 | #![feature(cell_update)]
[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:8:1
[INFO] [stdout]   |
[INFO] [stdout] 8 | #![feature(get_mut_unchecked)]
[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:9:1
[INFO] [stdout]   |
[INFO] [stdout] 9 | #![feature(specialization)]
[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:10:1
[INFO] [stdout]    |
[INFO] [stdout] 10 | #![feature(coerce_unsized)]
[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:11:1
[INFO] [stdout]    |
[INFO] [stdout] 11 | #![feature(unsize)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: Compilation failed, aborting rustdoc
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 10 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 `antlr-rust`.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type lib --crate-name antlr_rust 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 backtrace=/opt/rustwide/target/debug/deps/libbacktrace-54056fab4ea44fab.rmeta --extern bit_set=/opt/rustwide/target/debug/deps/libbit_set-df0c224ca93765ae.rmeta --extern byteorder=/opt/rustwide/target/debug/deps/libbyteorder-cdbbc07100f440a1.rmeta --extern lazy_static=/opt/rustwide/target/debug/deps/liblazy_static-57a7edc7f441d44c.rmeta --extern murmur3=/opt/rustwide/target/debug/deps/libmurmur3-9dc241a75c60c3f8.rmeta --extern once_cell=/opt/rustwide/target/debug/deps/libonce_cell-8810c110b9f3557a.rmeta --extern typed_arena=/opt/rustwide/target/debug/deps/libtyped_arena-c514a86958ee377f.rmeta --extern uuid=/opt/rustwide/target/debug/deps/libuuid-43e4351045352f11.rmeta --cap-lints=warn` (exit code: 1)
[INFO] running `Command { std: "docker" "inspect" "ce4893d0271699f2c63b8751396da4d935a406bc21491cf3f159ab76b8e89699", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ce4893d0271699f2c63b8751396da4d935a406bc21491cf3f159ab76b8e89699", kill_on_drop: false }`
[INFO] [stdout] ce4893d0271699f2c63b8751396da4d935a406bc21491cf3f159ab76b8e89699