[INFO] cloning repository https://github.com/iyuroch/rust_word_counter
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/iyuroch/rust_word_counter" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fiyuroch%2Frust_word_counter", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fiyuroch%2Frust_word_counter'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 12ee883c7ff016ca88ac16f4d8e9fc7a7682612c
[INFO] documenting iyuroch/rust_word_counter against 1.46.0 for beta-1.47-rustdoc-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fiyuroch%2Frust_word_counter" "/workspace/builds/worker-4/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/iyuroch/rust_word_counter 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 git repo https://github.com/iyuroch/rust_word_counter
[INFO] finished tweaking git repo https://github.com/iyuroch/rust_word_counter
[INFO] tweaked toml for git repo https://github.com/iyuroch/rust_word_counter written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/iyuroch/rust_word_counter 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] 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] 4743922b336e6b78ae932539381e8da67539bb1f10a6df8b238ed88ec26778cc
[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" "4743922b336e6b78ae932539381e8da67539bb1f10a6df8b238ed88ec26778cc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4743922b336e6b78ae932539381e8da67539bb1f10a6df8b238ed88ec26778cc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4743922b336e6b78ae932539381e8da67539bb1f10a6df8b238ed88ec26778cc", kill_on_drop: false }`
[INFO] [stdout] 4743922b336e6b78ae932539381e8da67539bb1f10a6df8b238ed88ec26778cc
[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] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] fb0a8e9d7816bbc3da2042430f220c7f737e74b114a26686984a37280d07b980
[INFO] running `Command { std: "docker" "start" "-a" "fb0a8e9d7816bbc3da2042430f220c7f737e74b114a26686984a37280d07b980", kill_on_drop: false }`
[INFO] [stderr]     Checking libc v0.2.42
[INFO] [stderr]     Checking cfg-if v0.1.3
[INFO] [stderr]     Checking lazy_static v1.0.1
[INFO] [stderr]    Compiling serde v1.0.66
[INFO] [stderr]     Checking smallvec v0.6.2
[INFO] [stderr]     Checking stable_deref_trait v1.1.0
[INFO] [stderr]    Compiling rayon-core v1.4.0
[INFO] [stderr]     Checking crossbeam-utils v0.4.1
[INFO] [stderr]     Checking rand_core v0.2.1
[INFO] [stderr]     Checking itoa v0.4.1
[INFO] [stderr]     Checking dtoa v0.4.2
[INFO] [stderr]     Checking spmc v0.2.2
[INFO] [stderr]     Checking canal v0.1.3
[INFO] [stderr]     Checking crossbeam v0.3.2
[INFO] [stderr]    Compiling proc-macro2 v0.4.6
[INFO] [stderr]     Checking crossbeam-utils v0.2.2
[INFO] [stderr]     Checking owning_ref v0.3.3
[INFO] [stderr]     Checking crossbeam-epoch v0.3.1
[INFO] [stderr]     Checking crossbeam-epoch v0.5.0
[INFO] [stderr]     Checking rand v0.4.2
[INFO] [stderr]     Checking num_cpus v1.8.0
[INFO] [stderr]     Checking rand v0.5.4
[INFO] [stderr]     Checking crossbeam-deque v0.2.0
[INFO] [stderr]    Compiling quote v0.6.3
[INFO] [stderr]    Compiling syn v0.14.2
[INFO] [stderr]     Checking parking_lot_core v0.2.14
[INFO] [stderr]     Checking rand v0.3.22
[INFO] [stderr]     Checking chan v0.1.21
[INFO] [stderr]     Checking rayon v1.0.1
[INFO] [stderr]     Checking parking_lot v0.5.5
[INFO] [stderr]     Checking crossbeam-channel v0.2.2
[INFO] [stderr]    Compiling serde_derive v1.0.66
[INFO] [stderr]     Checking serde_json v1.0.20
[INFO] [stderr]  Documenting word_counter v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/main.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(io)]
[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 `word_counter`.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --crate-type bin --crate-name word_counter src/main.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi --document-private-items -L dependency=/opt/rustwide/target/debug/deps --extern canal=/opt/rustwide/target/debug/deps/libcanal-323d04137bd1b2ec.rmeta --extern chan=/opt/rustwide/target/debug/deps/libchan-7e5d3d70365dddda.rmeta --extern crossbeam=/opt/rustwide/target/debug/deps/libcrossbeam-231a0c85844dc0d3.rmeta --extern crossbeam_channel=/opt/rustwide/target/debug/deps/libcrossbeam_channel-a4de4cb926b0f31e.rmeta --extern rayon=/opt/rustwide/target/debug/deps/librayon-247bd2e03d7eda0a.rmeta --extern serde=/opt/rustwide/target/debug/deps/libserde-7af0aff6800d18fd.rmeta --extern serde_derive=/opt/rustwide/target/debug/deps/libserde_derive-ac34582fb9a14e26.so --extern serde_json=/opt/rustwide/target/debug/deps/libserde_json-029de87e72a4ed93.rmeta --extern spmc=/opt/rustwide/target/debug/deps/libspmc-66d8330bbf51ee26.rmeta --cap-lints=warn` (exit code: 1)
[INFO] running `Command { std: "docker" "inspect" "fb0a8e9d7816bbc3da2042430f220c7f737e74b114a26686984a37280d07b980", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "fb0a8e9d7816bbc3da2042430f220c7f737e74b114a26686984a37280d07b980", kill_on_drop: false }`
[INFO] [stdout] fb0a8e9d7816bbc3da2042430f220c7f737e74b114a26686984a37280d07b980