[INFO] cloning repository https://github.com/VictorKoenders/rust_neural_network
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/VictorKoenders/rust_neural_network" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FVictorKoenders%2Frust_neural_network", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FVictorKoenders%2Frust_neural_network'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 249a720c2e11040f4f0abb4d85041afea07bc9bd
[INFO] documenting VictorKoenders/rust_neural_network 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%2FVictorKoenders%2Frust_neural_network" "/workspace/builds/worker-3/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/VictorKoenders/rust_neural_network 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/VictorKoenders/rust_neural_network
[INFO] finished tweaking git repo https://github.com/VictorKoenders/rust_neural_network
[INFO] tweaked toml for git repo https://github.com/VictorKoenders/rust_neural_network written to /workspace/builds/worker-3/source/Cargo.toml
[INFO] crate git repo https://github.com/VictorKoenders/rust_neural_network 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-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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] 4dff40f58d8fca4d2f4eb7b93d627b316021b8d805cbdac79fada5fd09bd7f1f
[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" "4dff40f58d8fca4d2f4eb7b93d627b316021b8d805cbdac79fada5fd09bd7f1f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4dff40f58d8fca4d2f4eb7b93d627b316021b8d805cbdac79fada5fd09bd7f1f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4dff40f58d8fca4d2f4eb7b93d627b316021b8d805cbdac79fada5fd09bd7f1f", kill_on_drop: false }`
[INFO] [stdout] 4dff40f58d8fca4d2f4eb7b93d627b316021b8d805cbdac79fada5fd09bd7f1f
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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] 1a60e60484a2c94efed1ae26f753f4075e10686085bd30ecd77180775a676bf9
[INFO] running `Command { std: "docker" "start" "-a" "1a60e60484a2c94efed1ae26f753f4075e10686085bd30ecd77180775a676bf9", kill_on_drop: false }`
[INFO] [stderr]     Checking c_vec v1.0.12
[INFO] [stderr]     Checking either v1.1.0
[INFO] [stderr]     Checking num-integer v0.1.34
[INFO] [stderr]     Checking sdl2-sys v0.30.0
[INFO] [stderr]     Checking itertools v0.6.0
[INFO] [stderr]     Checking num-iter v0.1.33
[INFO] [stderr]     Checking num v0.1.37
[INFO] [stderr]     Checking sdl2 v0.30.0
[INFO] [stderr]  Documenting rust_nn 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(step_by)]
[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 `rust_nn`.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --crate-type lib --crate-name rust_nn 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 itertools=/opt/rustwide/target/debug/deps/libitertools-28794238aa58dfdd.rmeta --extern rand=/opt/rustwide/target/debug/deps/librand-2839799ecc2d3843.rmeta --extern sdl2=/opt/rustwide/target/debug/deps/libsdl2-12fcbef78f9ff75d.rmeta --cap-lints=warn` (exit code: 1)
[INFO] running `Command { std: "docker" "inspect" "1a60e60484a2c94efed1ae26f753f4075e10686085bd30ecd77180775a676bf9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1a60e60484a2c94efed1ae26f753f4075e10686085bd30ecd77180775a676bf9", kill_on_drop: false }`
[INFO] [stdout] 1a60e60484a2c94efed1ae26f753f4075e10686085bd30ecd77180775a676bf9