[INFO] cloning repository https://github.com/mgraczyk/fractional_cascading
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/mgraczyk/fractional_cascading" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmgraczyk%2Ffractional_cascading", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmgraczyk%2Ffractional_cascading'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 5d0001e28c8ac5180d82bdd85576da4dbaa7ad64
[INFO] documenting mgraczyk/fractional_cascading 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%2Fmgraczyk%2Ffractional_cascading" "/workspace/builds/worker-6/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/mgraczyk/fractional_cascading 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/mgraczyk/fractional_cascading
[INFO] finished tweaking git repo https://github.com/mgraczyk/fractional_cascading
[INFO] tweaked toml for git repo https://github.com/mgraczyk/fractional_cascading written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] crate git repo https://github.com/mgraczyk/fractional_cascading 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] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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] 55d16fe48b2c1acca88e3f75ca124d6b68979b4789fda4fb1188b6177237e75d
[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" "55d16fe48b2c1acca88e3f75ca124d6b68979b4789fda4fb1188b6177237e75d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "55d16fe48b2c1acca88e3f75ca124d6b68979b4789fda4fb1188b6177237e75d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "55d16fe48b2c1acca88e3f75ca124d6b68979b4789fda4fb1188b6177237e75d", kill_on_drop: false }`
[INFO] [stdout] 55d16fe48b2c1acca88e3f75ca124d6b68979b4789fda4fb1188b6177237e75d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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] [stdout] 94b4f5edf294a753dace48a8e8b7d8333db75843dd80139f788236b01bc116c7
[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" "94b4f5edf294a753dace48a8e8b7d8333db75843dd80139f788236b01bc116c7", kill_on_drop: false }`
[INFO] [stderr]    Compiling getrandom v0.1.10
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling serde v1.0.98
[INFO] [stderr]     Checking superslice v1.0.0
[INFO] [stderr]     Checking c2-chacha v0.2.2
[INFO] [stderr]     Checking rand_core v0.5.0
[INFO] [stderr]     Checking rand_chacha v0.2.1
[INFO] [stderr]     Checking rand v0.7.0
[INFO] [stderr]    Compiling serde_derive v1.0.98
[INFO] [stderr]     Checking serde_json v1.0.40
[INFO] [stderr]  Documenting fractional_cascading 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(test)]
[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 `fractional_cascading`.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type bin --crate-name fractional_cascading 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 rand=/opt/rustwide/target/debug/deps/librand-4229542779b5c4d1.rmeta --extern serde=/opt/rustwide/target/debug/deps/libserde-6471e48d07c0216d.rmeta --extern serde_json=/opt/rustwide/target/debug/deps/libserde_json-69e67c3e1874a507.rmeta --extern superslice=/opt/rustwide/target/debug/deps/libsuperslice-06499d2d5e3b75da.rmeta --cap-lints=warn` (exit code: 1)
[INFO] running `Command { std: "docker" "inspect" "94b4f5edf294a753dace48a8e8b7d8333db75843dd80139f788236b01bc116c7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "94b4f5edf294a753dace48a8e8b7d8333db75843dd80139f788236b01bc116c7", kill_on_drop: false }`
[INFO] [stdout] 94b4f5edf294a753dace48a8e8b7d8333db75843dd80139f788236b01bc116c7