[INFO] fetching crate maths-traits 0.2.1...
[INFO] documenting maths-traits-0.2.1 against 1.46.0 for beta-1.47-rustdoc-1
[INFO] extracting crate maths-traits 0.2.1 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate maths-traits 0.2.1 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 maths-traits 0.2.1
[INFO] finished tweaking crates.io crate maths-traits 0.2.1
[INFO] tweaked toml for crates.io crate maths-traits 0.2.1 written to /workspace/builds/worker-4/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] 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] 4c669fa03e13e6f563769b2c39ca8a155b765c3d5a14cb09986a905e88fe5e91
[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" "4c669fa03e13e6f563769b2c39ca8a155b765c3d5a14cb09986a905e88fe5e91", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4c669fa03e13e6f563769b2c39ca8a155b765c3d5a14cb09986a905e88fe5e91", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4c669fa03e13e6f563769b2c39ca8a155b765c3d5a14cb09986a905e88fe5e91", kill_on_drop: false }`
[INFO] [stdout] 4c669fa03e13e6f563769b2c39ca8a155b765c3d5a14cb09986a905e88fe5e91
[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] [stdout] a98965d961856c3224e69d9ac7d258c04db49328bbb080008c39ecc1400992f8
[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" "a98965d961856c3224e69d9ac7d258c04db49328bbb080008c39ecc1400992f8", kill_on_drop: false }`
[INFO] [stderr]  Documenting maths-traits v0.2.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:317:1
[INFO] [stdout]     |
[INFO] [stdout] 317 | #![feature(trait_alias)]
[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:318:1
[INFO] [stdout]     |
[INFO] [stdout] 318 | #![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:319:1
[INFO] [stdout]     |
[INFO] [stdout] 319 | #![feature(extra_log_consts)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: Compilation failed, aborting rustdoc
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 4 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 `maths-traits`.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type lib --crate-name maths_traits src/lib.rs -o /opt/rustwide/target/doc --cfg 'feature="default"' --cfg 'feature="std"' --error-format=json --json=diagnostic-rendered-ansi --document-private-items -L dependency=/opt/rustwide/target/debug/deps --extern num_traits=/opt/rustwide/target/debug/deps/libnum_traits-b32ff6efe189bdd2.rmeta --cap-lints=warn` (exit code: 1)
[INFO] running `Command { std: "docker" "inspect" "a98965d961856c3224e69d9ac7d258c04db49328bbb080008c39ecc1400992f8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a98965d961856c3224e69d9ac7d258c04db49328bbb080008c39ecc1400992f8", kill_on_drop: false }`
[INFO] [stdout] a98965d961856c3224e69d9ac7d258c04db49328bbb080008c39ecc1400992f8