[INFO] cloning repository https://github.com/eonil/cargo-ipcgen-swift
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/eonil/cargo-ipcgen-swift" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Feonil%2Fcargo-ipcgen-swift", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Feonil%2Fcargo-ipcgen-swift'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] b93d463b5a0260aec9db5335d93579e36300f188
[INFO] documenting eonil/cargo-ipcgen-swift 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%2Feonil%2Fcargo-ipcgen-swift" "/workspace/builds/worker-8/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-8/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/eonil/cargo-ipcgen-swift 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/eonil/cargo-ipcgen-swift
[INFO] finished tweaking git repo https://github.com/eonil/cargo-ipcgen-swift
[INFO] tweaked toml for git repo https://github.com/eonil/cargo-ipcgen-swift written to /workspace/builds/worker-8/source/Cargo.toml
[INFO] crate git repo https://github.com/eonil/cargo-ipcgen-swift 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] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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] 6f87981ce41d6481fb9fb3210fe63ac2211a6698aeff6a5bd0def675eaf926f0
[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" "6f87981ce41d6481fb9fb3210fe63ac2211a6698aeff6a5bd0def675eaf926f0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "6f87981ce41d6481fb9fb3210fe63ac2211a6698aeff6a5bd0def675eaf926f0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6f87981ce41d6481fb9fb3210fe63ac2211a6698aeff6a5bd0def675eaf926f0", kill_on_drop: false }`
[INFO] [stdout] 6f87981ce41d6481fb9fb3210fe63ac2211a6698aeff6a5bd0def675eaf926f0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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] 9c03fd4bea2c80fcfa3f33a159532a132f042fa26b44450062e5b02674c25865
[INFO] running `Command { std: "docker" "start" "-a" "9c03fd4bea2c80fcfa3f33a159532a132f042fa26b44450062e5b02674c25865", kill_on_drop: false }`
[INFO] [stderr]     Checking log v0.4.1
[INFO] [stderr]    Compiling num-traits v0.2.4
[INFO] [stderr]     Checking rls-span v0.4.0
[INFO] [stderr]     Checking radix_trie v0.1.3
[INFO] [stderr]    Compiling rustc_version v0.2.2
[INFO] [stderr]    Compiling syn v0.13.10
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/rls-span-0.4.0/src/lib.rs:12:1
[INFO] [stdout]    |
[INFO] [stdout] 12 | #![feature(proc_macro)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Checking log v0.3.9
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `rls-span`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "9c03fd4bea2c80fcfa3f33a159532a132f042fa26b44450062e5b02674c25865", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9c03fd4bea2c80fcfa3f33a159532a132f042fa26b44450062e5b02674c25865", kill_on_drop: false }`
[INFO] [stdout] 9c03fd4bea2c80fcfa3f33a159532a132f042fa26b44450062e5b02674c25865