[INFO] cloning repository https://github.com/masp/rustmine
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/masp/rustmine" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmasp%2Frustmine", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmasp%2Frustmine'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 30cbbf6e614dd5aebd22f9c46700ba7d6178d791
[INFO] documenting masp/rustmine 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%2Fmasp%2Frustmine" "/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/masp/rustmine 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/masp/rustmine
[INFO] finished tweaking git repo https://github.com/masp/rustmine
[INFO] tweaked toml for git repo https://github.com/masp/rustmine written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/masp/rustmine 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] 557e6bbecf291ccd4d406a1e8709ae9b7277e342d9c5fa6410b9422bcb4ecebc
[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" "557e6bbecf291ccd4d406a1e8709ae9b7277e342d9c5fa6410b9422bcb4ecebc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "557e6bbecf291ccd4d406a1e8709ae9b7277e342d9c5fa6410b9422bcb4ecebc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "557e6bbecf291ccd4d406a1e8709ae9b7277e342d9c5fa6410b9422bcb4ecebc", kill_on_drop: false }`
[INFO] [stdout] 557e6bbecf291ccd4d406a1e8709ae9b7277e342d9c5fa6410b9422bcb4ecebc
[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] 76a68aaf899373ebcf0c2b8363e3aa130d389a6bb96d19407c71ed8019eba41b
[INFO] running `Command { std: "docker" "start" "-a" "76a68aaf899373ebcf0c2b8363e3aa130d389a6bb96d19407c71ed8019eba41b", kill_on_drop: false }`
[INFO] [stderr]     Checking lazycell v1.2.0
[INFO] [stderr]     Checking byteorder v0.4.2
[INFO] [stderr]     Checking net2 v0.2.33
[INFO] [stderr]     Checking mio v0.6.16
[INFO] [stderr]  Documenting rustmine 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(read_initializer)]
[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 `rustmine`.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --crate-type lib --crate-name rustmine 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 byteorder=/opt/rustwide/target/debug/deps/libbyteorder-5937cd9768535d85.rmeta --extern bytes=/opt/rustwide/target/debug/deps/libbytes-83942e19a52444f9.rmeta --extern mio=/opt/rustwide/target/debug/deps/libmio-0fbf364f831b664c.rmeta --cap-lints=warn` (exit code: 1)
[INFO] running `Command { std: "docker" "inspect" "76a68aaf899373ebcf0c2b8363e3aa130d389a6bb96d19407c71ed8019eba41b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "76a68aaf899373ebcf0c2b8363e3aa130d389a6bb96d19407c71ed8019eba41b", kill_on_drop: false }`
[INFO] [stdout] 76a68aaf899373ebcf0c2b8363e3aa130d389a6bb96d19407c71ed8019eba41b