[INFO] cloning repository https://github.com/plorefice/b2048
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/plorefice/b2048" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fplorefice%2Fb2048", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fplorefice%2Fb2048'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 7c0b69071e81abb9bdb12a77ab73f33af61b8576
[INFO] documenting plorefice/b2048 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%2Fplorefice%2Fb2048" "/workspace/builds/worker-2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/plorefice/b2048 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/plorefice/b2048
[INFO] finished tweaking git repo https://github.com/plorefice/b2048
[INFO] tweaked toml for git repo https://github.com/plorefice/b2048 written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] crate git repo https://github.com/plorefice/b2048 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-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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] f057c270bd6f702af5bec81044ae5c2bbe8de8a76d67577e5a93eb9fe1b332ad
[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" "f057c270bd6f702af5bec81044ae5c2bbe8de8a76d67577e5a93eb9fe1b332ad", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "f057c270bd6f702af5bec81044ae5c2bbe8de8a76d67577e5a93eb9fe1b332ad", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f057c270bd6f702af5bec81044ae5c2bbe8de8a76d67577e5a93eb9fe1b332ad", kill_on_drop: false }`
[INFO] [stdout] f057c270bd6f702af5bec81044ae5c2bbe8de8a76d67577e5a93eb9fe1b332ad
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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] 7337cc3ae273583b7f1b57523f994b4d15cea516787ac700ec663a88f2bb5bb9
[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" "7337cc3ae273583b7f1b57523f994b4d15cea516787ac700ec663a88f2bb5bb9", kill_on_drop: false }`
[INFO] [stderr]     Checking num-traits v0.1.42
[INFO] [stderr]     Checking libc v0.2.36
[INFO] [stderr]     Checking rustc-serialize v0.3.24
[INFO] [stderr]    Compiling pkg-config v0.3.9
[INFO] [stderr]    Compiling gcc v0.3.54
[INFO] [stderr]     Checking cfg-if v0.1.2
[INFO] [stderr]     Checking stable_deref_trait v1.0.0
[INFO] [stderr]     Checking serde v1.0.27
[INFO] [stderr]     Checking unicode-width v0.1.4
[INFO] [stderr]     Checking unicode-segmentation v1.2.0
[INFO] [stderr]     Checking maplit v1.0.1
[INFO] [stderr]     Checking log v0.4.1
[INFO] [stderr]     Checking owning_ref v0.3.3
[INFO] [stderr]     Checking log v0.3.9
[INFO] [stderr]     Checking rand v0.3.20
[INFO] [stderr]     Checking num-integer v0.1.35
[INFO] [stderr]    Compiling ncurses v5.91.0
[INFO] [stderr]     Checking num-iter v0.1.34
[INFO] [stderr]     Checking num-bigint v0.1.41
[INFO] [stderr]     Checking num-complex v0.1.41
[INFO] [stderr]     Checking num-rational v0.1.41
[INFO] [stderr]     Checking num v0.1.41
[INFO] [stderr]     Checking toml v0.4.5
[INFO] [stderr]     Checking cursive v0.7.5
[INFO] [stderr]  Documenting b2048 v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] error: Could not document `b2048`.
[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(conservative_impl_trait)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] 
[INFO] [stdout] error: Compilation failed, aborting rustdoc
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] Caused by:
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]   process didn't exit successfully: `rustdoc --crate-type bin --crate-name b2048 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 cursive=/opt/rustwide/target/debug/deps/libcursive-80656a08b66fd82d.rmeta --extern rand=/opt/rustwide/target/debug/deps/librand-619fd1486d5b969a.rmeta --cap-lints=warn` (exit code: 1)
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "7337cc3ae273583b7f1b57523f994b4d15cea516787ac700ec663a88f2bb5bb9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7337cc3ae273583b7f1b57523f994b4d15cea516787ac700ec663a88f2bb5bb9", kill_on_drop: false }`
[INFO] [stdout] 7337cc3ae273583b7f1b57523f994b4d15cea516787ac700ec663a88f2bb5bb9