[INFO] fetching crate mg 0.13.1...
[INFO] documenting mg-0.13.1 against 1.46.0 for beta-1.47-rustdoc-1
[INFO] extracting crate mg 0.13.1 into /workspace/builds/worker-6/source
[INFO] validating manifest of crates.io crate mg 0.13.1 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 mg 0.13.1
[INFO] finished tweaking crates.io crate mg 0.13.1
[INFO] tweaked toml for crates.io crate mg 0.13.1 written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] crate crates.io crate mg 0.13.1 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-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] 6b278b9e514d83b0d63c645fc7e479b565e62ff257f05761865fa8bd669d4777
[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" "6b278b9e514d83b0d63c645fc7e479b565e62ff257f05761865fa8bd669d4777", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "6b278b9e514d83b0d63c645fc7e479b565e62ff257f05761865fa8bd669d4777", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6b278b9e514d83b0d63c645fc7e479b565e62ff257f05761865fa8bd669d4777", kill_on_drop: false }`
[INFO] [stdout] 6b278b9e514d83b0d63c645fc7e479b565e62ff257f05761865fa8bd669d4777
[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] 0437e4251109f872aedc65663548db0d8e1c8490bf760d0711c5c6340bcf81ba
[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" "0437e4251109f872aedc65663548db0d8e1c8490bf760d0711c5c6340bcf81ba", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v1.0.35
[INFO] [stderr]    Compiling pkg-config v0.3.14
[INFO] [stderr]    Compiling memchr v2.2.0
[INFO] [stderr]     Checking bitflags v1.0.4
[INFO] [stderr]    Compiling lazy_static v1.3.0
[INFO] [stderr]    Compiling gio v0.9.0
[INFO] [stderr]    Compiling pango v0.9.0
[INFO] [stderr]    Compiling regex v1.1.2
[INFO] [stderr]    Compiling syn v0.15.29
[INFO] [stderr]    Compiling ucd-util v0.1.3
[INFO] [stderr]    Compiling cfg-if v0.1.7
[INFO] [stderr]    Compiling gdk v0.13.0
[INFO] [stderr]    Compiling utf8-ranges v1.0.2
[INFO] [stderr]    Compiling quick-error v1.2.2
[INFO] [stderr]    Compiling termcolor v1.0.4
[INFO] [stderr]     Checking futures-task v0.3.5
[INFO] [stderr]    Compiling itertools v0.9.0
[INFO] [stderr]    Compiling proc-macro2 v0.3.8
[INFO] [stderr]     Checking log v0.4.6
[INFO] [stderr]    Compiling serde v1.0.114
[INFO] [stderr]    Compiling thread_local v0.3.6
[INFO] [stderr]     Checking proc-macro2 v0.4.27
[INFO] [stderr]    Compiling humantime v1.2.0
[INFO] [stderr]    Compiling regex-syntax v0.6.5
[INFO] [stderr]    Compiling atty v0.2.11
[INFO] [stderr]    Compiling quote v0.5.2
[INFO] [stderr]    Compiling gtk v0.9.0
[INFO] [stderr]     Checking quote v0.6.11
[INFO] [stderr]    Compiling syn v0.13.11
[INFO] [stderr]    Compiling aho-corasick v0.6.10
[INFO] [stderr]    Compiling env_logger v0.5.13
[INFO] [stderr]    Compiling mg-settings-macros v0.4.2
[INFO] [stderr]    Compiling toml v0.5.6
[INFO] [stderr]    Compiling syn-mid v0.5.0
[INFO] [stderr]     Checking mg-settings v0.4.3
[INFO] [stderr]    Compiling proc-macro-crate v0.1.5
[INFO] [stderr]    Compiling relm-derive v0.20.0
[INFO] [stderr]    Compiling thiserror-impl v1.0.20
[INFO] [stderr]    Compiling strum_macros v0.18.0
[INFO] [stderr]    Compiling pin-project-internal v0.4.22
[INFO] [stderr]    Compiling futures-macro v0.3.5
[INFO] [stderr]    Compiling proc-macro-error-attr v1.0.3
[INFO] [stderr]    Compiling proc-macro-error v1.0.3
[INFO] [stderr]    Compiling glib-macros v0.10.1
[INFO] [stderr]    Compiling thiserror v1.0.20
[INFO] [stderr]    Compiling system-deps v1.3.2
[INFO] [stderr]     Checking pin-project v0.4.22
[INFO] [stderr]    Compiling glib-sys v0.10.0
[INFO] [stderr]    Compiling gobject-sys v0.10.0
[INFO] [stderr]    Compiling gio-sys v0.10.0
[INFO] [stderr]    Compiling pango-sys v0.10.0
[INFO] [stderr]    Compiling gdk-pixbuf-sys v0.10.0
[INFO] [stderr]    Compiling cairo-sys-rs v0.10.0
[INFO] [stderr]    Compiling atk-sys v0.10.0
[INFO] [stderr]    Compiling gdk-sys v0.10.0
[INFO] [stderr]    Compiling gtk-sys v0.10.0
[INFO] [stderr]     Checking futures-util v0.3.5
[INFO] [stderr]    Compiling atk v0.9.0
[INFO] [stderr]    Compiling cairo-rs v0.9.1
[INFO] [stderr]    Compiling gdk-pixbuf v0.9.0
[INFO] [stderr]     Checking futures-executor v0.3.5
[INFO] [stderr]     Checking glib v0.10.1
[INFO] [stderr]     Checking futures v0.3.5
[INFO] [stderr]     Checking relm v0.20.0
[INFO] [stderr]  Documenting mg v0.13.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:42:1
[INFO] [stdout]    |
[INFO] [stdout] 42 | #![feature(unboxed_closures)]
[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 `mg`.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --crate-type lib --crate-name mg src/lib.rs -o /opt/rustwide/target/doc --cfg 'feature="default"' --error-format=json --json=diagnostic-rendered-ansi --document-private-items -L dependency=/opt/rustwide/target/debug/deps --extern gdk=/opt/rustwide/target/debug/deps/libgdk-25ba100148cc89b3.rmeta --extern glib=/opt/rustwide/target/debug/deps/libglib-2416305cffd9ce4d.rmeta --extern gtk=/opt/rustwide/target/debug/deps/libgtk-b6601a82748c1d9b.rmeta --extern log=/opt/rustwide/target/debug/deps/liblog-d6ed6d827e1a2292.rmeta --extern mg_settings=/opt/rustwide/target/debug/deps/libmg_settings-d02c3817c2db1468.rmeta --extern pango=/opt/rustwide/target/debug/deps/libpango-b3b48016d9fec0e6.rmeta --extern relm=/opt/rustwide/target/debug/deps/librelm-d8fb0385e8771332.rmeta --extern relm_derive=/opt/rustwide/target/debug/deps/librelm_derive-cd2f5f3bb92e3389.so --cap-lints=warn` (exit code: 1)
[INFO] running `Command { std: "docker" "inspect" "0437e4251109f872aedc65663548db0d8e1c8490bf760d0711c5c6340bcf81ba", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0437e4251109f872aedc65663548db0d8e1c8490bf760d0711c5c6340bcf81ba", kill_on_drop: false }`
[INFO] [stdout] 0437e4251109f872aedc65663548db0d8e1c8490bf760d0711c5c6340bcf81ba