[INFO] cloning repository https://github.com/mingyli/mrust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/mingyli/mrust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmingyli%2Fmrust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmingyli%2Fmrust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] c87e65902a4c4e88240728bd825d667ac7ac96cc
[INFO] documenting mingyli/mrust against 1.61.0 for beta-1.62-rustdoc-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmingyli%2Fmrust" "/workspace/builds/worker-18/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-18/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/mingyli/mrust on toolchain 1.61.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.61.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/mingyli/mrust
[INFO] finished tweaking git repo https://github.com/mingyli/mrust
[INFO] tweaked toml for git repo https://github.com/mingyli/mrust written to /workspace/builds/worker-18/source/Cargo.toml
[INFO] crate git repo https://github.com/mingyli/mrust already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.61.0" "fetch" "--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-18/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-18/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:d190cb871061d98bc6d0581d85cb2ecb09a0f8a142ba5463de30be9999fc3251" "/opt/rustwide/cargo-home/bin/cargo" "+1.61.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 5fdb122ea22a8443b0addfc1ce0f4ca7e6964e195633aee1e9f18a195a3dae4d
[INFO] running `Command { std: "docker" "start" "-a" "5fdb122ea22a8443b0addfc1ce0f4ca7e6964e195633aee1e9f18a195a3dae4d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5fdb122ea22a8443b0addfc1ce0f4ca7e6964e195633aee1e9f18a195a3dae4d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5fdb122ea22a8443b0addfc1ce0f4ca7e6964e195633aee1e9f18a195a3dae4d", kill_on_drop: false }`
[INFO] [stdout] 5fdb122ea22a8443b0addfc1ce0f4ca7e6964e195633aee1e9f18a195a3dae4d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-18/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-18/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:d190cb871061d98bc6d0581d85cb2ecb09a0f8a142ba5463de30be9999fc3251" "/opt/rustwide/cargo-home/bin/cargo" "+1.61.0" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 031c955a5c91705d13c05eeab412a2069ebc1329fded5735c03d24f66612bcf1
[INFO] running `Command { std: "docker" "start" "-a" "031c955a5c91705d13c05eeab412a2069ebc1329fded5735c03d24f66612bcf1", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling memchr v2.3.4
[INFO] [stderr]    Compiling proc-macro2 v1.0.24
[INFO] [stderr]    Compiling regex-syntax v0.6.21
[INFO] [stderr]    Compiling unicode-xid v0.2.1
[INFO] [stderr]    Compiling lazy_static v1.4.0
[INFO] [stderr]    Compiling syn v1.0.57
[INFO] [stderr]    Compiling libc v0.2.81
[INFO] [stderr]    Compiling cc v1.0.66
[INFO] [stderr]     Checking cfg-if v1.0.0
[INFO] [stderr]     Checking smallvec v1.6.0
[INFO] [stderr]     Checking scopeguard v1.1.0
[INFO] [stderr]    Compiling utf8-ranges v1.0.4
[INFO] [stderr]     Checking either v1.6.1
[INFO] [stderr]    Compiling fnv v1.0.7
[INFO] [stderr]    Compiling beef v0.4.4
[INFO] [stderr]    Compiling inkwell v0.1.0 (https://github.com/TheDan64/inkwell?branch=master#3eab4db4)
[INFO] [stderr]     Checking once_cell v1.5.2
[INFO] [stderr]     Checking instant v0.1.9
[INFO] [stderr]    Compiling thread_local v1.0.1
[INFO] [stderr]     Checking lock_api v0.4.2
[INFO] [stderr]     Checking itertools v0.10.0
[INFO] [stderr]    Compiling aho-corasick v0.7.15
[INFO] [stderr]    Compiling quote v1.0.8
[INFO] [stderr]     Checking parking_lot_core v0.8.2
[INFO] [stderr]     Checking parking_lot v0.11.1
[INFO] [stderr]     Checking regex v1.4.2
[INFO] [stderr]    Compiling llvm-sys v100.2.0
[INFO] [stderr]    Compiling logos-derive v0.11.5
[INFO] [stderr]    Compiling inkwell_internals v0.2.0 (https://github.com/TheDan64/inkwell?branch=master#3eab4db4)
[INFO] [stderr]     Checking logos v0.11.4
[INFO] [stderr]  Documenting mrust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/main.rs:1:12
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(peekable_next_if)]
[INFO] [stdout]   |            ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[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 document `mrust`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type bin --crate-name mrust src/main.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=e6bd97eed9b4a4a8 -L dependency=/opt/rustwide/target/debug/deps --extern inkwell=/opt/rustwide/target/debug/deps/libinkwell-e0a9851f56a4222a.rmeta --extern itertools=/opt/rustwide/target/debug/deps/libitertools-e863c567f0841ee3.rmeta --extern logos=/opt/rustwide/target/debug/deps/liblogos-374a5987cd7805ac.rmeta --cap-lints=warn --crate-version 0.1.0` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "031c955a5c91705d13c05eeab412a2069ebc1329fded5735c03d24f66612bcf1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "031c955a5c91705d13c05eeab412a2069ebc1329fded5735c03d24f66612bcf1", kill_on_drop: false }`
[INFO] [stdout] 031c955a5c91705d13c05eeab412a2069ebc1329fded5735c03d24f66612bcf1